Ameresco (AMRC) 10-K 28 Feb 25 2024 FY Annual report Financial data

Cover Page

Cover Page - USD ($)	12 Months Ended
	Dec. 31, 2024	Feb. 24, 2025	Jun. 30, 2024
Entity Information [Line Items]
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2024
Current Fiscal Year End Date	--12-31
Document Transition Report	false
Entity File Number	001-34811
Entity Registrant Name	Ameresco, Inc.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	04-3512838
Entity Address, Address Line One	111 Speen Street
Entity Address, Address Line Two	Suite 410
Entity Address, City or Town	Framingham
Entity Address, State or Province	MA
Entity Address, Postal Zip Code	01701
City Area Code	508
Local Phone Number	661-2200
Title of 12(b) Security	Class A Common Stock, par value $0.0001 per share
Trading Symbol	AMRC
Security Exchange Name	NYSE
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
ICFR Auditor Attestation Flag	true
Document Financial Statement Error Correction [Flag]	false
Entity Shell Company	false
Entity Public Float			$ 919,337,629
Documents Incorporated by Reference	Portions of the definitive proxy statement for our 2025 annual meeting of stockholders are incorporated by reference into Part III.
Entity Central Index Key	0001488139
Document Fiscal Year Focus	2024
Document Fiscal Period Focus	FY
Amendment Flag	false
Class A Common Stock
Entity Information [Line Items]
Entity Common Stock, Shares Outstanding (in shares)		34,541,213
Class B Common Stock
Entity Information [Line Items]
Entity Common Stock, Shares Outstanding (in shares)		18,000,000

Audit Information

Audit Information	12 Months Ended
	Dec. 31, 2024
Audit Information [Abstract]
Auditor Name	RSM US LLP
Auditor Location	Boston, Massachusetts
Auditor Firm ID	49

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands		Dec. 31, 2024	Dec. 31, 2023
Current assets:
Cash and cash equivalents	[1]	$ 108,516	$ 79,271
Restricted cash	[1]	69,706	62,311
Accounts receivable, net	[1]	256,961	153,362
Accounts receivable retainage		39,843	33,826
Unbilled revenue	[1]	644,105	636,163
Inventory		11,556	13,637
Prepaid expenses and other current assets	[1]	145,906	123,391
Income tax receivable		1,685	5,775
Project development costs, net		22,856	20,735
Total current assets	[1]	1,301,134	1,128,471
Federal ESPC receivable		609,128	609,265
Property and equipment, net	[1]	11,040	17,395
Energy assets, net	[1]	1,915,311	1,689,424
Goodwill, net		66,305	75,587
Intangible assets, net		8,814	6,808
Right-of-use assets, net	[1]	80,149	58,586
Restricted cash, non-current portion		20,156	12,094
Deferred income tax assets, net		56,523	26,411
Other assets	[1]	89,948	89,735
Total assets	[1]	4,158,508	3,713,776
Current liabilities:
Current portions of long-term debt and financing lease liabilities, net of unamortized discount	[1]	149,363	322,247
Accounts payable	[1]	529,338	402,752
Accrued expenses and other current liabilities	[1]	107,293	108,831
Current portions of operating lease liabilities	[1]	10,536	13,569
Deferred revenue		91,734	52,903
Income taxes payable		744	1,169
Total current liabilities	[1]	889,008	901,471
Long-term debt and financing lease liabilities, net of current portion, unamortized discount, and debt issuance costs	[1]	1,483,900	1,170,075
Federal ESPC liabilities		555,396	533,054
Deferred income tax liabilities, net		2,223	4,479
Deferred grant income		6,436	6,974
Long-term operating lease liabilities, net of current portion	[1]	59,479	42,258
Other liabilities	[1]	114,454	82,714
Commitments and contingencies (Note 15)
Redeemable non-controlling interests, net		2,463	46,865
Stockholders’ equity:
Preferred stock, $0.0001 par value, 5,000,000 shares authorized, no shares issued and outstanding at December 31, 2024 and 2023		0	0
Additional paid-in capital		378,321	320,892
Retained earnings		652,561	595,911
Accumulated other comprehensive loss, net		(5,874)	(3,045)
Treasury stock, at cost, 2,101,835 shares at December 31, 2024 and 2,101,795 at December 31, 2023		(11,788)	(11,788)
Stockholders’ equity before non-controlling interest		1,013,225	901,975
Non-controlling interests		31,924	23,911
Total stockholders’ equity		1,045,149	925,886
Total liabilities, redeemable non-controlling interests and stockholders’ equity		4,158,508	3,713,776
Class A Common Stock
Stockholders’ equity:
Common stock		3	3
Class B Common Stock
Stockholders’ equity:
Common stock		$ 2	$ 2
[1]Includes restricted assets of consolidated variable interest entities (“VIEs”) of $158,548 as of December 31, 2024 and $312,701 as of December 31, 2023. Includes liabilities of consolidated VIEs of $16,871 as of December 31, 2024 and $199,063 as of December 31, 2023. See Note 11.

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands		Dec. 31, 2024	Dec. 31, 2023
Assets	[1]	$ 4,158,508	$ 3,713,776
Preferred stock, par value (in usd per share)		$ 0.0001	$ 0.0001
Preferred stock, shares authorized (in shares)		5,000,000	5,000,000
Preferred stock, shares issued (in shares)		0	0
Preferred stock, shares outstanding (in shares)		0	0
Treasury stock, shares (in shares)		2,101,835	2,101,795
Class A Common Stock
Common stock, par value (in usd per share)		$ 0.0001	$ 0.0001
Common stock, shares authorized (in shares)		500,000,000	500,000,000
Common stock, shares issued (in shares)		36,603,048	36,378,990
Common stock, shares outstanding (in shares)		34,501,213	34,277,195
Class B Common Stock
Common stock, par value (in usd per share)		$ 0.0001	$ 0.0001
Common stock, shares authorized (in shares)		144,000,000	144,000,000
Common stock, shares issued (in shares)		18,000,000	18,000,000
Common stock, shares outstanding (in shares)		18,000,000	18,000,000
Variable Interest Entity
Assets		$ 158,548	$ 312,701
Liabilities		$ 16,871	$ 199,063
[1]Includes restricted assets of consolidated variable interest entities (“VIEs”) of $158,548 as of December 31, 2024 and $312,701 as of December 31, 2023. Includes liabilities of consolidated VIEs of $16,871 as of December 31, 2024 and $199,063 as of December 31, 2023. See Note 11.

Consolidated Statements of Inco

Consolidated Statements of Income - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Income Statement [Abstract]
Revenues	$ 1,769,928	$ 1,374,633	$ 1,824,422
Cost of revenues	1,513,837	1,128,204	1,533,589
Gross profit	256,091	246,429	290,833
Selling, general and administrative expenses	173,761	162,138	159,488
Gain on sale of business, net	38,007	0	0
Asset impairments	12,384	3,831	0
Earnings from unconsolidated entities	792	1,758	1,647
Operating income	108,745	82,218	132,992
Interest and other expenses, net	74,805	43,949	27,273
Income before income taxes	33,940	38,269	105,719
Income tax (benefit) provision	(20,000)	(25,635)	7,170
Net income	53,940	63,904	98,549
Net loss (income) attributable to non-controlling interest and redeemable non-controlling interest	2,817	(1,434)	(3,623)
Net income attributable to common shareholders	$ 56,757	$ 62,470	$ 94,926
Net income per share attributable to common shareholders:
Basic (in usd per share)	$ 1.08	$ 1.20	$ 1.83
Diluted (in usd per share)	$ 1.07	$ 1.17	$ 1.78
Weighted average common shares outstanding:
Basic (in shares)	52,380	52,140	51,841
Diluted (in shares)	53,140	53,228	53,278

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Statement of Comprehensive Income [Abstract]
Net income	$ 53,940	$ 63,904	$ 98,549
Other comprehensive (loss) income:
Unrealized gain (loss) from interest rate hedges, net of tax effect of $139, $(190), and $2,039, respectively	394	(538)	6,017
Foreign currency translation adjustment	(3,172)	1,574	(3,401)
Total other comprehensive (loss) income	(2,778)	1,036	2,616
Comprehensive income	51,162	64,940	101,165
Comprehensive income attributable to non-controlling interests and redeemable non-controlling interests:
Net loss (income)	2,817	(1,434)	(3,623)
Foreign currency translation adjustments	(51)	(30)	0
Comprehensive loss (income) attributable to non-controlling interests and redeemable non-controlling interests	2,766	(1,464)	(3,623)
Comprehensive income attributable to common shareholders	$ 53,928	$ 63,476	$ 97,542

Consolidated Statements of Co_2

Consolidated Statements of Comprehensive Income (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Statement of Comprehensive Income [Abstract]
Unrealized (loss) gain from interest rate hedges, tax effect	$ 139	$ (190)	$ 2,039

Consolidated Statements of Chan

Consolidated Statements of Changes in Redeemable Non-controlling Interests and Stockholders' Equity - USD ($) $ in Thousands	Total	Additional Paid-in Capital	Retained Earnings	Treasury Stock	Accumulated Other Comprehensive Loss	Non-controlling Interest (“NCI”)	Class A Common Stock	Class A Common Stock Common Stock	Class B Common Stock	Class B Common Stock Common Stock
Redeemable non-controlling interests beginning balance at Dec. 31, 2021	$ 46,182
Increase (Decrease) in Temporary Equity [Roll Forward]
Distributions to RNCI	(1,039)
Accretion of tax equity financing fees	109
Investment fund call option exercise	(2,162)
Net income	3,533
Redeemable non-controlling interests ending balance at Dec. 31, 2022	46,623
Beginning balance (in shares) at Dec. 31, 2021								33,716,309		18,000,000
Treasury stock, beginning balance (in shares) at Dec. 31, 2021				2,101,795
Beginning balance at Dec. 31, 2021	704,264	$ 283,982	$ 438,732	$ (11,788)	$ (6,667)	$ 0		$ 3		$ 2
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of stock options (in shares)								195,888
Exercise of stock options	3,954	3,954
Stock-based compensation expense	15,046	15,046
Employee stock purchase plan (in shares)								36,165
Employee stock purchase plan	2,009	2,009
Unrealized gain (loss) from interest rate hedges, net	6,017				6,017
Foreign currency translation adjustment	(3,401)				(3,401)
Accretion of tax equity financing fees	(109)		(109)
Investment fund call option exercise	1,323	1,323
Contributions from NCI	48,912					48,912
Net income	95,016		94,926			90
Ending balance (in shares) at Dec. 31, 2022								33,948,362		18,000,000
Treasury stock, ending balance (in shares) at Dec. 31, 2022				2,101,795
Ending balance at Dec. 31, 2022	873,031	306,314	533,549	$ (11,788)	(4,051)	49,002		$ 3		$ 2
Increase (Decrease) in Temporary Equity [Roll Forward]
Distributions to RNCI	(632)
Accretion of tax equity financing fees	108
Investment fund call option exercise	195
Net income	571
Redeemable non-controlling interests ending balance at Dec. 31, 2023	46,865
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of stock options (in shares)								246,250
Exercise of stock options	2,438	2,438
Stock-based compensation expense	10,318	10,318
Employee stock purchase plan (in shares)								60,003
Employee stock purchase plan	2,017	2,017
Restricted stock units released (in shares)								22,580
Unrealized gain (loss) from interest rate hedges, net	(538)				(538)
Foreign currency translation adjustment	1,574				1,544	30
Accretion of tax equity financing fees	(108)		(108)
Investment fund call option exercise	(195)	(195)
Contributions from NCI	4,203					4,203
Distributions to NCI	(30,187)					(30,187)
Net income	$ 63,333		62,470			863
Ending balance (in shares) at Dec. 31, 2023							34,277,195	34,277,195	18,000,000	18,000,000
Treasury stock, ending balance (in shares) at Dec. 31, 2023	2,101,795			2,101,795
Ending balance at Dec. 31, 2023	$ 925,886	320,892	595,911	$ (11,788)	(3,045)	23,911		$ 3		$ 2
Increase (Decrease) in Temporary Equity [Roll Forward]
Distributions to RNCI	(288)
Accretion of tax equity financing fees	107
Investment fund call option exercise	(40,455)
Net income	(3,766)
Redeemable non-controlling interests ending balance at Dec. 31, 2024	$ 2,463
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of stock options (in shares)	97,000							97,489
Exercise of stock options	$ 942	942
Stock-based compensation expense	14,130	14,130
Employee stock purchase plan (in shares)								63,903
Employee stock purchase plan	1,821	1,821
Restricted stock units released (in shares)								62,626
Restricted stock units released				40
Unrealized gain (loss) from interest rate hedges, net	394				394
Foreign currency translation adjustment	(3,172)				(3,223)	51
Accretion of tax equity financing fees	(107)		(107)
Investment fund call option exercise	37,269	37,269
Contributions from NCI	35,407	3,040				32,367
Distributions to NCI	(1,368)					(1,368)
Purchase of shares from NCI	(23,759)	227				(23,986)
Net income	$ 57,706		56,757			949
Ending balance (in shares) at Dec. 31, 2024							34,501,213	34,501,213	18,000,000	18,000,000
Treasury stock, ending balance (in shares) at Dec. 31, 2024	2,101,835			2,101,835
Ending balance at Dec. 31, 2024	$ 1,045,149	$ 378,321	$ 652,561	$ (11,788)	$ (5,874)	$ 31,924		$ 3		$ 2

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Cash flows from operating activities:
Net income	$ 53,940	$ 63,904	$ 98,549
Adjustments to reconcile net income to net cash flows from operating activities:
Depreciation of energy assets, net	82,114	59,390	49,755
Depreciation of property and equipment	4,963	4,155	2,665
Amortization of debt discount and debt issuance costs	5,151	4,201	4,211
Amortization of intangible assets	2,134	2,366	1,858
Increase in contingent consideration	149	347	1,614
Accretion of ARO liabilities	332	258	146
Impairment of goodwill	0	2,222	0
Provision (recoveries of) for bad debts	1,340	356	(382)
Impairment of long-lived assets / loss on disposal	12,815	1,710	937
Gain on sale of business, net of transaction costs	(38,007)	0	0
Non-cash project revenue related to in-kind leases	(4,164)	(3,164)	0
Earnings from unconsolidated entities	(792)	(1,758)	(1,647)
Net gain from derivatives	(1,027)	(1,108)	(212)
Stock-based compensation expense	14,130	10,318	15,046
Deferred income taxes, net	(24,315)	(27,602)	3,918
Unrealized foreign exchange loss (gain)	2,216	(368)	(123)
Changes in operating assets and liabilities:
Accounts receivable	(96,867)	52,647	3,477
Accounts receivable retainage	(14,342)	4,337	4,716
Federal ESPC receivable	(158,937)	(260,378)	(259,499)
Inventory, net	2,081	581	(5,411)
Unbilled revenue	54,953	(13,211)	(272,629)
Prepaid expenses and other current assets	22,576	(41,125)	(3,182)
Project development costs	(3,255)	(5,486)	(685)
Other assets	(5,287)	(6,896)	(11,327)
Accounts payable, accrued expenses, and other current liabilities	143,776	53,238	36,155
Deferred revenue	50,738	26,202	449
Other liabilities	7,504	3,559	(5,074)
Income taxes receivable (payable), net	3,679	1,314	(1,613)
Cash flows from operating activities	117,598	(69,991)	(338,288)
Cash flows from investing activities:
Purchases of property and equipment	(4,291)	(5,713)	(5,296)
Capital investment in energy assets	(416,992)	(538,418)	(304,596)
Capital investment in major maintenance of energy assets	(17,063)	(7,636)	(18,007)
Grant award received on energy asset	400	0	0
Net proceeds from sale of business	54,249	0	0
Net proceeds from sale of equity investment	13,091	0	0
Acquisitions, net of cash received	0	(9,182)	0
Contributions to equity and other investments	(11,757)	(5,429)	0
Loans to joint venture investments	0	(565)	(459)
Purchases of subsurface land easements	(4,274)	0	0
Cash flows from investing activities	(386,637)	(566,943)	(328,358)
Cash flows from financing activities:
Payments on long-term corporate debt financings	(127,000)	(155,000)	(52,813)
Proceeds from long-term corporate debt financings	100,000	0	295,000
(Payments on) proceeds from senior secured revolving credit facility, net	(4,900)	(43,000)	137,900
Proceeds from long-term energy asset debt financings	643,529	843,498	173,476
Payments on long-term energy asset debt and financing leases	(424,421)	(148,057)	(109,044)
Payment on seller's promissory note	(61,941)	0	0
Payments of debt discount and debt issuance costs	(15,308)	(9,315)	(3,695)
Proceeds from Federal ESPC projects	164,779	154,338	238,360
Net proceeds from energy asset receivable financing arrangements	6,012	14,512	14,341
Proceeds from exercises of options and ESPP	2,763	4,455	5,963
Contributions from non-controlling interest	35,407	3,738	32,706
Distributions to non-controlling interest	(1,368)	(21,842)	0
Distributions to redeemable non-controlling interests, net	(422)	(658)	(1,128)
Investment fund call option exercise	(3,186)	0	(839)
Payment of contingent consideration	0	(1,866)	0
Cash flows from financing activities	313,944	640,803	730,227
Effect of exchange rate changes on cash	(203)	(81)	(747)
Net increase in cash, cash equivalents, and restricted cash	44,702	3,788	62,834
Cash, cash equivalents, and restricted cash, beginning of year	153,676	149,888	87,054
Cash, cash equivalents, and restricted cash, end of year	198,378	153,676	149,888
Supplemental disclosures of cash flow information:
Cash paid for interest	110,387	80,251	32,954
Cash paid for income taxes	4,456	3,834	7,278
Non-cash Federal ESPC settlement	143,936	99,164	293,427
Accrued purchases of energy assets	67,704	78,382	88,793
Non-cash contributions from non-controlling interest	0	464	16,206
Non-cash financing for energy asset project acquisition	32,500	82,964	0
Non-cash portion of investment fund call option exercise	$ 37,269	$ 0	$ 1,323

Description of Business

Description of Business	12 Months Ended
	Dec. 31, 2024
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Description of Business	DESCRIPTION OF BUSINESS Ameresco, Inc. (including its subsidiaries, the “Company,” “Ameresco”, “we,” “our,” or “us”) was organized as a Delaware corporation on April 25, 2000. We are a leading energy solutions provider dedicated to helping customers reduce costs, enhance resilience, and decarbonize to net zero in the global energy transition. Our comprehensive portfolio includes implementing smart energy efficiency solutions, upgrading aging infrastructure, and developing, constructing, and operating distributed energy resources. We provide solutions, both services and products, and also sell certain solar photovoltaic (“solar PV”) equipment and have completed projects that reduce energy use and deliver diversified generation solutions to Federal, state and local governments, utilities, educational and healthcare institutions, housing authorities, and commercial and industrial customers. Headquartered in Framingham, MA, we have more than 1,500 employees providing local expertise in North America and Europe. We are compensated through a variety of methods, including: 1) direct payments based on fee-for-services contracts (utilizing lump-sum or cost-plus pricing methodologies), 2) the sale of energy from our energy assets, and 3) direct payment for solar PV equipment and systems.

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2024
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Principles of Consolidation The accompanying consolidated financial statements include the accounts of Ameresco, our subsidiaries, certain contracts in which we have a controlling financial interest and one investment fund formed to fund the purchase and operation of solar energy systems, which are consolidated with Ameresco as variable interest entities (“VIEs”). We use a qualitative approach in assessing the consolidation requirement for VIEs. This approach focuses on determining whether we have the power to direct the activities of the VIE that most significantly affect the VIE’s economic performance and whether we have the obligation to absorb losses or the right to receive benefits that could potentially be significant to the VIE. For all periods presented, we have determined that we are the primary beneficiary in a majority of our operational VIEs. When we have determined we are the primary beneficiary, we evaluate our relationships with the VIEs on an ongoing basis to ensure that we continue to be the primary beneficiary. All significant intercompany accounts and transactions have been eliminated. Gains and losses from the translation of all foreign currency financial statements are recorded in accumulated other comprehensive loss, net, within stockholders’ equity. We prepare our consolidated financial statements in conformity with the accounting principles generally accepted in the United States of America (“GAAP”). Reclassification and Rounding Certain prior period amounts were reclassified to conform to the presentation in the current period. We round amounts in the consolidated financial statements to thousands and calculate all percentages and per-share data from the underlying whole-dollar amounts. Thus, certain amounts may not foot, crossfoot, or recalculate based on reported numbers due to rounding. Use of Estimates GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of the consolidated financial statements and the reported amounts of revenue and expenses during the reporting period. Changes in circumstances could cause actual results to differ materially from those estimates. The estimates and assumptions used in these consolidated financial statements relate to management’s estimates of final construction contract profit in accordance with accounting for long-term contracts, allowance for credit losses, realization of project development costs, leases, fair value of derivative financial instruments, accounting for business acquisitions, stock-based awards, impairment of goodwill and long-lived assets, income taxes, and potential liability in conjunction with contingent consideration. Self-insured Health Insurance We are self-insured for employee health insurance and the maximum exposure in fiscal year 2024 under the plan was $200 per covered participant, after which reinsurance takes effect. The liability for unpaid claims and associated expenses, including incurred but not reported claims, is determined by management and reflected in our consolidated balance sheets in accrued expenses and other current liabilities. The liability is calculated based on historical data, which considers both the frequency and settlement amount of claims. Our estimated accrual for this liability could be different than our ultimate obligation if variables such as the frequency or amount of future claims differ significantly from management’s assumptions. Significant Risks and Uncertainties Global factors have continued to result in global supply chain disruptions, certain governmental trav el and other restrictions, and inflationary pressures. We have considered the impact of general global economic conditions on the assumptions and estimates used, which may change in response to this evolving situation. Results of future operations and liquidity could be adversely impacted by a number of factors including supply chain disruptions, varying levels of inflation, payments of outstanding receivable amounts beyond normal payment terms, workforce disruptions, and uncertain demand. As of the date of issuance of these consolidated financial statements, we cannot reasonably estimate the extent to which macroeconomic conditions may impact our financial condition, liquidity, or results of operations in the foreseeable future. The ultimate impact of the general global economic conditions on our business is highly uncertain and will depend on future developments, and such impacts could exist for an extended period of time. Cash and Cash Equivalents Cash and cash equivalents include cash on deposit, overnight repurchase agreements and amounts invested in highly liquid money market funds. Cash equivalents consist of short-term investments with original maturities of three months or less. We maintain our accounts with financial institutions and the balances in such accounts, at times, exceed federally insured limits. This credit risk is divided among a number of financial institutions that management believes to be of high quality. The carrying amount of cash and cash equivalents approximates its fair value measured using level 1 inputs per the fair value hierarchy as defined in Note 18. Restricted Cash Restricted cash consists of cash and cash equivalents held in escrow accounts in association with operations and maintenance (“O&M”) reserve accounts, cash collateralized letters of credit, as well as cash required under term loans to be maintained in reserve accounts until all obligations have been indefeasibly paid in full for energy assets. The carrying amount of the cash and cash equivalents in these accounts approximates its fair value measured using level 1 inputs per the fair value hierarchy as defined in Note 18. Restricted cash also includes funds held for clients, which represent assets that, based upon our intent, are restricted for use solely for the purposes of satisfying the obligations to remit funds to third parties, primarily utility service providers, relating to our enterprise energy management services. Accounts Receivable, Net Accounts receivable, net are stated at the amount management expects to collect from outstanding balances. Our methodology to estimate the allowance for credit losses includes quarterly assessments of historical bad debt write-off experience, current economic and market conditions, management’s evaluation of outstanding accounts receivable, anticipated recoveries and our forecasts. Due to the short-term nature of our receivables, the estimate of credit losses is primarily based on aged accounts receivable balances and the financial condition of our customers. In addition, specific allowance amounts are established to record the appropriate provision for customers that have a higher probability of default. Bad debts are written off against the allowance when identified. As part of our assessment, we also considered the current and expected future economic and market conditions due to global factors and determined that the estimate of credit losses was not significantly impacted as of December 31, 2024 and 2023. Changes in the allowance for credit losses was as follows: Year Ended December 31, 2024 2023 2022 Allowance for credit loss, beginning of period $ 903 $ 911 $ 2,263 Charges to (recoveries of) costs and expenses, net 1,340 356 (382) Account write-offs and other (1,398) (364) (970) Allowance for credit loss, end of period $ 845 $ 903 $ 911 Accounts Receivable Retainage Accounts receivable retainage represents amounts due from customers, but where payments are withheld contractually until certain construction milestones are met. Amounts retained typically range from 5% to 10% of the total invoice. We classify retainages that are expected to be billed in the next twelve months as current assets. As of December 31, 2024 and 2023, no amounts were determined to be uncollectible. Inventory Inventories, which consist primarily of PV solar panels, batteries and related accessories, are stated at the lower of cost (“first-in, first-out” method) or net realizable value (determined as the estimated selling prices in the ordinary course of business, less reasonably predictable costs of completion, disposal, and transportation). Provisions have been made to reduce the carrying value of inventory to the net realizable value. Prepaid Expenses and Other Current Assets Prepaid expenses and other current assets consist primarily of other receivables, deferred project costs, and other short-term prepaid expenditures that will be expensed within one year. Prepaid expenses and other current assets comprised of the following: Year Ended December 31, 2024 2023 Other receivables $ 16,336 $ 74,454 Deferred project costs 117,573 38,240 Prepaid expenses 11,997 10,697 Prepaid expenses and other current assets $ 145,906 $ 123,391 Other Receivables Ameresco’s wholly-owned subsidiary in Italy entered into agreements to sell certain receivables to unrelated third-party financial institutions for a discount on a non-recourse basis. These transactions are accounted for in accordance with Accounting Standards Codification (“ASC”) Topic 860, Transfers and Servicing, and result in a reduction in accounts receivable because the agreements transfer effective control over the receivables, and related risk, to the buyers. Our Italian subsidiary does not retain any interest in the underlying accounts receivable once sold. Trade accounts receivables balances sold are removed from the consolidated balance sheets, and cash received is reflected in operating activities in the consolidated statements of cash flows. Other receivables sold without recourse total $3,994 and $39,923 at December 31, 2024 and 2023, respectively, and are included in other receivables in the table above. Bank discount fees during the twelve months ended December 31, 2024 and 2023 were $1,471 and $5,844, respectively, and are included in other expense, net in the consolidated statements of income. See Note 17. Interest and Other Expenses, Net. At December 31, 2023, other receivables also included $20,970 which represents the fair value of the portion of investment tax credits (“ITC”) that we agreed to sell back to the seller for the project acquired on August 4, 2023. See the Government Grants paragraph below and Note 7. Energy Assets, Net for additional details. Deferred Project Costs Deferred project costs include costs incurred on active projects which will be reclassified to energy assets or project revenues once a change order or new contract is finalized which is expected within one year. Federal ESPC Receivable Federal ESPC receivable represents the amount to be paid by various federal government agencies for work performed and earned by Ameresco under specific ESPCs. We assign certain of our rights to receive those payments to third-parties that provide construction and permanent financing for such contracts. Upon completion and acceptance of the project by the government, typically within 24 to 36 months of construction commencement, the assigned ESPC receivable from the government and corresponding ESPC liability are eliminated from our consolidated financial statements. Project Development Costs We capitalize only those costs incurred in connection with the development of energy projects, primarily direct labor, interest costs, outside contractor services, consulting fees, legal fees, and travel, if incurred after a point in time where the realization of related revenue becomes probable. Project development costs incurred prior to the probable realization of revenue are expensed as incurred. We classify project development efforts that are expected to proceed to construction activity in the next twelve months as a current asset. We periodically review these balances and write off any amounts where the realization of the related revenue is no longer probable. Property and Equipment Property and equipment consist primarily of office and computer equipment and is recorded at cost. Major additions and improvements are capitalized as additions to the property and equipment accounts, while replacements, maintenance, and repairs that do not improve or extend the life of the respective assets, are expensed as incurred. Depreciation and amortization of property and equipment are computed on a straight-line basis over the following estimated useful lives: Asset Classification Estimated Useful Life Furniture and office equipment Five years Computer equipment and software costs Three Leasehold improvements Lesser of term of lease or five years Automobiles Five years Land Unlimited Gains or losses on disposal of property and equipment are reflected in selling, general, and administrative expenses in the consolidated statements of income. Energy Assets Energy assets consist of costs of materials, direct labor, interest costs, outside contract services, deposits, asset retirement obligations (“AROs”), and project development costs incurred in connection with the construction of small-scale renewable energy plants that we own. These amounts are capitalized and amortized to cost of revenues in our consolidated statements of income on a straight-line basis over the lives of the related assets or the terms of the related contracts. Routine maintenance costs are expensed as incurred in our consolidated statements of income to the extent that they do not extend the life of the asset. Major maintenance includes upgrades and the refurbishment or replacing of components that are integral to the energy assets operating. In these instances, the costs associated with major maintenance are capitalized and are depreciated over the shorter of the remaining life of the asset or the period up to the next required major maintenance. Financing lease assets and accumulated depreciation of financing lease assets are included in energy assets. For additional information see the Sale-Leaseback section below and Notes 7 and 8. Capitalized Interest We capitalize interest costs relating to construction financing during the period of construction on energy assets we own. Capitalized interest is included in energy assets, net, in our consolidated balance sheets. Capitalized interest is amortized to cost of revenues in our consolidated statements of income on a straight-line basis over the useful life of the associated energy asset. For additional information see Note 7. Long-lived Asset Impairment We evaluate our long-lived assets, including operating lease right-of-use assets, for impairment as events or changes in circumstances indicate the carrying value of these assets may not be fully recoverable. Examples of such triggering events applicable to our assets include a significant decrease in the market price of a long-lived asset or asset group or a current-period operating or cash flow loss combined with a history of operating or cash flow losses or a projection or forecast that demonstrates continuing losses associated with the use of a long-lived asset or asset group. We evaluate recoverability of long-lived assets to be held and used by estimating the undiscounted future cash flows before interest associated with the expected uses and eventual disposition of those assets. When these comparisons indicate that the carrying value of those assets is greater than the undiscounted cash flows, we recognize an impairment loss for the amount that the carrying value exceeds the fair value of the asset group. Impairment losses are reflected in selling, general, and administrative expenses in the consolidated statements of income. See Note 7. for disclosure on our long-lived asset impairment during the year ended December 31, 2024. Government Grants From time to time, we have applied for and received cash grant awards from the U.S. Treasury Department (the “Treasury”) under Section 1603 of the American Recovery and Reinvestment Act of 2009 (the “Act”). The Act authorized the Treasury to make payments to eligible persons who place in service qualifying renewable energy projects. The grants are paid in lieu of ITCs. All of the cash proceeds from the grants were used and recorded as a reduction in the cost basis of the applicable energy assets. For tax purposes, the Section 1603 payments are not included in federal and certain state taxable income and the basis of the property is reduced by 50% of the payment received. We last received a Section 1603 grant during the year ended December 31, 2014. No further Section 1603 grant payments are expected to be received as the program has expired and no repayments will be required. We received grant proceeds from the Canadian government in connection with the construction of our energy assets in Canada during the years ended December 31, 2019 and 2020. We have a contribution agreement in place with Natural Resources Canada to fund 50% of the construction costs on a specific pilot project in Ontario. Cash proceeds are recorded as a deferred grant liability. Following commercial operation, the grant is subject to repayment to the government for a five-year period. Deferred grant income of $6,436 and $6,974 in the accompanying consolidated balance sheets as of December 31, 2024 and 2023, respectively, represents the benefit of the basis difference to be amortized to depreciation expense over the life of the related property. Non-refundable Transferable Credits Policy Elections We elect to apply government grant accounting, outside of income taxes, to the portion of the transferable ITC that we intend to sell. We have an existing policy to account for government grants by analogy to International Accounting Standard (“IAS”) 20 and shall present the credit as a reduction in the cost of the related energy asset and shall measure the grant of the nonmonetary asset at fair value. Based on these policy elections, the benefit of the grant will be recognized in profit or loss as a reduction to depreciation expense over the life of the energy asset. See Note 7. Energy Assets, Net for additional information. We elect to account for credits we intend to use to offset our tax liability under Topic 740. We recognize a deferred tax asset for allowable carryforwards as we benefit in the year the credit was generated. Possible limitations on the carryforward were considered and it was determined that no valuation allowance was required. We also utilized the flow-through method regarding the presentation in the consolidated statements of income, which resulted in a reduction in the income tax provision. Acquisitions For acquisitions that meet the definition of a business combination, we apply the acquisition method of accounting in accordance with ASC 805, Business Combinations, where assets acquired, and liabilities assumed are recorded at fair value at the date of each acquisition. Any excess of the consideration we transferred over the amounts recognized for assets acquired and liabilities assumed is recorded as goodwill. Intangible assets, if identified, are also recorded. Determining the fair value of certain assets and liabilities assumed is judgmental in nature, often involves the use of significant estimates and assumptions, and is calculated using level 3 inputs per the fair value hierarchy as defined in Note 18. We continue to evaluate acquisitions for a period not to exceed one year after the acquisition date of each transaction to determine whether any additional adjustments are needed to the allocation of the purchase price. The results of the acquired companies are included in our consolidated statements of income, comprehensive income, and cash flows from the date of the respective acquisition. The consideration for our acquisitions often includes future payments that are contingent upon the occurrence of a particular event. We record a contingent consideration obligation for such contingent consideration payments at fair value on the acquisition date. We estimate the fair value of contingent consideration obligations through valuation models that incorporate probability adjusted assumptions related to the achievement of the milestones and the likelihood of making related payments. Each reporting period we revalue the contingent consideration obligations associated with our acquisitions to fair value and record changes in the fair value within the selling, general, and administrative expenses in our consolidated statements of income. Increases or decreases in the fair value of the contingent consideration obligations can result from changes in assumed discount periods and rates, changes in the assumed timing and amount of revenue and expense estimates and changes in assumed probability with respect to the attainment of certain financial and operational metrics, among others. Significant judgment is employed in determining these assumptions as of the acquisition date and for each subsequent period. Accordingly, future business and economic conditions, as well as changes in any of the assumptions described above, can materially impact the fair value of contingent consideration recorded at each reporting period. Deferred consideration related to certain holdbacks and completion payments are considered short-term in nature. These amounts are recorded at full value and are only revalued if one of those underlying assumptions changes. See Note 4 for additional information about our acquisitions. In accordance with ASC 805, Business Combinations, our solar project acquisitions do not constitute a business as the assets acquired in each case could be considered a single asset or group of similar assets that made up substantially all of the fair market value of the acquisitions. See Note 7 for information on solar projects we have purchased or are under definitive agreement to purchase. Goodwill As noted in the Acquisitions section above, our goodwill is derived when we acquire another business. Goodwill is not amortized, but the potential impairment of goodwill is assessed at least annually during the fourth quarter and on an interim basis whenever events or changes in circumstances indicate that the carrying value may not be fully recoverable. In 2023, we changed the assessment date from December 31st to October 31st. We estimate the fair value of our reporting units and compare it with the carrying value of the reporting unit, including goodwill. If the fair value is greater than the carrying value of the reporting unit, no impairment is recorded. Fair value is determined using both an income approach and a market approach. If the fair value is less than the carrying value, an impairment loss is recognized for the amount that the carrying amount of a reporting unit, including goodwill, exceeds its fair value, limited to the total amount of goodwill allocated to that reporting unit. The impairment charge would be recorded to earnings in the consolidated statements of income. Judgment is required in determining whether an event has occurred that may impair the value of goodwill or identifiable intangible assets. See Note 5 for discussion about our goodwill assessments. Intangible Assets Acquired intangible assets, other than goodwill, that are subject to amortization include customer contracts, customer relationships, technology, trade names, and non-compete agreements. The intangible assets are amortized over periods ranging from one Leases Operating lease right-of-use (“ROU”) assets represent our right to use an underlying asset during the reasonably certain lease term and lease liabilities represent our obligation to make lease payments arising from the lease. ROU assets and lease liabilities for significant lease arrangements are recognized at commencement based on the present value of lease payments over the lease term. We use our incremental borrowing rate, which is updated annually or when a significant event occurs that would indicate a significant change in rates, to calculate the present value of lease payments. The operating lease ROU asset also includes any lease payments related to initial direct cost and prepayments and excludes lease incentives. Lease expense is recognized on a straight-line basis over the lease term which may include options to extend or terminate the lease when it is reasonably certain that we will exercise that option. Our ROU assets are evaluated for impairment using the same method as described above under the Long-lived Asset Impairment section. We do not record ROU assets and corresponding lease liabilities for leases with an initial term of 12 months or less (“short-term leases”) as we recognize lease expense for these leases as incurred over the lease term. We elected the package of practical expedients and did not reassess lease classifications of existing contracts or leases at adoption or the initial direct costs associated with existing leases. Accordingly, our sale-leaseback arrangements entered into as of December 31, 2018 remain under the previous guidance. See the Sale-leasebacks and Financing Leases section below and Note 8 for additional information on these sale-leasebacks. We have historical leases under ASC 840, Leases, which may have lease and non-lease components. Upon adoption of Topic 842, we elected to continue to account for these historical leases as a single component, as it relates to all prospective leases, we allocate consideration to lease and non-lease components based on pricing information in the respective lease agreement, or, if this information is not available, we make a good faith estimate based on the available pricing information at the time of the lease agreement. See Note 8 for additional information about our leases. Other Assets Other assets consist primarily of notes and contracts receivable due to Ameresco from various customers and also includes the fair value of derivatives determined to be assets, investments in unconsolidated joint ventures, the non-current portions of project development costs, accounts receivable retainages, sale-leaseback deferred loss, deferred contract costs, and assets held for sale. For additional information about assets held for sale, please see Note 21. Accrued Expenses and Other Current Liabilities Accrued expenses and other current liabilities includes use and other taxes payable of $40,000 and $39,974 as of December 31, 2024 and 2023, respectively, as well as accrued payroll and payroll related expenses, sales tax payable, current portion of contingent consideration, and other accrued operating expenses. Asset Retirement Obligations We recognize a liability for the fair value of required AROs on a discounted basis when these obligations are incurred and can be reasonably estimated, which is typically at the time the assets are in development, installed or operating. Over time, the liabilities increase due to the change in present value, and initial capitalized costs are depreciated over the useful life of the related assets. Upon satisfaction of the ARO conditions, any difference between the recorded ARO liability and the actual retirement cost incurred is recognized as an operating gain or loss in the consolidated statements of income. See Note 7 for additional disclosures on our AROs. Federal ESPC Liabilities Federal ESPC liabilities, for both projects and energy assets, represent the advances received from third-parties under agreements to finance certain ESPC projects with various federal government agencies. For projects related to the construction or installation of certain energy savings equipment or facilities developed for the government customer, the ESPC receivable from the government and corresponding ESPC liability is eliminated from our consolidated balance sheets upon completion and acceptance of the project by the government, typically within 24 to 36 months of construction commencement. We remain the primary obligor for financing received until recourse to us ceases for the ESPC receivables transferred to the investor upon final acceptance of the work by the government customer. For small-scale energy assets developed for a government customer that we own and operate, we remain the primary obligor for financing received until the liability is eliminated from our consolidated balance sheets as contract payments assigned by the customer are transferred to the investor upon final acceptance of the work by the government customer. Sale-leasebacks and Financing Leases We entered into sale-leaseback arrangements that provided for the sale of solar PV energy assets to third-party investors and the simultaneous leaseback of the energy assets, which we then operate and maintain, recognizing revenue through the sale of the electricity and solar renewable energy credits generated by these energy assets. In sale-leaseback arrangements, we first determine whether the solar PV energy asset under the sale-leaseback arrangement is “integral equipment”. A solar PV energy asset is determined to be integral equipment when the cost to remove the energy asset from its existing location, including the shipping and reinstallation costs of the solar PV energy asset at the new site, and any diminution in fair value, exceeds 10% of the fair value of the solar PV energy asset at the time of its original installation. When the leaseback arrangement expires, we have the option to purchase the solar PV energy asset for the then fair market value or, in certain circumstances, renew the lease for an extended term. We have determined that none of the solar PV energy assets sold to date under the sale-leaseback program have been considered integral equipment as the cost to remove the energy asset from its existing location would not exceed 10% of its original fair value. In accordance with our adoption of Topic 842, sale-leaseback transactions are accounted for as financing liabilities on a prospective basis as we retain control of the underlying assets. As these transactions meet the criteria of a failed sale, the proceeds received in prospective transactions are accounted for as long-term financing liabilities with interest rates based upon the underlying details of each specific transaction. We entered into sale-leaseback arrangements for solar PV energy assets prior to January 1, 2019, which remain under the previous guidance. We recorded a financing lease asset and financing lease obligation in our consolidated balance sheets equal to the lower of the present value of our future minimum leaseback payments or the fair value of the solar PV energy asset. We deferred any gain or loss, which represents the excess or shortfall of cash received from the investor compared to the net book value of the asset, at the time of the sale. We recorded the long-term portion of any deferred gain in other liabilities or deferred loss in other assets and the current portion in accrued expenses and other current liabilities or prepaid expenses and other current assets in our consolidated balance sheets. The deferred amounts are amortized over the lease term and are included in cost of revenues in our consolidated statements of income. See Notes 8 and 9 for details of our sales-leaseback and financing lease transactions. Debt Issuance Costs Debt issuance costs include external costs incurred to obtain financing. Debt issuance costs are amortized over the respective term of the financing using the effective interest method, with the exception of our revolving credit facility and construction loans, as discussed in Note 9, which are amortized on a straight-line basis over the term of the agreement. Debt issuance costs are presented on the consolidated balance sheets along with unamortized debt discounts as a reduction to long-term debt and financing lease liabilities. Other Liabilities Other liabilities consist primarily of the long-term portion of deferred revenue related to multi-year operations and maintenance (“O&M”) contracts which expire at various dates through 2051. Other liabilities also include the fair value of derivatives, the long-term portions of sale-leaseback deferred gains, and liabilities recognized in association with customer energy assets for obligations to the customer for performance of the asset. See Note 19 for additional derivative disclosures and Note 7 for additional energy asset disclosures. Revenue Recognition We are a provider of comprehensive energy services, including energy efficiency, infrastructure upgrades, energy security and resilience, asset sustainability, and renewable energy solutions for businesses and organizations. Our sustainability services include capital and operational upgrades to a

Revenue from Contracts with Cus

Revenue from Contracts with Customers	12 Months Ended
	Dec. 31, 2024
Revenue from Contract with Customer [Abstract]
Revenue from Contracts with Customers	REVENUE FROM CONTRACTS WITH CUSTOMERS Disaggregation of Revenue Our reportable segments for the year ended December 31, 2024 were North America Regions, U.S. Federal, Europe, and Renewable Fuels (formerly Alternative Fuels). On January 1, 2024, we changed the structure of our internal organization, and our U.S. Regions and Canada are now included in North America Regions. Additionally, our Asset Sustainability Group was formerly included in Canada, but is now included in “All Other”. As a result, previously reported amounts have been reclassified for comparative purposes. The following table presents our revenue disaggregated by line of business and reportable segment for the year ended December 31, 2024: North America Regions U.S. Federal Renewable Fuels Europe All Other Total Project revenue $ 762,404 $ 294,082 $ 43,353 $ 238,848 $ — $ 1,338,687 O&M revenue 35,707 60,057 7,895 2,807 — 106,466 Energy assets 73,059 17,449 121,960 847 29 213,344 Other 7,658 948 134 8,072 94,619 111,431 Total revenues $ 878,828 $ 372,536 $ 173,342 $ 250,574 $ 94,648 $ 1,769,928 The following table presents our revenue disaggregated by line of business and reportable segment for the year ended December 31, 2023: North America Regions U.S. Federal Renewable Fuels Europe All Other Total Project revenue $ 519,079 $ 342,238 $ — $ 138,730 $ 1,250 $ 1,001,297 O&M revenue 26,310 53,496 10,697 1,979 1 92,483 Energy assets 64,668 6,326 106,359 1,392 145 178,890 Other 6,377 824 19 7,253 87,490 101,963 Total revenues $ 616,434 $ 402,884 $ 117,075 $ 149,354 $ 88,886 $ 1,374,633 The following table presents our revenue disaggregated by line of business and reportable segment for the year ended December 31, 2022: North America Regions U.S. Federal Renewable Fuels Europe All Other Total Project revenue $ 1,093,738 $ 333,846 $ — $ 53,680 $ — $ 1,481,264 O&M revenue 22,259 51,857 10,377 456 16 84,965 Energy assets 51,818 5,822 104,082 281 87 162,090 Other 5,466 366 — 3,993 86,278 96,103 Total revenues $ 1,173,281 $ 391,891 $ 114,459 $ 58,410 $ 86,381 $ 1,824,422 See Note 16 for our revenue disaggregated by geographical region. The following table presents information related to our revenue recognized over time: Year Ended December 31, 2024 2023 2022 Percentage of revenue recognized over time 96 % 95 % 96 % The remainder of our revenue is for products and services transferred at a point in time, at which point revenue is recognized. Contract Balances The following table provides information about receivables, contract assets, and contract liabilities from contracts with customers: December 31, 2024 December 31, 2023 January 1, 2023 Accounts receivable, net $ 256,961 $ 153,362 $ 174,009 Accounts receivable retainage 39,843 33,826 38,057 Contract Assets Unbilled revenue 644,105 636,163 576,363 Contract Liabilities Deferred revenue 91,734 52,903 34,796 Deferred revenue, non-current (1) 29,885 18,393 7,617 Total contract liabilities $ 121,619 $ 71,296 $ 42,413 (1) Performance obligations that are expected to be completed beyond the next twelve months and are included in other liabilities in the consolidated balance sheets. The increase in contract assets for the year ended December 31, 2024 was primarily due to revenue recognized of $1,192,464, as well as reclassifications primarily from contract liabilities as a result of timing of customer payments, offset by billings of $1,213,716. The increase in contract liabilities was primarily driven by the receipt of advance payments from customers, and related billings, as well as reclassifications from contract assets as a result of timing of customer payments. The advance payments and reclassifications exceeded the recognition of revenue as performance obligations were satisfied. For the year ended December 31, 2024, we recognized revenue of $377,569 and billed $377,591 to customers that had balances which were included in contract liabilities at December 31, 2023. The increase in contract assets for the year ended December 31, 2023 was primarily due to revenue recognized of $940,317, offset in part by billings of $886,788. Contract assets also increased due to reclassifications, primarily from contract liabilities as a result of timing of customer payments. The increase in contract liabilities was primarily driven by the receipt of advance payments from customers, and related billings, as well as reclassifications from contract assets as a result of timing of customer payments. The advance payments and reclassifications exceeded the recognition of revenue as performance obligations were satisfied. For the year ended December 31, 2023, we recognized revenue of $160,713 and billed $184,174 to customers that had balances which were included in contract liabilities at January 1, 2023. Performance Obligations Our remaining performance obligations (“fully-contracted backlog”) represent the unrecognized revenue value of our contract commitments. Our backlog may vary significantly each reporting period based on the timing of major new contract commitments and the fully-contracted backlog may fluctuate with currency movements. In addition, our customers have the right, under some circumstances, to terminate contracts or defer the timing of our services and their payments to us. At December 31, 2024, we had fully-contracted backlog of $3,922,391 and approximately 32% of our fully-contracted backlog is anticipated to be recognized as revenue in the next twelve months. The remaining performance obligations primarily relate to the energy efficiency and renewable energy construction projects, including long-term O&M services related to these projects. The long-term services have varying initial contract terms, up to 25 years. We applied the practical expedient for certain revenue streams to exclude the value of remaining performance obligations for (i) contracts with an original expected term of one year or less or (ii) contracts for which we recognize revenue in proportion to the amount we have the right to invoice for services performed. Contract Acquisition Costs As of December 31, 2024 and 2023, we had capitalized commission costs of $1,623 and $1,735, respectively, related to contracts that were not completed, which were included in other assets in the accompanying consolidated balance sheets. For contracts that have a duration of less than one year, we follow a practical expedient and expense these costs when incurred. During the years ended December 31, 2024 and 2023, the amortization of commission costs related to contracts was not material and have been included in the accompanying consolidated statements of income. Project Development Costs The following table presents information related to our project development costs recognized in the consolidated statements of income on projects that converted to customer contracts: Year Ended December 31, 2024 2023 2022 Project development costs recognized $ 18,023 $ 13,051 $ 15,507

Business Acquisitions and Dives

Business Acquisitions and Divestitures	12 Months Ended
	Dec. 31, 2024
Business Combination, Asset Acquisition, and Joint Venture Formation [Abstract]
Business Acquisitions and Divestitures	BUSINESS ACQUISITIONS AND DIVESTITURES Business Acquisitions Enerqos Energy Solutions S.r.l. (“Enerqos”) On February 24, 2023, we signed a definitive purchase and sale agreement to acquire Enerqos, a renewable energy and energy efficiency company headquartered in Milan, Italy. The acquisition closed on March 30, 2023 and the total purchase consideration was $13,445, of which $9,535 has been paid. There is no contingent consideration related to this acquisition. Cash acquired was $353, debt assumed was $3,951, and a deferred tax liability, net of $931 was recorded. In accordance with the SEC’s Regulation S-X and GAAP, we evaluated and determined that Enerqos is not deemed to be a significant subsidiary, therefore, we are not presenting the pro-forma effects of this acquisition on our operations. The estimated goodwill of $6,855 from the Enerqos acquisition consists largely of expected benefits, including the combined entities experience and the acquired workforce. This goodwill is not deductible for income tax purposes. The estimated fair value of tangible and intangible assets acquired, and liabilities assumed are based on management's estimates and assumptions that are preliminary and subject to adjustments. Any measurement period adjustments made within one year from acquisition date, are recorded as adjustments to goodwill. Any adjustments made beyond the measurement period will be included in our consolidated statements of income. The results of the acquisition since the date of the acquisition have been included in our operations as presented in the accompanying consolidated statements of income, consolidated statements of comprehensive income and consolidated statements of cash flows. The following table sets forth the revenue and net (loss) income for Enerqos: Twelve Months Ended December 31, 2024 2023 Revenue $ 27,809 $ 52,241 Net (loss) income (2,961) 1,758 A summary of the cumulative consideration paid, allocation of the purchase price, and adjustments made for the Enerqos acquisition are presented in the table below: Preliminary March 31, 2023 Measurement Period Adjustment As Adjusted December 31, 2023 Cash $ 9,535 $ — $ 9,535 Long-term debt assumed, net of current portions 3,951 — 3,951 FX adjustment (41) — (41) Fair value of consideration transferred $ 13,445 $ — $ 13,445 Cash and cash equivalents 190 — 190 Accounts receivable 6,230 — 6,230 Unbilled revenue 8,985 — 8,985 Prepaid expenses and other current assets 16,504 — 16,504 Project development costs 5,140 — 5,140 Property and equipment and energy assets 1,234 — 1,234 Intangible assets 4,438 — 4,438 Long-term restricted cash 163 — 163 Accounts payable (15,480) — (15,480) Accrued expenses and other current liabilities (4,510) 165 (4,345) Current portions of long-term debt (15,165) — (15,165) Deferred income tax liabilities, net (931) — (931) Other liabilities (208) — (208) Recognized identifiable assets acquired and liabilities assumed $ 6,590 $ 165 $ 6,755 Goodwill $ 6,855 $ (165) $ 6,690 Business Divestiture On October 23, 2024, Ameresco’s board of directors approved the divestiture of a wholly-owned subsidiary (“the sub”). On December 31, 2024, we completed the sale of our entire interest in the sub to an unrelated party, for an estimated closing price of $60,400 in exchange for all of our shares. As a result of this transaction, the net assets of the sub were deconsolidated from our consolidated financial statements, we received net proceeds of $54,249, and recorded a gain of $38,007, net of transaction costs of $2,179, from this disposition. We have 90 days to finalize the closing price. At closing we used the proceeds to prepay $57,000 towards our senior secured term loan. The sub is an energy technology and advisory services company, was not considered core to our business, and the divestiture is not considered a strategic shift, therefore, the net gain was included in a separate line item within operating income in the consolidated statements of income during the year ended December 31, 2024. The sub was not a reportable segment and was included in “All Other”. As part of the deconsolidation we disposed of $8,529 in goodwill related to this reporting unit. See Note 5. Goodwill and Intangible Assets, Net.

Goodwill and Intangible Assets,

Goodwill and Intangible Assets, Net	12 Months Ended
	Dec. 31, 2024
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Intangible Assets, Net	GOODWILL AND INTANGIBLE ASSETS, NET Goodwill, Net Our annual goodwill impairment review is performed during the fourth quarter each year-end using a quantitative approach. We tested goodwill for impairment at the reporting unit level utilizing the income approach which included a discounted cash flow method with a market approach, and we determined that there was no goodwill impairment for the year ended December 31, 2024. All reporting units with goodwill had estimated fair values that exceeded their carrying values by at least 49% as of December 31, 2024. During our assessment during the fourth quarter ended December 31, 2023, one reporting unit had a fair value that was 2% less than the carrying value and we recorded a $1,644 goodwill impairment, which was $2,222 after taking into account the effect of deferred income taxes. The impairment was primarily driven by a decline in projected cash flows, including revenues and profitability. The impairment charges are included in the asset impairments within the consolidated statements of income for the year ended December 31, 2023. All other reporting units with goodwill had estimated fair values that exceeded their carrying values by at least 16% as of December 31, 2023. There was no goodwill impairment for the year ended December 31, 2022. The changes in the goodwill balances by reportable segment are as follows: North America Regions U.S. Federal Europe Other Total Carrying Value of Goodwill Balance, December 31, 2022 $ 42,829 $ 3,981 $ 5,932 $ 17,891 $ 70,633 Goodwill acquired during the year — — 6,855 — 6,855 Remeasurement adjustments — — (165) — (165) Impairment charges, net of tax (2,222) — — — (2,222) Foreign currency translation 73 — 413 — 486 Balance, December 31, 2023 40,680 3,981 13,035 17,891 75,587 Fair value allocation for change in reportable segments (1,474) — — 1,474 — Goodwill disposed of through sale of business (1) — — — (8,529) (8,529) Foreign currency translation (257) — (496) — (753) Balance, December 31, 2024 $ 38,949 $ 3,981 $ 12,539 $ 10,836 $ 66,305 (1) See Note 4. Business Acquisitions and Divestitures for additional information. Accumulated Goodwill Impairment Balance, December 31, 2023 $ (2,222) $ — $ (1,016) $ — $ (3,238) Balance, December 31, 2024 $ (2,222) $ — $ (1,016) $ — $ (3,238) Intangible Assets, Net Definite-lived intangible assets, net consisted of the following: As of December 31, 2024 2023 Gross carrying amount Customer contracts $ 6,898 $ 8,859 Customer relationships 17,572 21,182 Non-compete agreements 2,535 3,013 Technology 1,754 2,723 Tradenames 927 1,370 Subsurface land easements 4,274 — Total gross carrying amount 33,960 37,147 Accumulated Amortization Customer contracts 6,898 8,859 Customer relationships 13,318 14,979 Non-compete agreements 2,535 3,013 Technology 1,753 2,723 Tradenames 642 765 Total accumulated amortization 25,146 30,339 Intangible assets, net $ 8,814 $ 6,808 Customer contracts are amortized ratably over the period of the acquired customer contracts ranging in periods from approximately one four Separable intangible assets that are not deemed to have indefinite lives are amortized over their useful lives. We annually assess whether a change in the useful life is necessary, or more frequently if events or circumstances warrant. During the year ended December 31, 2024, we included purchased subsurface land easements in intangible assets, which shall be amortized over the twenty-year life of the pipelines. No other changes to useful lives were made during the years ended December 31, 2024, 2023, and 2022. The table below sets forth amortization expense: Year Ended December 31, Location 2024 2023 2022 Customer contracts Cost of revenues $ — $ — $ 551 Customer relationships Selling, general and administrative expenses 1,833 2,141 1,303 Technology Selling, general and administrative expenses — — 1 Tradenames Selling, general and administrative expenses 296 225 3 Subsurface land easements Selling, general and administrative expenses 5 — — Total amortization expense $ 2,134 $ 2,366 $ 1,858 Amortization expense for our definite-lived intangible assets for the next five years to be included in selling, general, and administrative expenses is as follows: Estimated Amortization Expense 2025 $ 2,238 2026 1,895 2027 821 2028 369 2029 214 Thereafter 3,277 Total $ 8,814

Property and Equipment, Net

Property and Equipment, Net	12 Months Ended
	Dec. 31, 2024
Property, Plant and Equipment [Abstract]
Property and Equipment, Net	PROPERTY AND EQUIPMENT, NET Property and equipment, net consisted of the following: December 31, 2024 2023 Furniture and office equipment $ 4,198 $ 4,207 Computer equipment and software costs 18,706 27,199 Leasehold improvements 2,312 2,570 Automobiles 1,956 2,041 Land 6,943 6,943 Property and equipment, gross 34,115 42,960 Less: accumulated depreciation (23,075) (25,565) Property and equipment, net $ 11,040 $ 17,395 The following table sets forth our depreciation expense on property and equipment: Year Ended December 31, Location 2024 2023 2022 Selling, general & administrative expenses $ 4,963 $ 4,155 $ 2,665

Energy Assets, Net

Energy Assets, Net	12 Months Ended
	Dec. 31, 2024
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Energy Assets, Net	ENERGY ASSETS, NET Energy assets, net consisted of the following: December 31, 2024 2023 Energy assets (1) $ 2,338,680 $ 2,054,145 Less: accumulated depreciation, net (423,369) (364,721) Energy assets, net $ 1,915,311 $ 1,689,424 (1) Includes financing lease assets (see Note 8), capitalized interest and ARO assets (see tables below). Also includes the energy asset projects acquired in August 2023 and January 2024. See section below for additional information. Energy Asset Acquisitions In order to expand our portfolio of energy assets, we have acquired energy projects, which did not constitute businesses under the guidance discussed in Note 2. August 2023 Purchase and Sale Agreement On August 4, 2023, we entered into a purchase and sale agreement to acquire an energy asset project and rights to acquire 100% of the stock of Bright Canyon Energy Corporation (“BCE”) in a two-phased transaction exclusive of each other. Phase 1, the purchase of the energy asset project, closed on August 4, 2023 and did not constitute a business in accordance with ASC 805-50, Business Combinations. The purchase price for phase 1 was $87,964, of which $5,000 was paid in cash, $46,694 was financed through a seller’s note, and we assumed a construction loan on the energy asset project for $36,270. We also acquired cash of $11,206. During the year ended December 31, 2023, we paid $18,400 in principal on the sellers note. In January 2024, the purchase price was increased by $1,147 and we paid off the seller’s note in the amount of $29,441. We also assumed a land lease for the energy asset project. On December 28, 2023, we executed an amended and restated purchase and sale agreement, which primarily revised the timing of payments on phase 2. In the second phase, which closed on January 12, 2024, we acquired BCE, including its interest in a consolidated joint venture and its interests in project subsidiaries developing or with rights to develop solar, battery, and microgrid assets for an adjusted purchase price of $48,035, of which $9,839 was paid in cash and $32,500 was financed through a seller’s note. The remaining balance due of $5,696 was paid during the twelve months ended December 31, 2024. During the year ended December 31, 2024, we paid off the remaining balance of the seller’s note in the amount of $32,500. We also assumed four land leases for the energy asset projects. Phase 2, the purchase of the energy asset projects did not constitute a business in accordance with ASC 805-50, Business Combinations. See Note 9 for additional information about the BCE-related loans, Note 8 for information on the leases and Note 15 for potential additional commitments. November 2023 Purchase Agreement On November 1, 2023, we purchased a solar asset project for $3,128, of which $2,676 has been paid to date. The remaining balance of $452 is included in accrued expenses and other current liabilities in the consolidated balance sheets at December 31, 2024. The payment is due when certain conditions as outlined in the agreement are met. Transfer of Investment Tax Credits Under phase 1 of the purchase and sale agreement with BCE noted above, we agreed to sell back to the seller ITC for the project acquired as part of this transaction for the fair market value of these credits and recorded $20,970 in other receivables which is included in prepaid expenses and other current assets in the consolidated balance sheets at December 31, 2023. This amount was collected in January 2024. During the year ended December 31, 2024 we sold ITC on eight energy assets to a third party at a fair value of $47,534 which was received as of December 31, 2024. The benefit from the sale of the ITC will be recognized in profit or loss as a reduction to depreciation expense over the life of the energy assets. Depreciation and Amortization The following table sets forth our depreciation and amortization expense on energy assets, net of deferred grant amortization: Year Ended December 31, Location 2024 2023 2022 Cost of revenues (1) $ 82,114 $ 59,390 $ 49,755 (1) Includes depreciation and amortization expense on financing lease assets. See Note 8. Capitalized Interest The following table presents the interest costs relating to construction financing during the period of construction, which were capitalized as part of energy assets, net: Year Ended December 31, 2024 2023 2022 Capitalized interest $ 50,889 $ 43,561 $ 13,050 Long-lived Asset Impairment During December 2024, there was a triggering event which caused us to perform an impairment analysis on an energy asset group. The triggering event was related to a landfill which ceased accepting waste material as of January 1, 2025, where we planned to build a RNG plant. As the landfill was no longer operational, we are no longer able to build the plant at the location. As a result, we recorded an impairment charge of $8,715 as of December 31, 2024, which fully impaired this asset group. Additionally, during December 2024, we recorded impairment charges of $3,669 for multiple energy asset projects which we no longer believe are viable and have been terminated, which partially impaired these asset groups. During December 2023, there was a triggering event which caused us to perform an impairment analysis on an energy asset group. The triggering event was related to the requirement to shut down the plant and replace transmission lines due to transfer trip issues. We determined that the cost to overhaul the transfer trip line would be cost prohibitive, therefore, we made a decision to shut the plant down. As a result, we recorded an impairment charge of $1,298, which fully impaired this asset group. During December 2023, there was an additional energy asset group that had successive years of losses, the PPA expired in November 2024, and we expected losses to continue in 2024, therefore, we recorded an impairment charge of $311, which fully impaired this asset group. The impairment charges are included in asset impairments within the consolidated statements of income for the years ended December 31, 2024 and 2023. There was no impairment charge for the year ended December 31, 2022. Customer Energy Asset Projects We include certain customer energy asset projects in our energy assets, as we control and operate the assets as well as obtain financing during the construction and operating periods of the assets. We also carry a liability associated with these energy assets as we have an obligation to the customer for performance of the asset. Provided that performance criteria are met, the customer is responsible for repayment of the liability to the financing party. As of December 31, 2024 and 2023, there were six energy asset projects which were included in energy assets. The liabilities recognized in association with these customer energy assets were as follows: December 31, Location 2024 2023 Accrued expenses and other current liabilities $ 651 $ 598 Other liabilities 47,692 41,680 Total customer energy asset projects liability $ 48,343 $ 42,278 ARO Assets and ARO Liabilities Our ARO assets and ARO liabilities relate to the removal of equipment and pipelines at certain renewable gas projects and obligations related to the decommissioning of certain solar facilities. The following tables sets forth information related to our ARO assets and ARO liabilities: December 31, Location 2024 2023 ARO assets, net Energy assets, net $ 4,414 $ 4,800 ARO liabilities, non-current Other liabilities $ 6,136 $ 5,960 Year Ended December 31, 2024 2023 2022 Depreciation expense of ARO assets $ 238 $ 215 $ 146 Accretion expense of ARO liabilities $ 332 $ 258 $ 146

Leases

Leases	12 Months Ended
	Dec. 31, 2024
Leases [Abstract]
Leases	LEASES We enter into a variety of operating lease agreements through the normal course of business including certain administrative offices. The leases are long-term, non-cancelable real estate lease agreements, expiring at various dates through fiscal 2032. The agreements generally provide for fixed minimum rental payments and the payment of utilities, real estate taxes, insurance, and repairs. We also lease vehicles, IT equipment and certain land parcels related to our energy projects, expiring at various dates through fiscal 2061. The office and land leases make up a significant portion of our operating lease activity. Many of these leases have one or more renewal options that allow us, at our discretion, to renew the lease for six months to seven years. Only renewal options that we believed were likely to be exercised were included in our lease calculations. Many land leases include minimum lease payments that commence or increase when the related project becomes operational. In these cases, we estimated the commercial operation date used to calculate the ROU asset and minimum lease payments. A portion of our real estate leases are generally subject to annual changes in the Consumer Price Index (“CPI”). We utilized each lease’s minimum lease payments to calculate the lease balances upon transition. The subsequent increases in rent based on changes in CPI were excluded and will be excluded for future leases from the calculation of the lease balances but will be recorded to the consolidated statements of income as part of our operating lease costs. The discount rate was calculated using an incremental borrowing rate based on financing rates on secured comparable notes with comparable terms and a synthetic credit rating calculated by a third party. We elected to apply the discount rate using the remaining lease term at the date of adoption. We also enter into leases for service agreements and other leases related to our construction projects such as equipment, mobile trailers, and other temporary structures. We utilize the portfolio approach for this class of lease, which are either short-term leases or are not material. Rent and related expenses were as follows: Year Ended December 31, 2024 2023 2022 Rent and related expenses $ 13,945 $ 10,504 $ 9,199 We have a number of leases that are classified as financing leases, which related to transactions that were considered sale-leasebacks under ASC 840. See the sale-leaseback section below for additional information on our financing leases. The table below sets forth supplemental balance sheet information related to leases: December 31, 2024 2023 Operating Leases Right-of-use assets, net $ 80,149 $ 58,586 Current portions of operating lease liabilities $ 10,536 $ 13,569 Long-term operating lease liabilities, net of current portion 59,479 42,258 Total operating lease liabilities $ 70,015 $ 55,827 Weighted-average remaining lease term 19 years 18 years Weighted-average discount rate 6.6 % 6.6 % Financing Leases (1) Energy assets, net $ 25,158 $ 27,262 Current portions of financing lease liabilities $ 637 $ 871 Long-term financing lease liabilities, net of current portion, unamortized discount and debt issuance costs 12,267 13,057 Total financing lease liabilities $ 12,904 $ 13,928 Weighted-average remaining lease term 12 years 13 years Weighted-average discount rate 12.03 % 12.05 % (1) Includes sale-leaseback transactions entered into prior to January 1, 2019. The costs related to our leases were as follows: Year Ended December 31, 2024 2023 2022 Operating Leases Operating lease costs $ 12,945 $ 9,416 $ 8,372 Financing Leases Amortization expense 2,104 2,103 2,104 Interest on lease liabilities 1,752 1,804 2,147 Total financing lease costs 3,856 3,907 4,251 Total lease costs $ 16,801 $ 13,323 $ 12,623 Supplemental cash flow information related to our leases was as follows: Year Ended December 31, 2024 2023 Cash paid for amounts included in the measurement of operating lease liabilities $ 19,428 $ 10,724 Right-of-use assets obtained in exchange for new operating lease liabilities (1) $ 29,808 $ 25,225 (1) Includes non-monetary lease transactions of $10,378 and $13,941 for the years ended December 31, 2024 and 2023, respectively. See disclosure below for additional information. The table below sets forth our estimated minimum future lease obligations under our leases: Operating Leases Financing Leases Year ended December 31, 2025 $ 14,527 $ 1,899 2026 9,702 2,054 2027 8,565 1,923 2028 7,174 1,955 2029 5,521 1,892 Thereafter 73,464 14,043 Total minimum lease payments $ 118,953 $ 23,766 Less: interest 48,938 10,862 Present value of lease liabilities $ 70,015 $ 12,904 Non-monetary Lease Transactions We have six lease liabilities consisting of payment obligations that will be settled with non-monetary consideration. The lease liabilities relating to non-monetary consideration were recorded during the year end December 31, 2024 based on the fair market value of the project services or back up power expected to be provided, as noted below. In January 2023, a 37-year land lease commenced with the Navy, which expires in 2059. We are working to complete an In-Kind Consideration Project (“IKCP”), which the Navy will credit as consideration towards our lease obligation upon the Navy’s final acceptance of the IKCP. In August 2023, we acquired an energy asset project and assumed the related 30-year land lease agreement with the United States Army (“Army”), which commenced in 2022 and expires in 2052. We are providing backup power as a stand ready obligation as consideration towards our lease obligation. In January 2024, we acquired four energy asset projects and assumed the related 35 to 37-year land leases agreements with the Navy, which expire between 2053 and 2056. We are working to complete IKCPs, which the Navy will credit as consideration towards our lease obligation upon the Navy’s final acceptance of the IKCP. We have a future lease commitment for a project lease with the United States Navy (“Navy”) which has not yet met the criteria for recording a right-of-use (“ROU”) asset or ROU liability. The estimated net present value of this commitment totals $161,169 as of December 31, 2024. We will provide IKCPs, over a thirty-six-year period, which the Navy will credit as consideration towards our lease obligation upon the Navy’s final acceptance of the IKCPs. Once the lease commences, the ROU asset and liability will be recorded, most likely in 2025. See Note 7 Energy Assets, Net for additional information on the energy asset projects acquired. Financing Leases We entered into sale-leaseback arrangements for solar PV energy assets prior to January 1, 2019, which remain under the previous guidance. The following table presents a summary of amounts related to these sale-leasebacks included in our consolidated balance sheets: December 31, 2024 2023 Deferred loss, short-term, net 115 115 Deferred loss, long-term, net 1,224 1,340 Total deferred loss $ 1,339 $ 1,455 Deferred gain, short-term, net 345 345 Deferred gain, long-term, net 3,739 4,085 Total deferred gain $ 4,084 $ 4,430 Net gains from amortization expense in cost of revenues related to deferred gains and losses were $230, $230 and $383 for the years ended December 31, 2024, 2023, and 2022, respectively. Sale-leasebacks These facilities are accounted for as failed sales and are classified as long-term financing facilities. August 2018 Master Sale-leaseback During the year ended December 31, 2024, we entered into an amended and restated participation agreement which extended the current maturity date to March 31, 2025. We sold and leased back six energy assets for $61,996 in cash proceeds under this facility during the year ended December 31, 2024. The agreements have interest rates ranging from 0% to 1.86%, as a result of tax credits which were transferred to the counterparty. During the year ended December 31, 2024, we discovered a defect in a Battery Energy Storage System (“BESS”) that we installed for a customer under a long-term power purchase agreement for a project financed under the August 2018 master sale-leaseback agreement. As a result, the BESS had to be removed. Our financing partner has agreed to temporarily waive any events of default and refrain from pursuing remedies available under the master sale-leaseback associated with the BESS failure until December 31, 2025 to allow remediation of the issue (subject to certain conditions). We have fully funded lease payments due under the master lease agreement through December 31, 2025 into a reserve account from which lease payments will be made. December 2020 Master Sale-leaseback We enter into amendments to our December 2020 master lease and participation agreement from to time to time, which may extend the maturity date, increase the availability, or modify other covenants. We were in default under this agreement as we had failed to satisfy the insurance requirements and historical coverage ratio under this agreement. On May 3, 2024, we received a waiver on this default. As of December 31, 2023, no further funding was available under this lending commitment. August 2024 Master Sale-leaseback On April 18, 2023 we entered into lease agreements with two investors for one energy asset and on August 14, 2024 we sold and leased back the energy asset for $234,788, of which 50% was allocated to each investor under these agreements. One lease has an expiration date of August 14, 2034 with an option to extend to August 14, 2044 while the other has an expiration date of August 14, 2044. At closing, we incurred $2,833 in lenders’ fees and debt issuance costs. In August 2024, we used $140,844 of the proceeds to pay off the April 2023 construction credit facility and made rent prepayments of $60.1 million. As of December 31, 2024, we have no available funds remaining under this lending commitment. See Note 9 for additional information on these financing facilities.
Leases	LEASES We enter into a variety of operating lease agreements through the normal course of business including certain administrative offices. The leases are long-term, non-cancelable real estate lease agreements, expiring at various dates through fiscal 2032. The agreements generally provide for fixed minimum rental payments and the payment of utilities, real estate taxes, insurance, and repairs. We also lease vehicles, IT equipment and certain land parcels related to our energy projects, expiring at various dates through fiscal 2061. The office and land leases make up a significant portion of our operating lease activity. Many of these leases have one or more renewal options that allow us, at our discretion, to renew the lease for six months to seven years. Only renewal options that we believed were likely to be exercised were included in our lease calculations. Many land leases include minimum lease payments that commence or increase when the related project becomes operational. In these cases, we estimated the commercial operation date used to calculate the ROU asset and minimum lease payments. A portion of our real estate leases are generally subject to annual changes in the Consumer Price Index (“CPI”). We utilized each lease’s minimum lease payments to calculate the lease balances upon transition. The subsequent increases in rent based on changes in CPI were excluded and will be excluded for future leases from the calculation of the lease balances but will be recorded to the consolidated statements of income as part of our operating lease costs. The discount rate was calculated using an incremental borrowing rate based on financing rates on secured comparable notes with comparable terms and a synthetic credit rating calculated by a third party. We elected to apply the discount rate using the remaining lease term at the date of adoption. We also enter into leases for service agreements and other leases related to our construction projects such as equipment, mobile trailers, and other temporary structures. We utilize the portfolio approach for this class of lease, which are either short-term leases or are not material. Rent and related expenses were as follows: Year Ended December 31, 2024 2023 2022 Rent and related expenses $ 13,945 $ 10,504 $ 9,199 We have a number of leases that are classified as financing leases, which related to transactions that were considered sale-leasebacks under ASC 840. See the sale-leaseback section below for additional information on our financing leases. The table below sets forth supplemental balance sheet information related to leases: December 31, 2024 2023 Operating Leases Right-of-use assets, net $ 80,149 $ 58,586 Current portions of operating lease liabilities $ 10,536 $ 13,569 Long-term operating lease liabilities, net of current portion 59,479 42,258 Total operating lease liabilities $ 70,015 $ 55,827 Weighted-average remaining lease term 19 years 18 years Weighted-average discount rate 6.6 % 6.6 % Financing Leases (1) Energy assets, net $ 25,158 $ 27,262 Current portions of financing lease liabilities $ 637 $ 871 Long-term financing lease liabilities, net of current portion, unamortized discount and debt issuance costs 12,267 13,057 Total financing lease liabilities $ 12,904 $ 13,928 Weighted-average remaining lease term 12 years 13 years Weighted-average discount rate 12.03 % 12.05 % (1) Includes sale-leaseback transactions entered into prior to January 1, 2019. The costs related to our leases were as follows: Year Ended December 31, 2024 2023 2022 Operating Leases Operating lease costs $ 12,945 $ 9,416 $ 8,372 Financing Leases Amortization expense 2,104 2,103 2,104 Interest on lease liabilities 1,752 1,804 2,147 Total financing lease costs 3,856 3,907 4,251 Total lease costs $ 16,801 $ 13,323 $ 12,623 Supplemental cash flow information related to our leases was as follows: Year Ended December 31, 2024 2023 Cash paid for amounts included in the measurement of operating lease liabilities $ 19,428 $ 10,724 Right-of-use assets obtained in exchange for new operating lease liabilities (1) $ 29,808 $ 25,225 (1) Includes non-monetary lease transactions of $10,378 and $13,941 for the years ended December 31, 2024 and 2023, respectively. See disclosure below for additional information. The table below sets forth our estimated minimum future lease obligations under our leases: Operating Leases Financing Leases Year ended December 31, 2025 $ 14,527 $ 1,899 2026 9,702 2,054 2027 8,565 1,923 2028 7,174 1,955 2029 5,521 1,892 Thereafter 73,464 14,043 Total minimum lease payments $ 118,953 $ 23,766 Less: interest 48,938 10,862 Present value of lease liabilities $ 70,015 $ 12,904 Non-monetary Lease Transactions We have six lease liabilities consisting of payment obligations that will be settled with non-monetary consideration. The lease liabilities relating to non-monetary consideration were recorded during the year end December 31, 2024 based on the fair market value of the project services or back up power expected to be provided, as noted below. In January 2023, a 37-year land lease commenced with the Navy, which expires in 2059. We are working to complete an In-Kind Consideration Project (“IKCP”), which the Navy will credit as consideration towards our lease obligation upon the Navy’s final acceptance of the IKCP. In August 2023, we acquired an energy asset project and assumed the related 30-year land lease agreement with the United States Army (“Army”), which commenced in 2022 and expires in 2052. We are providing backup power as a stand ready obligation as consideration towards our lease obligation. In January 2024, we acquired four energy asset projects and assumed the related 35 to 37-year land leases agreements with the Navy, which expire between 2053 and 2056. We are working to complete IKCPs, which the Navy will credit as consideration towards our lease obligation upon the Navy’s final acceptance of the IKCP. We have a future lease commitment for a project lease with the United States Navy (“Navy”) which has not yet met the criteria for recording a right-of-use (“ROU”) asset or ROU liability. The estimated net present value of this commitment totals $161,169 as of December 31, 2024. We will provide IKCPs, over a thirty-six-year period, which the Navy will credit as consideration towards our lease obligation upon the Navy’s final acceptance of the IKCPs. Once the lease commences, the ROU asset and liability will be recorded, most likely in 2025. See Note 7 Energy Assets, Net for additional information on the energy asset projects acquired. Financing Leases We entered into sale-leaseback arrangements for solar PV energy assets prior to January 1, 2019, which remain under the previous guidance. The following table presents a summary of amounts related to these sale-leasebacks included in our consolidated balance sheets: December 31, 2024 2023 Deferred loss, short-term, net 115 115 Deferred loss, long-term, net 1,224 1,340 Total deferred loss $ 1,339 $ 1,455 Deferred gain, short-term, net 345 345 Deferred gain, long-term, net 3,739 4,085 Total deferred gain $ 4,084 $ 4,430 Net gains from amortization expense in cost of revenues related to deferred gains and losses were $230, $230 and $383 for the years ended December 31, 2024, 2023, and 2022, respectively. Sale-leasebacks These facilities are accounted for as failed sales and are classified as long-term financing facilities. August 2018 Master Sale-leaseback During the year ended December 31, 2024, we entered into an amended and restated participation agreement which extended the current maturity date to March 31, 2025. We sold and leased back six energy assets for $61,996 in cash proceeds under this facility during the year ended December 31, 2024. The agreements have interest rates ranging from 0% to 1.86%, as a result of tax credits which were transferred to the counterparty. During the year ended December 31, 2024, we discovered a defect in a Battery Energy Storage System (“BESS”) that we installed for a customer under a long-term power purchase agreement for a project financed under the August 2018 master sale-leaseback agreement. As a result, the BESS had to be removed. Our financing partner has agreed to temporarily waive any events of default and refrain from pursuing remedies available under the master sale-leaseback associated with the BESS failure until December 31, 2025 to allow remediation of the issue (subject to certain conditions). We have fully funded lease payments due under the master lease agreement through December 31, 2025 into a reserve account from which lease payments will be made. December 2020 Master Sale-leaseback We enter into amendments to our December 2020 master lease and participation agreement from to time to time, which may extend the maturity date, increase the availability, or modify other covenants. We were in default under this agreement as we had failed to satisfy the insurance requirements and historical coverage ratio under this agreement. On May 3, 2024, we received a waiver on this default. As of December 31, 2023, no further funding was available under this lending commitment. August 2024 Master Sale-leaseback On April 18, 2023 we entered into lease agreements with two investors for one energy asset and on August 14, 2024 we sold and leased back the energy asset for $234,788, of which 50% was allocated to each investor under these agreements. One lease has an expiration date of August 14, 2034 with an option to extend to August 14, 2044 while the other has an expiration date of August 14, 2044. At closing, we incurred $2,833 in lenders’ fees and debt issuance costs. In August 2024, we used $140,844 of the proceeds to pay off the April 2023 construction credit facility and made rent prepayments of $60.1 million. As of December 31, 2024, we have no available funds remaining under this lending commitment. See Note 9 for additional information on these financing facilities.
Leases	LEASES We enter into a variety of operating lease agreements through the normal course of business including certain administrative offices. The leases are long-term, non-cancelable real estate lease agreements, expiring at various dates through fiscal 2032. The agreements generally provide for fixed minimum rental payments and the payment of utilities, real estate taxes, insurance, and repairs. We also lease vehicles, IT equipment and certain land parcels related to our energy projects, expiring at various dates through fiscal 2061. The office and land leases make up a significant portion of our operating lease activity. Many of these leases have one or more renewal options that allow us, at our discretion, to renew the lease for six months to seven years. Only renewal options that we believed were likely to be exercised were included in our lease calculations. Many land leases include minimum lease payments that commence or increase when the related project becomes operational. In these cases, we estimated the commercial operation date used to calculate the ROU asset and minimum lease payments. A portion of our real estate leases are generally subject to annual changes in the Consumer Price Index (“CPI”). We utilized each lease’s minimum lease payments to calculate the lease balances upon transition. The subsequent increases in rent based on changes in CPI were excluded and will be excluded for future leases from the calculation of the lease balances but will be recorded to the consolidated statements of income as part of our operating lease costs. The discount rate was calculated using an incremental borrowing rate based on financing rates on secured comparable notes with comparable terms and a synthetic credit rating calculated by a third party. We elected to apply the discount rate using the remaining lease term at the date of adoption. We also enter into leases for service agreements and other leases related to our construction projects such as equipment, mobile trailers, and other temporary structures. We utilize the portfolio approach for this class of lease, which are either short-term leases or are not material. Rent and related expenses were as follows: Year Ended December 31, 2024 2023 2022 Rent and related expenses $ 13,945 $ 10,504 $ 9,199 We have a number of leases that are classified as financing leases, which related to transactions that were considered sale-leasebacks under ASC 840. See the sale-leaseback section below for additional information on our financing leases. The table below sets forth supplemental balance sheet information related to leases: December 31, 2024 2023 Operating Leases Right-of-use assets, net $ 80,149 $ 58,586 Current portions of operating lease liabilities $ 10,536 $ 13,569 Long-term operating lease liabilities, net of current portion 59,479 42,258 Total operating lease liabilities $ 70,015 $ 55,827 Weighted-average remaining lease term 19 years 18 years Weighted-average discount rate 6.6 % 6.6 % Financing Leases (1) Energy assets, net $ 25,158 $ 27,262 Current portions of financing lease liabilities $ 637 $ 871 Long-term financing lease liabilities, net of current portion, unamortized discount and debt issuance costs 12,267 13,057 Total financing lease liabilities $ 12,904 $ 13,928 Weighted-average remaining lease term 12 years 13 years Weighted-average discount rate 12.03 % 12.05 % (1) Includes sale-leaseback transactions entered into prior to January 1, 2019. The costs related to our leases were as follows: Year Ended December 31, 2024 2023 2022 Operating Leases Operating lease costs $ 12,945 $ 9,416 $ 8,372 Financing Leases Amortization expense 2,104 2,103 2,104 Interest on lease liabilities 1,752 1,804 2,147 Total financing lease costs 3,856 3,907 4,251 Total lease costs $ 16,801 $ 13,323 $ 12,623 Supplemental cash flow information related to our leases was as follows: Year Ended December 31, 2024 2023 Cash paid for amounts included in the measurement of operating lease liabilities $ 19,428 $ 10,724 Right-of-use assets obtained in exchange for new operating lease liabilities (1) $ 29,808 $ 25,225 (1) Includes non-monetary lease transactions of $10,378 and $13,941 for the years ended December 31, 2024 and 2023, respectively. See disclosure below for additional information. The table below sets forth our estimated minimum future lease obligations under our leases: Operating Leases Financing Leases Year ended December 31, 2025 $ 14,527 $ 1,899 2026 9,702 2,054 2027 8,565 1,923 2028 7,174 1,955 2029 5,521 1,892 Thereafter 73,464 14,043 Total minimum lease payments $ 118,953 $ 23,766 Less: interest 48,938 10,862 Present value of lease liabilities $ 70,015 $ 12,904 Non-monetary Lease Transactions We have six lease liabilities consisting of payment obligations that will be settled with non-monetary consideration. The lease liabilities relating to non-monetary consideration were recorded during the year end December 31, 2024 based on the fair market value of the project services or back up power expected to be provided, as noted below. In January 2023, a 37-year land lease commenced with the Navy, which expires in 2059. We are working to complete an In-Kind Consideration Project (“IKCP”), which the Navy will credit as consideration towards our lease obligation upon the Navy’s final acceptance of the IKCP. In August 2023, we acquired an energy asset project and assumed the related 30-year land lease agreement with the United States Army (“Army”), which commenced in 2022 and expires in 2052. We are providing backup power as a stand ready obligation as consideration towards our lease obligation. In January 2024, we acquired four energy asset projects and assumed the related 35 to 37-year land leases agreements with the Navy, which expire between 2053 and 2056. We are working to complete IKCPs, which the Navy will credit as consideration towards our lease obligation upon the Navy’s final acceptance of the IKCP. We have a future lease commitment for a project lease with the United States Navy (“Navy”) which has not yet met the criteria for recording a right-of-use (“ROU”) asset or ROU liability. The estimated net present value of this commitment totals $161,169 as of December 31, 2024. We will provide IKCPs, over a thirty-six-year period, which the Navy will credit as consideration towards our lease obligation upon the Navy’s final acceptance of the IKCPs. Once the lease commences, the ROU asset and liability will be recorded, most likely in 2025. See Note 7 Energy Assets, Net for additional information on the energy asset projects acquired. Financing Leases We entered into sale-leaseback arrangements for solar PV energy assets prior to January 1, 2019, which remain under the previous guidance. The following table presents a summary of amounts related to these sale-leasebacks included in our consolidated balance sheets: December 31, 2024 2023 Deferred loss, short-term, net 115 115 Deferred loss, long-term, net 1,224 1,340 Total deferred loss $ 1,339 $ 1,455 Deferred gain, short-term, net 345 345 Deferred gain, long-term, net 3,739 4,085 Total deferred gain $ 4,084 $ 4,430 Net gains from amortization expense in cost of revenues related to deferred gains and losses were $230, $230 and $383 for the years ended December 31, 2024, 2023, and 2022, respectively. Sale-leasebacks These facilities are accounted for as failed sales and are classified as long-term financing facilities. August 2018 Master Sale-leaseback During the year ended December 31, 2024, we entered into an amended and restated participation agreement which extended the current maturity date to March 31, 2025. We sold and leased back six energy assets for $61,996 in cash proceeds under this facility during the year ended December 31, 2024. The agreements have interest rates ranging from 0% to 1.86%, as a result of tax credits which were transferred to the counterparty. During the year ended December 31, 2024, we discovered a defect in a Battery Energy Storage System (“BESS”) that we installed for a customer under a long-term power purchase agreement for a project financed under the August 2018 master sale-leaseback agreement. As a result, the BESS had to be removed. Our financing partner has agreed to temporarily waive any events of default and refrain from pursuing remedies available under the master sale-leaseback associated with the BESS failure until December 31, 2025 to allow remediation of the issue (subject to certain conditions). We have fully funded lease payments due under the master lease agreement through December 31, 2025 into a reserve account from which lease payments will be made. December 2020 Master Sale-leaseback We enter into amendments to our December 2020 master lease and participation agreement from to time to time, which may extend the maturity date, increase the availability, or modify other covenants. We were in default under this agreement as we had failed to satisfy the insurance requirements and historical coverage ratio under this agreement. On May 3, 2024, we received a waiver on this default. As of December 31, 2023, no further funding was available under this lending commitment. August 2024 Master Sale-leaseback On April 18, 2023 we entered into lease agreements with two investors for one energy asset and on August 14, 2024 we sold and leased back the energy asset for $234,788, of which 50% was allocated to each investor under these agreements. One lease has an expiration date of August 14, 2034 with an option to extend to August 14, 2044 while the other has an expiration date of August 14, 2044. At closing, we incurred $2,833 in lenders’ fees and debt issuance costs. In August 2024, we used $140,844 of the proceeds to pay off the April 2023 construction credit facility and made rent prepayments of $60.1 million. As of December 31, 2024, we have no available funds remaining under this lending commitment. See Note 9 for additional information on these financing facilities.

Debt and Financing Lease Liabil

Debt and Financing Lease Liabilities	12 Months Ended
	Dec. 31, 2024
Debt Disclosure [Abstract]
Debt and Financing Lease Liabilities	DEBT AND FINANCING LEASE LIABILITIES Debt was comprised of the following: As of December 31, 2024 2023 Senior secured credit facility, 7.90%, due January 2024 to December 2028 (1) (2) (8) $ 148,000 $ 279,900 Second lien term loan, 10.57%, due June 2029 (1) (2) (8) 100,000 — Energy Asset Construction Facilities June 2020, 6.14%, due March 2025 (2) (8) $ 20,385 $ 20,705 April 2023, 6.82%, due July 2024 — 134,415 August 2023, 8.53%, due December 2027 (1) (2) (8) 318,824 278,858 August 2023, 6.33%, due February 2024 — 36,270 Subtotal energy asset construction facilities $ 339,209 $ 470,248 Energy Asset Operating Facilities October 2011 fixed rate 6.11% due June 2028 (5) $ 1,417 $ 1,976 October 2012 variable rate 7.22%, due June 2025 (4) (8) 31,660 34,453 September 2015 variable rate 6.54%, due March 2028 (4) (8) 13,271 13,747 August 2016 fixed rate 4.95%, due June 2031 (4) 1,813 2,253 April 2017 fixed rate 5.61%, due February 2034 (4) 1,128 1,348 June 2017 variable rate 7.14%, due December 2027 (4) (8) 4,944 7,158 June 2018 fixed rate 5.15%, due December 2038 (2) (4) 18,883 21,063 June 2018 variable rate 6.74%, due June 2033 (2) (8) (3) 5,500 6,592 October 2018 variable rate 7.20%, due October 2029 (2) (8) (5) 5,264 6,145 November 2020 fixed rate 3.58%, due December 2027 (4) 1,400 2,004 June 2021 fixed rate 4.92%, due June 2045 (4) 3,154 3,489 July 2021 fixed rate 3.25%, due March 2046 (2) (4) 33,214 35,090 July 2021 variable rate 8.34%, due July 2030 (2) (4) (8) — 2,140 June 2022 fixed rate 5.45%, due March 2042 (2) (4) 5,942 6,395 October 2022 fixed rate 6.70%, due August 2039 (2) (4) 362,583 349,093 March 2023 fixed rate 5.99%, due, December 2047 (2) (4) 21,290 21,984 August 2023 seller's promissory note, 5.00%, due January 2024 — 28,294 August 2023 fixed rate 5.83%, due April 2047 (2) 12,290 3,520 April 2024 fixed rate 6.20%, due June 2042 (2) (4) 89,846 — April 2024 fixed rate 8.00%, due June 2042 (2) (4) 12,566 — February 2024 variable rate 6.33%, due April 2030 (2) (4) 34,605 — Various Enerqos financing facilities 13,934 17,786 Subtotal energy asset operating facilities $ 674,704 $ 564,530 Sale-leasebacks August 2018 master sale-leaseback, 0.00% to 1.86%, due July 2039 to December 2049 (3) (6) $ 205,565 $ 163,504 December 2020 master sale-leaseback, 0.00%, due December 2040 to March 2043 (4) (6) 21,111 22,194 August 2024 master sale-leaseback, 0.00%, due August 2034 to August 2044 (2) (4)(6) 172,694 — Subtotal sale-leasebacks $ 399,370 $ 185,698 Financing Leases (7) $ 12,904 $ 13,928 Total debt and financing leases $ 1,674,187 $ 1,514,304 Less: current maturities, net of unamortized discount 149,363 322,247 Less: unamortized discount and debt issuance costs 40,924 21,982 Long-term debt and financing lease liabilities, net of current portion, unamortized discount and debt issuance costs $ 1,483,900 $ 1,170,075 (1) Facility has interest at varying rates monthly or quarterly in arrears. (2) These agreements have acceleration causes that, in the event of default, as defined, the payee has the option to accelerate payment terms and make the remaining principal and the required interest balance due according to the agreement. (3) Facility is payable in semi-annual installments. (4) Facility is payable in quarterly installments. (5) Facility is payable in monthly installments. (6) These agreements are sale-leaseback arrangements and are accounted for as failed sales under the guidance and are classified as financing liabilities. See Note 8. (7) Financing leases are sale-leaseback arrangements under previous guidance and do not include approximately $10,862 in future interest payments as of December 31, 2024 and $12,468 as of December 31, 2023. See Note 8. (8) These agreements are now using the Secured Overnight Financing Rate (“SOFR”) as the primary reference rate used to calculate interest. The following table presents the aggregate maturities of long-term debt and financing leases as of December 31, 2024: 2025 $ 149,363 2026 78,201 2027 395,886 2028 206,115 2029 167,686 Thereafter 676,936 Total maturities $ 1,674,187 Senior Secured Credit Facility - Revolver and Term Loans During the years ended December 31, 2023 and 2024, we entered into a number of amendments to the fifth amended and restated senior secured credit facility. At December 31, 2023 and 2024 (unless further amended as noted below), the major terms of the senior secured credit facility were as follows: • the aggregate amount of total commitments was $495,000, • the aggregate amount of the revolving commitments was $200,000, • the aggregate amount of the delayed draw term loan A (“DDTLA”) commitment was $220,000, • increased the existing term loan A to $75,000, • extended the maturity date of the DDTLA and modified the payment schedule such that the last payment was due on April 15, 2024, • a debt service coverage ratio (as defined in the agreement) of at least 1.5 to 1.0, • increased the total funded debt to EBITDA covenant ratio from a maximum of 3.50 to 3.75 for the quarter ending December 31, 2023, and 3.50 thereafter, • the overall rate table for all loans under the current agreement was also increased by 0.25%, • the maximum indebtedness incurred under an energy conservation project financing reverted back to $650,000, • the revolving credit facility may be increased up to an additional $100,000 in increments of at least $25,000 at the approval of lenders, subject to certain conditions, and • a covenant was also added that required Ameresco to use commercially reasonable efforts assuming normal market conditions to raise and, by April 15, 2024, close on a minimum of $100,000 equity or subordinated debt financing if the Cathode site under the Southern California Edison (“SCE”) contract does not achieve substantial completion by January 31, 2024, which was not achieved. Net proceeds from such financing would be required to be used to repay outstanding amounts on the senior secured credit facility. We are the sole borrower under the credit facility. The obligations under the credit facility are guaranteed by certain of our direct and indirect wholly owned domestic subsidiaries and are secured by a pledge of all of Ameresco’s and such subsidiary guarantors’ assets, other than the equity interests of certain subsidiaries and assets held in non-core subsidiaries (as defined in the agreement). On April 10, 2024, we entered into amendment number five to the fifth amended and restated senior secured credit facility to extend the maturity date of the DDTLA from April 15, 2024 to August 15, 2024. The amendment also included the following modifications: • principal installments on the DDTLA of $5,000 at closing of the amendment and $7,500 each on or before May 15, 2024, June 15, 2024, and July 15, 2024, with the balance of $7,500 due on August 15, 2024, • the date by which we shall use commercially reasonable efforts to raise $100,000 in equity or subordinated debt financing was changed from April 15, 2024 to May 15, 2024. On June 28, 2024, we entered into amendment number six to the fifth amended and restated senior secured credit facility to modify certain of the covenants and other terms to permit us to enter into the second lien credit agreement (as defined below) and to incur indebtedness and make certain other conforming changes in connection with our entry into the second lien credit agreement. The remaining balance on the DDTLA of $15,000 was paid off with the proceeds from the second lien credit agreement. On January 23, 2025, we refinanced our term loan and revolving credit facility by enteri ng into a sixth amended and restated senior secured credit agreement (“Restated Credit Agreement”) with the lenders party thereto. At closing we paid approximately $2,000 in lender’s fees. The restated credit amendment replaces and extends Ameresco's existing credit agreement dated March 4, 2022, and subsequently amended (the “Original Credit Agreement”). The Restated Credit Agreement refinance the credit facilities under the Original Credit Agreement and replaced it with the following facilities: • a $225,000 revolving credit facility, maturing on December 28, 2028, and • a $100,000 term loan A, maturing on December 28, 2028. The revolver may be increased by up to an additional $100,000 at Ameresco's option if lenders are willing to provide such increased commitments, subject to certain conditions. The table below sets forth amounts outstanding under the senior secured credit facility: Rate as of December 31, 2024 As of December 31, 2024 2023 Revolving credit facility 7.99 % $ 135,000 $ 139,900 Term loan A 6.96 % 13,000 75,000 Delayed draw term loan A — % — 65,000 Total senior secured credit facility outstanding 148,000 279,900 Less: unamortized debt discount and debt issuance costs (177) (884) Total senior secured credit facility outstanding, net $ 147,823 $ 279,016 As of December 31, 2024, funds of $21,099 were available for borrowing under the revolving credit facility and we had $14,554 in letters of credit outstanding. We expect to use the remaining funds available under the credit facility for general corporate purposes, including permitted acquisitions, refinancing of existing indebtedness and working capital. The interest rate for borrowings under the credit facility is based on (i) each term loan shall bear interest at the term SOFR for such interest period plus the applicable rate for such facility; (ii) each base rate loan shall bear interest at a rate per annum equal to the base rate plus the applicable rate; (iii) each alternative currency daily rate loan shall bear at a rate per annum equal to the alternative currency daily rate plus the applicable rate; (iv) each alternative currency term rate loan shall bear interest at a rate per annum equal to the alternative currency term rate for such interest period plus the applicable rate; and (v) each swingline loan shall bear interest at a rate per annum equal to the base rate plus the applicable rate. The revolving credit facility does not require amortization of principal. The term loan requires quarterly principal payments of $1,250 which began in the first quarter of 2024, with the balance due at maturity. All borrowings may be paid before maturity in whole or in part at our option without penalty or premium, other than reimbursement of any breakage and deployment costs in the case of LIBOR borrowings. The credit facility limits Ameresco’s and our subsidiaries’ ability to, among other things: incur additional indebtedness; incur liens or guarantee obligations; merge, liquidate or dispose of assets; make acquisitions or other investments; enter into hedging agreements; pay dividends and make other distributions and engage in transactions with affiliates, except in the ordinary course of business on an arms’ length basis. Under the credit facility, Ameresco and our core domestic subsidiaries may not invest cash or property in, or loan to, our non-core subsidiaries in aggregate amounts exceeding 49% of our consolidated stockholders’ equity. In addition, we and our core subsidiaries must maintain a ratio of total funded debt to EBITDA and a debt service coverage ratio as noted above. Any failure to comply with the financial or other covenants of the credit facility would not only prevent us from being able to borrow additional funds, but would constitute a default, permitting the lenders to, among other things, accelerate the amounts outstanding, including all accrued interest and unpaid fees, under the credit facility, to terminate the credit facility, and enforce liens against the collateral. The credit facility also includes several other customary events of default, including a change in control of Ameresco, permitting the lenders to accelerate the indebtedness, terminate the credit facility, and enforce liens against the collateral. For purposes of our senior secured facility, EBITDA, as defined, excludes the results of certain renewable energy projects that we own and for which financing from others remains outstanding; total funded debt, as defined, includes amounts outstanding under both the term loan and revolver portions of the senior secured credit facility plus other indebtedness, but excludes limited recourse indebtedness of project company subsidiaries; and debt service, as defined, includes principal and interest payments on the indebtedness included in total funded debt other than principal payments on the revolver portion of the facility. Second Lien Credit Facility - Term Loan On June 28, 2024, we entered into a second lien credit agreement which provided a term loan in a principal amount of $100,000 with a maturity date of June 28, 2029. The term loan bears an interest rate of SOFR (4.692% at December 31, 2024), plus an applicable margin of 5.875% per annum. Interest is payable quarterly and unpaid interest and principal is due in the aggregate on June 28, 2029. As of December 31, 2024, we incurred $5,124 in lenders fees and debt issuance costs. Proceeds from this term loan in the amount of $82,105 and $15,000 were used to pay towards our revolving credit facility and the outstanding portion of the DDTLA, respectively, under our senior secured credit facility at closing. Energy Asset Construction Facilities June 2020 Construction Revolver, 6.14%, due March 2025 In June 2020, we entered into a revolving construction loan agreement with a bank, with an aggregate borrowing capacity of $100,000 for use in financing the construction cost of our owned projects. During the year ended December 31, 2024, we entered into an amendment to extend this revolver and the current maturity date is March 2025. During the year ended December 31, 2024, we drew down $9,356 under this revolver and as of December 31, 2024, $20,385 was outstanding and $79,615 was available for borrowing. March 2023 Construction Credit Facility, 2.00% On March 31, 2023, we entered into a credit agreement for a construction facility with a total commitment of CAD$100,000 which has an availability period of five years. As of December 31, 2024, no funds were drawn under this facility. During the availability period the loans will bear interest at a fixed rate of 2.00% and during the operating period the rate will range from 1.00% to 3.00% as set forth in the agreement. The maturity date is the earlier of twenty years from project commencement date or one year prior to the termination date of the last remaining energy services agreements. April 2023 Construction Credit Facility, 6.82%, due July 2024 On April 18, 2023, one of our consolidated joint venture subsidiaries (“JV”) entered into a construction loan agreement with two lenders for a principal amount of up to $140,844 under an energy asset credit facility. At the closing, the JV drew down $90,921 for construction of an energy asset. We acquired the remaining interest in this JV in January 2024 when we closed on the acquisition of BCE. On July 31, 2024, we executed an extension on this facility updating the maturity date from July 31, 2024 to August 16, 2024. In connection with the August 2024 Sale-leaseback, as disclosed in Note 8, the loan was repaid in the amount of $140,844 when the energy asset project achieved provisional acceptance. August 2023 Construction Credit Facility, 8.53%, due December 2027 On August 18, 2023, we entered into a construction and development loan agreement which provides a loan in a principal amount of up to $300,000. At the closing, we drew down $200,000 under this facility, of which approximately $187,000 was used to reimburse Ameresco for development and construction costs. Prior to the amendment described below, the loan bore interest at a rate of 4.00% plus the greater of (i) Term SOFR for a one-month tenor and (ii) the 10-year United States treasury rate and a fee equal to 0.250% of any unused committed principal amount. The loan matured on August 31, 2026, with a one-year extension option that could be exercised if certain circumstances are met, including payment of a $3,000 extension fee. On December 18, 2024 we amended the 2023 construction and development loan agreement to increase the principal amount from $300,000 up to $400,000, extend the maturity date to December 15, 2027, and set a minimum rate of interest at 6.00% and a Term SOFR Floor of 2.00%. Additionally, an accordion option was added that would increase the principal amount to $500,000, for which we paid a $250 accordion option fee. The accordion option can be exercised no later than eighteen During the year ended December 31, 2024, we drew down $178,117 under this facility. As of December 31, 2024, $312,612 was outstanding, net of unamortized debt discount and issuance costs of $6,212. The obligations under the loan are guaranteed by all the related subsidiaries and are secured by the subsidiaries’ assets as well as our equity interest in the borrower entity and in the case of default under the facility, a default under our Senior Secured Credit Facility or a change in control of Ameresco, Inc., we are required to make capital contributions to the borrower entity who then would be required to use the proceeds from the capital contributions to repay the construction and development loan. Energy Asset Operating Facilities October 2022 Financing Facility, 6.70%, due August 2039 On May 31, 2023, we entered into the first amendment to the October 2022 loan agreement that increased the original commitment of $125,000 by an additional $90,000 to $215,000 and at closing we drew down the $90,000. The first amendment also contained the following amended terms: • The loan bears interest on the unpaid principal amount thereof from the date made through repayment at an interest rate of 6.38% per annum compared to the original rate of 6.50%. • The loan maturity date was changed from October 26, 2037 to May 31, 2038 On September 28, 2023, we amended and restated this facility to increase the maximum commitment from $215,000 to $500,000, to continue existing loans to project companies, to add certain renewable natural gas project companies to the loan portfolio, and to provide that additional wholly- and majority-owned project companies may be added to the loan portfolio subject to certain conditions. At the closing of the amendment and restatement, we drew down an additional $135,544 under the loan, which was used to pay transaction costs, reimburse project costs incurred by us, make other permitted distributions to Ameresco, and to fund the required reserve accounts. Subject to certain conditions, the facility allows for additional draws to be made up to the remaining principal amount to fund the construction and operation of renewable natural gas projects owned and operated by the project companies. The amendment and restatement also contained the following amended terms: • The loan bears interest at a rate of 6.70% with a residual percentage of distributable cash flows payable after the maturity date of the loan, until the earlier of the lender achieving an 8.51% internal rate of return (“IRR”) on funds borrowed under the facility, or the facility discharge date which was extended to August 31, 2049. • The loan maturity date was changed from May 31, 2038 to August 31, 2039 • All borrowings may be paid before maturity in whole or in part at RNG Holdings’ option after August 30, 2027 provided that the lender’s IRR is achieved, and against a prepayment of 102% of par for prepayments between August 31, 2027 and August 31, 2029 and 101% of par for prepayments between September 1, 2029 and August 30, 2031. No call premium applies for payments after August 30, 2031. At closing, we incurred lender’s fees of $509, which was recorded as debt discount, and $305 in debt issuance costs which were expensed in interest and other expenses, net during the year ended December 31, 2023. During the year ended December 31, 2024, we drew down an additional $38,280 under this facility. As of December 31, 2024, $361,666 was outstanding, net of unamortized debt discount and issuance costs of $917. March 2023 Term Shelf Notes 5.99%, due December 2047 under July 2021 Financing Facility On March 28, 2023, three senior secured notes (“Shelf Notes”) due December 31, 2047 were issued under our shelf facility, with gross proceeds of $22,625. The Shelf Notes bear interest at a fixed rate of 5.99% per annum and are payable quarterly commencing June 30, 2023. At closing, we incurred $282 in lender fees and debt issuance costs. In connection with the Shelf Notes, we recorded a derivative instrument for make-whole provisions with an initial value of $3,123, which was recorded as a debt discount. April 2024 Term Shelf Notes 6.20% and 8.00%, due June 30, 2042 under July 2021 Financing Facility On April 5, 2024, an omnibus amendment and reaffirmation agreement was executed with reference to the note purchase and private shelf agreement, dated as of July 27, 2021, and two new series B notes (first lien and second lien) were authorized in the amounts of $92,512 and $12,657, with a maturity date of June 30, 2042. Gross proceeds from the initial issuance on April 5, 2024 were $83,282 and $12,292 with the remainder of $9,595 issued on August 8, 2024 upon achieving certain permitting-related and other administrative conditions. The notes bear interest at fixed rates of 6.20% and 8.00%, respectively, per annum and the interest is payable quarterly and commenced September 30, 2024. At closing, we incurred $1,359 in lenders fees and debt issuance costs. Proceeds from the initial closing in the amount of $86,462 were used to pay a portion of the August 2023 construction credit facility. In connection with these notes, we recorded two derivative instruments for make-whole provisions with initial values of $8,733 and $647, respectively, which were recorded as debt discount. September 2015 Variable Rate Term Loan, 6.54% , due March 2028 On March 30, 2023, we entered into an amended and restated financing agreement (“Amended Agreement”) with the existing bank that extended the maturity date of the loan from March 30, 2023 to March 28, 2028. The Amended Agreement consists of a term loan of $14,084, an incremental term loan of $359 and a letter of credit of $899. The term loan bears interest at a variable rate, with interest payments due in quarterly installments. The rate at December 31, 2024 was 6.54% per annum. The remaining principal balance and unpaid interest is due March 28, 2028. As a result of this refinancing, we entered into a new interest rate swap contract with an initial notional amount of $14,084 and termination date of December 31, 2040. See Note 19 Derivative Instruments and Hedging Activities for additional information on this new swap contract. Debt Instruments - Energy Project Asset Acquisitions August 2023 Construction Revolver, 6.85% , due February 2024 and Seller’s Promissory Note, 5.00%, due January 2024 In connection with the acquisition of an energy asset on August 4, 2023 as discussed in Note 7, $46,694 was financed through a seller’s note and we assumed a construction loan in the amount of $36,270. The seller’s note in the amount of $29,441 was paid off in January 2024. On February 26, 2024, the construction loan in the amount of $36,270 was converted into the term loan described below. February 2024 Variable Rate Term Loan, 6.33%, due April 2030 On February 26, 2024 we converted the $36,270 construction loan into a term loan that bears a base SOFR interest rate of 6.33% at December 31, 2024, and an applicable margin of 1.635% per annum for four years after the term conversion date and 1.76% per annum for the following two years. The interest and principal are paid quarterly commencing on March 31, 2024. We failed to achieve the final conditions required to convert the term loan on or prior to June 30, 2024. We received a waiver and met the final conditions on August 14, 2024 and the current and non-current debt was classified accordingly at December 31, 2024. January 2024, Seller’s Promissory Note, 5.0%, due November 2024

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2024
Income Tax Disclosure [Abstract]
Income Taxes	INCOME TAXES The following table sets forth components of income before income taxes: Year Ended December 31, 2024 2023 2022 Domestic $ 28,256 $ 30,211 $ 98,004 Foreign 5,684 8,058 7,715 Income before income taxes $ 33,940 $ 38,269 $ 105,719 The components of the provision (benefit) for income taxes were as follows: Year Ended December 31, 2024 2023 2022 Current income tax provision (benefit): Federal $ 1,246 $ 34 $ (722) State 805 372 733 Foreign 2,414 1,255 1,202 Total current 4,465 1,661 1,213 Deferred income tax (benefit) provision: Federal (28,552) (22,677) 2,528 State 4,265 (5,657) 2,300 Foreign (178) 1,038 1,129 Total deferred (24,465) (27,296) 5,957 Total income tax (benefit) provision $ (20,000) $ (25,635) $ 7,170 Our deferred tax assets and liabilities result primarily from temporary differences between financial reporting and tax recognition of depreciation, energy efficiency, sale-leasebacks and other accruals, and net operating loss carryforwards. Deferred tax assets and liabilities consisted of the following: December 31, 2024 2023 Deferred income tax assets: Compensation accruals $ 5,622 $ 4,137 Reserves 8,009 5,906 Sale-leasebacks and other accruals 39,231 49,300 Net operating losses 9,882 28,565 Interest limitation 16,706 8,273 Energy efficiency 138,647 82,827 Deferred revenue 2,402 2,114 Gross deferred income tax assets 220,499 181,122 Valuation allowance (4,015) (3,704) Total deferred income tax assets $ 216,484 $ 177,418 Deferred income tax liabilities: Depreciation $ (148,217) $ (145,880) Deferred effect of derivative liability (5,606) (2,166) Outside basis difference (6,759) (6,599) Interest rate swaps (1,602) (841) Total deferred income tax liabilities (162,184) (155,486) Deferred income tax assets (liabilities), net $ 54,300 $ 21,932 Our valuation allowance related to the following items: December 31, 2024 2023 Foreign net operating loss (1) $ 4,013 $ 3,702 State net operating loss at one of our subsidiaries (2) 2 2 Total valuation allowance $ 4,015 $ 3,704 (1) It is more likely than not that we will not generate sufficient taxable income at the foreign subsidiary level to utilize the net operating loss. (2) It is more likely than not that we will not generate sufficient taxable income at the subsidiary level to utilize the net operating loss. As of December 31, 2024, we had the following tax loss and credit carryforwards to offset taxable income in prior and future years: Amount Expiration Period Federal net operating loss carryforwards $ — Indefinite State net operating loss carryforwards 72,865 Various Canadian net operating loss carryforwards 20,922 2028 through 2043 Ireland net operating loss carryforwards 2,110 Indefinite Italy net operating loss carryforwards 2,970 Indefinite Spain net operating loss carryforwards 2,463 Indefinite Other foreign country net operating loss carryforwards 127 2030 Total tax loss carryforwards $ 101,457 Federal Energy Investment and Production tax credit carryforward $ 114,839 2030 through 2043 The provision for income taxes is based on the various rates set by federal and local authorities and is affected by permanent and temporary differences between financial accounting and tax reporting requirements. The principle reason for the difference between the statutory rate and the estimated annual effective rate for 2024 were the effects of tax deductions related to the Section 179D Commercial Buildings Energy-Efficiency deduction and ITCs we are entitled from solar plants and renewable natural gas projects which have been placed into service during 2024. The Section 179D deduction available for 2024 was substantially lower compared to prior years due to timing of project completions. We also incurred additional tax expense from the deferred effect of an increase in our future effective state tax rates resulting from apportionment changes. The principle reason for the difference between the statutory rate and the estimated annual effective rate for 2023 were the effects of tax deductions related to the Section 179D Commercial Buildings Energy-Efficiency deduction, ITCs we are entitled from solar plants which have been placed into service during 2023 and, the deferred benefit for a reduction in future state taxes. The Section 179D deduction available for 2023 was substantially higher compared to prior years because of enhancements to Section 179D in the IRA. In addition, we were able to identify and document a large Section 179D eligible from a prior year that had not previously been available. We also benefited from the deferred effect of a reduction in our future state tax rates resulting from apportionment changes in a major state. The ITCs and production tax credits we may be entitled to fluctuate from year to year based on the cost of the renewable energy plants we place in service and production levels at facilities we own in that year. On December 27, 2020 the President signed the Consolidated Appropriations Act, 2021 H.R. 133, which among other things made the Section 179D Energy Efficient Commercial Building Deduction permanent. The Section had previously been extended for years up to December 31, 2020. That Act also made changes to the way in which the deduction is calculated including adding an inflation adjustment and an update of the American Society of Heating, Refrigerating and Air-Conditioning Engineers (“ASHRAE”) Standard by which energy improvements are measured. On December 23, 2022, the IRS issued Announcement 2023-1 which clarified the ASHRAE energy efficiency standards which will be applied to projects placed in service for 2021 and 2022. The following is a reconciliation of the effective tax rates: Year Ended December 31, 2024 2023 2022 Income before (benefit) provision for income taxes $ 33,940 $ 38,269 $ 105,719 Federal statutory tax expense $ 7,128 $ 8,036 $ 22,201 State income taxes, net of federal benefit 2,345 (774) 3,844 Net state impact of deferred rate change 2,919 (3,213) (575) Nondeductible expenses 1,182 667 2,198 Impact of reserve for uncertain tax positions (265) (200) 59 Stock-based compensation expense 1,240 4 353 Energy efficiency preferences (38,929) (30,359) (21,410) Foreign items and rate differential 2,629 458 37 State tax adjustment — (66) — Redeemable non-controlling interests 729 (227) (411) Valuation allowance 311 81 (159) Miscellaneous 711 (42) 1,033 Total income tax (benefit) provision $ (20,000) $ (25,635) $ 7,170 Effective tax rate: Federal statutory rate expense 21.0 % 21.0 % 21.0 % State income taxes, net of federal benefit 6.9 % (2.0) % 3.6 % Net state impact of deferred rate change 8.6 % (8.4) % (0.5) % Nondeductible expenses 3.5 % 1.7 % 2.1 % Impact of reserve for uncertain tax positions (0.8) % (0.5) % 0.1 % Stock-based compensation expense 3.7 % — % 0.3 % Energy efficiency preferences (114.7) % (79.3) % (20.3) % Foreign items and rate differential 7.7 % 1.2 % — % State tax adjustment — % (0.2) % — % Redeemable non-controlling interests 2.1 % (0.6) % (0.4) % Valuation allowance 0.9 % 0.2 % (0.2) % Miscellaneous 2.2 % (0.1) % 1.1 % Effective tax rate (58.9) % (67.0) % 6.8 % The following table provides a reconciliation of gross unrecognized tax benefits which are included in other liabilities within the consolidated balance sheets: Year Ended December 31, 2024 2023 Balance, beginning of year $ 800 $ 900 Additions for current year tax positions 104 100 Reductions of prior year tax positions — (200) Balance, end of year $ 904 $ 800 The amount of unrecognized tax benefits that, if recognized, would favorably affect the effective income tax rate in any future periods was $904 as of December 31, 2024 and $310 as of December 31, 2023 (both net of the federal benefit on state amounts). We do not accrue U.S. tax for foreign earnings that we consider to be permanently reinvested outside the United States. Consequently, we have not provided any withholding tax on the unremitted earnings of our foreign subsidiaries. As of December 31, 2024 and 2023, we estimated that there were no earnings for which repatriation tax has not been provided. The tax years 2021 through 2024 remain open to examination by major taxing jurisdictions. We recognize interest and penalties related to uncertain tax positions as components of our income tax provision (benefit) in our consolidated statements of income. We increased income tax expense for these items by $29 in 2024, $22 in 2023, and $22 in 2022.

Variable Interest Entities and

Variable Interest Entities and Equity Method Investments	12 Months Ended
	Dec. 31, 2024
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Variable Interest Entities and Equity Method Investments	VARIABLE INTEREST ENTITIES AND EQUITY METHOD INVESTMENTS Investment Funds Over a period of five years (2015 through 2019), we formed five investment funds (tax equity partnerships) with third party investors which granted the applicable investor ownership interests in the net assets of certain of our renewable energy project subsidiaries. As of December 31, 2024, we had one such investment funds each with a different third-party investor. We consolidate the investment funds, and all inter-company balances and transactions between Ameresco and the investment funds are eliminated in our consolidated financial statements. We determined that the investment funds meet the definition of a VIE. We use a qualitative approach in assessing the consolidation requirement for VIEs that focuses on determining whether we have the power to direct the activities of the VIE that most significantly affect the VIE’s economic performance and whether we have the obligation to absorb losses or the right to receive benefits that could potentially be significant to the VIE. We have considered the provisions within the contractual arrangements that grant us power to manage and make decisions that affect the operation of these VIEs, including determining the solar energy systems and associated long term customer contracts to be sold or contributed to the VIEs, and installation, operation, and maintenance of the solar energy systems. We considered the rights granted to the other investors under the contractual arrangements to be more protective in nature rather than participating rights. As such, we determined that we are the primary beneficiary of the VIEs for all periods presented. We evaluate our relationships with VIEs on an ongoing basis to ensure that we continue to be the primary beneficiary. Under the related agreements, cash distributions of income and other receipts by the funds, net of agreed-upon expenses and estimated expenses, tax benefits and detriments of income and loss, and tax benefits of tax credits, are assigned to the funds’ investor and our subsidiaries as specified in contractual arrangements. Certain of these arrangements have call and put options to acquire the investor’s equity interest as specified in the contractual agreements. See Note 12 for additional information about these investment funds and the call and put options. Other Variable Interest Entities We execute certain contracts jointly with third parties through various forms of joint ventures. Although the joint ventures own and hold the contracts with the clients, the services required by the contracts are typically performed by us and our joint venture partners, or by other subcontractors under subcontracting agreements with the joint ventures. Many of these joint ventures are formed for a specific project. The assets of these joint ventures generally consist almost entirely of cash and land, and the liabilities of our joint ventures generally consist almost entirely of amounts due to the joint venture partners. We follow guidance on the consolidation of VIEs that requires companies to utilize a qualitative approach to determine whether it is the primary beneficiary of a VIE. The process for identifying the primary beneficiary of a VIE requires consideration of the factors that indicate a party has the power to direct the activities that most significantly impact the joint ventures economic performance, including powers granted to the joint ventures program manager, powers contained in the joint venture governing board and, to a certain extent, a company's economic interest in the joint venture. We analyze our joint ventures and classify them as either: • a VIE that must be consolidated because we are the primary beneficiary or the joint venture is not a VIE and we hold the majority voting interest with no significant participative rights available to the other partners, or • a VIE that does not require consolidation and is treated as an equity or cost method investment because we are not the primary beneficiary, or the joint venture is not a VIE and we do not hold the majority voting interest. Many of our joint ventures are deemed to be VIEs because they lack sufficient equity to finance the activities of the joint venture. The table below presents a summary of amounts related to our VIEs reflected in Note 1 on our consolidated balance sheets: As of December 31, 2024 2023 Investment Fund Other VIEs Total VIEs Investment Fund Other VIEs Total VIEs Cash and cash equivalents $ 89 $ 8,691 $ 8,780 $ 5,099 $ 16,780 $ 21,879 Accounts receivable, net — 14,607 14,607 — 1,977 1,977 Unbilled revenue 230 4,040 4,270 662 13,409 14,071 Prepaid expenses and other current assets 30 1,293 1,323 33 3,749 3,782 Income taxes receivable — 672 672 — — — Project development costs, net — 5,795 5,795 — — — Total VIE current assets 349 35,098 35,447 5,794 35,915 41,709 Property and equipment, net — — — — 267 267 Energy assets, net 23,538 98,876 122,414 79,104 173,808 252,912 Intangible assets, net — 20 20 — — — Right-of-use assets, net 471 — 471 4,748 12,908 17,656 Restricted cash, non-current portion — — — 73 — 73 Other assets — 196 196 10 74 84 Total VIE assets $ 24,358 $ 134,190 $ 158,548 $ 89,729 $ 222,972 $ 312,701 Current portions of long-term debt and financing lease liabilities $ — $ — $ — $ 2,190 $ 132,427 $ 134,617 Accounts payable 27 5,140 5,167 1,440 6,490 7,930 Accrued expenses and other current liabilities 25 577 602 241 22,780 23,021 Current portions of right-of-use liabilities 13 — 13 133 6,953 7,086 Deferred revenue — 10,063 10,063 — — — Income taxes payable — 526 526 — — — Total VIE current liabilities 65 16,306 16,371 4,004 168,650 172,654 Long-term debt and financing lease liabilities, net of current portion, unamortized discount and debt issuance costs — — — 17,167 — 17,167 Long-term right-of-use liabilities, net of current portion 500 — 500 5,063 3,823 8,886 Other liabilities — — — 356 — 356 Total VIE liabilities $ 565 $ 16,306 $ 16,871 $ 26,590 $ 172,473 $ 199,063 Non-controlling Interests Non-controlling interests represents the equity owned by the other joint venture members of consolidated joint ventures. On February 9, 2024, we entered into an agreement to sell a 40% interest in an energy asset, thus forming a joint venture, and we received $28,864 in cash. We also received additional contributions totaling $6,543 as of December 31, 2024. During the twelve months ended December 31, 2024, we acquired the remaining interest in one joint venture when we closed on the phase 2 acquisition of BCE as discussed in Note 7. Equity and Cost Method Investments Unconsolidated VIEs/joint ventures are accounted for under the equity or cost method. As of the years ended December 31, 2024 and December 31, 2023, we had seven unconsolidated joint ventures. During the year ended December 31, 2024, one of our equity method investments was sold to another company. We received distributions and net proceeds totaling $13,091 and recognized a gain on the sale in the amount of $224, which is included in earnings from unconsolidated entities in the consolidated statements of income. Our investment balances for these equity and cost method investments are included in other assets on the consolidated balance sheets and our pro rata share of net income or loss is included in operating income in the consolidated statements of income. The following table sets forth the carrying value of our equity and cost method investments in joint ventures: As of December 31, 2024 2023 Equity and cost method investments $ 16,987 $ 18,709 We are not aware of any situations where the maximum exposure to loss significantly exceeds the carrying value show above.

Redeemable Non-Controlling Inte

Redeemable Non-Controlling Interests	12 Months Ended
	Dec. 31, 2024
Equity, Attributable to Parent [Abstract]
Redeemable Non-Controlling Interests	REDEEMABLE NON-CONTROLLING INTERESTS Our subsidiaries with membership interests in the investment funds we formed have the right to elect to require the non-controlling interest holder to sell all of its membership units to our subsidiaries, a call option. Our investment funds also include rights for the non-controlling interest holder to elect to require our subsidiaries to purchase all of the non-controlling membership interests in the fund, a put option. In December 2024 we finalized our purchase of the investor’s membership interests of two investment funds for $3,186 in cash and reclassified the remaining redeemable non-controlling interest balance of $37,269 to paid-in capital to reflect the additional contribution from us to our wholly-owned subsidiaries. Therefore, we have one investment fund remaining and the following table sets forth information about the call and put options for our investment fund outstanding as of December 31, 2024: Call Option Put Option Investment Fund Number Formation Date Start Date End Date Purchase Price Start Date End Date Purchase Price 1 December 2019 March 2026 September 2026 (1) September 2026 September 2027 (2) (1) Purchase price is equal to the greater of (i) the fair market value of such interests at the time the option is exercised or (ii) 5% of the investors’ contributed capital balance at the time the option is exercisable. The call options are exercisable beginning on the date that specified conditions are met for each respective fund. These dates are estimate and subject to change based on last funding date. (2) Purchase price is the lessor of fair market value at the time the option is exercised and the sum of (i) 5% of the investors’ contributed capital balance at the time the option is exercisable, and (ii) the fair market value of any unpaid tax law change losses incurred by the investor in connection with the exercise of the put option. The call options are exercisable beginning on the date that specified conditions are met for the fund. Because the put options represent redemption features that are not solely within our control, the non-controlling interest in this fund is presented outside of permanent equity. Redeemable non-controlling interests are reported using the greater of their carrying value (which is impacted by attribution under the HLBV method) or their estimated redemption value at each reporting period. At both December 31, 2024 and 2023, redeemable non-controlling interests were reported in the accompanying consolidated balance sheets at their carrying values, as the carrying value at each reporting period was greater than the estimated redemption value.

Equity and Earnings Per Share

Equity and Earnings Per Share	12 Months Ended
	Dec. 31, 2024
Earnings Per Share [Abstract]
Equity and Earnings Per Share	EQUITY AND EARNINGS PER SHARE Common and Preferred Stock The rights of the holders of our Class A common stock and Class B common stock are identical, except with respect to voting and conversion. Each share of our Class A common stock is entitled to one vote per share and is not convertible into any other shares of our capital stock. Each share of our Class B common stock is entitled to five votes per share, is convertible at any time into one share of Class A common stock at the option of the holder of such share and will automatically convert into one share of Class A common stock upon the occurrence of certain specified events, including a transfer of such shares (other than to such holder’s family members, descendants or certain affiliated persons or entities). Our Board of Directors is authorized to fix the rights and terms for any series of preferred stock without additional shareholder approval. Earnings Per Share The following is a reconciliation of the numerator and denominator for the computation of basic and diluted earnings per share: Year Ended December 31, 2024 2023 2022 Numerator: Net income attributable to common shareholders $ 56,757 $ 62,470 $ 94,926 Adjustment for accretion of tax equity financing fees (107) (108) (116) Income attributable to common shareholders $ 56,650 $ 62,362 $ 94,810 Denominator: Basic weighted-average shares outstanding 52,380 52,140 51,841 Effect of dilutive securities: Stock options 760 1,087 1,437 Diluted weighted-average shares outstanding 53,140 53,228 53,278 Net income per share attributable to common shareholders: Basic $ 1.08 $ 1.20 $ 1.83 Diluted $ 1.07 $ 1.17 $ 1.78 Potentially dilutive shares (1) 2,154 1,707 1,108 (1) Potentially dilutive shares attributable to stock options were excluded from the computation of diluted earnings per share as the effect would have been anti-dilutive.

Stock-Based Compensation and Ot

Stock-Based Compensation and Other Employee Benefits	12 Months Ended
	Dec. 31, 2024
Share-Based Payment Arrangement [Abstract]
Stock-Based Compensation and Other Employee Benefits	STOCK-BASED COMPENSATION AND OTHER EMPLOYEE BENEFITS Our 2020 Stock Incentive Plan (the “2020 Plan”), was adopted by our Board of Directors in February 2020 and approved by our stockholders in May 2020. The 2020 Plan provides for the grant of incentive stock options, non-statutory stock options, stock appreciation rights, RSUs, and other stock-based awards. As of December 31, 2024, there were 1,380 shares available for grant under the 2020 Plan. Stock Options We did not grant awards to individuals who were not either an employee or director of ours during the years ended December 31, 2024, 2023, and 2022. The following table summarizes the collective activity under the plan: Number of Options Weighted-Average Exercise Price Weighted-Average Remaining Contractual Term Aggregate Intrinsic Value Outstanding at December 31, 2023 4,255 $ 46.932 Granted 792 23.280 Exercised (97) 9.666 Forfeited (227) 63.059 Expired (86) 46.675 Outstanding at December 31, 2024 4,637 $ 42.895 6.4 years $ 15,174 Options exercisable at December 31, 2024 2,098 $ 29.495 4.8 years $ 13,932 Expected to vest as of December 31, 2024 2,538 $ 53.970 7.8 years $ 1,242 The following table sets forth additional disclosures about our plan: Year Ended December 31, 2024 2023 2022 Aggregate intrinsic value of options exercised $ 1,602 $ 8,511 $ 9,775 Cash received from stock option exercises $ 942 $ 2,438 $ 3,954 Weighted-average fair value of stock options granted $ 14.16 $ 23.99 $ 37.87 Stock-based compensation expense (1) $ 14,130 $ 10,318 $ 15,046 Income tax benefit from stock-based compensation expense $ 105 $ 1,102 $ 659 (1) Included in selling, general, and administrative expenses in the accompanying consolidated statements of income and includes expense in connection with our ESPP and RSUs. Under the terms of our 2020 Plan, all options expire if not exercised within ten years after the grant date. We typically award options that vest over a five-year period on an annual ratable basis. From time to time, we award options providing for vesting over three years, with one-third vesting on each of the first three anniversaries of the grant date. If the employee ceases to be employed by us for any reason before vested options have been exercised, the employee has 90 days to exercise options that have vested as of the date of such employee’s termination, or they are forfeited. We use the Black-Scholes option pricing model to determine the weighted-average fair value of options granted. We recognize the compensation cost of stock-based awards on a straight-line basis over the requisite service period of the award. The determination of the fair value of stock-based payment awards utilizing the Black-Scholes model is affected by the stock price and a number of assumptions, including expected volatility, expected life, risk-free interest rate and expected dividends. The following table sets forth the significant assumptions used in the model: Year Ended December 31, 2024 2023 2022 Expected dividend yield —% —% —% Risk-free interest rate 3.78% -4.45% 3.35%-4.44% 1.69%-3.82% Expected volatility 58%-62% 54%-56% 51%-53% Expected life 6.5 years 6.5 years 6.5 years We will continue to use judgment in evaluating the expected term and volatility related to stock-based compensation on a prospective basis and incorporate these factors into the Black-Scholes pricing model. We record forfeitures as they occur. Higher volatility and longer expected lives result in an increase to stock-based compensation expense determined at the date of grant. As of December 31, 2024, there was approximately $28,019 of unrecognized compensation expense related to non-vested stock option awards and RSUs that is expected to be recognized over a weighted-average period of 1.9 years. Restricted Stock Units During the year ended December 31, 2024, we granted awards of RSUs to our employees and non-employee directors under our 2020 Plan. These RSUs represent a promise to deliver shares to participants at a future date after certain vesting conditions are met. RSUs do not have the voting rights of common stock and the shares underlying RSUs are not considered issued and outstanding upon grant. The fair value of RSUs is based on the closing stock price of our common stock on the grant-date and expensed over the requisite service period of the award. The following table summarizes the activity under the plan: Number of Options Weighted-Average Grant Date Fair Value Per Share Outstanding at December 31, 2023 52 $ 45.90 Granted 122 24.38 Vested (63) 37.60 Forfeited (6) 27.98 Outstanding at December 31, 2024 105 $ 27.02 Total stock-based compensation expense for the year ended December 31, 2024 related to RSUs was $2,685. As of December 31, 2024, 63 of the RSUs were vested and there was $1,721 of unrecognized compensation expense related to RSUs that is expected to be recognized over a period of approximately one year. Employee Stock Purchase Plan Our 2017 Employee Stock Purchase Plan permits eligible employees to purchase up to an aggregate of 200 shares of the Company’s Class A common stock. In May 2020, we amended our ESPP, which permits eligible employees to purchase up to an aggregate of 350 shares of our Class A common stock. This plan commenced December 1, 2017 and was subsequently amended in August 2018. The ESPP allows participants to purchase shares of common stock at a 5% discount from the fair market value of the stock as determined on specific dates at six-month intervals. During the years ended December 31, 2024 and 2023, we issued 64 and 60 shares, respectively, under the ESPP. As of December 31, 2024 and 2023, the amount that had been withheld from employees for future purchases under the ESPP was $99 and $182, respectively. Other Employee Benefits We maintain a qualified 401(k) plan covering eligible U.S. employees who have completed the minimum service requirement, as defined by the plans. The plans require us to contribute 100% of the first six percent of base compensation that a participant contributes to the plans. In 2016, we established a Group Personal Pension Plan for employees in the United Kingdom, for eligible employees who may contribute a portion of their compensation, subject to their age and other limitations established by HM Revenue & Customs. The plan requires us to contribute 100% of the first six percent of base compensation that a participant contributes to the plans. We also have a Registered Retirement Savings Plan for employees in Canada, for eligible employees who may contribute a portion of their compensation. The plan requires us to contribute 100% of the first six percent of base compensation that a participant contributes to the plans. The following table sets forth our matching contributions under the plans: Year Ended December 31, 2024 2023 2022 401(k) plan $ 8,090 $ 7,561 $ 6,974 Group Personal Pension Plan 574 652 290 Registered Retirement Savings Plan 454 429 406 Total matching contributions $ 9,118 $ 8,642 $ 7,670

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2024
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	COMMITMENTS AND CONTINGENCIES From time to time, we issue letters of credit and performance bonds with our third-party lenders, to provide collateral. Legal Proceedings We are involved in a variety of other claims and other legal proceedings generally incidental to our normal business activities. When we conclude that it is probable that a liability has been incurred and the amount of the liability can be reasonably estimated, it is accrued through a charge to earnings and, if material, disclosed below. When only a range of amounts is reasonably estimable and no amount within the range is more likely than another, the low end of the range is recorded. While the ultimate amount of liability incurred in any of these matters is dependent on future developments, in our opinion, the recorded liability is adequate to cover the future payment of such liability and claims. However, the final outcome of any of these claims and legal proceedings cannot be predicted with certainty, and unfavorable or unexpected outcomes could result in additional accruals that could be significant to results of operations in a particular year or quarter. Any adjustments to the recorded liability will be reflected in earnings in the periods in which such adjustments become known. For any other claims where a loss may be reasonably possible, but not probable, or is probable but not reasonably estimable, no accrual is established, but the matter, if potentially material, is disclosed below. We routinely review relevant information with respect to our matters and update our accruals, disclosures and estimates of reasonably possible loss based on such reviews. While the outcome of any of these matters cannot be accurately predicted, we do not believe the ultimate resolution of any of these existing matters would have a material adverse effect on our financial condition or results of operations. In October 2021, we entered into a contract with Southern California Edison (“SCE”) to design and build three grid scale BESS at three sites near existing substation parcels throughout SCE’s service territory in California with an aggregate capacity of 537.5 MW (“the SCE Agreement”). As previously disclosed, due to supply chain delays, weather and other events, we were unable to complete the projects by August 1, 2022 (the “Guaranteed Completion Date”) and made related force majeure claims. In late 2022, SCE also instructed us to adjust the completion of the sites into 2023. Under the SCE Agreement, a failure to reach the Guaranteed Completion Date could, under certain circumstances, result in liquidated damages up to a maximum amount of $89 million being applied. On August 30 2024, we reached an agreement with SCE on the substantial completion of two out of three battery energy storage system projects. We received approximately $110 million on September 5, 2024 as milestone payments, reflecting an offset of liquidated damages for these two projects. The agreement confirmed that the final resolution related to our obligation to pay the liquidated damages withheld and the applicability and scope of any force majeure relief as well as any cost recovery we may be entitled to remain subject to dispute. We are continuing discussions with SCE on these matters and our view continues to be that liquidated damages should not be applied. It is at least reasonably possible we may incur an obligation to pay liquidated damages up to the maximum amount. Commitments as a Result of Acquisitions In December 2021, we completed an acquisition of Plug Smart which provided for an earn-out based on future EBITDA targets beginning with EBITDA performance for the month of December 2021 and each fiscal year thereafter, over a five-year period through December 31, 2026. The maximum cumulative earn-out is $5,000 and we evaluated financial forecasts of the acquired business and concluded that the fair value of this earn-out was approximately $2,160 upon acquisition and remained consistent as of December 31, 2023. During the year ended December 31, 2023, a payment of $3,040 was made for the month of December 2022 EBITDA target. The fair value of the remaining contingent consideration was $1,614 at December 31, 2024. An increase of $149 in the fair value of contingent consideration was included in selling, general and administrative expenses in our consolidated statements of income during the year ended December 31, 2024. The current portion of the contingent consideration is included in accrued expenses and other current liabilities and the non-current portion is included in other liabilities on the consolidated balance sheets. The August 4, 2023 purchase and sale agreement with BCE includes a potential earn-out that could be earned if the projects achieve specified value thresholds in certain phase 2 projects, each of which is very early in development, or if milestones are achieved on other future projects that are not yet started. The total earn-out is limited to $40,000 over a seven-year period beginning on January 12, 2024. We will record a liability for the phase 2 earn-out payments when the amounts are probable and estimable. As of December 31, 2024, none of the earn-out amounts are considered probable and estimable and no payments have been made to date. See Notes 4 and 18 for additional information.

Geographic Information

Geographic Information	12 Months Ended
	Dec. 31, 2024
Segments, Geographical Areas [Abstract]
Geographic Information	GEOGRAPHIC INFORMATION The following table presents our long-lived assets related to our operations by geographic area: As of December 31, 2024 2023 Long-lived Tangible Assets United States $ 1,888,440 $ 1,670,322 Canada 20,509 23,549 Europe 17,402 12,948 Total long-lived assets $ 1,926,351 $ 1,706,819 We attribute revenues to customers based on the location of the customer. The following table presents revenues by geographic region: Year Ended December 31, 2024 2023 2022 Revenues United States $ 1,446,879 $ 1,161,775 $ 1,712,326 Canada 72,371 63,367 53,461 Europe 250,678 149,491 58,635 Total revenues $ 1,769,928 $ 1,374,633 $ 1,824,422 Our reportable segments for the year ended December 31, 2024 were North America Regions, U.S. Federal, Europe, and Renewable Fuels (formerly Alternative Fuels). On January 1, 2024, we changed the structure of our internal organization, and our U.S. Regions and Canada are now included in North America Regions. Additionally, our Asset Sustainability Group was formerly included in Canada, but is now included in “All Other”. As a result, previously reported amounts have been reclassified for comparative purposes. Our North America Regions, U.S. Federal, and Europe segments offer energy efficiency products and services which include the design, engineering, and installation of equipment and other measures to improve the efficiency and control the operation of a facility’s energy infrastructure, renewable energy solutions, and services which include the construction of small-scale plants that Ameresco owns or develops for customers that produce electricity, gas, heat, or cooling from renewable sources of energy and O&M services. Our Renewable Fuels segment sells electricity, processed renewable gas fuel, heat or cooling, produced from renewable sources of energy, other than solar, and generated by small-scale plants that we own and O&M services for customer owned small-scale plants. Our North America Regions segment also includes certain small-scale solar grid-tie plants developed for customers. The “All Other” category offers consulting services and the sale of solar PV energy products and systems which we refer to as integrated-PV. These segments do not include results of other activities, such as corporate operating expenses not specifically allocated to the segments. Certain reportable segments are an aggregation of operating segments. Our Chief Executive Officer and President is our chief operating decision maker (“CODM”). The CODM is responsible for making operating decisions, allocating resources, and assessing performance of the business segments. The CODM uses the segments’ income before income taxes as the profitability measure in making these decisions. For the years ended December 31, 2024, 2023, and 2022, 67.3%, 71.8%, and 46.0%, respectively, of our revenues have been derived from federal, state, provincial, or local government entities, including public housing authorities, public universities and municipal utilities. The U.S. federal government, which is considered a single customer for reporting purposes, constituted 21.0%, 29.3%, and 21.5% of our consolidated revenues for the years ended December 31, 2024, 2023, and 2022, respectively. Revenues from the U.S. federal government are included in our U.S. Federal segment. The reports of our CODM do not include assets at the operating segment level. The table below presents our business segment information and reconciliation to our consolidated financial statements for the years ending December 31: North America Regions U.S. Federal Renewable Fuels Europe All Other Corporate Total 2024 Revenues $ 878,828 $ 372,536 $ 173,342 $ 250,574 $ 94,648 $ 1,769,928 Cost of revenues 773,205 313,413 136,720 227,163 63,336 1,513,837 Gross profit 105,623 59,123 36,622 23,411 31,312 256,091 Add: Earnings from unconsolidated entities 51 687 — 54 — — 792 Gain on sale of business, net — — — — 38,007 — 38,007 Less: Selling, general and administrative expenses 50,985 13,064 2,909 16,951 22,203 67,649 173,761 Asset impairments 527 — 9,233 — — 2,624 12,384 Loss (gain) on derivatives 193 (1,083) (137) — — — (1,027) Interest expense, net of interest income 9,894 4,982 25,552 4,271 (1) 20,333 65,031 Other expenses 3,172 883 460 1,467 34 4,785 10,801 Income before income taxes 40,903 41,964 (1,395) 776 47,083 (95,391) 33,940 Other Non-cash Segment Disclosures: Depreciation and intangible asset amortization (1) 36,400 14,206 31,968 2,090 2,684 1,863 89,211 Amortization of debt discount & debt issuance costs (1) 2,056 883 460 — — 1,752 5,151 (1) These amounts disclosed by reportable segment are included within the other segment expense captions. North America Regions U.S. Federal Renewable Fuels Europe All Other Corporate Total 2023 Revenues 616,434 402,884 117,075 149,354 88,886 1,374,633 Cost of revenues 515,986 340,989 87,819 123,215 60,195 1,128,204 Gross profit 100,448 61,895 29,256 26,139 28,691 246,429 Add: Earnings from unconsolidated entities — 1,758 — — — — 1,758 Less: Selling, general and administrative expenses 51,161 12,090 4,383 14,110 21,969 58,425 162,138 Asset impairments 2,222 — 1,609 — — — 3,831 (Gain) loss on derivatives (2,461) 857 496 — — — (1,108) Interest expense, net of interest income 7,003 1,429 16,019 2,477 (6) 9,247 36,169 Other expenses 1,654 11 533 5,915 75 700 8,888 Income before income taxes 40,869 49,266 6,216 3,637 6,653 (68,372) 38,269 Other Non-cash Segment Disclosures: Depreciation and intangible asset amortization (1) $ 28,682 $ 5,343 $ 26,160 $ 2,082 $ 1,861 $ 1,783 $ 65,911 Amortization of debt discount & debt issuance costs (1) 2,444 50 533 — — 1,174 4,201 North America Regions U.S. Federal Renewable Fuels Europe All Other Corporate Total 2022 Revenues 1,173,281 391,891 114,459 58,410 86,381 1,824,422 Cost of revenues 1,020,266 329,527 78,359 46,808 58,629 1,533,589 Gross profit 153,015 62,364 36,100 11,602 27,752 290,833 Add: Earnings from unconsolidated entities — 1,647 — — — — 1,647 Less: Selling, general and administrative expenses 57,401 11,757 2,962 6,626 18,640 62,102 159,488 Asset impairments — — — — — — — (Gain) loss on derivatives (506) — 294 — — — (212) Interest expense, net of interest income 7,865 1,231 8,657 24 (3) 7,955 25,729 Other (income) expenses (580) 157 1,198 (150) 7 1,124 1,756 Income before income taxes 88,835 50,866 22,989 5,102 9,108 (71,181) 105,719 Other Non-cash Segment Disclosures: Depreciation and intangible asset amortization (1) 23,152 4,905 23,354 275 746 1,846 54,278 Amortization of debt discount & debt issuance costs (1) 1,712 157 1,198 — — 1,144 4,211 (1) These amounts disclosed by reportable segment are included within the other segment expense captions. See Note 3 for additional information about our revenues by product line.

Interest And Other Expenses, Ne

Interest And Other Expenses, Net	12 Months Ended
	Dec. 31, 2024
Other Income and Expenses [Abstract]
Other Expenses, Net	INTEREST AND OTHER EXPENSES, NET The following table presents the components of interest and other expenses, net: Year Ended December 31, 2024 2023 2022 Gain on derivatives $ (1,027) $ (1,108) $ (906) Interest expense, net of interest income 65,031 36,169 26,423 Amortization of debt discount and debt issuance costs 5,151 4,201 4,211 Foreign currency transaction loss (gain) 3,840 (581) 144 Government incentives 339 (576) (2,599) Bank discount fees 1,471 5,844 — Interest and other expenses, net $ 74,805 $ 43,949 $ 27,273 Estimated amortization expense for existing debt discount and debt issuance costs for the next five succeeding fiscal years is as follows: Estimated Amortization 2025 $ 6,128 2026 $ 5,898 2027 $ 6,334 2028 $ 3,805 2029 $ 3,105

Fair Value Measurement

Fair Value Measurement	12 Months Ended
	Dec. 31, 2024
Fair Value Disclosures [Abstract]
Fair Value Measurement	FAIR VALUE MEASUREMENT We recognize certain financial assets and liabilities at fair value on a recurring basis (at least annually). Fair value is defined as the price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. Three levels of inputs that may be used to measure fair value are as follows: Level 1: Inputs are based on unadjusted quoted prices for identical instruments traded in active markets. Level 2: Inputs are based on quoted prices for similar instruments in active markets, quoted prices for identical or similar instruments in markets that are not active, and model-based valuation techniques for which all significant assumptions are observable in the market or can be corroborated by observable market data for substantially the full term of the assets or liabilities. Level 3: Inputs are generally unobservable and typically reflect management’s estimates of assumptions that market participants would use in pricing the asset or liability. The fair values are therefore determined using model-based techniques that include option pricing models, discounted cash flow models, and similar techniques. The following table presents the input level used to determine the fair values of our financial instruments measured at fair value on a recurring basis: Fair Value as of December 31, Level 2024 2023 Assets Interest rate swap instruments 2 $ 5,096 $ 3,970 Liabilities Interest rate swap instruments 2 $ — $ 629 Make-whole provisions 2 15,574 6,012 Contingent consideration 3 1,614 1,465 Total liabilities $ 17,188 $ 8,106 The fair value of our interest rate swaps was determined using cash flow analysis on the expected cash flow of the contract in combination with observable market-based inputs, including interest rate curves and implied volatility. As part of this valuation, we considered the credit ratings of the counterparties to the interest rate swaps to determine if a credit risk adjustment was required. The fair value of our make-whole provisions was determined by comparing them against the rates of similar debt instruments under similar terms without a make-whole provision obtained from various highly rated third-party pricing sources. The fair value of our contingent consideration liabilities was determined by evaluating the acquired asset’s future financial forecasts and evaluating which, if any, of the cumulative revenue targets, financial metrics and/or milestones are likely to be met. We classified contingent consideration related to certain acquisitions within level 3 of the fair value hierarchy because the fair value is derived using significant unobservable inputs, which include discount rates, probability-weighted cash flows, and volatility. We determined the fair value of our contingent consideration obligations based on a probability-weighted income approach derived from financial performance estimates and probability assessments of the attainment of certain targets for some acquisitions. For other acquisitions, we derived the fair value of contingent consideration using a Monte Carlo simulation in an option pricing framework. We established discount rates utilized in our valuation models based on the cost to borrow that would be required by a market participant for similar instruments. In determining the probability of attaining certain technical, financial and operational targets, we utilized data regarding similar milestone events from our own experience, while considering the inherent difficulties and uncertainties in developing a product. On a quarterly basis, we reassess the probability factors associated with the financial, operational, and technical targets for our contingent consideration obligations. Significant judgment is employed in determining the appropriateness of these assumptions as of the acquisition date and for each subsequent period. We derived the fair value of the contingent consideration of $2,160 from the acquisition of Plug Smart in December 2021 using a Monte Carlo simulated model. The key assumptions used in the model include two scenarios of EBITDA projections, a base case and a higher case, a risk-adjusted discount rate of 16.9%, and estimated EBITDA volatility of 70.0%. The balances and subsequent key assumptions used in the model were as follows: At December 31, 2024 2023 Balance of remaining contingent consideration $ 1,614 $ 1,465 Risk-adjusted discount rate 16.9 % 16.9 % Estimated EBITDA volatility 70.0 % 70.0 % The balance of contingent consideration from the acquisition of certain assets of Chelsea Group Limited was decreased to $0 at December 31, 2023 from $358 at December 31, 2022 as the cumulative revenue earn-out targets were not achieved and the term expired. The following table sets forth a summary of changes in the fair value of contingent consideration liabilities classified as level 3: Year Ended December 31, 2024 2023 Contingent consideration liabilities balance at the beginning of year $ 1,465 $ 4,158 Changes in fair value included in earnings 149 347 Payment of contingent consideration — (3,040) Contingent consideration liabilities balance at the end of year $ 1,614 $ 1,465 The fair value of financial instruments is determined by reference to observable market data and other valuation techniques, as appropriate. Long-term debt is the only category of financial instruments where the difference between fair value and recorded book value is notable. At December 31, 2024 and 2023, the fair value of our long-term debt was estimated using discounted cash flows analysis, based on our current incremental borrowing rates for similar types of borrowing arrangements which are considered to be level two inputs. There have been no transfers in or out of level two or three for the years ended December 31, 2024 and 2023. The following table sets forth the fair value and the carrying value of our long-term debt, excluding financing leases: December 31, 2024 December 31, 2023 Fair Value Carrying Value Fair Value Carrying Value Long-term debt value (level 2) $ 1,618,208 $ 1,620,359 $ 1,466,458 $ 1,478,394 We are also required to periodically measure certain other assets at fair value on a nonrecurring basis, including long-lived assets, goodwill, and other intangible assets. We calculated the fair value used in our annual goodwill impairment analysis utilizing a discounted cash flow analysis and determined that the inputs used were level 3 inputs. Other than intangible assets acquired from the Enerqos acquisition, as noted in Note 4, there were no other assets recorded at fair value on a non-recurring basis as of December 31, 2024 or 2023.

Derivative Instruments and Hedg

Derivative Instruments and Hedging Activities	12 Months Ended
	Dec. 31, 2024
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative Instruments and Hedging Activities	DERIVATIVE INSTRUMENTS AND HEDGING ACTIVITIES During the twelve months ended December 31, 2023, we adopted ASU 2020-04, Reference Rate Reform, for six interest rate swap contracts with the transition from LIBOR to SOFR as the reference rate. In March 2023, we dedesignated one interest rate swap contract for a previous loan facility and entered into a new interest rate swap contract to hedge $14,084 of the extended loan facility. The new interest rate swap was designated as a cash flow hedge. In June 2023, we prepaid one loan facility and terminated the related swap prior to its maturity date. In August 2023, we acquired one interest rate swap through an energy asset project acquisition. This interest rate swap was not designated as an effective hedge and we recorded the change in the valuation in interest and other expenses, net in our consolidated statements of income. See Note 7 for additional information about this energy asset project acquisition. The following table presents information about the fair value amounts of our derivative instruments: Derivatives as of December 31, 2024 2023 Balance Sheet Location Fair Value Fair Value Derivatives Designated as Hedging Instruments Interest rate swap contracts Other assets $ 1,556 $ 1,023 Derivatives Not Designated as Hedging Instruments Interest rate swap contracts Other assets $ 3,540 $ 2,947 Interest rate swap contracts Other liabilities $ — $ 629 Make-whole provisions Other liabilities $ 15,574 $ 6,012 As of December 31, 2024 and 2023, all but three of our freestanding derivatives were designated as hedging instruments. The following tables present information about the effects of our derivative instruments on the consolidated statements of income and consolidated statements of comprehensive income: Location of (Gain) Loss Recognized in Net Income Amount of (Gain) Loss Recognized in Net Income for the Year Ended December 31, 2024 2023 2022 Derivatives Designated as Hedging Instruments Interest rate swap contracts Interest and other expenses, net $ (994) $ (770) $ 1,037 Derivatives Not Designated as Hedging Instruments Interest rate swap contracts Interest and other expenses, net $ (1,220) $ 1,354 $ (2,738) Commodity swap contracts Interest and other expenses, net $ — $ — $ 2,338 Make-whole provisions Interest and other expenses, net $ 193 $ (2,462) $ (506) The following table presents the changes in AOCI, net of taxes, from our hedging instruments: Years ended December 31, 2024 2023 Derivatives Designated as Hedging Instruments: Accumulated gain in AOCI at the beginning of the year $ 746 $ 1,284 Unrealized gain recognized in AOCI 1,388 232 Gain reclassified from AOCI to interest and other expenses, net (994) (770) Gain (loss) on derivatives 394 $ (538) AOCI at the end of the year $ 1,140 $ 746 The following tables present all of our active derivative instruments as of December 31, 2024: Active Interest Rate Swaps Expiration Date Initial Notional Amount ($) Status 11-Year, 5.77% Fixed October 2029 $ 9,200 Designated 15-Year, 5.24% Fixed June 2033 $ 10,000 Designated 10-Year, 4.74% Fixed December 2027 $ 14,100 Designated 8-Year, 3.49% Fixed June 2028 $ 14,643 Designated 8-Year, 3.49% Fixed June 2028 $ 10,734 Designated 13-Year, 0.72% Fixed March 2033 $ 9,505 Not Designated 13-Year, 0.72% Fixed March 2033 $ 6,968 Not Designated 17.75-Year, 3.16% Fixed December 2040 $ 14,084 Designated 18-Year, 3.81% Fixed July 2041 $ 32,021 Not Designated Other Derivatives Classification Effective Date Expiration Date Fair Value ($) Make-whole provisions Liability June/August 2018 December 2038 $ 348 Make-whole provisions Liability August 2016 April 2031 $ 35 Make-whole provisions Liability April 2017 February 2034 $ 28 Make-whole provisions Liability November 2020 December 2027 $ 18 Make-whole provisions Liability October 2011 May 2028 $ 4 Make-whole provisions Liability May 2021 April 2045 $ 78 Make-whole provisions Liability July 2021 March 2046 $ 2,158 Make-whole provisions Liability June 2022 March 2042 $ 885 Make-whole provisions Liability March 2023 December 2047 $ 1,968 Make-whole provisions Liability April 2024 June 2042 $ 9,442 Make-whole provisions Liability April 2024 June 2042 $ 609

Business Segment Information

Business Segment Information	12 Months Ended
	Dec. 31, 2024
Segment Reporting [Abstract]
Business Segment Information	GEOGRAPHIC INFORMATION The following table presents our long-lived assets related to our operations by geographic area: As of December 31, 2024 2023 Long-lived Tangible Assets United States $ 1,888,440 $ 1,670,322 Canada 20,509 23,549 Europe 17,402 12,948 Total long-lived assets $ 1,926,351 $ 1,706,819 We attribute revenues to customers based on the location of the customer. The following table presents revenues by geographic region: Year Ended December 31, 2024 2023 2022 Revenues United States $ 1,446,879 $ 1,161,775 $ 1,712,326 Canada 72,371 63,367 53,461 Europe 250,678 149,491 58,635 Total revenues $ 1,769,928 $ 1,374,633 $ 1,824,422 Our reportable segments for the year ended December 31, 2024 were North America Regions, U.S. Federal, Europe, and Renewable Fuels (formerly Alternative Fuels). On January 1, 2024, we changed the structure of our internal organization, and our U.S. Regions and Canada are now included in North America Regions. Additionally, our Asset Sustainability Group was formerly included in Canada, but is now included in “All Other”. As a result, previously reported amounts have been reclassified for comparative purposes. Our North America Regions, U.S. Federal, and Europe segments offer energy efficiency products and services which include the design, engineering, and installation of equipment and other measures to improve the efficiency and control the operation of a facility’s energy infrastructure, renewable energy solutions, and services which include the construction of small-scale plants that Ameresco owns or develops for customers that produce electricity, gas, heat, or cooling from renewable sources of energy and O&M services. Our Renewable Fuels segment sells electricity, processed renewable gas fuel, heat or cooling, produced from renewable sources of energy, other than solar, and generated by small-scale plants that we own and O&M services for customer owned small-scale plants. Our North America Regions segment also includes certain small-scale solar grid-tie plants developed for customers. The “All Other” category offers consulting services and the sale of solar PV energy products and systems which we refer to as integrated-PV. These segments do not include results of other activities, such as corporate operating expenses not specifically allocated to the segments. Certain reportable segments are an aggregation of operating segments. Our Chief Executive Officer and President is our chief operating decision maker (“CODM”). The CODM is responsible for making operating decisions, allocating resources, and assessing performance of the business segments. The CODM uses the segments’ income before income taxes as the profitability measure in making these decisions. For the years ended December 31, 2024, 2023, and 2022, 67.3%, 71.8%, and 46.0%, respectively, of our revenues have been derived from federal, state, provincial, or local government entities, including public housing authorities, public universities and municipal utilities. The U.S. federal government, which is considered a single customer for reporting purposes, constituted 21.0%, 29.3%, and 21.5% of our consolidated revenues for the years ended December 31, 2024, 2023, and 2022, respectively. Revenues from the U.S. federal government are included in our U.S. Federal segment. The reports of our CODM do not include assets at the operating segment level. The table below presents our business segment information and reconciliation to our consolidated financial statements for the years ending December 31: North America Regions U.S. Federal Renewable Fuels Europe All Other Corporate Total 2024 Revenues $ 878,828 $ 372,536 $ 173,342 $ 250,574 $ 94,648 $ 1,769,928 Cost of revenues 773,205 313,413 136,720 227,163 63,336 1,513,837 Gross profit 105,623 59,123 36,622 23,411 31,312 256,091 Add: Earnings from unconsolidated entities 51 687 — 54 — — 792 Gain on sale of business, net — — — — 38,007 — 38,007 Less: Selling, general and administrative expenses 50,985 13,064 2,909 16,951 22,203 67,649 173,761 Asset impairments 527 — 9,233 — — 2,624 12,384 Loss (gain) on derivatives 193 (1,083) (137) — — — (1,027) Interest expense, net of interest income 9,894 4,982 25,552 4,271 (1) 20,333 65,031 Other expenses 3,172 883 460 1,467 34 4,785 10,801 Income before income taxes 40,903 41,964 (1,395) 776 47,083 (95,391) 33,940 Other Non-cash Segment Disclosures: Depreciation and intangible asset amortization (1) 36,400 14,206 31,968 2,090 2,684 1,863 89,211 Amortization of debt discount & debt issuance costs (1) 2,056 883 460 — — 1,752 5,151 (1) These amounts disclosed by reportable segment are included within the other segment expense captions. North America Regions U.S. Federal Renewable Fuels Europe All Other Corporate Total 2023 Revenues 616,434 402,884 117,075 149,354 88,886 1,374,633 Cost of revenues 515,986 340,989 87,819 123,215 60,195 1,128,204 Gross profit 100,448 61,895 29,256 26,139 28,691 246,429 Add: Earnings from unconsolidated entities — 1,758 — — — — 1,758 Less: Selling, general and administrative expenses 51,161 12,090 4,383 14,110 21,969 58,425 162,138 Asset impairments 2,222 — 1,609 — — — 3,831 (Gain) loss on derivatives (2,461) 857 496 — — — (1,108) Interest expense, net of interest income 7,003 1,429 16,019 2,477 (6) 9,247 36,169 Other expenses 1,654 11 533 5,915 75 700 8,888 Income before income taxes 40,869 49,266 6,216 3,637 6,653 (68,372) 38,269 Other Non-cash Segment Disclosures: Depreciation and intangible asset amortization (1) $ 28,682 $ 5,343 $ 26,160 $ 2,082 $ 1,861 $ 1,783 $ 65,911 Amortization of debt discount & debt issuance costs (1) 2,444 50 533 — — 1,174 4,201 North America Regions U.S. Federal Renewable Fuels Europe All Other Corporate Total 2022 Revenues 1,173,281 391,891 114,459 58,410 86,381 1,824,422 Cost of revenues 1,020,266 329,527 78,359 46,808 58,629 1,533,589 Gross profit 153,015 62,364 36,100 11,602 27,752 290,833 Add: Earnings from unconsolidated entities — 1,647 — — — — 1,647 Less: Selling, general and administrative expenses 57,401 11,757 2,962 6,626 18,640 62,102 159,488 Asset impairments — — — — — — — (Gain) loss on derivatives (506) — 294 — — — (212) Interest expense, net of interest income 7,865 1,231 8,657 24 (3) 7,955 25,729 Other (income) expenses (580) 157 1,198 (150) 7 1,124 1,756 Income before income taxes 88,835 50,866 22,989 5,102 9,108 (71,181) 105,719 Other Non-cash Segment Disclosures: Depreciation and intangible asset amortization (1) 23,152 4,905 23,354 275 746 1,846 54,278 Amortization of debt discount & debt issuance costs (1) 1,712 157 1,198 — — 1,144 4,211 (1) These amounts disclosed by reportable segment are included within the other segment expense captions. See Note 3 for additional information about our revenues by product line.

Assets Held For Sale

Assets Held For Sale	12 Months Ended
	Dec. 31, 2024
Discontinued Operations and Disposal Groups [Abstract]
Assets Held For Sale	ASSETS HELD FOR SALE During the year ended December 31, 2024, we entered into fifteen membership interest purchase agreements in which we sold energy assets designated as held for sale during 2024. We will continue to build the energy assets and recognize project revenues under their respective engineering, procurement, and construction (“EPC”) contracts. These assets had a carrying value of $69,806 at the time of the sale and during the year ended December 31, 2024, we recognized revenue of $87,465 and gross profit of $15,545 in the consolidated statements of income under the EPC contracts. During the year ended December 31, 2024, we identified five assets that previously met the criteria to be classified as held for sale, but we no longer have the intent to sell the assets. As of December 31, 2023, the carrying value of these assets was $33,851 with liabilities associated with assets classified as held for sale of $5,546. As a result of the change in circumstances, the balances for these assets were reclassified to held and used and the reclassification did not have a material impact to current period results. As of December 31, 2024, we determined that there were three energy asset projects under construction that were considered to be assets held for sale, since these assets were being marketed for sale and all the criteria to be classified as held for sale under ASC 360, Property, Plant and Equipment—Impairment or Disposal of Long-Lived Assets, had been met. Assets held for sale are measured at the lower of their carrying value or the fair value less cost to sell. The carrying value of these assets was $8,372, with liabilities directly associated with assets classified as held for sale of $771 as of December 31, 2024. During the year ended December 31, 2023, we determined that there were five energy asset projects under construction that were considered to be assets held for sale, since these assets were being marketed for sale and all the criteria to be classified as held for sale had been met. The carrying value of these assets was $38,404, with liabilities directly associated with assets classified as held for sale of $8,351 as of December 31, 2023. Assets held for sale are measured at the lower of their carrying value or the fair value less cost to sell. The table below reflects the assets and liabilities associated with assets held for sale by segment: December 31, 2024 December 31, 2023 North America Regions U.S. Federal Total North America Regions U.S. Federal Total Other assets $ 7,778 $ 401 $ 8,179 $ 18,895 $ 18,253 $ 37,148 Right-of-use assets, net 193 — 193 1,256 — 1,256 Assets classified as held for sale $ 7,971 $ 401 $ 8,372 $ 20,151 $ 18,253 $ 38,404 Accounts payable 482 — 482 5,418 601 6,019 Current portions of operating lease liabilities 11 — 11 14 — 14 Deferred revenue 60 — 60 — 1,088 1,088 Long-term operating lease liabilities, net of current portion 218 — 218 1,230 — 1,230 Liabilities directly associated with assets classified as held for sale $ 771 $ — $ 771 $ 6,662 $ 1,689 $ 8,351

Pay vs Performance Disclosure

Pay vs Performance Disclosure - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Pay vs Performance Disclosure
Net income attributable to common shareholders	$ 56,757	$ 62,470	$ 94,926

Insider Trading Arrangements

Insider Trading Arrangements	3 Months Ended	12 Months Ended
	Dec. 31, 2024 shares	Dec. 31, 2024 shares
Trading Arrangements, by Individual
Material Terms of Trading Arrangement		Director and Officer Trading Arrangements A portion of the compensation of our directors and officers (as defined in Rule 16a-1(f) under the Exchange Act) is in the form of equity awards and, from time to time, directors and officers engage in open-market transactions with respect to the securities acquired pursuant to such equity awards or other shares of Class A common stock held by such individuals, including to satisfy tax withholding obligations when equity awards vest or are exercised, and for diversification or other personal reasons. Transactions in our securities by directors and officers are required to be made in accordance with our insider trading policy, which requires that the transactions be in accordance with applicable U.S. federal securities laws that prohibit trading while in possession of material nonpublic information. Rule 10b5-1 under the Exchange Act provides an affirmative defense that enables directors and officers to prearrange transactions in a company’s securities in a manner that avoids concerns about initiating transactions while in possession of material nonpublic information. The following table describes contracts, instructions or written plans for the sale or purchase of our Class A common stock adopted by our directors and officers during the quarter ended December 31, 2024, that are intended to satisfy the affirmative defense conditions of Rule 10b5-1(c) (a “Rule 10b5-1 trading arrangement”): Name (Title) Action Taken (Date of Action) Nature of Trading Arrangement Duration of Trading Arrangement Aggregate Number of Securities Jennifer Miller, Director Adoption (December 6, 2024) Sale Until May 25, 2026 or such earlier date upon which all transactions are completed or expire without execution 10,000
Non-Rule 10b5-1 Arrangement Adopted	false
Rule 10b5-1 Arrangement Terminated	false
Non-Rule 10b5-1 Arrangement Terminated	false
Jennifer Miller [Member]
Trading Arrangements, by Individual
Name	Jennifer Miller
Title	Director
Rule 10b5-1 Arrangement Adopted	true
Adoption Date	December 6, 2024
Expiration Date	May 25, 2026
Arrangement Duration	535 days
Aggregate Available	10,000	10,000

Insider Trading Policies and Pr

Insider Trading Policies and Procedures	12 Months Ended
	Dec. 31, 2024
Insider Trading Policies and Procedures [Line Items]
Insider Trading Policies and Procedures Adopted	true

Cybersecurity Risk Management a

Cybersecurity Risk Management and Strategy Disclosure	12 Months Ended
	Dec. 31, 2024
Cybersecurity Risk Management, Strategy, and Governance [Line Items]
Cybersecurity Risk Management Processes for Assessing, Identifying, and Managing Threats [Text Block]	As is the case for all large companies, we are regularly subject to cyberattacks and other cyber incidents and, therefore, cybersecurity occupies a pivotal role within our risk management process. We adhere to a risk-based, multi-layered “defense in depth” approach that is dedicated to the identification, protection, detection, response, and recovery from cyber threats and incidents. We understand that a single technology, process, or business control cannot wholly prevent or mitigate all potential risks. Therefore, we employ a multitude of technologies, processes, and controls, each functioning independently but collectively forming a cohesive strategy aimed at minimizing risk. This strategy is evaluated through various means, such as frequent research and industry security briefings among our information technology group, internal and external audits, independent program assessments, control attestation reports, penetration testing, and other exercises that gauge its effectiveness. Threats and incidents connected with third party service providers are considered and managed under this process as well. We engage external parties, including consultants, independent privacy assessors, computer security firms and risk management and governance experts, to enhance our cybersecurity oversight. For example, we have engaged an outside consulting firm with expertise in the field to help us assess our systems, monitor risk and implement best practices and to support the internal audit of our cyber security programs and we regularly consult with industry groups on emerging industry trends. In addition, as part of our overall risk mitigation strategy, we also maintain cyber insurance coverage. Our cybersecurity policies, standards and procedures include cyber and data breach response plans, which are periodically assessed against the National Institute of Standards and Technology Cybersecurity Framework. We do not believe that there are currently any risks from cybersecurity threats that are reasonably likely to materially affect us or our business strategy, results of operations or financial condition.
Cybersecurity Risk Management Processes Integrated [Flag]	true
Cybersecurity Risk Management Processes Integrated [Text Block]	As is the case for all large companies, we are regularly subject to cyberattacks and other cyber incidents and, therefore, cybersecurity occupies a pivotal role within our risk management process. We adhere to a risk-based, multi-layered “defense in depth” approach that is dedicated to the identification, protection, detection, response, and recovery from cyber threats and incidents. We understand that a single technology, process, or business control cannot wholly prevent or mitigate all potential risks. Therefore, we employ a multitude of technologies, processes, and controls, each functioning independently but collectively forming a cohesive strategy aimed at minimizing risk. This strategy is evaluated through various means, such as frequent research and industry security briefings among our information technology group, internal and external audits, independent program assessments, control attestation reports, penetration testing, and other exercises that gauge its effectiveness.
Cybersecurity Risk Management Third Party Engaged [Flag]	true
Cybersecurity Risk Third Party Oversight and Identification Processes [Flag]	true
Cybersecurity Risk Materially Affected or Reasonably Likely to Materially Affect Registrant [Flag]	false
Cybersecurity Risk Board of Directors Oversight [Text Block]	The Audit Committee of our Board of Directors provides direct oversight over cybersecurity risk. The Audit Committee receives and provides feedback on periodic updates from management regarding cybersecurity. Agendas for quarterly updates are developed and adjusted throughout the year to adapt to any emerging risks or key topics and include, a wide range of information, including the prevailing cybersecurity threat landscape, investments in infrastructure, trainings programs and opportunities for bolstering the security of our company's systems and the protection of our products and operations. The full Board of Directors receives regular reports from the Audit Committee and our management on our cyber security program and the emerging threat landscape. Our Senior Vice President of Information Technology is responsible for leading our company-wide cybersecurity strategy, policy, standards and processes and together with our whole information technology team works across relevant units of Ameresco. Our Senior Vice President of Information Technology has more than thirty years of experience in cybersecurity and information technology and based on his long career with Ameresco he has a deep understanding of our information technology and business needs and the cyber security opportunities and risks we face. In actioning our cyber security strategy, our management together with our Senior Vice President of Information Technology evaluate the materiality of any cybersecurity threats and incidents utilizing both qualitative and quantitative considerations. Our internal audit team also provides independent testing on aspects of the operations of our cybersecurity program and the supporting control framework. Our cybersecurity program is designed to ensure the confidentiality, integrity, and availability of data and systems as well as to ensure timely identification of and response to any incidents. This design is geared toward supporting our business objectives and the needs of our valued customers, employees, and other stakeholders. We firmly believe that cybersecurity is a collective responsibility that extends to every employee, and we prioritize it as an ongoing objective. To increase our employees' awareness of cyber threats, we provide education and share best practices through a security awareness training program. This includes receiving regular exercises, cyber-event simulations, training programs and an annual attestation to our Technology Acceptable Use Policy. See “A failure of our information technology (“IT”) and data security infrastructure or cyber or other security incidents, vulnerabilities or other deficiencies, could adversely impact our business, reputation or results of operation or could cause us to default under our contractual obligations.” in Item 1A, Risk Factors.
Cybersecurity Risk Board Committee or Subcommittee Responsible for Oversight [Text Block]	The Audit Committee of our Board of Directors provides direct oversight over cybersecurity risk. The Audit Committee receives and provides feedback on periodic updates from management regarding cybersecurity.
Cybersecurity Risk Process for Informing Board Committee or Subcommittee Responsible for Oversight [Text Block]	Agendas for quarterly updates are developed and adjusted throughout the year to adapt to any emerging risks or key topics and include, a wide range of information, including the prevailing cybersecurity threat landscape, investments in infrastructure, trainings programs and opportunities for bolstering the security of our company's systems and the protection of our products and operations. The full Board of Directors receives regular reports from the Audit Committee and our management on our cyber security program and the emerging threat landscape.
Cybersecurity Risk Role of Management [Text Block]	The Audit Committee receives and provides feedback on periodic updates from management regarding cybersecurity. Agendas for quarterly updates are developed and adjusted throughout the year to adapt to any emerging risks or key topics and include, a wide range of information, including the prevailing cybersecurity threat landscape, investments in infrastructure, trainings programs and opportunities for bolstering the security of our company's systems and the protection of our products and operations. The full Board of Directors receives regular reports from the Audit Committee and our management on our cyber security program and the emerging threat landscape.
Cybersecurity Risk Management Positions or Committees Responsible [Flag]	true
Cybersecurity Risk Management Positions or Committees Responsible [Text Block]	Our Senior Vice President of Information Technology is responsible for leading our company-wide cybersecurity strategy, policy, standards and processes and together with our whole information technology team works across relevant units of Ameresco. Our Senior Vice President of Information Technology has more than thirty years of experience in cybersecurity and information technology and based on his long career with Ameresco he has a deep understanding of our information technology and business needs and the cyber security opportunities and risks we face.
Cybersecurity Risk Management Expertise of Management Responsible [Text Block]	Our Senior Vice President of Information Technology has more than thirty years of experience in cybersecurity and information technology and based on his long career with Ameresco he has a deep understanding of our information technology and business needs and the cyber security opportunities and risks we face.
Cybersecurity Risk Process for Informing Management or Committees Responsible [Text Block]	In actioning our cyber security strategy, our management together with our Senior Vice President of Information Technology evaluate the materiality of any cybersecurity threats and incidents utilizing both qualitative and quantitative considerations. Our internal audit team also provides independent testing on aspects of the operations of our cybersecurity program and the supporting control framework. Our cybersecurity program is designed to ensure the confidentiality, integrity, and availability of data and systems as well as to ensure timely identification of and response to any incidents. This design is geared toward supporting our business objectives and the needs of our valued customers, employees, and other stakeholders. We firmly believe that cybersecurity is a collective responsibility that extends to every employee, and we prioritize it as an ongoing objective. To increase our employees' awareness of cyber threats, we provide education and share best practices through a security awareness training program. This includes receiving regular exercises, cyber-event simulations, training programs and an annual attestation to our Technology Acceptable Use Policy. See “A failure of our information technology (“IT”) and data security infrastructure or cyber or other security incidents, vulnerabilities or other deficiencies, could adversely impact our business, reputation or results of operation or could cause us to default under our contractual obligations.” in Item 1A, Risk Factors.
Cybersecurity Risk Management Positions or Committees Responsible Report to Board [Flag]	true

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2024
Accounting Policies [Abstract]
Principles of Consolidation	Principles of Consolidation
Reclassification and Rounding	Reclassification and Rounding Certain prior period amounts were reclassified to conform to the presentation in the current period. We round amounts in the consolidated financial statements to thousands and calculate all percentages and per-share data from the underlying whole-dollar amounts. Thus, certain amounts may not foot, crossfoot, or recalculate based on reported numbers due to rounding.
Use of Estimates	Use of Estimates GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of the consolidated financial statements and the reported amounts of revenue and expenses during the reporting period. Changes in circumstances could cause actual results to differ materially from those estimates. The estimates and assumptions used in these consolidated financial statements relate to management’s estimates of final construction contract profit in accordance with accounting for long-term contracts, allowance for credit losses, realization of project development costs, leases, fair value of derivative financial instruments, accounting for business acquisitions, stock-based awards, impairment of goodwill and long-lived assets, income taxes, and potential liability in conjunction with contingent consideration.
Self-insured Health Insurance	Self-insured Health Insurance We are self-insured for employee health insurance and the maximum exposure in fiscal year 2024 under the plan was $200 per covered participant, after which reinsurance takes effect. The liability for unpaid claims and associated expenses, including incurred but not reported claims, is determined by management and reflected in our consolidated balance sheets in accrued expenses and other current liabilities. The liability is calculated based on historical data, which considers both the frequency and settlement amount of claims. Our estimated accrual for this liability could be different than our ultimate obligation if variables such as the frequency or amount of future claims differ significantly from management’s assumptions.
Cash and Cash Equivalents	Cash and Cash Equivalents
Restricted Cash	Restricted Cash Restricted cash consists of cash and cash equivalents held in escrow accounts in association with operations and maintenance (“O&M”) reserve accounts, cash collateralized letters of credit, as well as cash required under term loans to be maintained in reserve accounts until all obligations have been indefeasibly paid in full for energy assets. The carrying amount of the cash and cash equivalents in these accounts approximates its fair value measured using level 1 inputs per the fair value hierarchy as defined in Note 18. Restricted cash also includes funds held for clients, which represent assets that, based upon our intent, are restricted for use solely for the purposes of satisfying the obligations to remit funds to third parties, primarily utility service providers, relating to our enterprise energy management services.
Accounts Receivable, Net	Accounts Receivable, Net Accounts receivable, net are stated at the amount management expects to collect from outstanding balances. Our methodology to estimate the allowance for credit losses includes quarterly assessments of historical bad debt write-off experience, current economic and market conditions, management’s evaluation of outstanding accounts receivable, anticipated recoveries and our forecasts. Due to the short-term nature of our receivables, the estimate of credit losses is primarily based on aged accounts receivable balances and the financial condition of our customers. In addition, specific allowance amounts are established to record the appropriate provision for customers that have a higher probability of default. Bad debts are written off against the allowance when identified. As part of our assessment, we also considered the current and expected future economic and market conditions due to global factors and determined that the estimate of credit losses was not significantly impacted as of December 31, 2024 and 2023.
Accounts Receivable Retainage	Accounts Receivable Retainage
Inventory	Inventory Inventories, which consist primarily of PV solar panels, batteries and related accessories, are stated at the lower of cost (“first-in, first-out” method) or net realizable value (determined as the estimated selling prices in the ordinary course of business, less reasonably predictable costs of completion, disposal, and transportation). Provisions have been made to reduce the carrying value of inventory to the net realizable value.
Prepaid Expenses and Other Current Assets	Prepaid Expenses and Other Current Assets
Other Receivables	Other Receivables Ameresco’s wholly-owned subsidiary in Italy entered into agreements to sell certain receivables to unrelated third-party financial institutions for a discount on a non-recourse basis. These transactions are accounted for in accordance with Accounting Standards Codification (“ASC”) Topic 860, Transfers and Servicing, and result in a reduction in accounts receivable because the agreements transfer effective control over the receivables, and related risk, to the buyers. Our Italian subsidiary does not retain any interest in the underlying accounts receivable once sold. Trade accounts receivables balances sold are removed from the consolidated balance sheets, and cash received is reflected in operating activities in the consolidated statements of cash flows. Other receivables sold without recourse total $3,994 and $39,923 at December 31, 2024 and 2023, respectively, and are included in other receivables in the table above. Bank discount fees during the twelve months ended December 31, 2024 and 2023 were $1,471 and $5,844, respectively, and are included in other expense, net in the consolidated statements of income. See Note 17. Interest and Other Expenses, Net.
Federal ESPC Receivable	Federal ESPC Receivable Federal ESPC receivable represents the amount to be paid by various federal government agencies for work performed and earned by Ameresco under specific ESPCs. We assign certain of our rights to receive those payments to third-parties that provide construction and permanent financing for such contracts. Upon completion and acceptance of the project by the government, typically within 24 to 36 months of construction commencement, the assigned ESPC receivable from the government and corresponding ESPC liability are eliminated from our consolidated financial statements.
Project Development Costs	Project Development Costs We capitalize only those costs incurred in connection with the development of energy projects, primarily direct labor, interest costs, outside contractor services, consulting fees, legal fees, and travel, if incurred after a point in time where the realization of related revenue becomes probable. Project development costs incurred prior to the probable realization of revenue are expensed as incurred. We classify project development efforts that are expected to proceed to construction activity in the next twelve months as a current asset. We periodically review these balances and write off any amounts where the realization of the related revenue is no longer probable.
Property and Equipment	Property and Equipment Gains or losses on disposal of property and equipment are reflected in selling, general, and administrative expenses in the consolidated statements of income.
Energy Assets	Energy Assets Energy assets consist of costs of materials, direct labor, interest costs, outside contract services, deposits, asset retirement obligations (“AROs”), and project development costs incurred in connection with the construction of small-scale renewable energy plants that we own. These amounts are capitalized and amortized to cost of revenues in our consolidated statements of income on a straight-line basis over the lives of the related assets or the terms of the related contracts. Routine maintenance costs are expensed as incurred in our consolidated statements of income to the extent that they do not extend the life of the asset. Major maintenance includes upgrades and the refurbishment or replacing of components that are integral to the energy assets operating. In these instances, the costs associated with major maintenance are capitalized and are depreciated over the shorter of the remaining life of the asset or the period up to the next required major maintenance. Financing lease assets and accumulated depreciation of financing lease assets are included in energy assets. For additional information see the Sale-Leaseback section below and Notes 7 and 8. Capitalized Interest We capitalize interest costs relating to construction financing during the period of construction on energy assets we own. Capitalized interest is included in energy assets, net, in our consolidated balance sheets. Capitalized interest is amortized to cost of revenues in our consolidated statements of income on a straight-line basis over the useful life of the associated energy asset. For additional information see Note 7. Long-lived Asset Impairment We evaluate our long-lived assets, including operating lease right-of-use assets, for impairment as events or changes in circumstances indicate the carrying value of these assets may not be fully recoverable. Examples of such triggering events applicable to our assets include a significant decrease in the market price of a long-lived asset or asset group or a current-period operating or cash flow loss combined with a history of operating or cash flow losses or a projection or forecast that demonstrates continuing losses associated with the use of a long-lived asset or asset group. We evaluate recoverability of long-lived assets to be held and used by estimating the undiscounted future cash flows before interest associated with the expected uses and eventual disposition of those assets. When these comparisons indicate that the carrying value of those assets is greater than the undiscounted cash flows, we recognize an impairment loss for the amount that the carrying value exceeds the fair value of the asset group. Impairment losses are reflected in selling, general, and administrative expenses in the consolidated statements of income. See Note 7. for disclosure on our long-lived asset impairment during the year ended December 31, 2024. Government Grants From time to time, we have applied for and received cash grant awards from the U.S. Treasury Department (the “Treasury”) under Section 1603 of the American Recovery and Reinvestment Act of 2009 (the “Act”). The Act authorized the Treasury to make payments to eligible persons who place in service qualifying renewable energy projects. The grants are paid in lieu of ITCs. All of the cash proceeds from the grants were used and recorded as a reduction in the cost basis of the applicable energy assets. For tax purposes, the Section 1603 payments are not included in federal and certain state taxable income and the basis of the property is reduced by 50% of the payment received. We last received a Section 1603 grant during the year ended December 31, 2014. No further Section 1603 grant payments are expected to be received as the program has expired and no repayments will be required. We received grant proceeds from the Canadian government in connection with the construction of our energy assets in Canada during the years ended December 31, 2019 and 2020. We have a contribution agreement in place with Natural Resources Canada to fund 50% of the construction costs on a specific pilot project in Ontario. Cash proceeds are recorded as a deferred grant liability. Following commercial operation, the grant is subject to repayment to the government for a five-year period. Deferred grant income of $6,436 and $6,974 in the accompanying consolidated balance sheets as of December 31, 2024 and 2023, respectively, represents the benefit of the basis difference to be amortized to depreciation expense over the life of the related property. Non-refundable Transferable Credits Policy Elections We elect to apply government grant accounting, outside of income taxes, to the portion of the transferable ITC that we intend to sell. We have an existing policy to account for government grants by analogy to International Accounting Standard (“IAS”) 20 and shall present the credit as a reduction in the cost of the related energy asset and shall measure the grant of the nonmonetary asset at fair value. Based on these policy elections, the benefit of the grant will be recognized in profit or loss as a reduction to depreciation expense over the life of the energy asset. See Note 7. Energy Assets, Net for additional information.
Acquisitions	Acquisitions For acquisitions that meet the definition of a business combination, we apply the acquisition method of accounting in accordance with ASC 805, Business Combinations, where assets acquired, and liabilities assumed are recorded at fair value at the date of each acquisition. Any excess of the consideration we transferred over the amounts recognized for assets acquired and liabilities assumed is recorded as goodwill. Intangible assets, if identified, are also recorded. Determining the fair value of certain assets and liabilities assumed is judgmental in nature, often involves the use of significant estimates and assumptions, and is calculated using level 3 inputs per the fair value hierarchy as defined in Note 18. We continue to evaluate acquisitions for a period not to exceed one year after the acquisition date of each transaction to determine whether any additional adjustments are needed to the allocation of the purchase price. The results of the acquired companies are included in our consolidated statements of income, comprehensive income, and cash flows from the date of the respective acquisition. The consideration for our acquisitions often includes future payments that are contingent upon the occurrence of a particular event. We record a contingent consideration obligation for such contingent consideration payments at fair value on the acquisition date. We estimate the fair value of contingent consideration obligations through valuation models that incorporate probability adjusted assumptions related to the achievement of the milestones and the likelihood of making related payments. Each reporting period we revalue the contingent consideration obligations associated with our acquisitions to fair value and record changes in the fair value within the selling, general, and administrative expenses in our consolidated statements of income. Increases or decreases in the fair value of the contingent consideration obligations can result from changes in assumed discount periods and rates, changes in the assumed timing and amount of revenue and expense estimates and changes in assumed probability with respect to the attainment of certain financial and operational metrics, among others. Significant judgment is employed in determining these assumptions as of the acquisition date and for each subsequent period. Accordingly, future business and economic conditions, as well as changes in any of the assumptions described above, can materially impact the fair value of contingent consideration recorded at each reporting period. Deferred consideration related to certain holdbacks and completion payments are considered short-term in nature. These amounts are recorded at full value and are only revalued if one of those underlying assumptions changes. See Note 4 for additional information about our acquisitions.
Goodwill and Intangible Assets	Goodwill As noted in the Acquisitions section above, our goodwill is derived when we acquire another business. Goodwill is not amortized, but the potential impairment of goodwill is assessed at least annually during the fourth quarter and on an interim basis whenever events or changes in circumstances indicate that the carrying value may not be fully recoverable. In 2023, we changed the assessment date from December 31st to October 31st. We estimate the fair value of our reporting units and compare it with the carrying value of the reporting unit, including goodwill. If the fair value is greater than the carrying value of the reporting unit, no impairment is recorded. Fair value is determined using both an income approach and a market approach. If the fair value is less than the carrying value, an impairment loss is recognized for the amount that the carrying amount of a reporting unit, including goodwill, exceeds its fair value, limited to the total amount of goodwill allocated to that reporting unit. The impairment charge would be recorded to earnings in the consolidated statements of income. Judgment is required in determining whether an event has occurred that may impair the value of goodwill or identifiable intangible assets. See Note 5 for discussion about our goodwill assessments. Intangible Assets one
Leases / Failed Sale-leasebacks and Financing Leases	Leases Operating lease right-of-use (“ROU”) assets represent our right to use an underlying asset during the reasonably certain lease term and lease liabilities represent our obligation to make lease payments arising from the lease. ROU assets and lease liabilities for significant lease arrangements are recognized at commencement based on the present value of lease payments over the lease term. We use our incremental borrowing rate, which is updated annually or when a significant event occurs that would indicate a significant change in rates, to calculate the present value of lease payments. The operating lease ROU asset also includes any lease payments related to initial direct cost and prepayments and excludes lease incentives. Lease expense is recognized on a straight-line basis over the lease term which may include options to extend or terminate the lease when it is reasonably certain that we will exercise that option. Our ROU assets are evaluated for impairment using the same method as described above under the Long-lived Asset Impairment section. We do not record ROU assets and corresponding lease liabilities for leases with an initial term of 12 months or less (“short-term leases”) as we recognize lease expense for these leases as incurred over the lease term. We elected the package of practical expedients and did not reassess lease classifications of existing contracts or leases at adoption or the initial direct costs associated with existing leases. Accordingly, our sale-leaseback arrangements entered into as of December 31, 2018 remain under the previous guidance. See the Sale-leasebacks and Financing Leases section below and Note 8 for additional information on these sale-leasebacks. We have historical leases under ASC 840, Leases, which may have lease and non-lease components. Upon adoption of Topic 842, we elected to continue to account for these historical leases as a single component, as it relates to all prospective leases, we Sale-leasebacks and Financing Leases We entered into sale-leaseback arrangements that provided for the sale of solar PV energy assets to third-party investors and the simultaneous leaseback of the energy assets, which we then operate and maintain, recognizing revenue through the sale of the electricity and solar renewable energy credits generated by these energy assets. In sale-leaseback arrangements, we first determine whether the solar PV energy asset under the sale-leaseback arrangement is “integral equipment”. A solar PV energy asset is determined to be integral equipment when the cost to remove the energy asset from its existing location, including the shipping and reinstallation costs of the solar PV energy asset at the new site, and any diminution in fair value, exceeds 10% of the fair value of the solar PV energy asset at the time of its original installation. When the leaseback arrangement expires, we have the option to purchase the solar PV energy asset for the then fair market value or, in certain circumstances, renew the lease for an extended term. We have determined that none of the solar PV energy assets sold to date under the sale-leaseback program have been considered integral equipment as the cost to remove the energy asset from its existing location would not exceed 10% of its original fair value. In accordance with our adoption of Topic 842, sale-leaseback transactions are accounted for as financing liabilities on a prospective basis as we retain control of the underlying assets. As these transactions meet the criteria of a failed sale, the proceeds received in prospective transactions are accounted for as long-term financing liabilities with interest rates based upon the underlying details of each specific transaction.
Other Assets	Other Assets
Asset Retirement Obligations	Asset Retirement Obligations
Federal ESPC Liabilities	Federal ESPC Liabilities Federal ESPC liabilities, for both projects and energy assets, represent the advances received from third-parties under agreements to finance certain ESPC projects with various federal government agencies. For projects related to the construction or installation of certain energy savings equipment or facilities developed for the government customer, the ESPC receivable from the government and corresponding ESPC liability is eliminated from our consolidated balance sheets upon completion and acceptance of the project by the government, typically within 24 to 36 months of construction commencement. We remain the primary obligor for financing received until recourse to us ceases for the ESPC receivables transferred to the investor upon final acceptance of the work by the government customer. For small-scale energy assets developed for a government customer that we own and operate, we remain the primary obligor for financing received until the liability is eliminated from our consolidated balance sheets as contract payments assigned by the customer are transferred to the investor upon final acceptance of the work by the government customer.
Debt Issuance Costs	Debt Issuance Costs Debt issuance costs include external costs incurred to obtain financing. Debt issuance costs are amortized over the respective term of the financing using the effective interest method, with the exception of our revolving credit facility and construction loans, as discussed in Note 9, which are amortized on a straight-line basis over the term of the agreement. Debt issuance costs are presented on the consolidated balance sheets along with unamortized debt discounts as a reduction to long-term debt and financing lease liabilities.
Other Liabilities	Other Liabilities
Revenue Recognition / Cost of Revenues	Revenue Recognition We are a provider of comprehensive energy services, including energy efficiency, infrastructure upgrades, energy security and resilience, asset sustainability, and renewable energy solutions for businesses and organizations. Our sustainability services include capital and operational upgrades to a facility's energy infrastructure and the development, construction, ownership, and operation of renewable energy plants. Our revenue is generated from the primary lines of business described below and is recognized in accordance with Revenue from Contracts with Customers (Topic 606). Projects Our Projects service relates to energy efficiency projects, which include the design, engineering, and installation of an array of innovative technologies and techniques to improve energy efficiency and control the operation of a building’s energy- and water-consuming systems. Renewable energy products and services include, but are not limited to, the design and construction of a central plant or cogeneration system providing power, heat and/or cooling to a building, or a small-scale plant that produces electricity, gas, heat or cooling from renewable sources of energy. We recognize revenue from the installation or construction of projects over time using the cost-based input method. We use the total costs incurred on the project relative to the total expected costs to account for the satisfaction of the performance obligation. When the estimate on a contract indicates a loss, or reduces the likelihood of recoverability of such costs, we record the entire estimated loss in the period the loss becomes known. In addition, some contracts contain an element of variable consideration, including liquidated damages and/or penalties, which requires payment to the customer in the event that construction timelines or milestones are not met. We estimate the total consideration payable by the customer when the contracts contain variable consideration provisions, based on the most likely amount anticipated to be recognized for transferring the promised goods or services. As a result, we may constrain revenue to the extent that a significant reversal in the amount of cumulative revenue recognized will not occur when the uncertainty associated with the variable consideration is subsequently resolved. Contracts are often modified for a change in scope or other requirements. Contract modifications exist when the modification either creates new or changes the existing enforceable rights and obligations. Most of our contract modifications are for goods or services that are not distinct from the existing performance obligations. The effect of a contract modification on the transaction price, and the measure of progress for the performance obligation to which it relates, is recognized as an adjustment to revenue (either as an increase or decrease) on a cumulative catch-up basis. O&M After an energy efficiency or renewable energy project is completed, we often provide ongoing O&M services under a multi-year contract. These services include operating, maintaining and repairing facility energy systems such as boilers, chillers, and building controls, as well as central power and other small-scale plants. For larger projects, we frequently maintain staff on-site to perform these services. Maintenance revenue is recognized using the input method. In most cases, O&M fees are fixed annual fees and we record the revenue on a straight-line basis because the on-site O&M services are typically a distinct series of promises and those services have the same pattern of transfer to the customer (i.e., evenly over time). Some O&M service contract fees are based on time expended and, in those cases, revenue is recorded based on the time expended in that month. Energy Assets Our service offerings include the sale of electricity, heat, cooling, processed biogas, and renewable biomethane fuel from the portfolio of assets that we own and operate. We have constructed and are currently designing and constructing a wide range of renewable energy plants using biogas, solar, biomass, other bio-derived fuels, wind, and hydro sources of energy. Most of our renewable energy projects to date have involved the generation of electricity from solar PV and the sale of electricity, thermal, renewable fuel, or biomethane using biogas as a feedstock. We purchase the biogas that otherwise would be combusted or vented, process it, and either sell it or use it in our energy plants. We have also designed and built, own, operate and maintain plants that take biogas generated in the anaerobic digesters of wastewater treatment plants and turn it into renewable natural gas that is either used to generate energy on-site or that can be sold through the nation’s natural gas pipeline grid. We typically enter into a long-term power purchase agreement (“PPA”) for the sale of the energy where we own and operate energy producing assets. Many of our energy assets also produce environmental attributes, including renewable energy credits and RINs. In most cases, we sell these attributes under separate agreements with parties other than the PPA customer. In accordance with specific PPA contract terms, we recognize revenues from the sale and delivery of the energy output from renewable energy plants over time as produced and delivered to the customer. Environmental attributes revenue is recognized at a point in time when the environmental attributes are transferred to the customer in accordance with the transfer protocols of the environmental attributes market that we operate in. In the cases where environmental attributes are sold to the same customer as the energy output, we record revenue monthly for both the energy output and the environmental attribute output, as generated and delivered to the customer. We have determined that certain PPAs contained a lease component in accordance with ASC 840, Leases, prior to the adoption of Topic 842. We recognized $12,160, $10,687 and $10,904 of operating lease revenue Other Our service and product offerings also include integrated-PV, engineering, consulting, and enterprise energy management services, which we recognize over time as the services are provided. We recognize revenue from the sale of solar materials at a point in time when we have transferred physical control of the asset to the customer upon shipment or delivery. Performance Obligations A performance obligation is a promise in a contract to transfer a distinct good or service to the customer and is the unit of account. Performance obligations are satisfied as of a point in time or over time and are supported by contracts with customers. For most of our contracts, there are multiple promises of goods or services. Typically, we provide a significant service of integrating a complex set of tasks and components such as design, engineering, construction management, and equipment procurement for a project contract. The bundle of goods and services are provided to deliver one output for which the customer has contracted. In these cases, we consider the bundle of goods and services to be a single performance obligation. We may also promise to provide distinct goods or services within a contract, such as a project contract for installation of energy conservation measures and post-installation O&M services. In these cases, we separate the contract into more than one performance obligation and allocate the total transaction price to each performance obligation in an amount based on the estimated relative standalone selling prices of the promised goods or services underlying each performance obligation. Contract Acquisition Costs We are required to account for certain acquisition costs over the life of the contract, consisting primarily of commissions. Commission costs are incurred commencing at contract signing. Commission costs are allocated across all performance obligations and deferred and amortized consistent with the pattern of revenue recognition. Contract Assets and Contract Liabilities Contract assets represent our rights to consideration in exchange for services transferred to a customer that have not been billed as of the reporting date. Our rights to consideration are generally unconditional at the time our performance obligations are satisfied. Unbilled revenue represents amounts earned and billable that were not invoiced at the end of the fiscal period. When we receive consideration, or such consideration is unconditionally due, from a customer prior to transferring goods or services to the customer under the terms of a sales contract, we record deferred revenue, which represents a contract liability. Deferred revenue typically results from billings in excess of costs incurred and advance payments received on project contracts. At the inception of a contract, we expect the period between when we satisfy our performance obligations, and when the customer pays for the services, will be one year or less. As such, we elected to apply the practical expedient which allows us not to adjust the promised amount of consideration for the effects of a significant financing component, when a financing component is present. Cost of Revenues Cost of revenues includes the cost of labor, materials, equipment, subcontracting and outside engineering that are required for the development and installation of projects, as well as preconstruction costs, sales incentives, associated travel, inventory obsolescence charges, amortization of intangible assets related to customer contracts, and, if applicable, costs of procuring financing. A majority of our contracts have fixed price terms, however, in some cases we negotiate protections, such as a cost-plus structure, to mitigate the risk of rising prices for materials, services, and equipment. Cost of revenues also includes the costs of maintaining and operating the small-scale renewable energy plants that we own, including the cost of fuel (if any) and depreciation charges.
Income Taxes	Income Taxes We account for income taxes based on the liability method that requires the recognition of deferred income taxes based on expected future tax consequences of differences between the financial statement basis and the tax basis of assets and liabilities. We calculate deferred income taxes using the enacted tax rates in effect for the year in which the differences are expected to be reflected in the tax return. We account for uncertain tax positions using a “more-likely-than-not” threshold for recognizing and resolving uncertain tax positions. The evaluation of uncertain tax positions is based on factors that include changes in tax law, the measurement of tax positions taken or expected to be taken in tax returns, the effective settlement of matters subject to audit, new audit activity and changes in facts or circumstances related to a tax position. We evaluate uncertain tax positions on a quarterly basis and adjust the level of the liability to reflect any subsequent changes in the relevant facts surrounding the uncertain positions. Our liabilities for uncertain tax positions can be relieved only if the contingency becomes legally extinguished through either payment to the taxing authority or the expiration of the statute of limitations, the recognition of the benefits associated with the position meet the “more-likely-than-not” threshold or the liability becomes effectively settled through the examination process. We consider matters to be effectively settled once the taxing authority has completed all of its required or expected examination procedures, including all appeals and administrative reviews; we have no plans to appeal or litigate any aspect of the tax position; and we believe that it is highly unlikely that the taxing authority would examine or re-examine the related tax position. We also accrue for potential interest and penalties related to unrecognized tax benefits as a component of income tax expense.
Foreign Currency	Foreign Currency
Fair Value Measurements	Fair Value Measurements We follow the guidance related to fair value measurements for all of our non-financial assets and non-financial liabilities, except for those recognized at fair value in the financial statements at least annually. These assets include goodwill and long-lived assets measured at fair value for impairment assessments, and non-financial assets and liabilities initially measured at fair value in a business combination. We recognize certain financial assets and liabilities at fair value on a recurring basis (at least annually). Fair value is defined as the price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. Three levels of inputs that may be used to measure fair value are as follows: Level 1: Inputs are based on unadjusted quoted prices for identical instruments traded in active markets. Level 2: Inputs are based on quoted prices for similar instruments in active markets, quoted prices for identical or similar instruments in markets that are not active, and model-based valuation techniques for which all significant assumptions are observable in the market or can be corroborated by observable market data for substantially the full term of the assets or liabilities. Level 3: Inputs are generally unobservable and typically reflect management’s estimates of assumptions that market participants would use in pricing the asset or liability. The fair values are therefore determined using model-based techniques that include option pricing models, discounted cash flow models, and similar techniques.
Financial Instruments	Financial instruments consist of cash and cash equivalents, restricted cash, accounts and notes receivable, accounts payable, accrued expenses and other current liabilities, financing lease assets and liabilities, contingent consideration, short- and long-term borrowings, make-whole provisions, interest rate swaps, and commodity swaps. Because of their short maturity, the carrying amounts of cash and cash equivalents, restricted cash, accounts and notes receivable, accounts payable, accrued expenses and other current liabilities, and short-term borrowings approximate fair value. The carrying value of long-term variable-rate debt approximates fair value. Fair value of our debt is based on quoted market prices or on rates available to us for debt with similar terms and maturities, which are level two inputs of the fair value hierarchy, as defined in Note 18.
Stock-based Compensation Expense	Stock-based Compensation Expense We measure and record stock-based compensation expense for all stock-based payment awards based on estimated fair value. We may provide stock-based awards of shares of restricted common stock and grants of stock options to employees, directors, outside consultants, and others through various equity plans including our Employee Stock Purchase Plan (the “ESPP”) for employees. Stock-based compensation expense, net of actual forfeitures, is recognized based on the grant-date fair value on a straight-line basis over the requisite service period of the awards. Certain option grants have performance conditions that must be achieved prior to vesting and are expensed based on the expected achievement at each reporting period. We estimate the fair value of the stock-based awards, including stock options, using the Black-Scholes option-pricing model. Determining the fair value of stock-based awards requires the use of highly subjective assumptions, including the fair value of the common stock underlying the award, the expected term of the award and expected stock price volatility. The assumptions used in determining the fair value of stock-based awards represent management’s estimates, which involve inherent uncertainties and the application of management judgment. The risk-free interest rates are based on the U.S. Treasury yield curve in effect at the time of grant, with maturities approximating the expected life of the stock options. We have no history of paying dividends. Additionally, as of each of the grant dates, there was no expectation that we would pay dividends over the expected life of the options. The expected life of the awards is estimated based upon the period stock option holders will retain their vested options before exercising them. We use historical volatility as the expected volatility assumption required in the Black-Scholes model. We recognize compensation expense for only the portion of options that are expected to vest. If there are any modifications or cancellations of the underlying invested securities or the terms of the stock option, it may be necessary to accelerate, increase, decrease, or cancel any remaining unamortized stock-based compensation expense.
Derivative Financial Instruments	Derivative Financial Instruments In the normal course of business, we utilize derivatives contracts as part of our risk management strategy to manage exposure to market fluctuations in interest and commodity rates. These instruments are subject to various credit and market risks. Controls and monitoring procedures for these instruments have been established and are routinely reevaluated. Credit risk represents the potential loss that may occur because a party to a transaction fails to perform according to the terms of the contract. The measure of credit exposure is the replacement cost of contracts with a positive fair value. We seek to manage credit risk by entering into financial instrument transactions only through counterparties that we believe are creditworthy. Market risk represents the potential loss due to the decrease in the value of a financial instrument caused primarily by changes in interest rates and commodity prices. We seek to manage market risk by establishing and monitoring limits on the types and degree of risk that may be undertaken. As a matter of policy, we do not use derivatives for speculative purposes and consider the use of derivatives with all financing transactions to mitigate risk. We account for our interest rate and commodity swaps as derivative financial instruments in accordance with ASC Topic 815, Derivatives and Hedging. Under this guidance, derivatives are carried on our consolidated balance sheets at fair value which is determined based on observable market data in combination with expected cash flows for each instrument. Some of our debt agreements contain make-whole provisions which we account for as embedded derivatives in accordance with related guidance. Under this guidance, the derivative is bifurcated from its host contract and recorded on our consolidated balance sheets at fair value by either comparing it against the rates of similar debt instruments under similar terms without a make-whole provision obtained from various highly rated third-party pricing sources or evaluating the present value of the prepayment fee.
Earnings Per Share	Earnings Per Share
Variable Interest Entities	Variable Interest Entities Certain contracts are executed jointly through partnership and joint venture arrangements with unrelated third parties. The arrangements are often formed for the single business purpose of executing a specific project and allow us to share risks and/or secure specialty skills required for project execution. We evaluate each partnership and joint venture at inception to determine if it qualifies as a VIE under ASC 810, Consolidation. A VIE is an entity used for business purposes that either (i) does not have equity investors with voting rights or (ii) has equity investors who are not required to provide sufficient financial resources for the entity to support its activities without additional subordinated financial support. Upon the occurrence of certain events outlined in ASC 810, we reassess our initial determination of whether the partnership or joint venture is a VIE. We also evaluate whether we are the primary beneficiary of each VIE and consolidate the VIE if we have both (i) the power to direct the economically significant activities of the entity and (ii) the obligation to absorb losses of, or the right to receive benefits from, the entity that could potentially be significant to the VIE. We consider the contractual agreements that define the ownership structure, distribution of profits and losses, risks, responsibilities, indebtedness, voting rights and board representation of the respective parties in determining whether we qualify as the primary beneficiary. We also consider all parties that have direct or implicit variable interests when determining whether we are the primary beneficiary. As required by ASC 810, management's assessment of whether we are the primary beneficiary of a VIE is continuously performed.
Equity and Cost Method Investments	Equity and Cost Method Investments
Equity and Cost Method Investments	Equity and Cost Method Investments
Non-Controlling Interests and Redeemable Non-Controlling Interests	Non-Controlling Interests and Redeemable Non-Controlling Interests Non-controlling interests represent the portion of equity (net assets) in a VIE not attributable, directly or indirectly, to us. For some of our VIEs we perform the attribution of income or loss and comprehensive income or loss on the basis of our relative ownership interests and the non-controlling interests. These non-controlling interests which do not contain redemption features are classified within equity on our consolidated balance sheets. During 2018 and 2019, we formed investment funds (tax equity partnerships) with different third-party investors which granted the applicable investor ownership interests in the net assets of certain of our renewable energy project subsidiaries. As of December 31, 2024, we had one such investment fund remaining. We entered into these agreements in order to finance the costs of constructing energy assets which are under long-term customer contracts. We have determined that these entities qualify as VIEs and that we are the primary beneficiary in the operational partnerships for accounting purposes. Accordingly, we consolidate the assets and liabilities and operating results of the entities in our consolidated financial statements. We recognize the investors’ share of the net assets of the subsidiaries as redeemable non-controlling interests in our consolidated balance sheets. We have determined that the provisions in the contractual arrangements represent substantive profit-sharing arrangements and that the appropriate methodology for attributing income and loss to the redeemable non-controlling interests each period is a balance sheet approach referred to as the hypothetical liquidation at book value (“HLBV”) method. Under the HLBV method, the amounts of income and loss attributed to the redeemable non-controlling interests in the consolidated statements of income reflect changes in the amounts the investors would hypothetically receive at each balance sheet date under the liquidation provisions of the contractual agreements, assuming the net assets of this funding structure were liquidated at recorded amounts. The investors’ non-controlling interest in the results of operations of this funding structure is determined as the difference in the non-controlling interest’s claim under the HLBV method at the start and end of each reporting period, after taking into account any capital transactions, such as contributions or distributions, between our subsidiaries and the investors.
Recent Accounting Pronouncements	Recent Accounting Pronouncements Business Combinations— Joint Venture Formations In August 2023, the FASB issued Accounting Standards Update (“ASU”) 2023-05, Business Combinations— Joint Venture Formations (Subtopic 805-60) Recognition and Initial Measurement, which addresses the accounting for contributions made to a joint venture, upon formation, in a joint venture’s separate financial statements. ASU 2023-05 is effective prospectively for all joint venture formations with a formation date on or after January 1, 2025. We are currently evaluating the impact that adopting this new accounting standard would have on our consolidated financial statements. Disclosure Improvements - Codification Amendments in Response to the SEC’s Disclosure Update and Simplification Initiative In October 2023, the FASB issued ASU 2023-06, Disclosure Improvements - Codification Amendments in Response to the SEC’s Disclosure Update and Simplification Initiative, which updates the disclosure or presentation requirements for a variety of topics in the codification. ASU 2023-06 is effective from the date on which the SEC’s removal of that related disclosure from Regulation S-X or Regulation S-K, with early adoption prohibited. We will monitor the removal of the requirements from the current regulations and adopt the related amendments, but we do not anticipate this new guidance will have a material impact on our consolidated financial statements as we are currently subject to SEC requirements. Segment Reporting (Topic 820) - Improvements to Reportable Segment Disclosures In November 2023, the FASB issued ASU 2023-07, Segment Reporting (Topic 820) - Improvements to Reportable Segment Disclosures, which improves reportable segment disclosures by requiring enhanced disclosures for significant segment expenses and other segment items. ASU 2023-07 is effective for fiscal years beginning after December 15, 2023, and interim periods within fiscal years beginning after December 15, 2024. We adopted this standard and applied the disclosure requirements retrospectively to all prior periods presented. The adoption of this guidance did not have an impact on our consolidated financial statements, although it did result in expanded segment disclosures, which are included in Note 20. Business Segment Information. Income Taxes (Topic 740) - Improvements to Income Tax Disclosures In December 2023, the FASB issued ASU 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures, to enhance the income tax disclosures, including disaggregation of information in the rate reconciliation table and disaggregated information related to income taxes paid. ASU 2023-09 is effective for fiscal years beginning after December 15, 2024. We are currently evaluating the impact that adopting this new accounting standard would have on our consolidated financial statements. Codification Improvements—Amendments to Remove References to the Concepts Statements In March 2024, the FASB issued ASU 2024-02, Codification Improvements—Amendments to Remove References to the Concepts Statements, to remove references to various FASB Concepts Statements based on suggestions received from stakeholders on the Accounting Standards Codification and other incremental improvements to GAAP. ASU 2024-02 is effective for fiscal years beginning after December 15, 2024. We are currently evaluating the impact that adopting this new accounting standard would have on our consolidated financial statements. Income Statement—Reporting Comprehensive Income—Expense Disaggregation Disclosures (Subtopic 220-40): Disaggregation of Income Statement Expenses In November 2024, the FASB issued ASU 2024-03, Income Statement—Reporting Comprehensive Income—Expense Disaggregation Disclosures (Subtopic 220-40): Disaggregation of Income Statement Expenses, to improve the disclosures by requiring more detailed information about the types of expenses (including purchases of inventory, employee compensation, depreciation, amortization, and depletion) in commonly presented expense captions (such as cost of sales, SG&A, and research and development). ASU 2024-03 is effective for fiscal years beginning after December 15, 2026, and interim periods within fiscal years beginning after December 15, 2027. We are currently evaluating the impact that adopting this new accounting standard would have on our consolidated financial statements. Debt—Debt with Conversion and Other Options (Subtopic 470-20) In November 2024, the FASB issued ASU 2024-04, Debt—Debt with Conversion and Other Options (Subtopic 470-20), to improve the consistency of the determination of whether a transaction should be accounted for as an induced conversion or extinguishment of convertible debt when the terms of a convertible debt instrument are changed to induce a conversion of the instrument. ASU 2024-04 is effective for annual reporting periods beginning after December 15, 2025, and interim periods within those annual reporting periods. We are currently evaluating the impact that adopting this new accounting standard would have on our consolidated financial statements. Income Statement—Reporting Comprehensive Income—Expense Disaggregation Disclosures (Subtopic 220-40) In January 2025, the FASB issued ASU 2025-01, Income Statement—Reporting Comprehensive Income—Expense Disaggregation Disclosures (Subtopic 220-40), to modify the effective date previously stated in ASU 2024-03 to clarify that all public business entities are required to adopt the guidance in annual reporting periods beginning after December 15, 2026, and interim periods within annual reporting periods beginning after December 15, 2027. Early adoption is permitted. We are currently evaluating the impact that adopting ASU 2024-03 new accounting standard would have on our consolidated financial statements and will adhere to the clarified effective date in ASU 2025-01 if implementation is necessary.

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2024
Accounting Policies [Abstract]
Summary of Accounts Receivable, Allowance for Credit Loss	Changes in the allowance for credit losses was as follows: Year Ended December 31, 2024 2023 2022 Allowance for credit loss, beginning of period $ 903 $ 911 $ 2,263 Charges to (recoveries of) costs and expenses, net 1,340 356 (382) Account write-offs and other (1,398) (364) (970) Allowance for credit loss, end of period $ 845 $ 903 $ 911
Prepaid Expenses And Other Current Assets	Prepaid expenses and other current assets comprised of the following: Year Ended December 31, 2024 2023 Other receivables $ 16,336 $ 74,454 Deferred project costs 117,573 38,240 Prepaid expenses 11,997 10,697 Prepaid expenses and other current assets $ 145,906 $ 123,391
Estimated Useful Lives of Property and Equipment	Depreciation and amortization of property and equipment are computed on a straight-line basis over the following estimated useful lives: Asset Classification Estimated Useful Life Furniture and office equipment Five years Computer equipment and software costs Three Leasehold improvements Lesser of term of lease or five years Automobiles Five years Land Unlimited Property and equipment, net consisted of the following: December 31, 2024 2023 Furniture and office equipment $ 4,198 $ 4,207 Computer equipment and software costs 18,706 27,199 Leasehold improvements 2,312 2,570 Automobiles 1,956 2,041 Land 6,943 6,943 Property and equipment, gross 34,115 42,960 Less: accumulated depreciation (23,075) (25,565) Property and equipment, net $ 11,040 $ 17,395 The following table sets forth our depreciation expense on property and equipment: Year Ended December 31, Location 2024 2023 2022 Selling, general & administrative expenses $ 4,963 $ 4,155 $ 2,665

Revenue from Contracts with C_2

Revenue from Contracts with Customers (Tables)	12 Months Ended
	Dec. 31, 2024
Revenue from Contract with Customer [Abstract]
Summary of Disaggregation of Revenue	The following table presents our revenue disaggregated by line of business and reportable segment for the year ended December 31, 2024: North America Regions U.S. Federal Renewable Fuels Europe All Other Total Project revenue $ 762,404 $ 294,082 $ 43,353 $ 238,848 $ — $ 1,338,687 O&M revenue 35,707 60,057 7,895 2,807 — 106,466 Energy assets 73,059 17,449 121,960 847 29 213,344 Other 7,658 948 134 8,072 94,619 111,431 Total revenues $ 878,828 $ 372,536 $ 173,342 $ 250,574 $ 94,648 $ 1,769,928 The following table presents our revenue disaggregated by line of business and reportable segment for the year ended December 31, 2023: North America Regions U.S. Federal Renewable Fuels Europe All Other Total Project revenue $ 519,079 $ 342,238 $ — $ 138,730 $ 1,250 $ 1,001,297 O&M revenue 26,310 53,496 10,697 1,979 1 92,483 Energy assets 64,668 6,326 106,359 1,392 145 178,890 Other 6,377 824 19 7,253 87,490 101,963 Total revenues $ 616,434 $ 402,884 $ 117,075 $ 149,354 $ 88,886 $ 1,374,633 The following table presents our revenue disaggregated by line of business and reportable segment for the year ended December 31, 2022: North America Regions U.S. Federal Renewable Fuels Europe All Other Total Project revenue $ 1,093,738 $ 333,846 $ — $ 53,680 $ — $ 1,481,264 O&M revenue 22,259 51,857 10,377 456 16 84,965 Energy assets 51,818 5,822 104,082 281 87 162,090 Other 5,466 366 — 3,993 86,278 96,103 Total revenues $ 1,173,281 $ 391,891 $ 114,459 $ 58,410 $ 86,381 $ 1,824,422 See Note 16 for our revenue disaggregated by geographical region. The following table presents information related to our revenue recognized over time: Year Ended December 31, 2024 2023 2022 Percentage of revenue recognized over time 96 % 95 % 96 %
Summary of Contract Balances	The following table provides information about receivables, contract assets, and contract liabilities from contracts with customers: December 31, 2024 December 31, 2023 January 1, 2023 Accounts receivable, net $ 256,961 $ 153,362 $ 174,009 Accounts receivable retainage 39,843 33,826 38,057 Contract Assets Unbilled revenue 644,105 636,163 576,363 Contract Liabilities Deferred revenue 91,734 52,903 34,796 Deferred revenue, non-current (1) 29,885 18,393 7,617 Total contract liabilities $ 121,619 $ 71,296 $ 42,413 (1) Performance obligations that are expected to be completed beyond the next twelve months and are included in other liabilities in the consolidated balance sheets.
Summary of Project Development Costs on Projects Converted to Customer Contracts	The following table presents information related to our project development costs recognized in the consolidated statements of income on projects that converted to customer contracts: Year Ended December 31, 2024 2023 2022 Project development costs recognized $ 18,023 $ 13,051 $ 15,507

Business Acquisitions and Div_2

Business Acquisitions and Divestitures (Tables)	12 Months Ended
	Dec. 31, 2024
Business Combination, Asset Acquisition, and Joint Venture Formation [Abstract]
Business Acquisition, Pro Forma Information	The following table sets forth the revenue and net (loss) income for Enerqos: Twelve Months Ended December 31, 2024 2023 Revenue $ 27,809 $ 52,241 Net (loss) income (2,961) 1,758
Schedule of Purchase Price Allocation by Acquisitions	A summary of the cumulative consideration paid, allocation of the purchase price, and adjustments made for the Enerqos acquisition are presented in the table below: Preliminary March 31, 2023 Measurement Period Adjustment As Adjusted December 31, 2023 Cash $ 9,535 $ — $ 9,535 Long-term debt assumed, net of current portions 3,951 — 3,951 FX adjustment (41) — (41) Fair value of consideration transferred $ 13,445 $ — $ 13,445 Cash and cash equivalents 190 — 190 Accounts receivable 6,230 — 6,230 Unbilled revenue 8,985 — 8,985 Prepaid expenses and other current assets 16,504 — 16,504 Project development costs 5,140 — 5,140 Property and equipment and energy assets 1,234 — 1,234 Intangible assets 4,438 — 4,438 Long-term restricted cash 163 — 163 Accounts payable (15,480) — (15,480) Accrued expenses and other current liabilities (4,510) 165 (4,345) Current portions of long-term debt (15,165) — (15,165) Deferred income tax liabilities, net (931) — (931) Other liabilities (208) — (208) Recognized identifiable assets acquired and liabilities assumed $ 6,590 $ 165 $ 6,755 Goodwill $ 6,855 $ (165) $ 6,690

Goodwill and Intangible Asset_2

Goodwill and Intangible Assets, Net (Tables)	12 Months Ended
	Dec. 31, 2024
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Goodwill	The changes in the goodwill balances by reportable segment are as follows: North America Regions U.S. Federal Europe Other Total Carrying Value of Goodwill Balance, December 31, 2022 $ 42,829 $ 3,981 $ 5,932 $ 17,891 $ 70,633 Goodwill acquired during the year — — 6,855 — 6,855 Remeasurement adjustments — — (165) — (165) Impairment charges, net of tax (2,222) — — — (2,222) Foreign currency translation 73 — 413 — 486 Balance, December 31, 2023 40,680 3,981 13,035 17,891 75,587 Fair value allocation for change in reportable segments (1,474) — — 1,474 — Goodwill disposed of through sale of business (1) — — — (8,529) (8,529) Foreign currency translation (257) — (496) — (753) Balance, December 31, 2024 $ 38,949 $ 3,981 $ 12,539 $ 10,836 $ 66,305 (1) See Note 4. Business Acquisitions and Divestitures for additional information. Accumulated Goodwill Impairment Balance, December 31, 2023 $ (2,222) $ — $ (1,016) $ — $ (3,238) Balance, December 31, 2024 $ (2,222) $ — $ (1,016) $ — $ (3,238)
Schedule of Intangible Assets, Net	Definite-lived intangible assets, net consisted of the following: As of December 31, 2024 2023 Gross carrying amount Customer contracts $ 6,898 $ 8,859 Customer relationships 17,572 21,182 Non-compete agreements 2,535 3,013 Technology 1,754 2,723 Tradenames 927 1,370 Subsurface land easements 4,274 — Total gross carrying amount 33,960 37,147 Accumulated Amortization Customer contracts 6,898 8,859 Customer relationships 13,318 14,979 Non-compete agreements 2,535 3,013 Technology 1,753 2,723 Tradenames 642 765 Total accumulated amortization 25,146 30,339 Intangible assets, net $ 8,814 $ 6,808 The table below sets forth amortization expense: Year Ended December 31, Location 2024 2023 2022 Customer contracts Cost of revenues $ — $ — $ 551 Customer relationships Selling, general and administrative expenses 1,833 2,141 1,303 Technology Selling, general and administrative expenses — — 1 Tradenames Selling, general and administrative expenses 296 225 3 Subsurface land easements Selling, general and administrative expenses 5 — — Total amortization expense $ 2,134 $ 2,366 $ 1,858
Schedule of Finite-Lived Intangible Assets, Future Amortization Expense	Amortization expense for our definite-lived intangible assets for the next five years to be included in selling, general, and administrative expenses is as follows: Estimated Amortization Expense 2025 $ 2,238 2026 1,895 2027 821 2028 369 2029 214 Thereafter 3,277 Total $ 8,814

Property and Equipment, Net (Ta

Property and Equipment, Net (Tables)	12 Months Ended
	Dec. 31, 2024
Property, Plant and Equipment [Abstract]
Summary of Property and Equipment	Depreciation and amortization of property and equipment are computed on a straight-line basis over the following estimated useful lives: Asset Classification Estimated Useful Life Furniture and office equipment Five years Computer equipment and software costs Three Leasehold improvements Lesser of term of lease or five years Automobiles Five years Land Unlimited Property and equipment, net consisted of the following: December 31, 2024 2023 Furniture and office equipment $ 4,198 $ 4,207 Computer equipment and software costs 18,706 27,199 Leasehold improvements 2,312 2,570 Automobiles 1,956 2,041 Land 6,943 6,943 Property and equipment, gross 34,115 42,960 Less: accumulated depreciation (23,075) (25,565) Property and equipment, net $ 11,040 $ 17,395 The following table sets forth our depreciation expense on property and equipment: Year Ended December 31, Location 2024 2023 2022 Selling, general & administrative expenses $ 4,963 $ 4,155 $ 2,665

Energy Assets, Net (Tables)

Energy Assets, Net (Tables)	12 Months Ended
	Dec. 31, 2024
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Summary of Energy Assets	Energy assets, net consisted of the following: December 31, 2024 2023 Energy assets (1) $ 2,338,680 $ 2,054,145 Less: accumulated depreciation, net (423,369) (364,721) Energy assets, net $ 1,915,311 $ 1,689,424 (1) Includes financing lease assets (see Note 8), capitalized interest and ARO assets (see tables below). Also includes the energy asset projects acquired in August 2023 and January 2024. See section below for additional information.
Summary of Depreciation and Amortization Expense of Energy Assets	The following table sets forth our depreciation and amortization expense on energy assets, net of deferred grant amortization: Year Ended December 31, Location 2024 2023 2022 Cost of revenues (1) $ 82,114 $ 59,390 $ 49,755 (1) Includes depreciation and amortization expense on financing lease assets. See Note 8.
Summary of Capitalized Interest	The following table presents the interest costs relating to construction financing during the period of construction, which were capitalized as part of energy assets, net: Year Ended December 31, 2024 2023 2022 Capitalized interest $ 50,889 $ 43,561 $ 13,050
Schedule of Customer Energy Liabilities	The liabilities recognized in association with these customer energy assets were as follows: December 31, Location 2024 2023 Accrued expenses and other current liabilities $ 651 $ 598 Other liabilities 47,692 41,680 Total customer energy asset projects liability $ 48,343 $ 42,278
Schedule of Asset and Liabilities Retirement Obligations	The following tables sets forth information related to our ARO assets and ARO liabilities: December 31, Location 2024 2023 ARO assets, net Energy assets, net $ 4,414 $ 4,800 ARO liabilities, non-current Other liabilities $ 6,136 $ 5,960 Year Ended December 31, 2024 2023 2022 Depreciation expense of ARO assets $ 238 $ 215 $ 146 Accretion expense of ARO liabilities $ 332 $ 258 $ 146

Leases (Tables)

Leases (Tables)	12 Months Ended
	Dec. 31, 2024
Leases [Abstract]
Schedule of Rent and Related Expenses and Lease Costs	Rent and related expenses were as follows: Year Ended December 31, 2024 2023 2022 Rent and related expenses $ 13,945 $ 10,504 $ 9,199 The costs related to our leases were as follows: Year Ended December 31, 2024 2023 2022 Operating Leases Operating lease costs $ 12,945 $ 9,416 $ 8,372 Financing Leases Amortization expense 2,104 2,103 2,104 Interest on lease liabilities 1,752 1,804 2,147 Total financing lease costs 3,856 3,907 4,251 Total lease costs $ 16,801 $ 13,323 $ 12,623 Supplemental cash flow information related to our leases was as follows: Year Ended December 31, 2024 2023 Cash paid for amounts included in the measurement of operating lease liabilities $ 19,428 $ 10,724 Right-of-use assets obtained in exchange for new operating lease liabilities (1) $ 29,808 $ 25,225 (1) Includes non-monetary lease transactions of $10,378 and $13,941 for the years ended December 31, 2024 and 2023, respectively. See disclosure below for additional information.
Schedule of Assets and Liabilities, Lessee	The table below sets forth supplemental balance sheet information related to leases: December 31, 2024 2023 Operating Leases Right-of-use assets, net $ 80,149 $ 58,586 Current portions of operating lease liabilities $ 10,536 $ 13,569 Long-term operating lease liabilities, net of current portion 59,479 42,258 Total operating lease liabilities $ 70,015 $ 55,827 Weighted-average remaining lease term 19 years 18 years Weighted-average discount rate 6.6 % 6.6 % Financing Leases (1) Energy assets, net $ 25,158 $ 27,262 Current portions of financing lease liabilities $ 637 $ 871 Long-term financing lease liabilities, net of current portion, unamortized discount and debt issuance costs 12,267 13,057 Total financing lease liabilities $ 12,904 $ 13,928 Weighted-average remaining lease term 12 years 13 years Weighted-average discount rate 12.03 % 12.05 % (1) Includes sale-leaseback transactions entered into prior to January 1, 2019.
Schedule of Finance Lease Liability Maturity	The table below sets forth our estimated minimum future lease obligations under our leases: Operating Leases Financing Leases Year ended December 31, 2025 $ 14,527 $ 1,899 2026 9,702 2,054 2027 8,565 1,923 2028 7,174 1,955 2029 5,521 1,892 Thereafter 73,464 14,043 Total minimum lease payments $ 118,953 $ 23,766 Less: interest 48,938 10,862 Present value of lease liabilities $ 70,015 $ 12,904
Schedule of Operating Lease Liability Maturity	The table below sets forth our estimated minimum future lease obligations under our leases: Operating Leases Financing Leases Year ended December 31, 2025 $ 14,527 $ 1,899 2026 9,702 2,054 2027 8,565 1,923 2028 7,174 1,955 2029 5,521 1,892 Thereafter 73,464 14,043 Total minimum lease payments $ 118,953 $ 23,766 Less: interest 48,938 10,862 Present value of lease liabilities $ 70,015 $ 12,904
Schedule of Amount Related to Sale Leasebacks	The following table presents a summary of amounts related to these sale-leasebacks included in our consolidated balance sheets: December 31, 2024 2023 Deferred loss, short-term, net 115 115 Deferred loss, long-term, net 1,224 1,340 Total deferred loss $ 1,339 $ 1,455 Deferred gain, short-term, net 345 345 Deferred gain, long-term, net 3,739 4,085 Total deferred gain $ 4,084 $ 4,430

Debt and Financing Lease Liab_2

Debt and Financing Lease Liabilities (Tables)	12 Months Ended
	Dec. 31, 2024
Debt Disclosure [Abstract]
Summary of Debt	Debt was comprised of the following: As of December 31, 2024 2023 Senior secured credit facility, 7.90%, due January 2024 to December 2028 (1) (2) (8) $ 148,000 $ 279,900 Second lien term loan, 10.57%, due June 2029 (1) (2) (8) 100,000 — Energy Asset Construction Facilities June 2020, 6.14%, due March 2025 (2) (8) $ 20,385 $ 20,705 April 2023, 6.82%, due July 2024 — 134,415 August 2023, 8.53%, due December 2027 (1) (2) (8) 318,824 278,858 August 2023, 6.33%, due February 2024 — 36,270 Subtotal energy asset construction facilities $ 339,209 $ 470,248 Energy Asset Operating Facilities October 2011 fixed rate 6.11% due June 2028 (5) $ 1,417 $ 1,976 October 2012 variable rate 7.22%, due June 2025 (4) (8) 31,660 34,453 September 2015 variable rate 6.54%, due March 2028 (4) (8) 13,271 13,747 August 2016 fixed rate 4.95%, due June 2031 (4) 1,813 2,253 April 2017 fixed rate 5.61%, due February 2034 (4) 1,128 1,348 June 2017 variable rate 7.14%, due December 2027 (4) (8) 4,944 7,158 June 2018 fixed rate 5.15%, due December 2038 (2) (4) 18,883 21,063 June 2018 variable rate 6.74%, due June 2033 (2) (8) (3) 5,500 6,592 October 2018 variable rate 7.20%, due October 2029 (2) (8) (5) 5,264 6,145 November 2020 fixed rate 3.58%, due December 2027 (4) 1,400 2,004 June 2021 fixed rate 4.92%, due June 2045 (4) 3,154 3,489 July 2021 fixed rate 3.25%, due March 2046 (2) (4) 33,214 35,090 July 2021 variable rate 8.34%, due July 2030 (2) (4) (8) — 2,140 June 2022 fixed rate 5.45%, due March 2042 (2) (4) 5,942 6,395 October 2022 fixed rate 6.70%, due August 2039 (2) (4) 362,583 349,093 March 2023 fixed rate 5.99%, due, December 2047 (2) (4) 21,290 21,984 August 2023 seller's promissory note, 5.00%, due January 2024 — 28,294 August 2023 fixed rate 5.83%, due April 2047 (2) 12,290 3,520 April 2024 fixed rate 6.20%, due June 2042 (2) (4) 89,846 — April 2024 fixed rate 8.00%, due June 2042 (2) (4) 12,566 — February 2024 variable rate 6.33%, due April 2030 (2) (4) 34,605 — Various Enerqos financing facilities 13,934 17,786 Subtotal energy asset operating facilities $ 674,704 $ 564,530 Sale-leasebacks August 2018 master sale-leaseback, 0.00% to 1.86%, due July 2039 to December 2049 (3) (6) $ 205,565 $ 163,504 December 2020 master sale-leaseback, 0.00%, due December 2040 to March 2043 (4) (6) 21,111 22,194 August 2024 master sale-leaseback, 0.00%, due August 2034 to August 2044 (2) (4)(6) 172,694 — Subtotal sale-leasebacks $ 399,370 $ 185,698 Financing Leases (7) $ 12,904 $ 13,928 Total debt and financing leases $ 1,674,187 $ 1,514,304 Less: current maturities, net of unamortized discount 149,363 322,247 Less: unamortized discount and debt issuance costs 40,924 21,982 Long-term debt and financing lease liabilities, net of current portion, unamortized discount and debt issuance costs $ 1,483,900 $ 1,170,075 (1) Facility has interest at varying rates monthly or quarterly in arrears. (2) These agreements have acceleration causes that, in the event of default, as defined, the payee has the option to accelerate payment terms and make the remaining principal and the required interest balance due according to the agreement. (3) Facility is payable in semi-annual installments. (4) Facility is payable in quarterly installments. (5) Facility is payable in monthly installments. (6) These agreements are sale-leaseback arrangements and are accounted for as failed sales under the guidance and are classified as financing liabilities. See Note 8. (7) Financing leases are sale-leaseback arrangements under previous guidance and do not include approximately $10,862 in future interest payments as of December 31, 2024 and $12,468 as of December 31, 2023. See Note 8. (8) These agreements are now using the Secured Overnight Financing Rate (“SOFR”) as the primary reference rate used to calculate interest. The table below sets forth amounts outstanding under the senior secured credit facility: Rate as of December 31, 2024 As of December 31, 2024 2023 Revolving credit facility 7.99 % $ 135,000 $ 139,900 Term loan A 6.96 % 13,000 75,000 Delayed draw term loan A — % — 65,000 Total senior secured credit facility outstanding 148,000 279,900 Less: unamortized debt discount and debt issuance costs (177) (884) Total senior secured credit facility outstanding, net $ 147,823 $ 279,016
Schedule of Aggregate Maturities of Long-Term Debt	The following table presents the aggregate maturities of long-term debt and financing leases as of December 31, 2024: 2025 $ 149,363 2026 78,201 2027 395,886 2028 206,115 2029 167,686 Thereafter 676,936 Total maturities $ 1,674,187

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2024
Income Tax Disclosure [Abstract]
Domestic and Foreign Income Taxes	The following table sets forth components of income before income taxes: Year Ended December 31, 2024 2023 2022 Domestic $ 28,256 $ 30,211 $ 98,004 Foreign 5,684 8,058 7,715 Income before income taxes $ 33,940 $ 38,269 $ 105,719
Income Tax Provision (Benefit)	The components of the provision (benefit) for income taxes were as follows: Year Ended December 31, 2024 2023 2022 Current income tax provision (benefit): Federal $ 1,246 $ 34 $ (722) State 805 372 733 Foreign 2,414 1,255 1,202 Total current 4,465 1,661 1,213 Deferred income tax (benefit) provision: Federal (28,552) (22,677) 2,528 State 4,265 (5,657) 2,300 Foreign (178) 1,038 1,129 Total deferred (24,465) (27,296) 5,957 Total income tax (benefit) provision $ (20,000) $ (25,635) $ 7,170
Deferred Income Tax Assets and Liabilities	Deferred tax assets and liabilities consisted of the following: December 31, 2024 2023 Deferred income tax assets: Compensation accruals $ 5,622 $ 4,137 Reserves 8,009 5,906 Sale-leasebacks and other accruals 39,231 49,300 Net operating losses 9,882 28,565 Interest limitation 16,706 8,273 Energy efficiency 138,647 82,827 Deferred revenue 2,402 2,114 Gross deferred income tax assets 220,499 181,122 Valuation allowance (4,015) (3,704) Total deferred income tax assets $ 216,484 $ 177,418 Deferred income tax liabilities: Depreciation $ (148,217) $ (145,880) Deferred effect of derivative liability (5,606) (2,166) Outside basis difference (6,759) (6,599) Interest rate swaps (1,602) (841) Total deferred income tax liabilities (162,184) (155,486) Deferred income tax assets (liabilities), net $ 54,300 $ 21,932
Summary of Valuation Allowance	Our valuation allowance related to the following items: December 31, 2024 2023 Foreign net operating loss (1) $ 4,013 $ 3,702 State net operating loss at one of our subsidiaries (2) 2 2 Total valuation allowance $ 4,015 $ 3,704 (1) It is more likely than not that we will not generate sufficient taxable income at the foreign subsidiary level to utilize the net operating loss. (2) It is more likely than not that we will not generate sufficient taxable income at the subsidiary level to utilize the net operating loss.
Summary of Operating Loss Carryforwards	As of December 31, 2024, we had the following tax loss and credit carryforwards to offset taxable income in prior and future years: Amount Expiration Period Federal net operating loss carryforwards $ — Indefinite State net operating loss carryforwards 72,865 Various Canadian net operating loss carryforwards 20,922 2028 through 2043 Ireland net operating loss carryforwards 2,110 Indefinite Italy net operating loss carryforwards 2,970 Indefinite Spain net operating loss carryforwards 2,463 Indefinite Other foreign country net operating loss carryforwards 127 2030 Total tax loss carryforwards $ 101,457 Federal Energy Investment and Production tax credit carryforward $ 114,839 2030 through 2043
Summary of Tax Credit Carryforwards	As of December 31, 2024, we had the following tax loss and credit carryforwards to offset taxable income in prior and future years: Amount Expiration Period Federal net operating loss carryforwards $ — Indefinite State net operating loss carryforwards 72,865 Various Canadian net operating loss carryforwards 20,922 2028 through 2043 Ireland net operating loss carryforwards 2,110 Indefinite Italy net operating loss carryforwards 2,970 Indefinite Spain net operating loss carryforwards 2,463 Indefinite Other foreign country net operating loss carryforwards 127 2030 Total tax loss carryforwards $ 101,457 Federal Energy Investment and Production tax credit carryforward $ 114,839 2030 through 2043
Reconciliation of Effective Tax Rates	The following is a reconciliation of the effective tax rates: Year Ended December 31, 2024 2023 2022 Income before (benefit) provision for income taxes $ 33,940 $ 38,269 $ 105,719 Federal statutory tax expense $ 7,128 $ 8,036 $ 22,201 State income taxes, net of federal benefit 2,345 (774) 3,844 Net state impact of deferred rate change 2,919 (3,213) (575) Nondeductible expenses 1,182 667 2,198 Impact of reserve for uncertain tax positions (265) (200) 59 Stock-based compensation expense 1,240 4 353 Energy efficiency preferences (38,929) (30,359) (21,410) Foreign items and rate differential 2,629 458 37 State tax adjustment — (66) — Redeemable non-controlling interests 729 (227) (411) Valuation allowance 311 81 (159) Miscellaneous 711 (42) 1,033 Total income tax (benefit) provision $ (20,000) $ (25,635) $ 7,170 Effective tax rate: Federal statutory rate expense 21.0 % 21.0 % 21.0 % State income taxes, net of federal benefit 6.9 % (2.0) % 3.6 % Net state impact of deferred rate change 8.6 % (8.4) % (0.5) % Nondeductible expenses 3.5 % 1.7 % 2.1 % Impact of reserve for uncertain tax positions (0.8) % (0.5) % 0.1 % Stock-based compensation expense 3.7 % — % 0.3 % Energy efficiency preferences (114.7) % (79.3) % (20.3) % Foreign items and rate differential 7.7 % 1.2 % — % State tax adjustment — % (0.2) % — % Redeemable non-controlling interests 2.1 % (0.6) % (0.4) % Valuation allowance 0.9 % 0.2 % (0.2) % Miscellaneous 2.2 % (0.1) % 1.1 % Effective tax rate (58.9) % (67.0) % 6.8 %
Unrecognized Tax Benefits	The following table provides a reconciliation of gross unrecognized tax benefits which are included in other liabilities within the consolidated balance sheets: Year Ended December 31, 2024 2023 Balance, beginning of year $ 800 $ 900 Additions for current year tax positions 104 100 Reductions of prior year tax positions — (200) Balance, end of year $ 904 $ 800

Variable Interest Entities an_2

Variable Interest Entities and Equity Method Investments (Tables)	12 Months Ended
	Dec. 31, 2024
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Schedule of Variable Interest Entities	The table below presents a summary of amounts related to our VIEs reflected in Note 1 on our consolidated balance sheets: As of December 31, 2024 2023 Investment Fund Other VIEs Total VIEs Investment Fund Other VIEs Total VIEs Cash and cash equivalents $ 89 $ 8,691 $ 8,780 $ 5,099 $ 16,780 $ 21,879 Accounts receivable, net — 14,607 14,607 — 1,977 1,977 Unbilled revenue 230 4,040 4,270 662 13,409 14,071 Prepaid expenses and other current assets 30 1,293 1,323 33 3,749 3,782 Income taxes receivable — 672 672 — — — Project development costs, net — 5,795 5,795 — — — Total VIE current assets 349 35,098 35,447 5,794 35,915 41,709 Property and equipment, net — — — — 267 267 Energy assets, net 23,538 98,876 122,414 79,104 173,808 252,912 Intangible assets, net — 20 20 — — — Right-of-use assets, net 471 — 471 4,748 12,908 17,656 Restricted cash, non-current portion — — — 73 — 73 Other assets — 196 196 10 74 84 Total VIE assets $ 24,358 $ 134,190 $ 158,548 $ 89,729 $ 222,972 $ 312,701 Current portions of long-term debt and financing lease liabilities $ — $ — $ — $ 2,190 $ 132,427 $ 134,617 Accounts payable 27 5,140 5,167 1,440 6,490 7,930 Accrued expenses and other current liabilities 25 577 602 241 22,780 23,021 Current portions of right-of-use liabilities 13 — 13 133 6,953 7,086 Deferred revenue — 10,063 10,063 — — — Income taxes payable — 526 526 — — — Total VIE current liabilities 65 16,306 16,371 4,004 168,650 172,654 Long-term debt and financing lease liabilities, net of current portion, unamortized discount and debt issuance costs — — — 17,167 — 17,167 Long-term right-of-use liabilities, net of current portion 500 — 500 5,063 3,823 8,886 Other liabilities — — — 356 — 356 Total VIE liabilities $ 565 $ 16,306 $ 16,871 $ 26,590 $ 172,473 $ 199,063
Schedule Equity Method Investments in Joint Ventures	The following table sets forth the carrying value of our equity and cost method investments in joint ventures: As of December 31, 2024 2023 Equity and cost method investments $ 16,987 $ 18,709

Redeemable Non-Controlling In_2

Redeemable Non-Controlling Interests (Tables)	12 Months Ended
	Dec. 31, 2024
Equity, Attributable to Parent [Abstract]
Schedule of Call and Put Options Investment Funds	Therefore, we have one investment fund remaining and the following table sets forth information about the call and put options for our investment fund outstanding as of December 31, 2024: Call Option Put Option Investment Fund Number Formation Date Start Date End Date Purchase Price Start Date End Date Purchase Price 1 December 2019 March 2026 September 2026 (1) September 2026 September 2027 (2) (1) Purchase price is equal to the greater of (i) the fair market value of such interests at the time the option is exercised or (ii) 5% of the investors’ contributed capital balance at the time the option is exercisable. The call options are exercisable beginning on the date that specified conditions are met for each respective fund. These dates are estimate and subject to change based on last funding date. (2) Purchase price is the lessor of fair market value at the time the option is exercised and the sum of (i) 5% of the investors’ contributed capital balance at the time the option is exercisable, and (ii) the fair market value of any unpaid tax law change losses incurred by the investor in connection with the exercise of the put option.

Equity and Earnings Per Share (

Equity and Earnings Per Share (Tables)	12 Months Ended
	Dec. 31, 2024
Earnings Per Share [Abstract]
Schedule of Earnings Per Share, Basic and Diluted	The following is a reconciliation of the numerator and denominator for the computation of basic and diluted earnings per share: Year Ended December 31, 2024 2023 2022 Numerator: Net income attributable to common shareholders $ 56,757 $ 62,470 $ 94,926 Adjustment for accretion of tax equity financing fees (107) (108) (116) Income attributable to common shareholders $ 56,650 $ 62,362 $ 94,810 Denominator: Basic weighted-average shares outstanding 52,380 52,140 51,841 Effect of dilutive securities: Stock options 760 1,087 1,437 Diluted weighted-average shares outstanding 53,140 53,228 53,278 Net income per share attributable to common shareholders: Basic $ 1.08 $ 1.20 $ 1.83 Diluted $ 1.07 $ 1.17 $ 1.78 Potentially dilutive shares (1) 2,154 1,707 1,108 (1) Potentially dilutive shares attributable to stock options were excluded from the computation of diluted earnings per share as the effect would have been anti-dilutive.

Stock-Based Compensation and _2

Stock-Based Compensation and Other Employee Benefits (Tables)	12 Months Ended
	Dec. 31, 2024
Share-Based Payment Arrangement [Abstract]
Schedule of Stock Options Activity	The following table summarizes the collective activity under the plan: Number of Options Weighted-Average Exercise Price Weighted-Average Remaining Contractual Term Aggregate Intrinsic Value Outstanding at December 31, 2023 4,255 $ 46.932 Granted 792 23.280 Exercised (97) 9.666 Forfeited (227) 63.059 Expired (86) 46.675 Outstanding at December 31, 2024 4,637 $ 42.895 6.4 years $ 15,174 Options exercisable at December 31, 2024 2,098 $ 29.495 4.8 years $ 13,932 Expected to vest as of December 31, 2024 2,538 $ 53.970 7.8 years $ 1,242 The following table sets forth additional disclosures about our plan: Year Ended December 31, 2024 2023 2022 Aggregate intrinsic value of options exercised $ 1,602 $ 8,511 $ 9,775 Cash received from stock option exercises $ 942 $ 2,438 $ 3,954 Weighted-average fair value of stock options granted $ 14.16 $ 23.99 $ 37.87 Stock-based compensation expense (1) $ 14,130 $ 10,318 $ 15,046 Income tax benefit from stock-based compensation expense $ 105 $ 1,102 $ 659 (1) Included in selling, general, and administrative expenses in the accompanying consolidated statements of income and includes expense in connection with our ESPP and RSUs.
Schedule of Stock Options Valuation Assumptions	The following table sets forth the significant assumptions used in the model: Year Ended December 31, 2024 2023 2022 Expected dividend yield —% —% —% Risk-free interest rate 3.78% -4.45% 3.35%-4.44% 1.69%-3.82% Expected volatility 58%-62% 54%-56% 51%-53% Expected life 6.5 years 6.5 years 6.5 years
Schedule of Restricted Stock Units	The following table summarizes the activity under the plan: Number of Options Weighted-Average Grant Date Fair Value Per Share Outstanding at December 31, 2023 52 $ 45.90 Granted 122 24.38 Vested (63) 37.60 Forfeited (6) 27.98 Outstanding at December 31, 2024 105 $ 27.02
Schedule of Defined Contribution Plan Disclosures	The following table sets forth our matching contributions under the plans: Year Ended December 31, 2024 2023 2022 401(k) plan $ 8,090 $ 7,561 $ 6,974 Group Personal Pension Plan 574 652 290 Registered Retirement Savings Plan 454 429 406 Total matching contributions $ 9,118 $ 8,642 $ 7,670

Geographic Information (Tables)

Geographic Information (Tables)	12 Months Ended
	Dec. 31, 2024
Segments, Geographical Areas [Abstract]
Composition of Assets and Revenues by Geographic Locations	The following table presents our long-lived assets related to our operations by geographic area: As of December 31, 2024 2023 Long-lived Tangible Assets United States $ 1,888,440 $ 1,670,322 Canada 20,509 23,549 Europe 17,402 12,948 Total long-lived assets $ 1,926,351 $ 1,706,819 We attribute revenues to customers based on the location of the customer. The following table presents revenues by geographic region: Year Ended December 31, 2024 2023 2022 Revenues United States $ 1,446,879 $ 1,161,775 $ 1,712,326 Canada 72,371 63,367 53,461 Europe 250,678 149,491 58,635 Total revenues $ 1,769,928 $ 1,374,633 $ 1,824,422

Interest And Other Expenses, _2

Interest And Other Expenses, Net (Tables)	12 Months Ended
	Dec. 31, 2024
Other Income and Expenses [Abstract]
Schedule of Other Expenses, Net	The following table presents the components of interest and other expenses, net: Year Ended December 31, 2024 2023 2022 Gain on derivatives $ (1,027) $ (1,108) $ (906) Interest expense, net of interest income 65,031 36,169 26,423 Amortization of debt discount and debt issuance costs 5,151 4,201 4,211 Foreign currency transaction loss (gain) 3,840 (581) 144 Government incentives 339 (576) (2,599) Bank discount fees 1,471 5,844 — Interest and other expenses, net $ 74,805 $ 43,949 $ 27,273
Schedule of Estimated Amortization Expense for the Next Five Years	Estimated amortization expense for existing debt discount and debt issuance costs for the next five succeeding fiscal years is as follows: Estimated Amortization 2025 $ 6,128 2026 $ 5,898 2027 $ 6,334 2028 $ 3,805 2029 $ 3,105

Fair Value Measurement (Tables)

Fair Value Measurement (Tables)	12 Months Ended
	Dec. 31, 2024
Fair Value Disclosures [Abstract]
Summary of Changes in Fair Value by Balance Sheet Grouping	The following table presents the input level used to determine the fair values of our financial instruments measured at fair value on a recurring basis: Fair Value as of December 31, Level 2024 2023 Assets Interest rate swap instruments 2 $ 5,096 $ 3,970 Liabilities Interest rate swap instruments 2 $ — $ 629 Make-whole provisions 2 15,574 6,012 Contingent consideration 3 1,614 1,465 Total liabilities $ 17,188 $ 8,106
Subsequent Key Assumptions	The balances and subsequent key assumptions used in the model were as follows: At December 31, 2024 2023 Balance of remaining contingent consideration $ 1,614 $ 1,465 Risk-adjusted discount rate 16.9 % 16.9 % Estimated EBITDA volatility 70.0 % 70.0 %
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation	The following table sets forth a summary of changes in the fair value of contingent consideration liabilities classified as level 3: Year Ended December 31, 2024 2023 Contingent consideration liabilities balance at the beginning of year $ 1,465 $ 4,158 Changes in fair value included in earnings 149 347 Payment of contingent consideration — (3,040) Contingent consideration liabilities balance at the end of year $ 1,614 $ 1,465
Fair Value and Carrying Value of Long-Term Debt	The following table sets forth the fair value and the carrying value of our long-term debt, excluding financing leases: December 31, 2024 December 31, 2023 Fair Value Carrying Value Fair Value Carrying Value Long-term debt value (level 2) $ 1,618,208 $ 1,620,359 $ 1,466,458 $ 1,478,394

Derivative Instruments and He_2

Derivative Instruments and Hedging Activities (Tables)	12 Months Ended
	Dec. 31, 2024
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Schedule of Fair Value of Derivative Instruments	The following table presents information about the fair value amounts of our derivative instruments: Derivatives as of December 31, 2024 2023 Balance Sheet Location Fair Value Fair Value Derivatives Designated as Hedging Instruments Interest rate swap contracts Other assets $ 1,556 $ 1,023 Derivatives Not Designated as Hedging Instruments Interest rate swap contracts Other assets $ 3,540 $ 2,947 Interest rate swap contracts Other liabilities $ — $ 629 Make-whole provisions Other liabilities $ 15,574 $ 6,012
Schedule of Derivative Effect on Consolidated Statement of Income (Loss)	The following tables present information about the effects of our derivative instruments on the consolidated statements of income and consolidated statements of comprehensive income: Location of (Gain) Loss Recognized in Net Income Amount of (Gain) Loss Recognized in Net Income for the Year Ended December 31, 2024 2023 2022 Derivatives Designated as Hedging Instruments Interest rate swap contracts Interest and other expenses, net $ (994) $ (770) $ 1,037 Derivatives Not Designated as Hedging Instruments Interest rate swap contracts Interest and other expenses, net $ (1,220) $ 1,354 $ (2,738) Commodity swap contracts Interest and other expenses, net $ — $ — $ 2,338 Make-whole provisions Interest and other expenses, net $ 193 $ (2,462) $ (506)
Schedule of Derivative Instruments Effect on Comprehensive Income (Loss)	The following table presents the changes in AOCI, net of taxes, from our hedging instruments: Years ended December 31, 2024 2023 Derivatives Designated as Hedging Instruments: Accumulated gain in AOCI at the beginning of the year $ 746 $ 1,284 Unrealized gain recognized in AOCI 1,388 232 Gain reclassified from AOCI to interest and other expenses, net (994) (770) Gain (loss) on derivatives 394 $ (538) AOCI at the end of the year $ 1,140 $ 746
Schedule of Derivative Instruments	The following tables present all of our active derivative instruments as of December 31, 2024: Active Interest Rate Swaps Expiration Date Initial Notional Amount ($) Status 11-Year, 5.77% Fixed October 2029 $ 9,200 Designated 15-Year, 5.24% Fixed June 2033 $ 10,000 Designated 10-Year, 4.74% Fixed December 2027 $ 14,100 Designated 8-Year, 3.49% Fixed June 2028 $ 14,643 Designated 8-Year, 3.49% Fixed June 2028 $ 10,734 Designated 13-Year, 0.72% Fixed March 2033 $ 9,505 Not Designated 13-Year, 0.72% Fixed March 2033 $ 6,968 Not Designated 17.75-Year, 3.16% Fixed December 2040 $ 14,084 Designated 18-Year, 3.81% Fixed July 2041 $ 32,021 Not Designated Other Derivatives Classification Effective Date Expiration Date Fair Value ($) Make-whole provisions Liability June/August 2018 December 2038 $ 348 Make-whole provisions Liability August 2016 April 2031 $ 35 Make-whole provisions Liability April 2017 February 2034 $ 28 Make-whole provisions Liability November 2020 December 2027 $ 18 Make-whole provisions Liability October 2011 May 2028 $ 4 Make-whole provisions Liability May 2021 April 2045 $ 78 Make-whole provisions Liability July 2021 March 2046 $ 2,158 Make-whole provisions Liability June 2022 March 2042 $ 885 Make-whole provisions Liability March 2023 December 2047 $ 1,968 Make-whole provisions Liability April 2024 June 2042 $ 9,442 Make-whole provisions Liability April 2024 June 2042 $ 609

Business Segment Information (T

Business Segment Information (Tables)	12 Months Ended
	Dec. 31, 2024
Segment Reporting [Abstract]
Schedule of Operational Results by Business Segments	The table below presents our business segment information and reconciliation to our consolidated financial statements for the years ending December 31: North America Regions U.S. Federal Renewable Fuels Europe All Other Corporate Total 2024 Revenues $ 878,828 $ 372,536 $ 173,342 $ 250,574 $ 94,648 $ 1,769,928 Cost of revenues 773,205 313,413 136,720 227,163 63,336 1,513,837 Gross profit 105,623 59,123 36,622 23,411 31,312 256,091 Add: Earnings from unconsolidated entities 51 687 — 54 — — 792 Gain on sale of business, net — — — — 38,007 — 38,007 Less: Selling, general and administrative expenses 50,985 13,064 2,909 16,951 22,203 67,649 173,761 Asset impairments 527 — 9,233 — — 2,624 12,384 Loss (gain) on derivatives 193 (1,083) (137) — — — (1,027) Interest expense, net of interest income 9,894 4,982 25,552 4,271 (1) 20,333 65,031 Other expenses 3,172 883 460 1,467 34 4,785 10,801 Income before income taxes 40,903 41,964 (1,395) 776 47,083 (95,391) 33,940 Other Non-cash Segment Disclosures: Depreciation and intangible asset amortization (1) 36,400 14,206 31,968 2,090 2,684 1,863 89,211 Amortization of debt discount & debt issuance costs (1) 2,056 883 460 — — 1,752 5,151 (1) These amounts disclosed by reportable segment are included within the other segment expense captions. North America Regions U.S. Federal Renewable Fuels Europe All Other Corporate Total 2023 Revenues 616,434 402,884 117,075 149,354 88,886 1,374,633 Cost of revenues 515,986 340,989 87,819 123,215 60,195 1,128,204 Gross profit 100,448 61,895 29,256 26,139 28,691 246,429 Add: Earnings from unconsolidated entities — 1,758 — — — — 1,758 Less: Selling, general and administrative expenses 51,161 12,090 4,383 14,110 21,969 58,425 162,138 Asset impairments 2,222 — 1,609 — — — 3,831 (Gain) loss on derivatives (2,461) 857 496 — — — (1,108) Interest expense, net of interest income 7,003 1,429 16,019 2,477 (6) 9,247 36,169 Other expenses 1,654 11 533 5,915 75 700 8,888 Income before income taxes 40,869 49,266 6,216 3,637 6,653 (68,372) 38,269 Other Non-cash Segment Disclosures: Depreciation and intangible asset amortization (1) $ 28,682 $ 5,343 $ 26,160 $ 2,082 $ 1,861 $ 1,783 $ 65,911 Amortization of debt discount & debt issuance costs (1) 2,444 50 533 — — 1,174 4,201 North America Regions U.S. Federal Renewable Fuels Europe All Other Corporate Total 2022 Revenues 1,173,281 391,891 114,459 58,410 86,381 1,824,422 Cost of revenues 1,020,266 329,527 78,359 46,808 58,629 1,533,589 Gross profit 153,015 62,364 36,100 11,602 27,752 290,833 Add: Earnings from unconsolidated entities — 1,647 — — — — 1,647 Less: Selling, general and administrative expenses 57,401 11,757 2,962 6,626 18,640 62,102 159,488 Asset impairments — — — — — — — (Gain) loss on derivatives (506) — 294 — — — (212) Interest expense, net of interest income 7,865 1,231 8,657 24 (3) 7,955 25,729 Other (income) expenses (580) 157 1,198 (150) 7 1,124 1,756 Income before income taxes 88,835 50,866 22,989 5,102 9,108 (71,181) 105,719 Other Non-cash Segment Disclosures: Depreciation and intangible asset amortization (1) 23,152 4,905 23,354 275 746 1,846 54,278 Amortization of debt discount & debt issuance costs (1) 1,712 157 1,198 — — 1,144 4,211 (1) These amounts disclosed by reportable segment are included within the other segment expense captions.

Assets Held For Sale (Tables)

Assets Held For Sale (Tables)	12 Months Ended
	Dec. 31, 2024
Discontinued Operations and Disposal Groups [Abstract]
Schedule of Assets and Liabilities	The table below reflects the assets and liabilities associated with assets held for sale by segment: December 31, 2024 December 31, 2023 North America Regions U.S. Federal Total North America Regions U.S. Federal Total Other assets $ 7,778 $ 401 $ 8,179 $ 18,895 $ 18,253 $ 37,148 Right-of-use assets, net 193 — 193 1,256 — 1,256 Assets classified as held for sale $ 7,971 $ 401 $ 8,372 $ 20,151 $ 18,253 $ 38,404 Accounts payable 482 — 482 5,418 601 6,019 Current portions of operating lease liabilities 11 — 11 14 — 14 Deferred revenue 60 — 60 — 1,088 1,088 Long-term operating lease liabilities, net of current portion 218 — 218 1,230 — 1,230 Liabilities directly associated with assets classified as held for sale $ 771 $ — $ 771 $ 6,662 $ 1,689 $ 8,351

Summary of Significant Accoun_4

Summary of Significant Accounting Policies - Principles of Consolidation (Details)	Dec. 31, 2024 investment_fund
Accounting Policies [Abstract]
Investment funds formed to fund the purchase of solar energy systems	1

Summary of Significant Accoun_5

Summary of Significant Accounting Policies - Use of Estimates (Details) $ / participant in Thousands	12 Months Ended
	Dec. 31, 2024 $ / participant
Accounting Policies [Abstract]
Maximum exposure, per participant	200

Summary of Significant Accoun_6

Summary of Significant Accounting Policies - Accounts Receivable (Details) - USD ($)	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for credit loss, beginning of period	$ 903,000	$ 911,000	$ 2,263,000
Charges to (recoveries of) costs and expenses, net	1,340,000	356,000	(382,000)
Account write-offs and other	(1,398,000)	(364,000)	(970,000)
Allowance for credit loss, end of period	845,000	903,000	$ 911,000
Accounts receivable retainage reserve	$ 0	$ 0
Minimum
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Accounts receivable retainage	5%
Maximum
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Accounts receivable retainage	10%

Summary of Significant Accoun_7

Summary of Significant Accounting Policies - Prepaid Expenses and Other Current Assets (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Accounting Policies [Abstract]
Other receivables		$ 16,336	$ 74,454
Deferred project costs		117,573	38,240
Prepaid expenses		11,997	10,697
Prepaid expenses and other current assets	[1]	145,906	123,391
Other receivables sold		3,994	39,923
Bank discount fees		$ 1,471	5,844	$ 0
Benefit of grant amount			$ 20,970
[1]Includes restricted assets of consolidated variable interest entities (“VIEs”) of $158,548 as of December 31, 2024 and $312,701 as of December 31, 2023. Includes liabilities of consolidated VIEs of $16,871 as of December 31, 2024 and $199,063 as of December 31, 2023. See Note 11.

Summary of Significant Accoun_8

Summary of Significant Accounting Policies - Property and Equipment (Details)	Dec. 31, 2024
Furniture and office equipment
Property, Plant and Equipment [Line Items]
Property and equipment estimated useful life	5 years
Computer equipment and software costs | Minimum
Property, Plant and Equipment [Line Items]
Property and equipment estimated useful life	3 years
Computer equipment and software costs | Maximum
Property, Plant and Equipment [Line Items]
Property and equipment estimated useful life	5 years
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property and equipment estimated useful life	5 years
Automobiles
Property, Plant and Equipment [Line Items]
Property and equipment estimated useful life	5 years

Summary of Significant Accoun_9

Summary of Significant Accounting Policies - Accrued Expenses and Other Current Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Accounting Policies [Abstract]
Use and other taxes payable	$ 40,000	$ 39,974

Summary of Significant Accou_10

Summary of Significant Accounting Policies - Energy Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023	Jan. 01, 2023
Revenue, Major Customer [Line Items]
Deferred grant income	$ 29,885	$ 18,393	$ 7,617
United States
Revenue, Major Customer [Line Items]
Deferred grant income	$ 6,436	$ 6,974

Summary of Significant Accou_11

Summary of Significant Accounting Policies - Goodwill and Intangible Assets (Details)	Dec. 31, 2024
Subsurface Land Easements
Goodwill [Line Items]
Intangible assets amortization period	20 years
Minimum
Goodwill [Line Items]
Intangible assets amortization period	1 year
Maximum
Goodwill [Line Items]
Intangible assets amortization period	15 years

Summary of Significant Accou_12

Summary of Significant Accounting Policies - Sales Leaseback (Details)	12 Months Ended
	Dec. 31, 2024
Solar PV project
Sale Leaseback Transaction [Line Items]
Percentage of fair value threshold integral equipment	10%

Summary of Significant Accou_13

Summary of Significant Accounting Policies - Revenue Recognition (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Accounting Policies [Abstract]
Operating lease revenue	$ 12,160	$ 10,687	$ 10,904
Operating Lease, Lease Income, Statement of Income or Comprehensive Income [Extensible Enumeration]	Revenue from Contract with Customer, Excluding Assessed Tax

Summary of Significant Accou_14

Summary of Significant Accounting Policies - Share Repurchase Program (Details) - Class A Common Stock - USD ($)	Dec. 31, 2024	Apr. 30, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock repurchase program, authorized amount (up to)		$ 17,553,000
Share Repurchase Program, Remaining Authorized, Amount	$ 5,745,000

Summary of Significant Accou_15

Summary of Significant Accounting Policies - Non-Controlling Interests and Redeemable Non-Controlling Interest (Details)	Dec. 31, 2024 investment_fund
Accounting Policies [Abstract]
Investment funds formed to fund the purchase of solar energy systems	1

Revenue from Contracts with C_3

Revenue from Contracts with Customers - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Disaggregation of Revenue [Line Items]
Revenues	$ 1,769,928	$ 1,374,633	$ 1,824,422
Percentage of revenue recognized over time	96%	95%	96%
Project revenue
Disaggregation of Revenue [Line Items]
Revenues	$ 1,338,687	$ 1,001,297	$ 1,481,264
O&M revenue
Disaggregation of Revenue [Line Items]
Revenues	106,466	92,483	84,965
Energy assets
Disaggregation of Revenue [Line Items]
Revenues	213,344	178,890	162,090
Other
Disaggregation of Revenue [Line Items]
Revenues	111,431	101,963	96,103
North America Regions
Disaggregation of Revenue [Line Items]
Revenues	878,828	616,434	1,173,281
North America Regions | Project revenue
Disaggregation of Revenue [Line Items]
Revenues	762,404	519,079	1,093,738
North America Regions | O&M revenue
Disaggregation of Revenue [Line Items]
Revenues	35,707	26,310	22,259
North America Regions | Energy assets
Disaggregation of Revenue [Line Items]
Revenues	73,059	64,668	51,818
North America Regions | Other
Disaggregation of Revenue [Line Items]
Revenues	7,658	6,377	5,466
U.S. Federal
Disaggregation of Revenue [Line Items]
Revenues	372,536	402,884	391,891
U.S. Federal | Project revenue
Disaggregation of Revenue [Line Items]
Revenues	294,082	342,238	333,846
U.S. Federal | O&M revenue
Disaggregation of Revenue [Line Items]
Revenues	60,057	53,496	51,857
U.S. Federal | Energy assets
Disaggregation of Revenue [Line Items]
Revenues	17,449	6,326	5,822
U.S. Federal | Other
Disaggregation of Revenue [Line Items]
Revenues	948	824	366
Renewable Fuels
Disaggregation of Revenue [Line Items]
Revenues	173,342	117,075	114,459
Renewable Fuels | Project revenue
Disaggregation of Revenue [Line Items]
Revenues	43,353	0	0
Renewable Fuels | O&M revenue
Disaggregation of Revenue [Line Items]
Revenues	7,895	10,697	10,377
Renewable Fuels | Energy assets
Disaggregation of Revenue [Line Items]
Revenues	121,960	106,359	104,082
Renewable Fuels | Other
Disaggregation of Revenue [Line Items]
Revenues	134	19	0
Europe
Disaggregation of Revenue [Line Items]
Revenues	250,574	149,354	58,410
Europe | Project revenue
Disaggregation of Revenue [Line Items]
Revenues	238,848	138,730	53,680
Europe | O&M revenue
Disaggregation of Revenue [Line Items]
Revenues	2,807	1,979	456
Europe | Energy assets
Disaggregation of Revenue [Line Items]
Revenues	847	1,392	281
Europe | Other
Disaggregation of Revenue [Line Items]
Revenues	8,072	7,253	3,993
All Other
Disaggregation of Revenue [Line Items]
Revenues	94,648	88,886	86,381
All Other | Project revenue
Disaggregation of Revenue [Line Items]
Revenues	0	1,250	0
All Other | O&M revenue
Disaggregation of Revenue [Line Items]
Revenues	0	1	16
All Other | Energy assets
Disaggregation of Revenue [Line Items]
Revenues	29	145	87
All Other | Other
Disaggregation of Revenue [Line Items]
Revenues	$ 94,619	$ 87,490	$ 86,278

Revenue from Contracts with C_4

Revenue from Contracts with Customers - Contract Balances (Details) - USD ($) $ in Thousands	Dec. 31, 2024		Dec. 31, 2023		Jan. 01, 2023
Revenue from Contract with Customer [Abstract]
Accounts receivable, net	$ 256,961	[1]	$ 153,362	[1]	$ 174,009
Accounts receivable retainage	39,843		33,826		38,057
Contract Assets
Unbilled revenue	644,105	[1]	636,163	[1]	576,363
Contract Liabilities
Deferred revenue	91,734		52,903		34,796
Deferred revenue, non-current	29,885		18,393		7,617
Total contract liabilities	$ 121,619		$ 71,296		$ 42,413
[1]Includes restricted assets of consolidated variable interest entities (“VIEs”) of $158,548 as of December 31, 2024 and $312,701 as of December 31, 2023. Includes liabilities of consolidated VIEs of $16,871 as of December 31, 2024 and $199,063 as of December 31, 2023. See Note 11.

Revenue from Contracts with C_5

Revenue from Contracts with Customers - Additional Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Contract with customer, asset, revenue recognized	$ 1,192,464	$ 940,317
Contract with customer, asset, reclassified to receivable	1,213,716	886,788
Revenue recognized	377,569	160,713
Contract with customer, liability, billings	377,591	184,174
Revenue, remaining performance obligation, amount	$ 3,922,391
Contract term	25 years
Capitalized commission costs	$ 1,623	$ 1,735
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2025-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation, percentage	32%
Revenue, remaining performance obligation, remaining satisfaction	12 months

Revenue from Contracts with C_6

Revenue from Contracts with Customers - Consolidated Statements of Income (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Revenue from Contract with Customer [Abstract]
Project development costs recognized	$ 18,023	$ 13,051	$ 15,507

Business Acquisitions and Div_3

Business Acquisitions and Divestitures - Additional Information (Details) - USD ($)				9 Months Ended	12 Months Ended
	Dec. 31, 2023	Mar. 31, 2023	Mar. 30, 2023	Dec. 31, 2023	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Business Acquisition [Line Items]
Contingent consideration	$ 1,465,000			$ 1,465,000	$ 1,614,000	$ 1,465,000
Goodwill, net	75,587,000			75,587,000	66,305,000	75,587,000	$ 70,633,000
Net proceeds from sale of business					54,249,000	0	$ 0
Goodwill disposed of through sale of business					8,529,000
Disposal Group, Disposed of by Sale, Not Discontinued Operations | Applied Energy Group, Inc
Business Acquisition [Line Items]
Net of transaction costs					60,400,000
Net proceeds from sale of business					54,249,000
Gain (loss) on disposition of stock in subsidiary					38,007,000
Sale of stock in subsidiary, transaction costs					2,179,000
Goodwill disposed of through sale of business					8,529,000
Disposal Group, Disposed of by Sale, Not Discontinued Operations | Applied Energy Group, Inc | Senior Loans
Business Acquisition [Line Items]
Repayments of long-term debt					$ 57,000,000
Enerqos
Business Acquisition [Line Items]
Fair value of consideration	13,445,000	$ 13,445,000	$ 13,445,000
Payments to acquire businesses, gross	9,535,000	9,535,000		9,535,000
Contingent consideration			0
Cash acquired from acquisition			353,000
Long-term debt assumed, net of current portions	3,951,000	3,951,000	3,951,000
Deferred tax liability	931,000	931,000	931,000	931,000		931,000
Goodwill, net	$ 6,690,000	$ 6,855,000	$ 6,855,000	$ 6,690,000		$ 6,690,000

Business Acquisitions and Div_4

Business Acquisitions and Divestitures - Revenue and Net (Loss) Income (Details) - Enerqos - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Business Acquisition [Line Items]
Revenue	$ 27,809	$ 52,241
Net (loss) income	$ (2,961)	$ 1,758

Business Acquisitions and Div_5

Business Acquisitions and Divestitures - Consideration Paid and the Allocation of the Purchase Price (Details) - USD ($) $ in Thousands				9 Months Ended	12 Months Ended
	Dec. 31, 2023	Mar. 31, 2023	Mar. 30, 2023	Dec. 31, 2023	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Business Acquisition [Line Items]
Goodwill	$ 75,587			$ 75,587	$ 66,305	$ 75,587	$ 70,633
Measurement period adjustment, Goodwill					$ 0	(165)
Enerqos
Business Acquisition [Line Items]
Cash	9,535	$ 9,535		9,535
Long-term debt assumed, net of current portions	3,951	3,951	$ 3,951
FX adjustment	(41)	(41)
Fair value of consideration transferred	13,445	13,445	13,445
Cash and cash equivalents	190	190		190		190
Accounts receivable	6,230	6,230		6,230		6,230
Unbilled revenue	8,985	8,985		8,985		8,985
Prepaid expenses and other current assets	16,504	16,504		16,504		16,504
Project development costs	5,140	5,140		5,140		5,140
Property and equipment and energy assets	1,234	1,234		1,234		1,234
Intangible assets	4,438	4,438		4,438		4,438
Long-term restricted cash	163	163		163		163
Accounts payable	(15,480)	(15,480)		(15,480)		(15,480)
Accrued expenses and other current liabilities	(4,345)	(4,510)		(4,345)		(4,345)
Measurement period adjustment, Accrued expenses and other current liabilities						165
Current portions of long-term debt	(15,165)	(15,165)		(15,165)		(15,165)
Deferred income tax liabilities, net	(931)	(931)	(931)	(931)		(931)
Other liabilities	(208)	(208)		(208)		(208)
Recognized identifiable assets acquired and liabilities assumed	6,755	6,590		6,755		6,755
Measurement period adjustment, Recognized identifiable assets acquired and liabilities assumed						165
Goodwill	$ 6,690	$ 6,855	$ 6,855	$ 6,690		6,690
Measurement period adjustment, Goodwill						$ (165)

Goodwill and Intangible Asset_3

Goodwill and Intangible Assets, Net - Additional Information (Details) - USD ($)	3 Months Ended	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Goodwill [Line Items]
Asset impairments	$ 1,644,000	$ 0		$ 0
Percentage of fair value that was less than carrying value	16%	49%	16%
Percentage of fair value that was less than carrying value	(2.00%)		(2.00%)
Goodwill impairment net of tax	$ 2,222,000	$ 0	$ 2,222,000	$ 0
Minimum
Goodwill [Line Items]
Intangible assets amortization period		1 year
Minimum | Customer contracts
Goodwill [Line Items]
Intangible assets amortization period		1 year
Minimum | Customer relationships, noncompete agreements, technology and trade names
Goodwill [Line Items]
Intangible assets amortization period		4 years
Maximum
Goodwill [Line Items]
Intangible assets amortization period		15 years
Maximum | Customer contracts
Goodwill [Line Items]
Intangible assets amortization period		8 years
Maximum | Customer relationships, noncompete agreements, technology and trade names
Goodwill [Line Items]
Intangible assets amortization period		20 years

Goodwill and Intangible Asset_4

Goodwill and Intangible Assets, Net - Goodwill (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Goodwill [Roll Forward]
Beginning Balance		$ 75,587	$ 70,633
Goodwill acquired during the year			6,855
Remeasurement adjustments		0	(165)
Goodwill disposed of through sale of business		(8,529)
Impairment charges, net of tax	$ (2,222)	0	(2,222)	$ 0
Foreign currency translation		(753)	486
Ending Balance	75,587	66,305	75,587	70,633
Accumulated Goodwill Impairment	(3,238)	(3,238)	(3,238)
North America Regions
Goodwill [Roll Forward]
Beginning Balance		40,680	42,829
Goodwill acquired during the year			0
Remeasurement adjustments		(1,474)	0
Goodwill disposed of through sale of business		0
Impairment charges, net of tax			(2,222)
Foreign currency translation		(257)	73
Ending Balance	40,680	38,949	40,680	42,829
Accumulated Goodwill Impairment	(2,222)	(2,222)	(2,222)
U.S. Federal
Goodwill [Roll Forward]
Beginning Balance		3,981	3,981
Goodwill acquired during the year			0
Remeasurement adjustments		0	0
Goodwill disposed of through sale of business		0
Impairment charges, net of tax			0
Foreign currency translation		0	0
Ending Balance	3,981	3,981	3,981	3,981
Accumulated Goodwill Impairment	0	0	0
Europe
Goodwill [Roll Forward]
Beginning Balance		13,035	5,932
Goodwill acquired during the year			6,855
Remeasurement adjustments		0	(165)
Goodwill disposed of through sale of business		0
Impairment charges, net of tax			0
Foreign currency translation		(496)	413
Ending Balance	13,035	12,539	13,035	5,932
Accumulated Goodwill Impairment	(1,016)	(1,016)	(1,016)
Other
Goodwill [Roll Forward]
Beginning Balance		17,891	17,891
Goodwill acquired during the year			0
Remeasurement adjustments		1,474	0
Goodwill disposed of through sale of business		(8,529)
Impairment charges, net of tax			0
Foreign currency translation		0	0
Ending Balance	17,891	10,836	17,891	$ 17,891
Accumulated Goodwill Impairment	$ 0	$ 0	$ 0

Goodwill and Intangible Asset_5

Goodwill and Intangible Assets, Net - Intangible Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	$ 33,960	$ 37,147
Accumulated Amortization	25,146	30,339
Intangible assets, net	8,814	6,808
Customer contracts
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	6,898	8,859
Accumulated Amortization	6,898	8,859
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	17,572	21,182
Accumulated Amortization	13,318	14,979
Non-compete agreements
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	2,535	3,013
Accumulated Amortization	2,535	3,013
Technology
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	1,754	2,723
Accumulated Amortization	1,753	2,723
Tradenames
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	927	1,370
Accumulated Amortization	642	765
Subsurface land easements
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	$ 4,274	$ 0

Goodwill and Intangible Asset_6

Goodwill and Intangible Assets, Net - Amortization (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Finite-Lived Intangible Assets [Line Items]
Total amortization expense	$ 2,134	$ 2,366	$ 1,858
Customer contracts
Finite-Lived Intangible Assets [Line Items]
Total amortization expense	0	0	551
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Total amortization expense	1,833	2,141	1,303
Technology
Finite-Lived Intangible Assets [Line Items]
Total amortization expense	0	0	1
Tradenames
Finite-Lived Intangible Assets [Line Items]
Total amortization expense	296	225	3
Subsurface land easements
Finite-Lived Intangible Assets [Line Items]
Total amortization expense	$ 5	$ 0	$ 0

Goodwill and Intangible Asset_7

Goodwill and Intangible Assets, Net - Future Amortization (Details) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Finite-Lived Intangible Assets [Line Items]
Intangible assets, net	$ 8,814	$ 6,808
Selling, general and administrative expense
Finite-Lived Intangible Assets [Line Items]
2025	2,238
2026	1,895
2027	821
2028	369
2029	214
Thereafter	3,277
Intangible assets, net	$ 8,814

Property and Equipment, Net (De

Property and Equipment, Net (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 34,115	$ 42,960
Less: accumulated depreciation	(23,075)	(25,565)
Property and equipment, net	11,040	17,395
Selling, general & administrative expenses	4,963	4,155	$ 2,665
Furniture and office equipment
Property, Plant and Equipment [Line Items]
Property and equipment, gross	4,198	4,207
Computer equipment and software costs
Property, Plant and Equipment [Line Items]
Property and equipment, gross	18,706	27,199
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property and equipment, gross	2,312	2,570
Automobiles
Property, Plant and Equipment [Line Items]
Property and equipment, gross	1,956	2,041
Land
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 6,943	$ 6,943

Energy Assets, Net - Energy Ass

Energy Assets, Net - Energy Assets (Details) - USD ($) $ in Thousands		Dec. 31, 2024	Dec. 31, 2023
Property, Plant and Equipment [Line Items]
Energy assets, net	[1]	$ 1,915,311	$ 1,689,424
Renewal Energy Program
Property, Plant and Equipment [Line Items]
Energy assets		2,338,680	2,054,145
Less: accumulated depreciation, net		(423,369)	(364,721)
Energy assets, net		$ 1,915,311	$ 1,689,424
[1]Includes restricted assets of consolidated variable interest entities (“VIEs”) of $158,548 as of December 31, 2024 and $312,701 as of December 31, 2023. Includes liabilities of consolidated VIEs of $16,871 as of December 31, 2024 and $199,063 as of December 31, 2023. See Note 11.

Energy Assets, Net - Additional

Energy Assets, Net - Additional Information (Details) $ in Thousands				1 Months Ended	12 Months Ended
	Jan. 12, 2024 USD ($)	Nov. 01, 2023 USD ($)	Aug. 04, 2023 USD ($)	Jan. 31, 2024 USD ($)	Dec. 31, 2024 USD ($) project energy_asset	Dec. 31, 2023 USD ($) project	Dec. 31, 2022 USD ($)	Feb. 26, 2024 USD ($)
Property, Plant and Equipment [Line Items]
Payment on seller's promissory note					$ 61,941	$ 0	$ 0
Benefit of grant amount						$ 20,970
Number of energy assets disposed of | energy_asset					8
Sale of investment tax credit					$ 47,534
Number of ESPC asset projects | project					6	6
Energy Asset Group One
Property, Plant and Equipment [Line Items]
Energy asset impairment charges					$ 8,715	$ 1,298
Energy Asset Group Two
Property, Plant and Equipment [Line Items]
Energy asset impairment charges					3,669	311
Bright Canyon Corporation
Property, Plant and Equipment [Line Items]
Asset acquisition, percentage of shares acquired			100%
Asset acquisition, total purchase price	$ 48,035		$ 87,964
Cash payment for asset acquisition	9,839		5,000
Payable to seller	$ 32,500		46,694		5,696
Asset acquisition, debt assumed								$ 36,270
Cash acquired			$ 11,206
Payment on seller's promissory note				$ 29,441	$ 32,500	$ 18,400
Adjustment, consideration transferred				$ 1,147
November 2023 Purchase Agreement
Property, Plant and Equipment [Line Items]
Asset acquisition, total purchase price		$ 3,128
Cash payment for asset acquisition		2,676
Payable to seller		$ 452

Energy Assets, Net - Depreciati

Energy Assets, Net - Depreciation and Amortization Expense of Energy Assets (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Cost of revenues	$ 82,114	$ 59,390	$ 49,755

Energy Assets, Net - Capitalize

Energy Assets, Net - Capitalized Interest (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Capitalized interest	$ 50,889	$ 43,561	$ 13,050

Energy Assets, Net - Customer E

Energy Assets, Net - Customer Energy Asset Projects (Details) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023	Jan. 01, 2023
Disaggregation of Revenue [Line Items]
Deferred revenue	$ 91,734	$ 52,903	$ 34,796
Deferred grant income	29,885	18,393	7,617
Total contract liabilities	121,619	71,296	$ 42,413
Renewal Energy Program
Disaggregation of Revenue [Line Items]
Deferred revenue	651	598
Deferred grant income	47,692	41,680
Total contract liabilities	$ 48,343	$ 42,278

Energy Assets, Net - Asset And

Energy Assets, Net - Asset And Liabilities Retirement Obligations (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Business Acquisition [Line Items]
ARO assets, net	$ 4,414	$ 4,800
ARO liabilities, non-current	6,136	5,960
Depreciation expense of ARO assets	4,963	4,155	$ 2,665
Accretion expense of ARO liabilities	332	258	146
Asset Retirement Obligation (ARO) Asset
Business Acquisition [Line Items]
Depreciation expense of ARO assets	$ 238	$ 215	$ 146

Leases - Narrative (Details)

Leases - Narrative (Details)		1 Months Ended	12 Months Ended
	Aug. 14, 2024 USD ($)	Aug. 31, 2024 USD ($)	Dec. 31, 2024 USD ($) project lease_liability renewal_option	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)	Jan. 31, 2024	Aug. 31, 2023	Apr. 18, 2023 investor	Jan. 31, 2023
Lessee, Lease, Description [Line Items]
Number of renewal options | renewal_option			1
Number of lease liabilities | lease_liability			6
Lease agreement period							30 years		37 years
Net present value of commitments			$ 161,169,000
Lease term			36 years
Net amortization expense (gains)			$ 230,000	$ 230,000	$ 383,000
Revolving Credit Facility | Line of Credit
Lessee, Lease, Description [Line Items]
Stated interest rate (percent)			7.99%
August 2018 Long Term Finance Liability | Solar PV project
Lessee, Lease, Description [Line Items]
Solar PV projects sold | project			6
Investment fund call option exercise			$ 61,996,000
December 2020 Long Term Finance Liability | Solar PV project | Revolving Credit Facility | Line of Credit
Lessee, Lease, Description [Line Items]
Available funding under lending commitment			$ 0	$ 0
August 2024 Long Term Finance Liability | August 2024 Sale-Leaseback
Lessee, Lease, Description [Line Items]
Investment fund call option exercise	$ 234,788,000
Number of investors | investor								2
Energy asset percentage	50%
Debt issuance costs	$ 2,833,000
Construction Credit Facility, Due August 2024 | Revolving Credit Facility | Line of Credit
Lessee, Lease, Description [Line Items]
Proceeds used to repay revolving credit facility		$ 140,844,000
Rent prepayment		$ 60,100,000
Minimum
Lessee, Lease, Description [Line Items]
Operating lease renewal term			6 months
Lease agreement period						35 years
Minimum | August 2018 Long Term Finance Liability | Solar PV project
Lessee, Lease, Description [Line Items]
Stated interest rate (percent)			0%
Maximum
Lessee, Lease, Description [Line Items]
Operating lease renewal term			7 years
Lease agreement period						37 years
Maximum | August 2018 Long Term Finance Liability | Solar PV project
Lessee, Lease, Description [Line Items]
Stated interest rate (percent)			1.86%

Leases - Rent and Related Expen

Leases - Rent and Related Expenses (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Leases [Abstract]
Rent and related expenses	$ 13,945	$ 10,504	$ 9,199

Leases - Supplemental Balance S

Leases - Supplemental Balance Sheet Information Related to Leases (Details) - USD ($) $ in Thousands		Dec. 31, 2024	Dec. 31, 2023
Operating Leases
Right-of-use assets, net	[1]	$ 80,149	$ 58,586
Current portions of operating lease liabilities	[1]	10,536	13,569
Long-term operating lease liabilities, net of current portion	[1]	59,479	42,258
Total operating lease liabilities		$ 70,015	$ 55,827
Operating leases, weighted-average remaining lease term (in years)		19 years	18 years
Operating leases, weighted-average discount rate (as a percent)		6.60%	6.60%
Financing Leases:
Energy assets, net		$ 25,158	$ 27,262
Current portions of financing lease liabilities		637	871
Long-term financing lease liabilities, net of current portion, unamortized discount and debt issuance costs		12,267	13,057
Total financing lease liabilities		$ 12,904	$ 13,928
Financing leases, weighted-average remaining lease term (in years)		12 years	13 years
Financing leases, weighted-average discount rate (as a percent)		12.03%	12.05%
Finance Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List]		Energy assets, net	Energy assets, net
Finance Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration]		Current portions of long-term debt and financing lease liabilities	Current portions of long-term debt and financing lease liabilities
Finance Lease, Liability, Noncurrent, Statement of Financial Position [Extensible List]		Long-term debt and financing lease liabilities, net of current portion, unamortized discount and debt issuance costs	Long-term debt and financing lease liabilities, net of current portion, unamortized discount and debt issuance costs
[1]Includes restricted assets of consolidated variable interest entities (“VIEs”) of $158,548 as of December 31, 2024 and $312,701 as of December 31, 2023. Includes liabilities of consolidated VIEs of $16,871 as of December 31, 2024 and $199,063 as of December 31, 2023. See Note 11.

Leases - Lease Cost (Details)

Leases - Lease Cost (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Operating Leases
Operating lease costs	$ 12,945	$ 9,416	$ 8,372
Financing Leases
Amortization expense	2,104	2,103	2,104
Interest on lease liabilities	1,752	1,804	2,147
Total financing lease costs	3,856	3,907	4,251
Total lease costs	$ 16,801	$ 13,323	$ 12,623

Leases - Supplemental of Cash F

Leases - Supplemental of Cash Flow (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Leases [Abstract]
Cash paid for amounts included in the measurement of operating lease liabilities	$ 19,428	$ 10,724
Right-of-use assets obtained in exchange for new operating lease liabilities	29,808	25,225
Non-monetary lease transactions	$ 10,378	$ 13,941

Leases - Minimum Future Lease O

Leases - Minimum Future Lease Obligations (Details) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Operating Leases
2025	$ 14,527
2026	9,702
2027	8,565
2028	7,174
2029	5,521
Thereafter	73,464
Total minimum lease payments	118,953
Less: interest	48,938
Present value of lease liabilities	70,015	$ 55,827
Financing Leases
2025	1,899
2026	2,054
2027	1,923
2028	1,955
2029	1,892
Thereafter	14,043
Total minimum lease payments	23,766
Less: interest	10,862	12,468
Present value of lease liabilities	$ 12,904	$ 13,928

Leases - Amounts Related to Sal

Leases - Amounts Related to Sale Leaseback (Details) - Solar PV project - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Sale Leaseback Transaction [Line Items]
Deferred loss, short-term, net	$ 115	$ 115
Deferred loss, long-term, net	1,224	1,340
Total deferred loss	1,339	1,455
Deferred gain, short-term, net	345	345
Deferred gain, long-term, net	3,739	4,085
Total deferred gain	$ 4,084	$ 4,430

Debt and Financing Lease Liab_3

Debt and Financing Lease Liabilities - Schedule of Debt (Details) - USD ($) $ in Thousands		Dec. 31, 2024	Dec. 31, 2023	Aug. 31, 2023	Jun. 30, 2022
Debt Instrument [Line Items]
Financing Leases		$ 12,904	$ 13,928
Total debt and financing leases		1,674,187	1,514,304
Less: current maturities, net of unamortized discount		149,363	322,247
Less: unamortized discount and debt issuance costs		40,924	21,982
Long-term debt and financing lease liabilities, net of current portion, unamortized discount and debt issuance costs	[1]	1,483,900	1,170,075
Future interest payments		10,862	12,468
Term Loan
Debt Instrument [Line Items]
Long-term debt, gross		674,704	564,530
Financing facilities | Enerqos
Debt Instrument [Line Items]
Long-term debt, gross		13,934	17,786
Master Sale-Leaseback
Debt Instrument [Line Items]
Long-term debt, gross		399,370	185,698
Senior Secured Credit Facility Due in January 2024 To March 2025
Debt Instrument [Line Items]
Long-term debt, gross		$ 148,000	279,900
Fixed Rate Due in June 2028 | Term Loan
Debt Instrument [Line Items]
Stated interest rate (percent)		6.11%
Long-term debt, gross		$ 1,417	1,976
Variable Rate Due In June 2025 | Term Loan
Debt Instrument [Line Items]
Debt interest rate (percent)		7.22%
Long-term debt, gross		$ 31,660	34,453
Variable Rate Due In March 2028 | Term Loan
Debt Instrument [Line Items]
Debt interest rate (percent)		6.54%
Long-term debt, gross		$ 13,271	13,747
Fixed Rate Due in June 2031 | Term Loan
Debt Instrument [Line Items]
Stated interest rate (percent)		4.95%
Long-term debt, gross		$ 1,813	2,253
Fixed Rate Due in February 2034 | Term Loan
Debt Instrument [Line Items]
Stated interest rate (percent)		5.61%
Long-term debt, gross		$ 1,128	1,348
Variable Rate Due In December 2027 | Term Loan
Debt Instrument [Line Items]
Debt interest rate (percent)		7.14%
Long-term debt, gross		$ 4,944	7,158
Fixed Rate Due in December 2038 | Term Loan
Debt Instrument [Line Items]
Debt interest rate (percent)		5.15%
Long-term debt, gross		$ 18,883	21,063
Variable Rate Due In June 2033 | Term Loan
Debt Instrument [Line Items]
Debt interest rate (percent)		6.74%
Long-term debt, gross		$ 5,500	6,592
Variable Rate Fixed Rate Due In October 2029 | Term Loan
Debt Instrument [Line Items]
Debt interest rate (percent)		7.20%
Long-term debt, gross		$ 5,264	6,145
Fixed Rate Due in December 2027 | Loans Payable
Debt Instrument [Line Items]
Stated interest rate (percent)		3.58%
Long-term debt, gross		$ 1,400	2,004
Fixed Rate Due in June 2045 | Loans Payable
Debt Instrument [Line Items]
Stated interest rate (percent)		4.92%
Long-term debt, gross		$ 3,154	3,489
Fixed Rate Due in March 2046 | Loans Payable
Debt Instrument [Line Items]
Stated interest rate (percent)		3.25%
Long-term debt, gross		$ 33,214	35,090
Variable Rate Term Loan Due In July 2030 | Term Loan
Debt Instrument [Line Items]
Debt interest rate (percent)		8.34%
Long-term debt, gross		$ 0	2,140
Variable Rate Term Loan Due In March 2042 | Loans Payable
Debt Instrument [Line Items]
Stated interest rate (percent)					5.45%
Long-term debt, gross		$ 5,942	6,395
Fixed Rate Due in August 2039 | Loans Payable
Debt Instrument [Line Items]
Stated interest rate (percent)		6.70%
Long-term debt, gross		$ 362,583	349,093
Fixed Rate Due in December 2047 | Loans Payable
Debt Instrument [Line Items]
Stated interest rate (percent)		5.99%
Long-term debt, gross		$ 21,290	21,984
Sellers Promissory Rate Due in January 2024 | Unsecured Debt
Debt Instrument [Line Items]
Stated interest rate (percent)		5%
Long-term debt, gross		$ 0	28,294
Fixed Rate Due in April 2047 | Loans Payable
Debt Instrument [Line Items]
Stated interest rate (percent)		5.83%
Long-term debt, gross		$ 12,290	3,520
Fixed Rate Note Payable, 6.20%, Due June 2042 | Loans Payable
Debt Instrument [Line Items]
Stated interest rate (percent)		6.20%
Long-term debt, gross		$ 89,846	0
Fixed Rate Due in June 2042 | Loans Payable
Debt Instrument [Line Items]
Stated interest rate (percent)		8%
Long-term debt, gross		$ 12,566	0
Variable Rate Due In April 2030 | Loans Payable
Debt Instrument [Line Items]
Stated interest rate (percent)		6.33%
Long-term debt, gross		$ 34,605	0
Master Sale-Leaseback Due In July 2039 | Master Sale-Leaseback
Debt Instrument [Line Items]
Debt interest rate (percent)		0%
Master Sale-Leaseback Due In December 2049 | Master Sale-Leaseback
Debt Instrument [Line Items]
Debt interest rate (percent)		1.86%
Master Sale-Leaseback Due In July 2039 To December 2049 | Master Sale-Leaseback
Debt Instrument [Line Items]
Long-term debt, gross		$ 205,565	163,504
Master Sale-Leaseback Due In December 2040 | Master Sale-Leaseback
Debt Instrument [Line Items]
Debt interest rate (percent)		0%
Master Sale-Leaseback Due In March 2043 | Master Sale-Leaseback
Debt Instrument [Line Items]
Debt interest rate (percent)		0%
Master Sale-Leaseback Due In December 2040 To March 2043 | Master Sale-Leaseback
Debt Instrument [Line Items]
Long-term debt, gross		$ 21,111	22,194
Master Sale-Leaseback In August 2034 | Master Sale-Leaseback
Debt Instrument [Line Items]
Debt interest rate (percent)		0%
Master Sale-Leaseback Due In August 2044 | Master Sale-Leaseback
Debt Instrument [Line Items]
Debt interest rate (percent)		0%
Master Sale-Leaseback Due In August 2034 to August 2044 | Master Sale-Leaseback
Debt Instrument [Line Items]
Long-term debt, gross		$ 172,694	0
Senior secured credit facility | Senior Secured Credit Facility Due in January 2024 To March 2025 | Line of Credit
Debt Instrument [Line Items]
Debt interest rate (percent)		7.90%
Long-term debt, gross		$ 148,000	279,900
Senior secured credit facility | Second Lien Term Loan Due In June 2029 | Line of Credit
Debt Instrument [Line Items]
Debt interest rate (percent)		10.57%
Long-term debt, gross		$ 100,000	0
Revolving Credit Facility | Line of Credit
Debt Instrument [Line Items]
Stated interest rate (percent)		7.99%
Long-term debt, gross		$ 339,209	470,248
Revolving Credit Facility | Senior Secured Credit Facility Due in January 2024 To March 2025 | Line of Credit
Debt Instrument [Line Items]
Long-term debt, gross		$ 135,000	139,900
Revolving Credit Facility | June 2020 Construction Revolver Loans Payable Due In March 2025 | Line of Credit
Debt Instrument [Line Items]
Debt interest rate (percent)		6.14%
Long-term debt, gross		$ 20,385	20,705
Revolving Credit Facility | April 2023 Construction Credit Facility Loans Payable Due In July 2024 | Line of Credit
Debt Instrument [Line Items]
Debt interest rate (percent)		6.82%
Long-term debt, gross		$ 0	134,415
Revolving Credit Facility | August 2023 Construction Credit Facility Loans Payable Due In December 2027 | Line of Credit
Debt Instrument [Line Items]
Debt interest rate (percent)		8.53%
Long-term debt, gross		$ 318,824	278,858
Revolving Credit Facility | August 2023 Construction Revolver Loans Payable Due In February 2024 | Line of Credit
Debt Instrument [Line Items]
Debt interest rate (percent)				6.85%
Long-term debt, gross		$ 0	$ 36,270
Revolving Credit Facility | Variable Rate Due In April 2030 | Line of Credit
Debt Instrument [Line Items]
Debt interest rate (percent)		6.33%
[1]Includes restricted assets of consolidated variable interest entities (“VIEs”) of $158,548 as of December 31, 2024 and $312,701 as of December 31, 2023. Includes liabilities of consolidated VIEs of $16,871 as of December 31, 2024 and $199,063 as of December 31, 2023. See Note 11.

Debt and Financing Lease Liab_4

Debt and Financing Lease Liabilities - Schedule of Maturities (Details) $ in Thousands	Dec. 31, 2024 USD ($)
Debt Disclosure [Abstract]
2025	$ 149,363
2026	78,201
2027	395,886
2028	206,115
2029	167,686
Thereafter	676,936
Total maturities	$ 1,674,187

Debt and Financing Lease Liab_5

Debt and Financing Lease Liabilities - Senior Secured Credit Facility - Revolver and Term Loans (Details)				12 Months Ended
	Jan. 23, 2025 USD ($)	Jun. 28, 2024 USD ($)	Apr. 10, 2024 USD ($)	Dec. 31, 2024 USD ($)	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)	Apr. 15, 2024 USD ($)	Dec. 11, 2023	Dec. 10, 2023
Debt Instrument [Line Items]
Payments on long-term corporate debt financings				$ 127,000,000	$ 155,000,000	$ 52,813,000
Revolving Credit Facility
Debt Instrument [Line Items]
Minimum debt service coverage ratio				1.5	1.5
Additional borrowing capacity (up to)				$ 650,000,000	$ 650,000,000
Subordinated debt							$ 100,000,000
Revolving Credit Facility | Maximum
Debt Instrument [Line Items]
Additional borrowing capacity (up to)				100,000,000	100,000,000
Revolving Credit Facility | Minimum
Debt Instrument [Line Items]
Additional borrowing capacity (up to)				25,000,000	25,000,000
Line of Credit | Revolving Credit Facility
Debt Instrument [Line Items]
Maximum borrowing capacity			$ 100,000,000	$ 200,000,000	$ 200,000,000
Increase in interest rate				0.25%	0.25%
Secured Debt | Term loan A
Debt Instrument [Line Items]
Original principal amount				$ 75,000,000	$ 75,000,000
Senior Secured Credit Facility, Revolver And Term Loans | Line of Credit
Debt Instrument [Line Items]
Original principal amount				495,000,000	495,000,000
Senior Secured Credit Facility, Revolver And Term Loans | Line of Credit | Revolving Credit Facility | Debt Covenant, Period Five
Debt Instrument [Line Items]
Total funded debt to EBITDA covenant ratio, maximum								3.75	3.50
Delayed draw term loan A | Line of Credit | Revolving Credit Facility
Debt Instrument [Line Items]
Maximum borrowing capacity				$ 220,000,000	$ 220,000,000
Senior Secured | Secured Debt
Debt Instrument [Line Items]
Subordinated debt			100,000,000
Payments on long-term corporate debt financings		$ 15,000,000	5,000,000
Debt instrument, periodic payment, principal		$ 15,000,000	7,500,000
Senior Secured | Secured Debt | Subsequent Event
Debt Instrument [Line Items]
Payments of debt issuance costs	$ 2,000,000
Term Loan Due December 28, 2028 | Secured Debt | Revolving Credit Facility
Debt Instrument [Line Items]
Payments on long-term corporate debt financings			225,000,000
Term Loan Due December 28, 2028 | Secured Debt | Term loan A
Debt Instrument [Line Items]
Payments on long-term corporate debt financings			$ 100,000,000

Debt and Financing Lease Liab_6

Debt and Financing Lease Liabilities - Outstanding Credit Facility Amounts (Details) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Senior Secured Credit Facility Due in January 2024 To March 2025
Debt Instrument [Line Items]
Long-term debt, gross	$ 148,000	$ 279,900
Less: unamortized debt discount and debt issuance costs	$ (177)	(884)
Term Loan A
Debt Instrument [Line Items]
Stated interest rate (percent)	6.96%
Term Loan A | Senior Secured Credit Facility Due in January 2024 To March 2025
Debt Instrument [Line Items]
Long-term debt, gross	$ 13,000	75,000
Delayed draw term loan A
Debt Instrument [Line Items]
Stated interest rate (percent)	0%
Delayed draw term loan A | Senior Secured Credit Facility Due in January 2024 To March 2025
Debt Instrument [Line Items]
Long-term debt, gross	$ 0	65,000
Revolving Credit Facility | Revolving credit facility
Debt Instrument [Line Items]
Stated interest rate (percent)	7.99%
Long-term debt, gross	$ 339,209	470,248
Revolving Credit Facility | Revolving credit facility | Senior Secured Credit Facility Due in January 2024 To March 2025
Debt Instrument [Line Items]
Long-term debt, gross	135,000	139,900
Senior secured credit facility | Revolving credit facility | Senior Secured Credit Facility Due in January 2024 To March 2025
Debt Instrument [Line Items]
Long-term debt, gross	148,000	279,900
Total maturities	$ 147,823	$ 279,016

Debt and Financing Lease Liab_7

Debt and Financing Lease Liabilities - Second Lien Credit Facility - Term Loan (Details) - USD ($)			12 Months Ended
	Jun. 28, 2024	Apr. 10, 2024	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Debt Instrument [Line Items]
Payments on long-term corporate debt financings			$ 127,000,000	$ 155,000,000	$ 52,813,000
Line of Credit | Senior secured credit facility
Debt Instrument [Line Items]
Proceeds used to repay revolving credit facility	$ 82,105,000
Junior Secured Notes, Due June 2029, Second Lien | Secured Debt
Debt Instrument [Line Items]
Original principal amount	$ 100,000,000
Basis spread on variable rate	5.875%
Debt issuance costs			$ 5,124,000
Senior Secured | Secured Debt
Debt Instrument [Line Items]
Payments on long-term corporate debt financings	$ 15,000,000	$ 5,000,000

Debt and Financing Lease Liab_8

Debt and Financing Lease Liabilities - Energy Asset Construction Facilities (Details) - Revolving Credit Facility - Line of Credit						1 Months Ended	12 Months Ended
	Dec. 18, 2024 USD ($)	Apr. 05, 2024 USD ($)	Aug. 18, 2023 USD ($)	Apr. 18, 2023 USD ($) lender	Mar. 31, 2023 CAD ($)	Aug. 31, 2024 USD ($)	Dec. 31, 2024 USD ($)	Apr. 10, 2024 USD ($)	Dec. 31, 2023 USD ($)	Jun. 30, 2020 USD ($)
Debt Instrument [Line Items]
Maximum borrowing capacity							$ 200,000,000	$ 100,000,000	$ 200,000,000
Long-term debt, gross							339,209,000		470,248,000
Remaining borrowing capacity							$ 21,099,000
Stated interest rate (percent)							7.99%
June 2020 Construction Revolver Loans Payable Due In March 2025
Debt Instrument [Line Items]
Debt interest rate (percent)							6.14%
Maximum borrowing capacity										$ 100,000,000
Net proceeds							$ 9,356,000
Long-term debt, gross							20,385,000		$ 20,705,000
Remaining borrowing capacity							79,615,000
March 2023 Construction Credit Facility
Debt Instrument [Line Items]
Maximum borrowing capacity					$ 100,000,000
Net proceeds							$ 0
Stated interest rate (percent)					2%		2%
Line of credit facility, availability period					5 years
March 2023 Construction Credit Facility | Minimum
Debt Instrument [Line Items]
Stated interest rate (percent)							1%
Agreement term							1 year
March 2023 Construction Credit Facility | Maximum
Debt Instrument [Line Items]
Stated interest rate (percent)							3%
Agreement term							20 years
Construction Credit Facility, Due July 2024
Debt Instrument [Line Items]
Stated interest rate (percent)				6.82%
Construction Credit Facility, Due July 2024 | Corporate Joint Venture
Debt Instrument [Line Items]
Maximum borrowing capacity				$ 140,844,000
Net proceeds				$ 90,921,000
Number of lenders | lender				2
Construction Credit Facility, Due August 2024
Debt Instrument [Line Items]
Proceeds used to repay revolving credit facility						$ 140,844,000
Construction Credit Facility Due August 2026
Debt Instrument [Line Items]
Stated interest rate (percent)			8.53%
Proceeds used to repay revolving credit facility		$ 86,462,000
Construction Credit Facility Due December 15,2027
Debt Instrument [Line Items]
Maximum borrowing capacity	$ 400,000,000		$ 300,000,000
Net proceeds							$ 178,117,000
Basis spread on variable rate	6%
Maturity extension option period	18 months
Debt instrument, basis spread on variable rate, interest rate floor	2%
Line of credit facility, accordion feature, increase limit	$ 500,000,000
Line of credit facility, accordion feature, option fee	250,000
Payments of debt issuance costs	$ 3,168,000
Total maturities							312,612,000
Unamortized discount and debt issuance costs							$ 6,212,000
Construction Credit Facility Due December 15,2027 | Corporate Joint Venture
Debt Instrument [Line Items]
Net proceeds			200,000,000
Proceeds used to reimburse development and construction cost			$ 187,000,000
Basis spread on variable rate			4%
Commitment fee percentage			0.25%
Maturity extension option period			1 year
Payment for extension fee			$ 3,000,000

Debt and Financing Lease Liab_9

Debt and Financing Lease Liabilities - Energy Asset Financing Facilities and Term Loans (Details)

12 Months Ended

Apr. 05, 2024 USD ($) derivative_instrument

Sep. 28, 2023 USD ($)

Aug. 24, 2023 USD ($)

May 31, 2023 USD ($)

Mar. 31, 2023 USD ($)

Dec. 31, 2024 USD ($)

Apr. 10, 2024 USD ($)

Dec. 31, 2023 USD ($) derivative_instrument

Aug. 18, 2023

Mar. 30, 2023 USD ($)

Mar. 28, 2023 USD ($) note

Oct. 31, 2022 USD ($)

Debt Instrument [Line Items]

Letters of credit outstanding

$ 14,554,000

Interest rate swap instruments

Debt Instrument [Line Items]

Number of instruments held | derivative_instrument

6

Interest rate swap instruments | Designated as Hedging Instrument

Debt Instrument [Line Items]

Initial notional amount

$ 14,084,000

$ 14,084,000

Term Shelf Notes Due December 31, 2047 | Senior Notes

Debt Instrument [Line Items]

Stated interest rate (percent)

5.99%

Unamortized discount

$ 3,123,000

Debt issuance costs

$ 282,000

Number of notes | note

3

Original principal amount

$ 22,625,000

Term Loan Due March 28, 2028 | Term loan A

Debt Instrument [Line Items]

Maximum borrowing capacity

359,000

Term Loan Due March 28, 2028 | Secured Debt

Debt Instrument [Line Items]

Maximum borrowing capacity

14,084,000

Term Loan Due March 28, 2028 | Letter of Credit

Debt Instrument [Line Items]

Maximum borrowing capacity

$ 899,000

Senior Secured Notes, Due June 2042 | Senior Notes

Debt Instrument [Line Items]

Debt issuance costs

$ 1,359,000

Proceeds from issuance of senior long-term debt

9,595,000

Senior Secured Notes, Due June 2042, First Lien | Senior Notes

Debt Instrument [Line Items]

Original principal amount

92,512,000

Proceeds from issuance of senior long-term debt

83,282,000

Senior Secured Notes, Due June 2042, Second Lien | Senior Notes

Debt Instrument [Line Items]

Original principal amount

12,657,000

Proceeds from issuance of senior long-term debt

$ 12,292,000

Fixed Rate Due in June 2042 | Loans Payable

Debt Instrument [Line Items]

Stated interest rate (percent)

8%

Variable Rate Due In March 2028 | Term loan A

Debt Instrument [Line Items]

Debt interest rate (percent)

6.54%

Revolving Credit Facility

Debt Instrument [Line Items]

Periodic principal payment

$ 1,250,000

Maximum amount of company's consolidated stockholders' equity eligible for investment in or loan to non-core subsidiaries

0.49

Revolving Credit Facility | Line of Credit

Debt Instrument [Line Items]

Stated interest rate (percent)

7.99%

Maximum borrowing capacity

$ 200,000,000

$ 100,000,000

$ 200,000,000

Remaining borrowing capacity

21,099,000

Revolving Credit Facility | Fixed Rate Note, Due August, 2039 | Line of Credit

Debt Instrument [Line Items]

Stated interest rate (percent)

6.70%

6.38%

6.50%

Maximum borrowing capacity

$ 500,000,000

$ 215,000,000

$ 125,000,000

Line of credit facility, additional borrowing capacity

90,000,000

Net proceeds

$ 135,544,000

$ 90,000,000

$ 38,280,000

Internal rate of return, percentage

8.51%

Unamortized discount

509,000

Debt issuance costs

$ 305,000

Total maturities

$ 361,666,000

Unamortized discount and debt issuance costs

$ 917,000

Revolving Credit Facility | Fixed Rate Note, Due August, 2039 | Line of Credit | Debt Covenant Period One

Debt Instrument [Line Items]

Internal rate of return prepayment percentage

102%

Revolving Credit Facility | Fixed Rate Note, Due August, 2039 | Line of Credit | Debt Covenant Period Two

Debt Instrument [Line Items]

Internal rate of return prepayment percentage

101%

Revolving Credit Facility | Senior Secured Notes, Due June 2042 | Senior Notes

Debt Instrument [Line Items]

Number of instruments held | derivative_instrument

2

Revolving Credit Facility | Senior Secured Notes, Due June 2042 | Senior Notes | Make-whole Provision June 2042

Debt Instrument [Line Items]

Initial notional amount

$ 8,733,000

Revolving Credit Facility | Senior Secured Notes, Due June 2042 | Senior Notes | Make-whole Provision June 2042

Debt Instrument [Line Items]

Initial notional amount

647,000

Revolving Credit Facility | Construction Credit Facility Due August 2026 | Line of Credit

Debt Instrument [Line Items]

Stated interest rate (percent)

8.53%

Proceeds used to repay revolving credit facility

$ 86,462,000

Debt and Financing Lease Lia_10

Debt and Financing Lease Liabilities - Energy Project Asset Acquisition (Details) $ in Thousands

1 Months Ended

12 Months Ended

Aug. 02, 2024 installment

Feb. 26, 2024 USD ($)

Jan. 31, 2024 USD ($)

Dec. 31, 2024 USD ($)

Dec. 31, 2023 USD ($)

Dec. 31, 2022 USD ($)

Jan. 12, 2024 USD ($)

Sep. 28, 2023

Aug. 31, 2023

Aug. 04, 2023 USD ($)

May 31, 2023

Mar. 30, 2023

Debt Instrument [Line Items]

Payment on seller's promissory note

$ 61,941

$ 0

$ 0

Sellers Promissory Rate Due in January 2024 | Unsecured Debt

Debt Instrument [Line Items]

Stated interest rate (percent)

5%

Bright Canyon Corporation

Debt Instrument [Line Items]

Stated interest rate (percent)

5%

Payable to seller

$ 5,696

$ 32,500

$ 46,694

Asset acquisition, debt assumed

$ 36,270

Payment on seller's promissory note

$ 29,441

$ 32,500

$ 18,400

Basis spread on variable rate

9%

Debt instrument, number of installments | installment

4

Bright Canyon Corporation | Secured Debt | Secured Overnight Financing Rate (SOFR), 4 Year Term

Debt Instrument [Line Items]

Basis spread on variable rate

1.635%

Bright Canyon Corporation | Secured Debt | Secured Overnight Financing Rate (SOFR), 2 Year Term

Debt Instrument [Line Items]

Basis spread on variable rate

1.76%

Revolving Credit Facility | Line of Credit

Debt Instrument [Line Items]

Stated interest rate (percent)

7.99%

Revolving Credit Facility | August 2023 Construction Revolver Loans Payable Due In February 2024 | Line of Credit

Debt Instrument [Line Items]

Debt interest rate (percent)

6.85%

Revolving Credit Facility | Fixed Rate Note, Due August, 2039 | Line of Credit

Debt Instrument [Line Items]

Stated interest rate (percent)

6.70%

6.38%

6.50%

Revolving Credit Facility | Variable Rate Due In April 2030 | Line of Credit

Debt Instrument [Line Items]

Debt interest rate (percent)

6.33%

Income Taxes - Domestic and For

Income Taxes - Domestic and Foreign Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Income Tax Disclosure [Abstract]
Domestic	$ 28,256	$ 30,211	$ 98,004
Foreign	5,684	8,058	7,715
Income before income taxes	$ 33,940	$ 38,269	$ 105,719

Income Taxes - Income Tax (Bene

Income Taxes - Income Tax (Benefit) Provision (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Current income tax provision (benefit):
Federal	$ 1,246	$ 34	$ (722)
State	805	372	733
Foreign	2,414	1,255	1,202
Total current	4,465	1,661	1,213
Deferred income tax (benefit) provision:
Federal	(28,552)	(22,677)	2,528
State	4,265	(5,657)	2,300
Foreign	(178)	1,038	1,129
Total deferred	(24,465)	(27,296)	5,957
Total income tax (benefit) provision	$ (20,000)	$ (25,635)	$ 7,170

Income Taxes - Deferred Income

Income Taxes - Deferred Income Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Deferred income tax assets:
Compensation accruals	$ 5,622	$ 4,137
Reserves	8,009	5,906
Sale-leasebacks and other accruals	39,231	49,300
Net operating losses	9,882	28,565
Interest limitation	16,706	8,273
Energy efficiency	138,647	82,827
Deferred revenue	2,402	2,114
Gross deferred income tax assets	220,499	181,122
Valuation allowance	(4,015)	(3,704)
Total deferred income tax assets	216,484	177,418
Deferred income tax liabilities:
Depreciation	(148,217)	(145,880)
Deferred effect of derivative liability	(5,606)	(2,166)
Outside basis difference	(6,759)	(6,599)
Interest rate swaps	(1,602)	(841)
Total deferred income tax liabilities	(162,184)	(155,486)
Deferred income tax assets (liabilities), net	$ 54,300	$ 21,932

Income Taxes - Valuation Allowa

Income Taxes - Valuation Allowance (Details) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Valuation Allowance [Line Items]
Total valuation allowance	$ 4,015	$ 3,704
Foreign net operating loss
Valuation Allowance [Line Items]
Total valuation allowance	4,013	3,702
State net operating loss at one of our subsidiaries
Valuation Allowance [Line Items]
Total valuation allowance	$ 2	$ 2

Income Taxes - Tax Loss and Cre

Income Taxes - Tax Loss and Credit Carryforwards (Details) $ in Thousands	Dec. 31, 2024 USD ($)
Income Tax Contingency [Line Items]
Operating loss carryforwards	$ 101,457
Federal
Income Tax Contingency [Line Items]
Operating loss carryforwards	0
Federal Energy Investment and Production tax credit carryforward	114,839
State
Income Tax Contingency [Line Items]
Operating loss carryforwards	72,865
Foreign Tax Jurisdiction | Canada
Income Tax Contingency [Line Items]
Operating loss carryforwards	20,922
Foreign Tax Jurisdiction | Ireland
Income Tax Contingency [Line Items]
Operating loss carryforwards	2,110
Foreign Tax Jurisdiction | Italy
Income Tax Contingency [Line Items]
Operating loss carryforwards	2,970
Foreign Tax Jurisdiction | Spain
Income Tax Contingency [Line Items]
Operating loss carryforwards	2,463
Foreign Tax Jurisdiction, Other
Income Tax Contingency [Line Items]
Operating loss carryforwards	$ 127

Income Taxes - Reconciliation o

Income Taxes - Reconciliation of Effective Tax Rates (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Income Tax Disclosure [Abstract]
Income before (benefit) provision for income taxes	$ 33,940	$ 38,269	$ 105,719
Federal statutory tax expense	7,128	8,036	22,201
State income taxes, net of federal benefit	2,345	(774)	3,844
Net state impact of deferred rate change	2,919	(3,213)	(575)
Nondeductible expenses	1,182	667	2,198
Impact of reserve for uncertain tax positions	(265)	(200)	59
Stock-based compensation expense	1,240	4	353
Energy efficiency preferences	(38,929)	(30,359)	(21,410)
Foreign items and rate differential	2,629	458	37
State tax adjustment	0	(66)	0
Redeemable non-controlling interests	729	(227)	(411)
Valuation allowance	311	81	(159)
Miscellaneous	711	(42)	1,033
Total income tax (benefit) provision	$ (20,000)	$ (25,635)	$ 7,170
Effective tax rate:
Federal statutory rate expense	21%	21%	21%
State income taxes, net of federal benefit	6.90%	(2.00%)	3.60%
Net state impact of deferred rate change	8.60%	(8.40%)	(0.50%)
Nondeductible expenses	3.50%	1.70%	2.10%
Impact of reserve for uncertain tax positions	(0.80%)	(0.50%)	0.10%
Stock-based compensation expense	3.70%	0%	0.30%
Energy efficiency preferences	(114.70%)	(79.30%)	(20.30%)
Foreign items and rate differential	7.70%	1.20%	0%
State tax adjustment	0%	(0.20%)	0%
Redeemable non-controlling interests	2.10%	(0.60%)	(0.40%)
Valuation allowance	0.90%	0.20%	(0.20%)
Miscellaneous	2.20%	(0.10%)	1.10%
Effective tax rate	(58.90%)	(67.00%)	6.80%

Income Taxes - Unrecognized Tax

Income Taxes - Unrecognized Tax Benefits (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Unrecognized Tax Benefits [Roll Forward]
Balance, beginning of year	$ 800	$ 900
Additions for current year tax positions	104	100
Reductions of prior year tax positions	0	(200)
Balance, end of year	$ 904	$ 800

Income Taxes - Additional Infor

Income Taxes - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Income Tax Disclosure [Abstract]
Unrecognized tax benefits that would impact effective tax rate	$ 904,000	$ 310,000
Earnings with no repatriation tax	0	0
Amount of (decrease) increase included in tax expense for interest and penalties related to uncertain tax positions	$ 29,000	$ 22,000	$ 22,000

Variable Interest Entities an_3

Variable Interest Entities and Equity Method Investments - Additional Information (Details) $ in Thousands		12 Months Ended
	Feb. 09, 2024 USD ($)	Dec. 31, 2024 USD ($) investment_fund joint_venture equity_investment	Dec. 31, 2023 USD ($) joint_venture	Dec. 31, 2022 USD ($)
Variable Interest Entity [Line Items]
Investment funds | investment_fund		5
Investment funds formed to fund the purchase of solar energy systems | investment_fund		1
Net proceeds from sale of equity investment		$ 13,091	$ 0	$ 0
Number of joint ventures, remaining interest acquired | joint_venture		1
Number of joint ventures | joint_venture		7	7
Number of equity method investments disposed of | equity_investment		1
Gain from sale of equity method investment		$ 224
Corporate Joint Venture
Variable Interest Entity [Line Items]
Additional contribution received from joint venture	$ 6,543
Equity method investment ownership percentage disposed of	40%
Net proceeds from sale of equity investment	$ 28,864

Variable Interest Entities An_4

Variable Interest Entities And Equity Method Investments - Schedule of Variable Interest Entity Financial Information (Details) - USD ($) $ in Thousands		Dec. 31, 2024		Dec. 31, 2023		Jan. 01, 2023
Current assets:
Cash and cash equivalents	[1]	$ 108,516		$ 79,271
Accounts receivable, net		256,961	[1]	153,362	[1]	$ 174,009
Unbilled revenue		644,105	[1]	636,163	[1]	576,363
Prepaid expenses and other current assets		11,997		10,697
Project development costs, net		22,856		20,735
Total current assets	[1]	1,301,134		1,128,471
Property and equipment, net	[1]	11,040		17,395
Energy assets, net	[1]	1,915,311		1,689,424
Intangible assets, net		8,814		6,808
Right-of-use assets, net	[1]	80,149		58,586
Restricted cash, non-current portion		20,156		12,094
Other assets	[1]	89,948		89,735
Total assets	[1]	4,158,508		3,713,776
Current liabilities:
Current portions of long-term debt and financing lease liabilities	[1]	149,363		322,247
Accounts payable	[1]	529,338		402,752
Accrued expenses and other current liabilities	[1]	107,293		108,831
Current portions of right-of-use liabilities	[1]	10,536		13,569
Deferred revenue		91,734		52,903		$ 34,796
Income taxes payable		744		1,169
Total current liabilities	[1]	889,008		901,471
Long-term debt and financing lease liabilities, net of current portion, unamortized discount and debt issuance costs	[1]	1,483,900		1,170,075
Long-term right-of-use liabilities, net of current portion	[1]	59,479		42,258
Other liabilities	[1]	114,454		82,714
Variable Interest Entity
Current assets:
Cash and cash equivalents		8,780		21,879
Accounts receivable, net		14,607		1,977
Unbilled revenue		4,270		14,071
Prepaid expenses and other current assets		1,323		3,782
Income taxes receivable		672		0
Project development costs, net		5,795		0
Total current assets		35,447		41,709
Property and equipment, net		0		267
Energy assets, net		122,414		252,912
Intangible assets, net		20		0
Right-of-use assets, net		471		17,656
Restricted cash, non-current portion		0		73
Other assets		196		84
Total assets		158,548		312,701
Current liabilities:
Current portions of long-term debt and financing lease liabilities		0		134,617
Accounts payable		5,167		7,930
Accrued expenses and other current liabilities		602		23,021
Current portions of right-of-use liabilities		13		7,086
Deferred revenue		10,063		0
Income taxes payable		526		0
Total current liabilities		16,371		172,654
Long-term debt and financing lease liabilities, net of current portion, unamortized discount and debt issuance costs		0		17,167
Long-term right-of-use liabilities, net of current portion		500		8,886
Other liabilities		0		356
Total VIE liabilities		16,871		199,063
Variable Interest Entity | Investment Fund
Current assets:
Cash and cash equivalents		89		5,099
Accounts receivable, net		0		0
Unbilled revenue		230		662
Prepaid expenses and other current assets		30		33
Income taxes receivable		0		0
Project development costs, net		0		0
Total current assets		349		5,794
Property and equipment, net		0		0
Energy assets, net		23,538		79,104
Intangible assets, net		0		0
Right-of-use assets, net		471		4,748
Restricted cash, non-current portion		0		73
Other assets		0		10
Total assets		24,358		89,729
Current liabilities:
Current portions of long-term debt and financing lease liabilities		0		2,190
Accounts payable		27		1,440
Accrued expenses and other current liabilities		25		241
Current portions of right-of-use liabilities		13		133
Deferred revenue		0		0
Income taxes payable		0		0
Total current liabilities		65		4,004
Long-term debt and financing lease liabilities, net of current portion, unamortized discount and debt issuance costs		0		17,167
Long-term right-of-use liabilities, net of current portion		500		5,063
Other liabilities		0		356
Total VIE liabilities		565		26,590
Variable Interest Entity | Other VIEs
Current assets:
Cash and cash equivalents		8,691		16,780
Accounts receivable, net		14,607		1,977
Unbilled revenue		4,040		13,409
Prepaid expenses and other current assets		1,293		3,749
Income taxes receivable		672		0
Project development costs, net		5,795		0
Total current assets		35,098		35,915
Property and equipment, net		0		267
Energy assets, net		98,876		173,808
Intangible assets, net		20		0
Right-of-use assets, net		0		12,908
Restricted cash, non-current portion		0		0
Other assets		196		74
Total assets		134,190		222,972
Current liabilities:
Current portions of long-term debt and financing lease liabilities		0		132,427
Accounts payable		5,140		6,490
Accrued expenses and other current liabilities		577		22,780
Current portions of right-of-use liabilities		0		6,953
Deferred revenue		10,063		0
Income taxes payable		526		0
Total current liabilities		16,306		168,650
Long-term debt and financing lease liabilities, net of current portion, unamortized discount and debt issuance costs		0		0
Long-term right-of-use liabilities, net of current portion		0		3,823
Other liabilities		0		0
Total VIE liabilities		$ 16,306		$ 172,473
[1]Includes restricted assets of consolidated variable interest entities (“VIEs”) of $158,548 as of December 31, 2024 and $312,701 as of December 31, 2023. Includes liabilities of consolidated VIEs of $16,871 as of December 31, 2024 and $199,063 as of December 31, 2023. See Note 11.

Variable Interest Entities an_5

Variable Interest Entities and Equity Method Investments - Investment in Joint Ventures (Details) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Equity and cost method investments	$ 16,987	$ 18,709

Redeemable Non-Controlling In_3

Redeemable Non-Controlling Interests (Details) - USD ($) $ in Thousands	1 Months Ended	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Equity, Attributable to Parent [Abstract]
Remaining redeemable non-controlling interest	$ 3,186	$ 3,186	$ 0	$ 839
Remaining redeemable paid-in capital to reflect the additional contribution	$ 37,269
Remaining investor contributed capital balance, percentage		5%

Equity and Earnings Per Share -

Equity and Earnings Per Share - Additional Information (Details)	Dec. 31, 2024 vote shares
Class A Common Stock
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Number of votes per share	1
Class B Common Stock
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Number of votes per share	5
Common stock, conversion basis (in shares) | shares	1

Equity & Earnings Per Share - S

Equity & Earnings Per Share - Schedule of Earnings Per Share, Basic and Diluted (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Numerator:
Net income attributable to common shareholders	$ 56,757	$ 62,470	$ 94,926
Adjustment for accretion of tax equity financing fees	(107)	(108)	(116)
Income attributable to common shareholders	$ 56,650	$ 62,362	$ 94,810
Denominator:
Basic weighted-average shares outstanding (in shares)	52,380	52,140	51,841
Effect of dilutive securities:
Stock options (in shares)	760	1,087	1,437
Diluted weighted-average shares outstanding (in shares)	53,140	53,228	53,278
Basic (in usd per share)	$ 1.08	$ 1.20	$ 1.83
Diluted (in usd per share)	$ 1.07	$ 1.17	$ 1.78
Potentially dilutive shares (in shares)	2,154	1,707	1,108

Stock-Based Compensation and _3

Stock-Based Compensation and Other Employee Benefits - Additional Information (Details) - USD ($) $ in Thousands	1 Months Ended	12 Months Ended
	May 31, 2020	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense		$ 14,130	$ 10,318	$ 15,046
401(k) plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Employer matching contribution percent		100%
Employer matching percent		6%
Group Personal Pension Plan | UNITED KINGDOM
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Employer matching contribution percent		100%
Employer matching percent		6%
Registered Retirement Savings Plan | Canada
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Employer matching contribution percent		100%
Employer matching percent		6%
Stock Options and Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Non-vested stock options unrecognized compensation expense		$ 28,019
Non-vested stock options unrecognized compensation expense, weighted-average period of recognition		1 year 10 months 24 days
Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Non-vested stock options unrecognized compensation expense, weighted-average period of recognition		1 year
Stock-based compensation expense		$ 2,685
Vested (in shares)		63,000
Non-vested stock options unrecognized compensation expense		$ 1,721
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expiration period		10 years
Ratable vesting percentage		33.33%
Exercise term upon termination		90 days
Stock Options | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options vesting period		5 years
Stock Options | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options vesting period		3 years
Class A Common Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares available for grant (in shares)		1,380,000
2017 Employee Stock Purchase Plan | Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of allocated shares (up to) (in shares)	350				200
Discount from fair value of stock (percent)	5%
Interval term	6 months
Stock issued during period (in shares)		64,000	60,000
Amount withheld for future purchases		$ 99	$ 182

Stock-Based Compensation and _4

Stock-Based Compensation and Other Employee Benefits - Stock Options Activity (Details) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2024 USD ($) $ / shares shares
Number of Options
Beginning balance (in shares) | shares	4,255
Granted (in shares) | shares	792
Exercised (in shares) | shares	(97)
Forfeited (in shares) | shares	(227)
Expired (in shares) | shares	(86)
Ending balance (in shares) | shares	4,637
Options exercisable (in shares) | shares	2,098
Options expected to vest (in shares) | shares	2,538
Weighted-Average Exercise Price
Beginning balance (in usd per share) | $ / shares	$ 46.932
Granted (in usd per share) | $ / shares	23.280
Exercised (in usd per share) | $ / shares	9.666
Forfeited (in usd per share) | $ / shares	63.059
Expired (in usd per share) | $ / shares	46.675
Ending balance (in usd per share) | $ / shares	42.895
Options exercisable (in usd per share) | $ / shares	29.495
Expected to vest (in usd per share) | $ / shares	$ 53.970
Outstanding, remaining contractual term	6 years 4 months 24 days
Exercisable, remaining contractual term	4 years 9 months 18 days
Expected to vest, remaining contractual term	7 years 9 months 18 days
Outstanding, aggregate intrinsic value | $	$ 15,174
Exercisable, aggregate intrinsic value | $	13,932
Expected to vest, aggregate intrinsic value | $	$ 1,242

Stock-Based Compensation and _5

Stock-Based Compensation and Other Employee Benefits - Additional Plans (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Share-Based Payment Arrangement [Abstract]
Aggregate intrinsic value of options exercised	$ 1,602	$ 8,511	$ 9,775
Cash received from stock option exercises	$ 942	$ 2,438	$ 3,954
Weighted-average fair value of stock options granted (in usd per share)	$ 14.16	$ 23.99	$ 37.87
Stock-based compensation expense	$ 14,130	$ 10,318	$ 15,046
Income tax benefit from stock-based compensation expense	$ 105	$ 1,102	$ 659

Stock-Based Compensation and _6

Stock-Based Compensation and Other Employee Benefits - Fair Value Assumptions (Details) - Stock Options - USD ($)	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Fair value significant assumptions:
Expected dividend yield	$ 0	$ 0	$ 0
Risk-free interest rate, minimum	3.78%	3.35%	1.69%
Risk-free interest rate, maximum	4.45%	4.44%	3.82%
Expected volatility, minimum	58%	54%	51%
Expected volatility, maximum	62%	56%	53%
Expected life	6 years 6 months	6 years 6 months	6 years 6 months

Stock-Based Compensation and _7

Stock-Based Compensation and Other Employee Benefits - Restricted Stock Units (Details) - Restricted Stock Units	12 Months Ended
	Dec. 31, 2024 $ / shares shares
Number of Options
Outstanding, beginning balance (in shares) | shares	52,000
Granted (in shares) | shares	122,000
Vested (in shares) | shares	(63,000)
Forfeited (in shares) | shares	(6,000)
Outstanding, ending balance (in shares) | shares	105,000
Weighted-Average Grant Date Fair Value Per Share
Outstanding, beginning balance (in usd per share) | $ / shares	$ 45.90
Granted (in usd per share) | $ / shares	24.38
Vested (usd per share) | $ / shares	37.60
Forfeited (usd per share) | $ / shares	27.98
Outstanding, ending balance (in usd per share) | $ / shares	$ 27.02

Stock-Based Compensation and _8

Stock-Based Compensation and Other Employee Benefits - Matching Contributions (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Employer contributions	$ 9,118	$ 8,642	$ 7,670
401(k) plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Employer contributions	8,090	7,561	6,974
Group Personal Pension Plan | UNITED KINGDOM
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Employer contributions	574	652	290
Registered Retirement Savings Plan | Canada
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Employer contributions	$ 454	$ 429	$ 406

Commitments and Contingencies (

Commitments and Contingencies (Details)			1 Months Ended		12 Months Ended
	Sep. 05, 2024 USD ($)	Aug. 04, 2023 USD ($)	Dec. 31, 2021 USD ($)	Oct. 31, 2021 USD ($) project	Dec. 31, 2024 USD ($)	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)	Aug. 30, 2024 project
Loss Contingencies [Line Items]
Number of battery energy storage system projects | project				3				3
Liquidated damages up to a maximum amount				$ 89,000,000
Maximum amount of liquidated damages	$ 110,000,000
Payment of contingent consideration					$ 0	$ 1,866,000	$ 0
Contingent consideration					1,614,000	1,465,000
Bright Canyon Corporation
Loss Contingencies [Line Items]
Consideration transferred, contingent consideration		$ 40,000,000
Contingent consideration, term		7 years
Plug Smart
Loss Contingencies [Line Items]
Contingent consideration, liability, revenue earn-outs, payment period			5 years
Maximum cumulative earn-out			$ 5,000,000
Contingent consideration, liability			$ 2,160,000
Payment of contingent consideration						$ 3,040,000
Contingent consideration					1,614,000
Plug Smart | Selling, general and administrative expense
Loss Contingencies [Line Items]
Increase (decrease) in contingent consideration					$ 149,000

Geographic Information (Details

Geographic Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived Tangible Assets	$ 1,926,351	$ 1,706,819
Revenues	1,769,928	1,374,633	$ 1,824,422
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived Tangible Assets	1,888,440	1,670,322
Revenues	1,446,879	1,161,775	1,712,326
Canada
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived Tangible Assets	20,509	23,549
Revenues	72,371	63,367	53,461
Europe
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived Tangible Assets	17,402	12,948
Revenues	$ 250,678	$ 149,491	$ 58,635

Interest And Other Expenses, _3

Interest And Other Expenses, Net - Components of Other Expenses, Net (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Other Income and Expenses [Abstract]
Gain on derivatives	$ (1,027)	$ (1,108)	$ (906)
Interest and other expenses, net	65,031	36,169	26,423
Amortization of debt discount and debt issuance costs	5,151	4,201	4,211
Foreign currency transaction loss (gain)	3,840	(581)	144
Government incentives	339	(576)	(2,599)
Bank discount fees	1,471	5,844	0
Other (income) expenses	$ (74,805)	$ (43,949)	$ (27,273)

Interest And Other Expenses, _4

Interest And Other Expenses, Net - Deferred Financing Costs (Details) $ in Thousands	Dec. 31, 2024 USD ($)
Estimated Amortization
2025	$ 6,128
2026	5,898
2027	6,334
2028	3,805
2029	$ 3,105

Fair Value Measurement - Fair V

Fair Value Measurement - Fair Value of Assets and Liabilities Measured on a Recurring Basis (Details) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Liabilities
Contingent consideration	$ 1,614	$ 1,465
Recurring
Liabilities
Total liabilities	17,188	8,106
Recurring | Level 2 | Interest rate swap instruments
Assets
Asset derivatives	5,096	3,970
Liabilities
Liability derivatives	0	629
Recurring | Level 2 | Make-whole provisions
Liabilities
Liability derivatives	15,574	6,012
Recurring | Level 3
Liabilities
Contingent consideration	$ 1,614	$ 1,465

Fair Value Measurement - Additi

Fair Value Measurement - Additional Information (Details) - USD ($)	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Fair Value, Nonrecurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets recorded at fair value on a non-recurring basis	$ 0	$ 0
Plug Smart
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Contingent consideration, liability				$ 2,160,000
Chelsea Group Limited
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Contingent consideration, liability		$ 0	$ 358,000

Fair Value Measurement - Subseq

Fair Value Measurement - Subsequent Key Assumptions (Details) $ in Thousands	Dec. 31, 2024 USD ($)	Dec. 31, 2023 USD ($)	Dec. 31, 2021
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Contingent consideration	$ 1,614	$ 1,465
Plug Smart
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Contingent consideration	$ 1,614
Plug Smart | Discount Rate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Contingent consideration, measurement input	0.169		0.169
Plug Smart | EBITDA Volatility
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Contingent consideration, measurement input	0.700		0.700

Fair Value Measurement - Fair_2

Fair Value Measurement - Fair Value of Contingent Liabilities (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Contingent consideration liabilities balance at the beginning of year	$ 1,465	$ 4,158
Changes in fair value included in earnings	149	347
Payment of contingent consideration	0	(3,040)
Contingent consideration liabilities balance at the end of year	$ 1,614	$ 1,465
Fair Value, Recurring Basis, Unobservable Input Reconciliation, Liability Gain (Loss), Statement Of Income, Extensible List, Not Disclosed Flag	Selling, general and administrative expenses

Fair Value Measurement - Fair_3

Fair Value Measurement - Fair Value and Carrying Value of Long-term Debt (Details) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Fair Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term debt value (level 2)	$ 1,618,208	$ 1,466,458
Carrying Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term debt value (level 2)	$ 1,620,359	$ 1,478,394

Derivative Instruments and He_3

Derivative Instruments and Hedging Activities - Additional Information (Details) $ in Thousands	Dec. 31, 2024 derivative_instrument	Dec. 31, 2023 derivative_instrument	Aug. 31, 2023 derivative_instrument	Jun. 30, 2023 loan_facility	Mar. 31, 2023 USD ($) derivative_instrument	Mar. 30, 2023 USD ($)
Interest rate swap instruments
Derivative Instruments, Gain (Loss) [Line Items]
Number of instruments held		6
Number of instruments designated					1
Number of instruments prepaid | loan_facility				1
Number of instruments acquired			1
Not Designated as Hedging Instrument
Derivative Instruments, Gain (Loss) [Line Items]
Number of instruments held	3	3
Designated as Hedging Instrument | Interest rate swap instruments
Derivative Instruments, Gain (Loss) [Line Items]
Initial notional amount | $					$ 14,084	$ 14,084

Derivative Instruments and He_4

Derivative Instruments and Hedging Activities - Fair Value of Derivative Instruments on the Balance Sheet (Details) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Derivatives Designated as Hedging Instruments | Interest rate swap contracts | Other assets
Derivatives, Fair Value [Line Items]
Fair value, asset derivatives	$ 1,556	$ 1,023
Derivatives Not Designated as Hedging Instruments | Interest rate swap contracts | Other assets
Derivatives, Fair Value [Line Items]
Fair value, asset derivatives	3,540	2,947
Derivatives Not Designated as Hedging Instruments | Interest rate swap contracts | Other liabilities
Derivatives, Fair Value [Line Items]
Fair value, liability derivatives	0	629
Derivatives Not Designated as Hedging Instruments | Make-whole provisions | Other liabilities
Derivatives, Fair Value [Line Items]
Fair value, liability derivatives	$ 15,574	$ 6,012

Derivative Instruments and He_5

Derivative Instruments and Hedging Activities - Effects on Statements of Income and Consolidated Statements of Comprehensive Income (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Derivative Instruments, Gain (Loss) [Line Items]
Amount of (gain) loss recognized in net income	$ (1,027)	$ (1,108)	$ (906)
Derivative, Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]	Nonoperating Income (Expense)
Designated as Hedging Instrument | Interest and other expenses, net | Interest rate swap contracts
Derivative Instruments, Gain (Loss) [Line Items]
Amount of (gain) loss recognized in net income	$ (994)	(770)	1,037
Not Designated as Hedging Instrument | Interest and other expenses, net | Interest rate swap contracts
Derivative Instruments, Gain (Loss) [Line Items]
Amount of (gain) loss recognized in net income	(1,220)	1,354	(2,738)
Not Designated as Hedging Instrument | Interest and other expenses, net | Commodity swap contracts
Derivative Instruments, Gain (Loss) [Line Items]
Amount of (gain) loss recognized in net income	0	0	2,338
Not Designated as Hedging Instrument | Interest and other expenses, net | Make-whole provisions
Derivative Instruments, Gain (Loss) [Line Items]
Amount of (gain) loss recognized in net income	$ 193	$ (2,462)	$ (506)

Derivative Instruments and He_6

Derivative Instruments and Hedging Activities - Effects of Derivative Instruments in Accumulated Other Comprehensive Income (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Accumulated gain in AOCI at the beginning of the year	$ 901,975
AOCI at the end of the year	1,013,225	$ 901,975
Accumulated Gain (Loss), Net, Cash Flow Hedge
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Accumulated gain in AOCI at the beginning of the year	746	1,284
Unrealized gain recognized in AOCI	1,388	232
Gain reclassified from AOCI to interest and other expenses, net	(994)	(770)
Gain (loss) on derivatives	394	(538)
AOCI at the end of the year	$ 1,140	$ 746

Derivative Instruments and He_7

Derivative Instruments and Hedging Activities - Summary of Active Derivative Instruments (Details)	12 Months Ended
	Dec. 31, 2024 USD ($)
Interest Rate Swap October 2029 | Designated as Hedging Instrument
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, term of contract	11 years
Derivative, active interest rate swap	5.77%
Initial notional amount	$ 9,200,000
Interest Rate Swap June 2033 | Designated as Hedging Instrument
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, term of contract	15 years
Derivative, active interest rate swap	5.24%
Initial notional amount	$ 10,000,000
Interest Rate Swap - December 2027 | Designated as Hedging Instrument
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, term of contract	10 years
Derivative, active interest rate swap	4.74%
Initial notional amount	$ 14,100,000
Interest Rate Swap - June 2028 - Contract 1 | Designated as Hedging Instrument
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, term of contract	8 years
Derivative, active interest rate swap	3.49%
Initial notional amount	$ 14,643,000
Interest Rate Swap - June 2028 - Contract 2 | Designated as Hedging Instrument
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, term of contract	8 years
Derivative, active interest rate swap	3.49%
Initial notional amount	$ 10,734,000
Interest Rate Swap - March 2033 - Contract 1 | Designated as Hedging Instrument
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, term of contract	13 years
Derivative, active interest rate swap	0.72%
Initial notional amount	$ 9,505,000
Interest Rate Swap - March 2033 - Contract 2 | Designated as Hedging Instrument
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, term of contract	13 years
Derivative, active interest rate swap	0.72%
Initial notional amount	$ 6,968,000
Interest Rate Swap - December 2040 | Designated as Hedging Instrument
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, term of contract	17 years 9 months
Derivative, active interest rate swap	3.16%
Initial notional amount	$ 14,084,000
Interest Rate Swap - July 2041 | Not Designated as Hedging Instrument
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, term of contract	18 years
Derivative, active interest rate swap	3.81%
Initial notional amount	$ 32,021,000
Make Whole Provision December 2038 | Not Designated as Hedging Instrument | Other liabilities
Derivative Instruments, Gain (Loss) [Line Items]
Liability derivatives, fair value	348,000
Make Whole Provision April 2031 | Not Designated as Hedging Instrument | Other liabilities
Derivative Instruments, Gain (Loss) [Line Items]
Liability derivatives, fair value	35,000
Make Whole Provision February 2034 | Not Designated as Hedging Instrument | Other liabilities
Derivative Instruments, Gain (Loss) [Line Items]
Liability derivatives, fair value	28,000
Make Whole Provision December 2027 | Not Designated as Hedging Instrument | Other liabilities
Derivative Instruments, Gain (Loss) [Line Items]
Liability derivatives, fair value	18,000
Make Whole Provision May 2028 | Not Designated as Hedging Instrument | Other liabilities
Derivative Instruments, Gain (Loss) [Line Items]
Liability derivatives, fair value	4,000
Make Whole Provision April 2045 | Not Designated as Hedging Instrument | Other liabilities
Derivative Instruments, Gain (Loss) [Line Items]
Liability derivatives, fair value	78,000
Make Whole Provision March 2046 | Not Designated as Hedging Instrument | Other liabilities
Derivative Instruments, Gain (Loss) [Line Items]
Liability derivatives, fair value	2,158,000
Make Whole Provision March 2042 | Not Designated as Hedging Instrument | Other liabilities
Derivative Instruments, Gain (Loss) [Line Items]
Liability derivatives, fair value	885,000
Make Whole Provision March 2047 | Not Designated as Hedging Instrument | Other liabilities
Derivative Instruments, Gain (Loss) [Line Items]
Liability derivatives, fair value	1,968,000
Make-whole Provision June 2042 | Not Designated as Hedging Instrument | Other liabilities
Derivative Instruments, Gain (Loss) [Line Items]
Liability derivatives, fair value	9,442,000
Make-whole Provision June 2042 | Not Designated as Hedging Instrument | Other liabilities
Derivative Instruments, Gain (Loss) [Line Items]
Liability derivatives, fair value	$ 609,000

Business Segment Information -

Business Segment Information - Additional Information (Details) - Sales Revenue, Net - Customer Concentration Risk	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Various Governments
Segment Reporting Information [Line Items]
Concentration risk percentage	67.30%	71.80%	46%
U.S. Federal Government
Segment Reporting Information [Line Items]
Concentration risk percentage	21%	29.30%	21.50%

Business Segment Information _2

Business Segment Information - Segment Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Segment Reporting Information [Line Items]
Revenues	$ 1,769,928	$ 1,374,633	$ 1,824,422
Cost of revenues	1,513,837	1,128,204	1,533,589
Gross profit	256,091	246,429	290,833
Earnings from unconsolidated entities	792	1,758	1,647
Gain on sale of business, net	38,007	0	0
Selling, general and administrative expenses	173,761	162,138	159,488
Asset impairments	12,384	3,831	0
Loss (gain) on derivatives	(1,027)	(1,108)	(212)
Interest expense, net of interest income	65,031	36,169	25,729
Other (income) expenses	10,801	8,888	1,756
Income before income taxes	33,940	38,269	105,719
Other Non-cash Segment Disclosures:
Depreciation and intangible asset amortization	89,211	65,911	54,278
Amortization of debt discount & debt issuance costs	5,151	4,201	4,211
North America Regions
Segment Reporting Information [Line Items]
Revenues	878,828	616,434	1,173,281
U.S. Federal
Segment Reporting Information [Line Items]
Revenues	372,536	402,884	391,891
Renewable Fuels
Segment Reporting Information [Line Items]
Revenues	173,342	117,075	114,459
Europe
Segment Reporting Information [Line Items]
Revenues	250,574	149,354	58,410
All Other
Segment Reporting Information [Line Items]
Revenues	94,648	88,886	86,381
Operating Segments | North America Regions
Segment Reporting Information [Line Items]
Revenues	878,828	616,434	1,173,281
Cost of revenues	773,205	515,986	1,020,266
Gross profit	105,623	100,448	153,015
Earnings from unconsolidated entities	51	0	0
Gain on sale of business, net	0
Selling, general and administrative expenses	50,985	51,161	57,401
Asset impairments	527	2,222	0
Loss (gain) on derivatives	193	(2,461)	(506)
Interest expense, net of interest income	9,894	7,003	7,865
Other (income) expenses	3,172	1,654	(580)
Income before income taxes	40,903	40,869	88,835
Other Non-cash Segment Disclosures:
Depreciation and intangible asset amortization	36,400	28,682	23,152
Amortization of debt discount & debt issuance costs	2,056	2,444	1,712
Operating Segments | U.S. Federal
Segment Reporting Information [Line Items]
Revenues	372,536	402,884	391,891
Cost of revenues	313,413	340,989	329,527
Gross profit	59,123	61,895	62,364
Earnings from unconsolidated entities	687	1,758	1,647
Gain on sale of business, net	0
Selling, general and administrative expenses	13,064	12,090	11,757
Asset impairments	0	0	0
Loss (gain) on derivatives	(1,083)	857	0
Interest expense, net of interest income	4,982	1,429	1,231
Other (income) expenses	883	11	157
Income before income taxes	41,964	49,266	50,866
Other Non-cash Segment Disclosures:
Depreciation and intangible asset amortization	14,206	5,343	4,905
Amortization of debt discount & debt issuance costs	883	50	157
Operating Segments | Renewable Fuels
Segment Reporting Information [Line Items]
Revenues	173,342	117,075	114,459
Cost of revenues	136,720	87,819	78,359
Gross profit	36,622	29,256	36,100
Earnings from unconsolidated entities	0	0	0
Gain on sale of business, net	0
Selling, general and administrative expenses	2,909	4,383	2,962
Asset impairments	9,233	1,609	0
Loss (gain) on derivatives	(137)	496	294
Interest expense, net of interest income	25,552	16,019	8,657
Other (income) expenses	460	533	1,198
Income before income taxes	(1,395)	6,216	22,989
Other Non-cash Segment Disclosures:
Depreciation and intangible asset amortization	31,968	26,160	23,354
Amortization of debt discount & debt issuance costs	460	533	1,198
Operating Segments | Europe
Segment Reporting Information [Line Items]
Revenues	250,574	149,354	58,410
Cost of revenues	227,163	123,215	46,808
Gross profit	23,411	26,139	11,602
Earnings from unconsolidated entities	54	0	0
Gain on sale of business, net	0
Selling, general and administrative expenses	16,951	14,110	6,626
Asset impairments	0	0	0
Loss (gain) on derivatives	0	0	0
Interest expense, net of interest income	4,271	2,477	24
Other (income) expenses	1,467	5,915	(150)
Income before income taxes	776	3,637	5,102
Other Non-cash Segment Disclosures:
Depreciation and intangible asset amortization	2,090	2,082	275
Amortization of debt discount & debt issuance costs	0	0	0
Operating Segments | All Other
Segment Reporting Information [Line Items]
Revenues	94,648	88,886	86,381
Cost of revenues	63,336	60,195	58,629
Gross profit	31,312	28,691	27,752
Earnings from unconsolidated entities	0	0	0
Gain on sale of business, net	38,007
Selling, general and administrative expenses	22,203	21,969	18,640
Asset impairments	0	0	0
Loss (gain) on derivatives	0	0	0
Interest expense, net of interest income	(1)	(6)	(3)
Other (income) expenses	34	75	7
Income before income taxes	47,083	6,653	9,108
Other Non-cash Segment Disclosures:
Depreciation and intangible asset amortization	2,684	1,861	746
Amortization of debt discount & debt issuance costs	0	0	0
Corporate
Segment Reporting Information [Line Items]
Earnings from unconsolidated entities	0	0	0
Gain on sale of business, net	0
Selling, general and administrative expenses	67,649	58,425	62,102
Asset impairments	2,624	0	0
Loss (gain) on derivatives	0	0	0
Interest expense, net of interest income	20,333	9,247	7,955
Other (income) expenses	4,785	700	1,124
Income before income taxes	(95,391)	(68,372)	(71,181)
Other Non-cash Segment Disclosures:
Depreciation and intangible asset amortization	1,863	1,783	1,846
Amortization of debt discount & debt issuance costs	$ 1,752	$ 1,174	$ 1,144

Assets Held For Sale - Addition

Assets Held For Sale - Additional Information (Details) $ in Thousands		12 Months Ended
		Dec. 31, 2024 USD ($) membership_interest_purchase_agreement energy_asset	Dec. 31, 2023 USD ($) energy_asset	Dec. 31, 2022 USD ($)
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Assets	[1]	$ 4,158,508	$ 3,713,776
Revenues		1,769,928	1,374,633	$ 1,824,422
Gross profit		$ 256,091	246,429	$ 290,833
Renewal Energy Program
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of membership interest purchase agreements | membership_interest_purchase_agreement		15
Assets		$ 87,465
Revenues		69,806
Gross profit		$ 15,545
Disposal Group, Held-for-Sale, Not Discontinued Operations | Five Energy Asset Projects Previously Held For Sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Energy asset projects held for sale | energy_asset		5
Assets held for sale			33,851
Liabilities held for sale			$ 5,546
Disposal Group, Held-for-Sale, Not Discontinued Operations | Three Energy Asset Projects
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Energy asset projects held for sale | energy_asset		3
Assets held for sale		$ 8,372
Liabilities held for sale		$ 771
Disposal Group, Held-for-Sale, Not Discontinued Operations | Five Energy Asset Projects
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Energy asset projects held for sale | energy_asset			5
Assets held for sale			$ 38,404
Liabilities held for sale			$ 8,351
[1]Includes restricted assets of consolidated variable interest entities (“VIEs”) of $158,548 as of December 31, 2024 and $312,701 as of December 31, 2023. Includes liabilities of consolidated VIEs of $16,871 as of December 31, 2024 and $199,063 as of December 31, 2023. See Note 11.

Assets Held For Sale - Assets a

Assets Held For Sale - Assets and Liabilities (Details) - Disposal Group, Held-for-Sale, Not Discontinued Operations - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Three Energy Asset Projects
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Other assets	$ 8,179
Right-of-use assets, net	193
Assets classified as held for sale	8,372
Accounts payable	482
Current portions of operating lease liabilities	11
Deferred revenue	60
Long-term operating lease liabilities, net of current portion	218
Liabilities directly associated with assets classified as held for sale	771
Five Energy Asset Projects
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Other assets		$ 37,148
Right-of-use assets, net		1,256
Assets classified as held for sale		38,404
Accounts payable		6,019
Current portions of operating lease liabilities		14
Deferred revenue		1,088
Long-term operating lease liabilities, net of current portion		1,230
Liabilities directly associated with assets classified as held for sale		8,351
North America Regions | Three Energy Asset Projects
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Other assets	7,778
Right-of-use assets, net	193
Assets classified as held for sale	7,971
Accounts payable	482
Current portions of operating lease liabilities	11
Deferred revenue	60
Long-term operating lease liabilities, net of current portion	218
Liabilities directly associated with assets classified as held for sale	771
North America Regions | Five Energy Asset Projects
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Other assets		18,895
Right-of-use assets, net		1,256
Assets classified as held for sale		20,151
Accounts payable		5,418
Current portions of operating lease liabilities		14
Deferred revenue		0
Long-term operating lease liabilities, net of current portion		1,230
Liabilities directly associated with assets classified as held for sale		6,662
U.S. Federal | Three Energy Asset Projects
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Other assets	401
Right-of-use assets, net	0
Assets classified as held for sale	401
Accounts payable	0
Current portions of operating lease liabilities	0
Deferred revenue	0
Long-term operating lease liabilities, net of current portion	0
Liabilities directly associated with assets classified as held for sale	$ 0
U.S. Federal | Five Energy Asset Projects
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Other assets		18,253
Right-of-use assets, net		0
Assets classified as held for sale		18,253
Accounts payable		601
Current portions of operating lease liabilities		0
Deferred revenue		1,088
Long-term operating lease liabilities, net of current portion		0
Liabilities directly associated with assets classified as held for sale		$ 1,689