Montauk Renewables (MNTK) 10-K 14 Mar 24 2023 FY Annual report Financial data

Cover Page

Cover Page - USD ($)	12 Months Ended
	Dec. 31, 2023	Mar. 08, 2024	Jun. 30, 2023
Document Information [Line Items]
Document Type	10-K
Amendment Flag	false
Document Annual Report	true
Document Transition Report	false
Document Period End Date	Dec. 31, 2023
Document Fiscal Year Focus	2023
Document Fiscal Period Focus	FY
Current Fiscal Year End Date	--12-31
Entity Registrant Name	MONTAUK RENEWABLES, INC.
Securities Act File Number	001-39919
Entity Incorporation, State or Country Code	DE
Entity Interactive Data Current	Yes
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Shell Company	false
Entity Filer Category	Accelerated Filer
Entity Tax Identification Number	85-3189583
Entity Small Business	false
Entity Emerging Growth Company	true
Entity Address, Address Line One	5313 Campbells Run Road
Entity Address, Address Line Two	Suite 200
Entity Address, State or Province	PA
Entity Address, City or Town	Pittsburgh
Entity Address, Postal Zip Code	15205
City Area Code	412
Local Phone Number	747-8700
Title of 12(b) Security	Common Stock, par value $0.01 per share
Trading Symbol	MNTK
Security Exchange Name	NASDAQ
ICFR Auditor Attestation Flag	false
Entity Common Stock, Shares Outstanding		143,698,263
Entity Central Index Key	0001826600
Entity Ex Transition Period	false
Entity Public Float			$ 452,482,145
Document Financial Statement Error Correction [Flag]	false
Documents Incorporated by Reference [Text Block]	DOCUMENTS INCORPORATED BY REFERENCE The information required by Part III of this Annual Report on Form 10-K, to the extent not set forth herein, is incorporated herein by reference from the registrant’s definitive proxy statement relating to the registrant’s Annual Meeting of Shareholders to be held in 2024 (the “Proxy Statement”), which definitive proxy statement shall be filed with the Securities and Exchange Commission not later than 120 days after the end of the fiscal year to which this report relates.
Auditor Name	GRANT THORNTON LLP
Auditor Firm ID	248
Auditor Location	Pittsburgh, Pennsylvania

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Current assets:
Cash and cash equivalents	$ 73,811	$ 105,177
Accounts and other receivables	12,752	7,222
Current restricted cash	8	22
Related party receivable	0	9,000
Current portion of derivative instruments	785	879
Prepaid expenses and other current assets	2,819	2,568
Total current assets	90,175	124,868
Non-current restricted cash	423	407
Property, plant and equipment, net	214,289	175,946
Goodwill and intangible assets, net	18,421	15,755
Deferred tax assets	2,076	3,952
Non-current portion of derivative instruments	470	936
Operating lease right-of-use assets	4,313	4,742
Finance lease right-of-use assets	36	96
Related party receivable	10,138	0
Other assets	9,897	5,614
Total assets	350,238	332,316
Current liabilities:
Accounts payable	7,916	4,559
Accrued liabilities	12,789	15,090
Income tax payable	313	402
Current portion of operating lease liability	420	410
Current portion of finance lease liability	26	71
Current portion of long-term debt	7,886	7,870
Total current liabilities	29,350	28,402
Long-term debt, less current portion	55,614	63,505
Non-current portion of operating lease liability	4,133	4,341
Non-current portion of finance lease liability	10	25
Asset retirement obligations	5,900	5,493
Other liabilities	4,992	3,459
Total liabilities	99,999	105,225
Commitments and contingencies (note 20)
STOCKHOLDERS' EQUITY
Common stock, $0.01 par value, authorized 690,000,000 shares; 143,732,811 and 143,682,811 shares issued at December 31, 2023 and December 31, 2022, respectively; 141,986,189 and 141,633,417 shares outstanding at December 31, 2023 and December 31, 2022, respectively	1,420	1,416
Treasury stock, at cost, 984,762 and 971,306 shares December 31, 2023 and December 31, 2022, respectively	(11,173)	(11,051)
Additional paid-in capital	214,378	206,060
Retained earnings	45,614	30,666
Total stockholders' equity	250,239	227,091
Total liabilities and stockholders' equity	$ 350,238	$ 332,316

CONSOLIDATED BALANCE SHEETS (Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Dec. 31, 2023	Dec. 31, 2022
Statement of Financial Position [Abstract]
Common stock par or stated value per share	$ 0.01	$ 0.01
Common stock shares authorized	690,000,000	690,000,000
Common stock shares issued	143,732,811	143,682,811
Common stock shares outstanding	141,986,189	141,633,417
Treasury stock, shares	984,762	971,306

CONSOLIDATED STATEMENTS OF OPER

CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Income Statement [Abstract]
Total operating revenues	$ 174,904	$ 205,559	$ 148,127
Operating expenses:
Operating and maintenance expenses	59,762	57,267	49,477
General and administrative expenses	34,403	34,139	42,552
Royalties, transportation, gathering and production fuel	34,861	44,163	28,683
Depreciation, depletion and amortization	21,158	20,700	22,869
Gain on insurance proceeds	0	(313)	(332)
Impairment loss	902	4,852	1,191
Transaction costs	178	185	352
Total operating expenses	151,264	160,993	144,792
Operating income	23,640	44,566	3,335
Other expenses (income):
Interest expense	5,753	1,792	2,928
Loss on extinguishment of debt	0	0	154
Other (income) expense	(479)	(468)	620
Total other expenses	5,274	1,324	3,702
Income (loss) before income taxes	18,366	43,242	(367)
Income tax expense	3,418	8,048	4,161
Net income (loss)	$ 14,948	$ 35,194	$ (4,528)
Income (loss) per share:
Basic	$ 0.11	$ 0.25	$ (0.03)
Diluted	$ 0.11	$ 0.25	$ (0.03)
Weighted-average common shares outstanding:
Basic	141,727,905	141,238,851	141,015,213
Diluted	142,151,640	142,579,389	141,015,213

CONSOLIDATED STATEMENTS OF STOC

CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (Unaudited) - USD ($) $ in Thousands	Total	Members Equity [Member]	Common Stock [Member]	Treasury Stock [Member]	Additional Paid-in Capital [Member]	Retained (Deficit) Earnings [Member]
Beginning balance at Dec. 31, 2020	$ 159,622	$ 159,622
Effect of reorganization transactions, shares			138,312,713
Effect of reorganization transactions		$ (159,622)	$ 1,383		$ 158,239
IPO common stock, shares			2,702,500
IPO common stock	15,593		$ 27		15,566
Treasury stock, Shares				950,214
Treasury stock	(10,813)			$ (10,813)
Net Income (Loss)	(4,528)					$ (4,528)
Stock-based compensation	22,419				22,419
Ending balance at Dec. 31, 2021	182,293		$ 1,410	$ (10,813)	196,224	(4,528)
Ending balance, shares at Dec. 31, 2021			141,015,213	950,214
Treasury stock, Shares				21,092
Treasury stock	(238)			$ (238)
Net Income (Loss)	35,194					35,194
Stock-based compensation	9,836				9,836
Vesting of stock awards (in shares)			618,204
Vesting of stock awards	6		$ 6
Ending balance at Dec. 31, 2022	227,091		$ 1,416	$ (11,051)	206,060	30,666
Ending balance, shares at Dec. 31, 2022			141,633,417	971,306
Treasury stock, Shares				13,456
Treasury stock	(122)			$ (122)
Net Income (Loss)	14,948					14,948
Stock-based compensation	8,318				8,318
Vesting of stock awards (in shares)			352,772
Vesting of stock awards	4		$ 4
Ending balance at Dec. 31, 2023	$ 250,239		$ 1,420	$ (11,173)	$ 214,378	$ 45,614
Ending balance, shares at Dec. 31, 2023			141,986,189	984,762

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Cash flows from operating activities:
Net Income (Loss)	$ 14,948	$ 35,194	$ (4,528)
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation, depletion and amortization	21,158	20,700	22,869
Provision for deferred income taxes	1,876	6,618	4,252
Loss on extinguishment of debt	0	0	154
Stock-based compensation	8,318	9,836	22,419
Gain on property insurance proceeds	0	(313)	(332)
Derivative mark-to-market adjustments and settlements	560	(2,652)	(1,421)
Net loss (gain) on sale of assets	94	(233)	822
Increase in earn-out liability	1,266	1,122	801
Accretion of asset retirement obligations	407	296	(160)
Amortization of debt issuance costs	367	412	483
Impairment loss	902	4,852	1,191
Accounts and other receivables and other current assets	(9,820)	(3,054)	(1,522)
Accounts payable and other accrued expenses	977	8,288	(2,149)
Net cash provided by operating activities	41,053	81,066	42,879
Cash flows from investing activities
Capital expenditures	(63,091)	(22,277)	(9,986)
Asset acquisitions	0	0	(9,673)
Cash collateral deposits, net	2	82	(220)
Proceeds from insurance recovery	0	313	332
Proceeds from sale of assets	2	1,088	73
Net cash used in investing activities	(63,087)	(20,794)	(19,474)
Cash flows from financing activities:
Borrowings of long-term debt	0	0	80,000
Repayments of long-term debt	(8,000)	(8,000)	(66,698)
Debt issuance costs	0	0	(339)
Debt extinguishment costs	0	0	(154)
Common stock issuance	4	6	15,593
Treasury stock purchase	(122)	(238)	(10,813)
Related party receivable	(1,138)	0	(8,940)
Finance lease payments	(74)	(47)	0
Net cash (used in) provided by financing activities	(9,330)	(8,279)	8,649
Net (decrease) increase in cash and cash equivalents and restricted cash	(31,364)	51,993	32,054
Cash and cash equivalents and restricted cash at beginning of period	105,606	53,613	21,559
Cash and cash equivalents and restricted cash at end of period	74,242	105,606	53,613
Reconciliation of cash, cash equivalents, and restricted cash at end of period:
Cash and cash equivalents	73,811	105,177	53,266
Restricted cash and cash equivalents - current	8	22	19
Restricted cash and cash equivalents - non-current	423	407	328
Reconciliation of cash, cash equivalents, and restricted cash at end of year	74,242	105,606	53,613
Supplemental cash flow information:
Cash paid for interest	5,003	3,463	3,787
Cash paid for income taxes	1,915	696	280
Accrual for purchase of property, plant and equipment included in accounts payable and accrued liabilities	$ 5,471	$ 2,635	$ 1,212

Pay vs Performance Disclosure

Pay vs Performance Disclosure - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Pay vs Performance Disclosure
Net Income (Loss)	$ 14,948	$ 35,194	$ (4,528)

Description of Business

Description of Business	12 Months Ended
	Dec. 31, 2023
Accounting Policies [Abstract]
Description of Business	NOTE 1—DESCRIPTION OF BUSINESS Operations and organization Montauk Renewables’ Business Montauk Renewables, Inc. (the “Company” or “Montauk Renewables”) is a renewable energy company specializing in the management, recovery and conversion of biogas into Renewable Natural Gas (“RNG”). The Company captures methane, preventing it from being released into the atmosphere, and converts it into either RNG or electrical power for the electrical grid (“Renewable Electricity”). The Company, headquartered in Pittsburgh, Pennsylvania, has more than 30 years of experience in the development, operation and management of landfill methane-fueled renewable energy projects. The Company has current operations at 15 operating projects located in California, Idaho, Ohio, Oklahoma, Pennsylvania, North Carolina and Texas. The Company sells RNG and Renewable Electricity, taking advantage of Environmental Attribute premiums available under federal and state policies that incentivize their use. Two of the Company’s key revenue drivers are sales of captured gas and sales of Renewable Identification Numbers (“RINs”) to fuel blenders. The Renewable Fuel Standard (“RFS”) is an Environmental Protection Agency (“EPA”) administered federal law that requires transportation fuel to contain a minimum volume of renewable fuel. RNG derived from landfill methane, agricultural digesters and wastewater treatment facilities used as a vehicle fuel qualifies as a D3 (cellulosic biofuel with a 60 % greenhouse gas reduction requirement) RIN. The RINs are compliance units for fuel blenders that were created by the RFS program in order to reduce greenhouse gases and imported petroleum into the United States. An additional program utilized by the Company is the Low Carbon Fuel Standard (“LCFS”). This is state specific and is designed to stimulate the use of low-carbon fuels. To the extent that RNG from the Company’s facilities is used as a transportation fuel in states that have adopted an LCFS program, it is eligible to receive an Environmental Attribute additional to the RIN value under the federal RFS. Another key revenue driver is the sale of captured electricity and the associated environmental premiums related to renewable sales. The Company’s electric facilities are designed to conform to and monetize various state renewable portfolio standards requiring a percentage of the electricity produced in that state to come from a renewable resource. Such premiums are in the form of Renewable Energy Credits (“RECs”). The Company’s largest electric facility, located in California, receives revenue for the monetization of RECs as a part of a purchase power agreement. Collectively, the Company benefits from federal and state government incentives in the United States, provided in the form of RINs, RECs, LCFS credits, tax credits and other incentives to end users, distributors, system integrators and manufacturers of renewable energy projects, that promote the use of renewable energy, as Environmental Attributes. Background and Reorganization Transactions On January 4, 2021, the Company, Montauk Holdings Limited (“MNK”) and Montauk Holdings USA, LLC (a direct wholly-owned subsidiary of MNK at the time, “Montauk USA”) entered into a series of transactions, including an equity exchange and a distribution collectively referred to as the “Reorganization Transactions,” that resulted in the Company owning all of the assets and entities (other than Montauk USA) previously owned by Montauk USA, and Montauk Renewables became a direct wholly-owned subsidiary of MNK. Prior to the Reorganization Transactions, MNK’s business and operations were conducted entirely through Montauk USA and its U.S. subsidiaries, and MNK held no substantial assets other than equity of Montauk USA. The Company had no significant operations or assets prior to January 4, 2021 when it engaged in the equity exchange with Montauk USA and MNK. After completion of the Reorganization Transactions, (i) Montauk USA ceased to own any substantial assets and (ii) all entities through which MNK’s business and operations were conducted became owned, directly or indirectly, by the Company. MNK adopted a plan contemporaneously with the completion of the Reorganization Transactions that authorized the liquidation and dissolution of MNK. On January 15, 2021, MNK sold the membership interest of Montauk USA to a third party. On January 26, 2021, MNK distributed all of the outstanding shares of the Company’s common stock as a pro rata dividend to the holders of MNK’s ordinary shares (the “Distribution”), subject to any tax withholding obligations under applicable South African law. Each ordinary share of MNK outstanding on January 21, 2021, the record date for the Distribution (the “Record Date”), entitled the holder thereof to receive one share of the Company’s common stock. On January 26, 2021, the Company closed the initial public offering of its common stock on the Nasdaq Capital Market (the “IPO”) with the shares traded under the symbol “MNTK”. Montauk Renewables issued 2,702,500 shares at $ 8.50 per share and received gross proceeds of $ 22,971 . The Company’s common stock was also secondarily listed on the Johannesburg Stock Exchange (“JSE”) under the trading symbol “MKR”. On January 26, 2021, the Company entered into a Loan Agreement and Secured Promissory Note (as amended on February 22, 2021, December 22, 2021, December 22, 2022 and December 27, 2023) with MNK pursuant to which the Company advanced a cash loan to MNK for MNK to pay its dividends tax liability arising from the Reorganization Transactions under the South African Income Tax Act, 1962 (Act No. 58 of 1962), as amended. The terms of the loan following the amendments are substantially similar to the initial loan agreement and were primarily entered into to (1) increase the principal amount outstanding under the loan to $ 10,040 in the aggregate (2) extended the maturity date to December 31, 2033 also, in accordance with Montauk Renewables’ obligations set forth in the Transaction Implementation Agreement. MNK is currently an affiliate of the Company and certain of the Company’s directors are also directors of MNK. See Note 17 for more information. MNK was delisted from the JSE on January 26, 2021. The MNK Board of Directors and Shareholders held its annual general meeting in March 2023 and voted to take MNK private.

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2023
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	NOTE 2—SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Principles of Consolidation The historical consolidated financial information included reflects the historical results of operations and financial position of Montauk USA through January 4, 2021 when MNK sold the membership interest of Montauk USA. The consolidated financial statements of Montauk USA became the Company’s historical financial statements following the IPO. Certain historical financial information included relates to periods prior to the Reorganization Transactions. All intercompany balances and transactions have been eliminated in consolidation. The Company utilizes the equity method of accounting for companies where its ownership is greater than 50 % and significant but controlling interest does not exist. Retrospective Presentation of Ownership Related to the Reorganization Transactions As discussed in Note 1, as a result of the Reorganization Transactions, the Company acquired the assets and entities (excluding Montauk USA) which were previously owned by MNK. As part of the Reorganization Transactions, a 1: 1 pro rata distribution of shares of the Company’s common stock was made to holders of MNK’s ordinary shares. The Reorganization Transactions resulted in a pro rata distribution whereby the ownership of the Company after the Reorganization Transactions was identical to the ownership of MNK prior to the Reorganization Transaction and was therefore akin to a common control transaction. All member’s equity in the financial statements and notes have been retrospectively adjusted to give effect to the Distribution, as if such pro rata distribution on a 1: 1 basis occurred as of all pre-IPO periods presented, including periods presented on the Consolidated Balance Sheets, Consolidated Statements of Operations, Consolidated Statements of Stockholders’ and Member’s Equity and notes to the Consolidated Financial Statements contained herein. Reclassifications Certain prior period amounts have been reclassified to conform to the current period financial statement presentation. These reclassifications had no effect on the previously reported total assets, total liabilities, stockholders’ equity, results of operations or cash flows . Segment Reporting The Company reports segment information in three segments: RNG, Renewable Electricity Generation and Corporate. This is consistent with the internal reporting provided to the chief operating decision maker who evaluates operating results and performance. The aforementioned business services and offerings described in Note 1 are grouped and defined by management as two distinct operating segments: RNG and Renewable Electricity Generation. Below is a description of the Company’s operating segments and other activities. The RNG segment represents the sale of gas sold at fixed-price contracts, counterparty share RNG volumes and applicable Environmental Attributes. This business unit represents the majority of the revenues generated by the Company. The Renewable Electricity Generation segment represents the sale of captured electricity and applicable Environmental Attributes. Corporate & Other relates to additional discrete financial information for the corporate function. It is primarily used as a shared service center for maintaining functions such as executive, accounting, treasury, legal, human resources, tax, environmental, engineering and other operations functions not otherwise allocated to a segment. As such, the corporate entity is not determined to be an operating segment but is discretely disclosed for purposes of reconciliation to the Company’s consolidated financial statements. Use of Estimates The preparation of financial statements, in conformity with accounting principles generally accepted in the United States (“GAAP”), requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates. Cash, Cash Equivalents and Restricted Cash Cash and cash equivalents include highly liquid investments with maturity dates of three months or less from the date of purchase and are recorded at cost. The Company may hold cash in excess of federally insured limits. Restricted cash is classified as current or non-current based on the terms of the underlying agreements and represents cash held as deposits, cash held in escrow and cash collateral for financial letters of credit. Accounts and Other Receivables Accounts and other receivables on the Consolidated Balance Sheets represent outstanding billings for goods and services delivered to customers on an unsecured basis as well as reimbursable expenses. In evaluating its allowance for doubtful accounts for accounts receivable, the Company performs ongoing reviews of its outstanding receivables to determine if any amounts are uncollectible and adjusts the allowance for doubtful accounts accordingly. Property, Plant and Equipment Property, plant and equipment purchases are stated at cost. Depreciation and amortization are based on costs less estimated salvage values, primarily using the straight-line method over the estimated useful lives or, if applicable, the term of the related gas rights agreements or power purchase agreements, whichever is shorter. Maintenance and repairs are expensed as incurred. Major improvements that extend the useful lives of property are capitalized. The estimated useful lives of the Company’s property, plant and equipment reflect the expected consumption of the economic benefit of these assets as noted in the following table: Buildings and improvements 5 - 30 years Machinery and equipment 1 - 43 years Gas mineral rights 15 - 25 years $ 313 and $ 332 in insurance proceeds were received for the years ended December 31, 2022 and 2021, respectively, related to an engine failure at an RNG Facility. These insurance proceeds are included in Gain on insurance proceeds for the years ended December 31, 2022 and 2021, respectively within the Consolidated Statements of Operations. Goodwill and Intangible Assets Goodwill is the cost of an acquisition less the fair value of the identified net assets of the acquired business. Separately identifiable intangible assets are recorded at their fair values upon acquisition. The Company accounts for its intangible assets in accordance with ASC 350, Intangibles—Goodwill and Other (“ASC 350”). Finite-lived intangible assets include interconnections, customer contracts and trade names & trademarks. The interconnection intangible asset is the exclusive right to utilize an interconnection line between the operating plant and a utility substation to transmit produced natural gas and electricity. Included in that right is full maintenance provided on this line by the utility. Intangible assets with finite useful lives are amortized on a straight-line basis over their estimated useful life as depicted in the chart below. Indefinite intangible assets are not amortized and include emission allowances and land use rights. The estimated useful lives of separately identified intangible assets are as follows: Interconnection 10 - 25 years Customer contracts 2 - 15 years Emissions allowances Indefinite Land use rights Indefinite Assets Held for Sale Assets classified as held for sale are reported at the lower of their carrying value or fair value less costs to sell. Assets are classified as held for sale if their carrying amounts will be recovered through a sale transaction, rather than through continued use. This condition is met only when the sale is highly probable and the assets are available for immediate sale in their present condition, subject only to terms that are usual and customary for sales of such assets. Management must be committed to a sale, which should be expected to qualify for recognition as a completed sale within one year from the date of classification as held for sale and actions required to complete the plan of sale indicate that it is unlikely that significant changes to the plan will be made or that the plan will be withdrawn. Impairment losses on initial classification as held-for-sale are recognized in the Consolidated Statement of Operations. Assets classified as held for sale are no longer depreciated or amortized. Leases The Company assesses leases in accordance with ASU 2016-02, Leases, (“ASU 2016-02”). This ASU requires lessees to recognize a right-of-use asset and lease liability on the Consolidated Balance Sheet for leases classified as either operating or finance leases. For leases with a term of 12 months or less, a lessee is permitted to make an accounting policy election by class of underlying asset not to recognize a right-of-use asset and lease liability. Additionally, when measuring assets and liabilities arising from a lease, optional payments should be included only if the lessee is reasonably certain to exercise an option to extend the lease, exercise a purchase option, or not exercise an option to terminate the lease. A right-of-use asset represents an entity’s right to use the underlying asset for the lease term, and a lease liability represents an entity’s obligation to make lease payments. The measurement, recognition and presentation of expenses and cash flows arising from leases by a lessee remains the same. The Company has included further lease disclosures in Note 19. Long-lived Asset Impairment In accordance with ASC 360, Property, plant, equipment and intangible assets with finite useful lives are evaluated for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. Recoverability of assets to be held and used is measured by comparing the carrying amount of an asset or asset group to future undiscounted cash flows expected to be generated by the asset or asset group. Such estimates are based on certain assumptions, which are subject to uncertainty and may materially differ from actual results. If such assets are considered to be impaired, the impairment to be recognized is measured by the amount by which the carrying amount of the assets exceeds the fair value of the assets. A summary of impairment losses on tangible and intangible assets for the year ended December 31, 2023, 2022 and 2021 is included in Note 3. Indefinite-Lived Asset Impairment Indefinite-lived intangible assets are required to be evaluated for impairment at least annually or whenever events or changes in circumstances indicate that the carrying value of the asset may not be recoverable. The evaluation of impairment under ASC 350 requires the use of projections, estimates and assumptions as to the future performance of the Company’s operations, including anticipated future revenues, expected operating costs and the discount factor used. Actual results may differ from projections. If such indefinite-lived assets are considered to be impaired, the impairment to be recognized is measured by the amount by which the carrying amount of the assets exceeds the fair value of the assets. Asset Retirement Obligations The Company accounts for asset retirement obligations as required under ASC 410, Asset Retirement and Environmental Obligations, (“ASC 410”). ASC 410 requires the fair value of a liability for an asset retirement obligation be recognized in the period in which the legal obligation arises, with the associated discounted asset retirement costs being capitalized as a part of the carrying amount of the long-lived asset and the annual accretion expense recorded in operations. The Company has recorded in the consolidated financial statements estimates for asset retirement obligations related to the decommissioning and removal requirements for specific gas processing and distribution assets, as required by their associated gas rights agreements. Revenue The Company recognizes revenue in accordance with ASC 606, Revenue from Contracts with Customers (“ASC 606”) . Revenue from the Company’s point in time product sales is recognized when products are transferred, or services are invoiced and control transferred. Revenue from the Company’s product and service sales provided under long-term agreements is recognized as the Company transfers control of the product or renders service to its customers, which approximates the time when the customer is invoiced. The Company has presented the disclosures required by ASC 606 in Note 4. Income Taxes The Company is treated as a corporation for income tax purposes. Therefore, income taxes are accounted for under the liability method on a consolidated basis by the Company and its consolidated subsidiaries in accordance with ASC 740, Income Taxes (“ASC 740”). Deferred tax assets and liabilities are determined based on differences between financial reporting and tax bases of assets and liabilities and are measured using the enacted tax rates and laws. The provision for income taxes includes federal and state income taxes. The Company recognizes the financial statement benefit of a tax position only after determining the relevant tax authority would more-likely-than-not sustain the position following an audit. For tax positions meeting the more-likely-than-not threshold, the amount recognized in the consolidated financial statements is the largest benefit that has a greater than 50 percent likelihood of being realized upon ultimate settlement with the relevant tax authority. The Company recognizes accrued interest and penalties related to unrecognized tax benefits in income tax expense. Derivative Instruments The Company applies the provisions of ASC 815, Derivatives and Hedging, (“ASC 815”). ASC 815 requires each derivative instrument to be recorded in the Consolidated Balance Sheets at its fair value. Changes in a derivative instrument’s fair value are recognized currently in earnings. Fair Value of Financial Instruments The Company employs varying methods and assumptions in estimating the fair value of each class of financial instruments for which it is practical to estimate fair value. For cash and cash equivalents, receivables and payables, the carrying amounts approximate fair value due to the short maturity of these instruments. For long-term debt, the carrying amounts approximate fair value as the interest rates obtained by the Company approximate the prevailing interest rates available to the Company for similar instruments. In accordance with ASC 820, Fair Value Measurement (“ASC 820”), a hierarchy is established which requires an entity to maximize the use of observable inputs and minimize the use of unobservable inputs when measuring fair value. The hierarchy defines three levels of inputs that may be used to measure fair value: Level 1—Unadjusted quoted prices in active markets for identical unrestricted assets and liabilities that the reporting entity has the ability to access at the measurement date. Level 2—Inputs other than quoted prices included within Level 1 that are observable for the assets and liabilities or can be corroborated with observable market data for substantially the entire contractual term of the assets or liabilities. Level 3—Unobservable inputs that reflect the entity’s own assumptions about the assumptions market participants would use in the pricing of the assets or liabilities and are consequently not based on market activity but rather through particular valuation techniques. The Company uses the fair value methodology to value the assets and liabilities recorded at fair value, including the Company’s asset retirement obligations and earn out liability. The values of the Level 2 interest rate derivatives were determined using a model, which incorporates market inputs including the implied forward interest rate yield curve for the same period as the future interest rate swap settlement. The Company has also considered both its own credit risk and counterparty credit risk in determining fair value and determined these adjustments were insignificant for the years ended December 31, 2023 and 2022. The Company’s asset retirement obligations are recorded at fair value at the time the liability is incurred if a reasonable estimate of fair value can be made. Fair value is determined by calculating the estimated present value of the cost to retire the asset as determined by qualified engineers, based on currently available information and inflation estimates and is considered a Level 3 measurement. The Company’s earn-out liability fair value is determined by calculating the estimated present value of future obligations based on currently available information and the discount factor used and is considered a Level 3 measurement. A summary of changes in the fair values of the Company’s Level 3 instruments, attributable to asset retirement obligations and the earn out liability, for the years ended December 31, 2023 and 2022 is included in Note 11. Renewable Identification Numbers (“RINs”) The Company generates D3 RINs through its production and sale of RNG used for transportation purposes as prescribed under the Federal Renewable Fuel Standard. The RINs that the Company generates as government incentives through its renewable operating projects can be separated and sold as credits independent from the energy produced and not a result of physical attributes of the Company’s production. Therefore, no cost is allocated to the RIN when it is generated. Revenue is recognized on these Environmental Attributes when there is an agreement in place to monetize the credits at an agreed upon price with a customer and transfer of control has occurred. Realized prices for Environmental Attributes monetized in a year may not correspond directly to index prices due to the forward selling of commitments. The Company had 0.1 and 0.7 million RINs generated and unsold as of December 31, 2023 and 2022, respectively. Renewable Energy Credits (“RECs”) The Company generates RECs through its production and sale of landfill methane into renewable electric energy as prescribed by the State of California Renewables Portfolio Standard or the EPA. The RECs that the Company generates as government incentives through its renewable operating projects are able to be separated and sold as credits independent from the electricity produced and not a result of physical attributes of the Company’s production. Therefore, no cost is allocated to the REC when it is generated. Revenue is recognized on these Environmental Attributes when there is an agreement in place to monetize the credits at an agreed upon price with a customer and transfer of control has occurred. Equity-Based Compensation The Company accounts for equity-based compensation under the provisions of ASC 718, Compensation—Stock Compensation, (“ASC 718”). ASC 718 requires compensation costs related to share-based payment transactions, measured based on the fair value of the instruments issued, be recognized in the consolidated financial statements over the requisite service period of the award. Stock options are initially measured on the grant date using the Black-Scholes valuation model, which requires the use of subjective assumptions related to the expected stock price volatility, term, risk-free interest rate and dividend yield. For restricted stock shares, the Company determines the grant date fair value based on the closing market price of the stock on the date of the grant. Employee Benefits Leave entitlement Employee entitlements to annual leave are recognized when they accrue to employees. An accrual is made for the estimated liability to the employees for annual leave up to the financial year end date. This liability is included in “Accrued liabilities” in the Consolidated Balance Sheets. Bonus Plans The Company recognizes a liability and an expense for incentive compensation bonuses awarded based on the achievement of Company and personnel goals where contractually obliged or where there is a past practice that has created a constructive obligation. An accrual is maintained for the appropriate proportion of the expected bonuses which would become payable at year end. Recently Adopted Accounting Standards In August 2020, the FASB issued ASU 2020-06, Debt: Debt with Conversion and Other Options (Subtopic 470-20) and Derivatives and Hedging—Contracts in Entity’s Own Equity (Subtopic 815-40), which simplifies the accounting for convertible instruments and contracts in an entity’s own equity. This guidance is effective for annual reporting periods beginning after December 15, 2021, including interim periods within those years, with early adoption permitted only as of annual reporting periods beginning after December 15, 2020. The ASU does not have a material impact on the Company’s consolidated financial statements or related financial statement disclosures. In June 2016, the FASB issued Accounting Standards Update 2016-13, Measurement of Credit Losses on Financial Instruments (“ASU 2016-13”). This ASU and subsequent amendments are codified as Accounting Standards Codification Topic 326, Financial Instruments—Credit Losses (“ASC 326”). Application of ASC 326 was effective for SEC Issuers (excluding smaller reporting companies) for fiscal years beginning after December 15, 2019. Adoption for smaller reporting companies, emerging growth companies and nonpublic entities was deferred due to the COVID-19 pandemic and was required for fiscal years beginning after December 15, 2022. The ASU did not have a material impact on the Company’s consolidated financial statements or related financial statement disclosures. Recently Issued Accounting Standards In March 2020, the FASB issued ASU No. 2020-04, Reference Rate Reform (Topic 848), which provides optional expedients and exceptions to the current guidance on contract modifications and hedging relationships to ease the financial reporting burdens of the expected market transition from London Interbank Offered Rate (“LIBOR”) and other interbank offered rates to alternative reference rates. The guidance was effective upon issuance and may be applied prospectively to contract modifications made and hedging relationships entered into or evaluated on or before December 31, 2022. The FASB included a sunset provision within Topic 848 based on expectations of when the LIBOR would cease being published. The sunset provision has been amended from December 31, 2022, to December 31, 2024, after which entities will no longer be permitted to apply the relief in Topic 848. The Company’s current debt agreement bears interest at the Bloomberg Short-Term Bank Yield Index Rate plus an applicable margin. LIBOR is no longer utilized as a reference rate. In November 2023, the FASB issued ASU No. 2023-07, Segment Reporting (Topic 280): Improvements to Reportable Segments. The amendments in 2023-07 aim to improve reportable segment disclosure requirements, primarily through enhanced disclosures about significant segment expenses. ASU 2023-07 is effective for the Company's Annual Report on Form 10-K for the year ended December 31, 2024, and subsequent interim periods, with early adoption permitted. The Company is currently evaluating the impact of this standard on its consolidated financial statements. In December 2023, the FASB issued ASU No. 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures. The amendments in 2023-09 aim to enhance the transparency and decision usefulness of income tax disclosures. ASU 2023-09 is effective for the Company's Annual Report on Form 10-K for the year ended December 31, 2025, with early adoption permitted. The Company is currently evaluating the impact of this standard on its consolidated financial statements.

Asset Impairment

Asset Impairment	12 Months Ended
	Dec. 31, 2023
Asset Impairment Charges [Abstract]
Asset Impairment	NOTE 3—ASSET IMPAIRMENT The Company recorded $ 902 , $ 4,852 and $ 1,191 in impairment losses for the years ended December 31, 2023, 2022 and 2021, respectively. 2023 impairments included $ 777 for specifically identified RNG machinery and feedstock processing equipment that were no longer in operational use and recorded in the Company's RNG segment. The remaining $ 125 in impairments were for specifically identified obsolete REG critical spares. The 2022 impairments included $ 2,133 for a REG site wherein the forecasted future cash flows did not exceed the carrying value of the site’s long lived assets. A second REG site was impaired for $ 1,393 due to a discrete conclusion that certain assets acquired in the May 2021 Asset acquisition would no longer be utilized by the Company. More information on the Asset acquisition can be found in Note 7. An RNG site was impaired for $ 1,108 due to the specific identification of certain assets no longer capable of being used as designed. Additional impairments were recorded for computer software and hardware no longer being utilized ($ 191 ) and an amended customer contract ($ 27 ) no longer in use. The 2021 impairment loss of $ 1,191 was due to the closure of two REG Sites and also the disposal of machinery at one RNG site. Impairment loss was recorded under Operating expenses within the Consolidated Statements of Operations for the years ended December 31, 2023, 2022, and 2021.

Revenues from Contracts with Cu

Revenues from Contracts with Customers	12 Months Ended
	Dec. 31, 2023
Revenue from Contract with Customer [Abstract]
Revenues from Contracts with Customers	NOTE 4—REVENUES FROM CONTRACTS WITH CUSTOMERS The Company’s revenues are comprised of renewable energy and related Environmental attribute sales provided under long-term contracts with its customers. All revenue is recognized when (or as) the Company satisfies its performance obligation(s) under the contract (either implicit or explicit) by transferring the promised product or service to its customer either when (or as) its customer obtains control of the product or service. A performance obligation is a promise in a contract to transfer a distinct product or service to a customer. A contract’s transaction price is allocated to each distinct performance obligation. The Company allocates the contract’s transaction price to each performance obligation using the product’s observable market standalone selling price for each distinct product in the contract. Revenue is measured as the amount of consideration the Company expects to receive in exchange for transferring its products or services. As such, revenue is recorded net of allowances and customer discounts as well as net of transportation and gathering costs incurred by the customer following the transfer of control of the commodities sold. To the extent applicable, sales, value add and other taxes collected from customers and remitted to governmental authorities are accounted for on a net (excluded from revenues) basis. The Company’s performance obligations related to the sale of renewable energy (i.e. RNG and Renewable Electricity) are generally satisfied over time. Revenue related to the sale of renewable energy is generally recognized over time using an output based upon the product quantity delivered to the customer. This measure is used to best depict the Company’s performance to date under the terms of the contract. Revenue from products transferred to customers over time accounted for approximately 23 %, 29 % and 28 % of revenue for the years ended December 31, 2023, 2022 and 2021, respectively. The nature of the Company’s long-term contracts may give rise to several types of variable consideration, such as periodic price increases. This variable consideration is outside of the Company’s influence as the variable consideration is dictated by the market. Therefore, the variable consideration associated with the long-term contracts is considered fully constrained. The Company’s performance obligations related to the sale of Environmental Attributes are generally satisfied at a point in time and were approximately 77 %, 71 % and 72 % of revenue for the years ended December 31, 2023, 2022 and 2021, respectively. The Company recognizes Environmental Attribute revenue at the point in time in which the customer obtains control of the Environmental Attributes, which is generally when the title of the Environmental Attribute passes to the customer upon delivery. In limited cases, title does not transfer to the customer and revenue is not recognized until the customer has accepted the Environmental Attributes. The Company’s performance obligations under its counterparty sharing agreements are generally satisfied at a point in time when the earnings process is completed by the counterparty. Counterparty sharing arrangement revenues were approximately 1 % and 10 % of revenue for the years ended December 31, 2022 and 2021, respectively. The Company does not currently recognize revenues under counterparty sharing arrangements. The following tables display the Company’s disaggregated revenue by major source, excluding realized and unrealized gains or losses under the Company’s gas hedge program, based on product type and timing of transfer of goods and services for the years ended December 31, 2023, 2022 and 2021: Year ended December 31, 2023 Goods transferred at a point in time Goods transferred over time Total Major goods/Service line: Natural gas commodity $ 977 $ 29,230 $ 30,207 Natural gas environmental attributes 125,874 — 125,874 Electric commodity — 11,301 11,301 Electric environmental attributes 7,522 — 7,522 $ 134,373 $ 40,531 $ 174,904 Operating segment: RNG $ 126,851 $ 29,230 $ 156,081 REG 7,522 11,301 18,823 $ 134,373 $ 40,531 $ 174,904 Year ended December 31, 2022 Goods transferred at a point in time Goods transferred over time Total Major goods/Service line: Natural gas commodity $ 2,053 $ 50,845 $ 52,898 Natural gas environmental attributes 143,025 — 143,025 Electric commodity — 10,449 10,449 Electric environmental attributes 7,016 — 7,016 $ 152,094 $ 61,294 $ 213,388 Operating segment: RNG $ 145,078 $ 50,845 $ 195,923 REG 7,016 10,449 17,465 $ 152,094 $ 61,294 $ 213,388 Year ended December 31, 2021 Goods transferred at a point in time Goods transferred over time Total Major goods/Service line: Natural gas commodity $ 15,178 $ 32,143 $ 47,321 Natural gas environmental attributes 84,906 — 84,906 Electric commodity — 9,692 9,692 Electric environmental attributes 6,208 — 6,208 $ 106,292 $ 41,835 $ 148,127 Operating segment: RNG $ 100,084 $ 32,143 $ 132,227 REG 6,208 9,692 15,900 $ 106,292 $ 41,835 $ 148,127 Practical expedients and remaining performance obligations The Company recognizes the sale of natural gas and electric commodities using the right to invoice practical expedient. The Company determined that the revenues recognized as of period end correspond directly with the value transferred to customers and the Company's satisfaction of the performance obligations to date. Furthermore, with the application of the right to invoice practical expedient and in consideration that contracts related to future environmental attributes sales do not exceed one year, there are no remaining unsatisfied or partially satisfied performance obligations as of December 31, 2023.

Accounts and Other Receivables

Accounts and Other Receivables	12 Months Ended
	Dec. 31, 2023
Receivables, Net, Current [Abstract]
Accounts and Other Receivables	NOTE 5—ACCOUNTS AND OTHER RECEIVABLES The Company extends credit based upon an evaluation of the customer’s financial condition. Credit terms are consistent with industry standards and practices. Accounts Receivable consist of sales to large creditworthy energy and utility companies. Reserves for uncollectible accounts, if any, are recorded as part of general and administrative expenses in the Consolidated Statements of Operations. No reserve expense was recorded for the years ended December 31, 2023, 2022 and 2021. Accounts and other receivables consist of the following as of December 31, 2023 and 2022: December 31, 2023 December 31, 2022 Accounts receivables $ 12,557 $ 7,148 Other receivables 148 57 Reimbursable expenses 47 17 Accounts and other receivables, net $ 12,752 $ 7,222

Assets Held For Sale

Assets Held For Sale	12 Months Ended
	Dec. 31, 2023
Asset Held For Sale [Abstract]
Assets Held For Sale	NOTE 6—ASSETS HELD FOR SALE In 2021, the Company initiated a plan to sell nitrogen oxide (“NOx”) emissions allowances credits. The Company concluded that it met the criteria under applicable guidance for a long-lived asset to be held for sale, and accordingly reclassified the emissions allowances of $ 777 as current assets held for sale on the Consolidated Balance Sheet at December 31, 2021. The Company estimated the fair value of these assets and concluded that the fair value exceeded the carrying value and no impairment was recorded by the Company for the year ended December 31, 2021. In March 2022, the NOx emissions allowances credits were sold for $ 1,088 . A $ 311 gain on sale of intangible assets was recorded for the year ended December 31, 2022.

Property, Plant and Equipment,

Property, Plant and Equipment, Net	12 Months Ended
	Dec. 31, 2023
Property, Plant and Equipment [Abstract]
Property, Plant and Equipment, Net	NOTE 7—PROPERTY, PLANT AND EQUIPMENT, NET Property, plant and equipment consists of the following as of December 31, 2023 and 2022: December 31, 2023 December 31, 2022 Land $ 748 $ 595 Buildings and improvements 30,329 29,268 Machinery and equipment 255,421 247,631 Gas mineral rights 35,526 34,526 Construction work in progress 67,747 20,745 Total $ 389,771 $ 332,765 Less: Accumulated depreciation and amortization ( 175,482 ) ( 156,819 ) Property, plant & equipment, net $ 214,289 $ 175,946 Depreciation expense for property plant and equipment was $ 19,624 , $ 19,251 and $ 19,617 and amortization expense for gas mineral rights was $ 489 , $ 515 and $ 1,828 for the years ended December 31, 2023, 2022 and 2021, respectively. In 2023, the Company specifically identified $ 777 in discrete RNG machinery and feedstock processing equipment that were no longer in operational use and recorded an impairment in the Company's RNG segment. The remaining $ 125 in impairments were for obsolete REG critical spares. In 2022, the Company performed a recoverability test for one REG site when it was determined that it was more likely than not the carrying value of the long-lived assets would not be recoverable. The results of the testing indicated that the site had carrying values in excess of the asset group’s fair value. As a result of the analysis, the company recorded an impairment totaling $ 2,089 in property, plant and equipment for the year ended December 31, 2022. Additionally, $ 1,393 in property, plant and equipment at another REG site was impaired due a discrete conclusion that certain assets acquired in the Asset acquisition would no longer be utilized by the Company. An RNG site was impaired for $ 1,108 due specific identification of certain assets no longer capable of being used as designed. Finally, computer software and hardware no longer being utilized ($ 191 ) were impaired in 2022. The 2021 impairment loss of $ 1,191 was due to the closure of two REG Sites and also the disposal of machinery at one RNG site.

Goodwill And Intangible Assets,

Goodwill And Intangible Assets, Net	12 Months Ended
	Dec. 31, 2023
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill And Intangible Assets, Net	NOTE 8—GOODWILL AND INTANGIBLE ASSETS, NET Intangible assets consist of the following as of December 31, 2023 and December 31, 2022: December 31, 2023 December 31, 2022 Goodwill $ 60 $ 60 Intangible assets with indefinite lives: Land use rights 329 329 Total intangible assets with indefinite lives: $ 329 $ 329 Intangible assets with finite lives: Interconnection, net of accumulated amortization 3,847 and $ 3,107 $ 14,584 $ 11,686 Customer contracts, net of accumulated 17,254 and $ 17,022 3,448 3,680 Total intangible assets with finite lives: $ 18,032 $ 15,366 Total Goodwill and Intangible assets $ 18,421 $ 15,755 The weighted average remaining useful life of the customer contracts and interconnection is approximately 15 years for both intangible asset categories. Amortization expense was $ 972 , $ 887 and $ 1,424 for the years ended December 31, 2023, 2022 and 2021, respectively. Impairments related to intangibles totaled $ 71 for the year ended December 31, 2022, which included $ 44 related to one REG site discussed in Note 7 and $ 27 related to an RNG site associated with the early termination of a customer contract. Amortization expense for customer contracts and interconnection the next five years is as follows: Customer Inter- Year ending Contracts connections 2024 $ 231 $ 740 2025 230 740 2026 230 740 2027 230 740 2028 230 740 Thereafter 2,297 10,884

Asset Retirement Obligations

Asset Retirement Obligations	12 Months Ended
	Dec. 31, 2023
Asset Retirement Obligation Disclosure [Abstract]
Asset Retirement Obligations	NOTE 9—ASSET RETIREMENT OBLIGATIONS The Company accounts for asset retirement obligations by recording the fair value of the liability in the period in which it is incurred. The Company estimates the fair value of asset retirement obligations by calculating the estimated present value of the cost to retire the asset. Factors that are considered when determining the present value of the cost to retire the asset include future inflation and discount rates, along with estimates date(s) of retiring the asset. Additionally, changes in legal, regulatory, environmental, and political environments can affect the fair value of the obligations. As such, asset retirement obligations are considered a level 3 financial instrument. The following table summarizes the activity associated with asset retirement obligations of the Company for the years ended December 31, 2023, 2022 and 2021: Year ended December 31, 2023 2022 2021 Asset retirement obligations—beginning of period $ 5,493 $ 5,301 $ 5,689 Accretion expense 407 296 ( 160 ) Decommissioning — ( 104 ) ( 228 ) Asset retirement obligations—end of period $ 5,900 $ 5,493 $ 5,301

Derivative Instruments

Derivative Instruments	12 Months Ended
	Dec. 31, 2023
Derivative Instrument Detail [Abstract]
Derivative Instruments	NOTE 10—DERIVATIVE INSTRUMENTS To mitigate market risk associated with fluctuations in energy commodity prices (natural gas) and interest rates, the Company utilizes various derivative contracts to secure energy commodity pricing and interest rates under a board-approved program. The Company does not apply hedge accounting to any of its derivative instruments, and all realized and unrealized gains and losses from changes in derivative values are recognized in earnings each period. As a result of the hedging strategy employed, the Company had the following cash received (paid) on derivatives in the Consolidated Statements of Operations for the years ended December 31, 2023, 2022 and 2021: Year ended December 31, Derivative Instrument Location 2023 2022 2021 Commodity contracts: Cash paid on derivatives Operating revenue $ — $ ( 7,829 ) $ — Interest rate swaps Interest expense ( 560 ) 2,652 1,422 Net gain (loss) $ ( 560 ) $ ( 5,177 ) $ 1,422

Fair Value of Financial Instrum

Fair Value of Financial Instruments	12 Months Ended
	Dec. 31, 2023
Fair Value Disclosures [Abstract]
Fair Value of Financial Instruments	NOTE 11—FAIR VALUE OF FINANCIAL INSTRUMENTS The Company’s assets and liabilities that are measured at fair value on a recurring basis include the following as of December 31, 2023 and 2022, set forth by level, within the fair value hierarchy: December 31, 2023 Level 1 Level 2 Level 3 Total Interest rate swap derivative asset $ — $ 1,255 $ — $ 1,255 Asset retirement obligations — — ( 5,900 ) ( 5,900 ) Pico earn-out liability — — ( 5,109 ) ( 5,109 ) $ — $ 1,255 $ ( 11,009 ) $ ( 9,754 ) December 31, 2022 Level 1 Level 2 Level 3 Total Interest rate swap derivative asset $ — $ 1,815 $ — $ 1,815 Asset retirement obligations — — ( 5,493 ) ( 5,493 ) Pico earn-out liability — — ( 3,843 ) ( 3,843 ) $ — $ 1,815 $ ( 9,336 ) $ ( 7,521 ) A summary of change in the fair value of the Company’s Level 3 instrument, attributable to asset retirement obligations, for the years ended December 31, 2023, 2022 and 2021 is included in Note 9. The Company’s earn-out fair value liability is determined by calculating the estimated present value of the future obligation. The present value is assessed quarterly and is based on macro-economic factors such as inflation and risk-free US Treasury rates. Company specific estimates utilized include current and future interest rates, inlet gas flow, and projected EBITDA, as defined in the underlying earnout agreement. The earn-out is classified as a Level 3 financial instrument. Interest rate swap derivatives are classified as Level 2 financial instruments and are valued utilizing quoted forward Bloomberg Short-Term Bank Yield Index Rates. In addition, certain assets are measured at fair value on a non-recurring basis when an indicator of impairment is identified and the assets’ fair values are determined to be less than its carrying value. See Note 3 for additional information.

Accrued Liabilities

Accrued Liabilities	12 Months Ended
	Dec. 31, 2023
Payables and Accruals [Abstract]
Accrued Liabilities	NOTE 12—ACCRUED LIABILITIES The Company’s accrued liabilities consists of the following as of December 31, 2023 and December 31, 2022: December 31, 2023 December 31, 2022 Accrued expenses $ 3,983 $ 3,221 Payroll and related benefits 2,355 1,561 Royalty 3,897 7,836 Utility 1,653 1,605 Accrued interest 827 794 Other 74 73 Accrued liabilities $ 12,789 $ 15,090

Debt

Debt	12 Months Ended
	Dec. 31, 2023
Debt Disclosure [Abstract]
Debt	NOTE 13—DEBT The Company’s debt consists of the following as of December 31, 2023 and December 31, 2022: December 31, 2023 December 31, 2022 Term loans $ 64,000 $ 72,000 Less: current principal maturities ( 8,000 ) ( 8,000 ) Less: debt issuance costs (on long-term debt) ( 386 ) ( 495 ) Long-term debt $ 55,614 $ 63,505 Current portion of long-term debt 7,886 7,870 Total debt $ 63,500 $ 71,375 Amended Credit Agreement On December 12, 2018, Montauk Energy Holdings LLC (“MEH”) entered into the Second Amended and Restated Revolving Credit and Term Loan Agreement (as amended, “Credit Agreement”), by and among MEH, the financial institutions from time to time party thereto as lenders and Comerica Bank, as the administrative agent, sole lead arranger and sole bookrunner (“Comerica”). The Credit Agreement (i) amended and restated in its entirety MEH’s prior revolving credit and term loan facility, dated as of August 4, 2017, as amended, with Comerica and certain other financial institutions and (ii) replaced in its entirety the prior credit agreement, dated as of August 4, 2017, as amended, between Comerica and Bowerman Power LFG, LLC, a wholly-owned subsidiary of MEH. On March 21, 2019, MEH entered into the first amendment to the Credit Agreement (the “First Amendment”), which clarified a variety of terms, definitions and calculations in the Credit Agreement. The Credit Agreement requires the Company to maintain customary affirmative and negative covenants, including certain financial covenants, which are measured at the end of each fiscal quarter. On August 28, 2019, the Company received a temporary waiver for an anticipated Event of Default (as defined in the Credit Agreement) for the consecutive three-month period ended on August 31, 2019 (the “Specified Event of Default”). The Specified Event of Default was waived through October 1, 2019. On September 12, 2019, the Company entered into the Second Amendment. Among other matters, the Second Amendment redefined the Fixed Charge Coverage Ratio (as defined in the Credit Agreement), reduced the commitments under the revolving credit facility to $ 80,000 , redefined the Total Leverage Ratio (as defined in the Credit Agreement) and eliminated the RIN Floor (as defined in the Second Amendment) as an Event of Default. In connection with the Second Amendment, the Company paid down the outstanding term loan by $ 38,250 and the resulting quarterly principal installments were reduced to $ 2,500 . In connection with the completion of the Reorganization Transactions and the IPO, the Company entered into the third amendment to the Credit Agreement (the “Third Amendment”). This amendment permitted the Change of Control provisions, as defined in the underlying agreement, to permit the Reorganization Transactions and IPO to be completed. On December 21, 2021, MEH entered into the Fourth Amendment to the Second Amended and Restated Revolving Credit and Term Loan Agreement. The current credit agreement, which is secured by a lien on substantially all assets of the Company and certain of its subsidiaries, provides for a $ 80,000 term loan and a $ 120,000 revolving credit facility. The term loan amortizes in quarterly installments of $ 2,000 through 2024, then increases to $ 3,000 from 2025 to 2026 with a final payment of $ 32,000 in late 2026. As of December 31, 2023, $ 64,000 was outstanding under the term loan. In addition, the Company had $ 2,505 of outstanding letters of credit as of December 31, 2023. Amounts available under the revolving credit facility are reduced by any amounts outstanding under letters of credit. As of December 31, 2023, the Company’s capacity available for borrowing under the revolving credit facility was $ 117,495 . Borrowings of the term loan and revolving credit facility bear interest at the Bloomberg Short-Term Bank Yield Index Rate plus an applicable margin. Interest rates as of December 31, 2023 and 2022 were 6.11 % and 4.12 %, respectively. The Company accounted for the Fourth amendment as both a debt modification and debt extinguishment in accordance with ASC 470, Debt (“ASC 470”). In connection with the Credit Agreement, the Company paid $ 2,027 in fees. Of this amount, $ 326 was expensed and $ 1,701 was capitalized and will be amortized over the life of the Credit Agreement. Amortized debt issuance expense in the amount of $ 367 , $ 412 and $ 483 for the years ended December 31, 2023, 2022 and 2021, respectively, was recorded in interest expense on the Statement of Operations. As of December 31, 2023, the Company was in compliance with all financial covenants related to the Credit Agreement. Annual Maturities of Long-Term Debt The following is a summary of annual principal maturities of long-term debt as of December 31, 2023: Year ending Amount 2024 $ 8,000 2025 12,000 2026 44,000 Total $ 64,000

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2023
Income Tax Disclosure [Abstract]
Income Taxes	NOTE 14—INCOME TAXES The Company is subject to income taxes in the U.S. federal jurisdiction and various state and local jurisdictions. Tax regulations within each jurisdiction are subject to the interpretation of the related tax laws and regulations and require significant judgment to apply. On March 11, 2021, the American Rescue Plan Act of 2021 (“ARPA”) was signed into law. The ARPA contains several corporate income tax provisions which include (i) extending the $ 1,000 limitation on deductions for compensation paid to executives of publicly traded corporations to include compensation paid to the eight highest paid individuals (rather than three highest), plus the chief executive officer and the chief financial officer (effective for tax years after 2026), and (ii) extending the period for which companies may claim an employee retention credit. The ARPA did not have a material impact on the Company’s financial statements for the years ending December 31, 2023, 2022 and 2021. The following table details the components of the Company’s income tax provision (benefit) for the years ended December 31, 2023, 2022 and 2021: Year ended December 31, 2023 2022 2021 Current expense (benefit): Federal $ 1,006 $ 321 $ — State 536 1,109 ( 91 ) $ 1,542 $ 1,430 $ ( 91 ) Deferred expense: Federal $ 1,869 $ 6,446 $ 3,368 State 7 172 884 $ 1,876 $ 6,618 $ 4,252 Income tax expense $ 3,418 $ 8,048 $ 4,161 The following table illustrates the deferred tax assets and liabilities as of December 31, 2023 and December 31, 2022: December 31, 2023 December 31, 2022 Deferred tax assets: Net operating loss carry forwards $ 4,107 $ 6,744 Federal tax credits 13,042 13,691 Book reserves 1,473 1,368 Intangible asset amortization 5,799 6,701 Stock compensation 1,370 1,087 Impairment 306 — Total deferred tax assets 26,097 29,591 Less: valuation analysis ( 3,950 ) ( 3,950 ) Net deferred tax assets $ 22,147 $ 25,641 Deferred tax liabilities: Property depreciation $ ( 20,048 ) $ ( 21,683 ) Other ( 23 ) ( 6 ) Total deferred tax liabilities ( 20,071 ) ( 21,689 ) Net deferred tax assets 2,076 3,952 As of December 31, 2023, the Company has no remaining federal net operating loss (“NOL”) carryforwards that it is able to utilize. The Company does have $ 12,986 of federal net operating losses that are not expected to be realizable due to loss limitation rules. In 2022, the Company utilized all of its non-limited NOLs. The Company has $ 13,042 of federal tax credit carryforwards that expire 20 years from the date incurred, which begin to expire in tax year 2026. The Company has pre-tax state net operating loss carryforwards of $ 18,059 which will begin to expire in tax year 2026. The following table details the components of the Company’s income tax provision for the years ended December 31, 2023, 2022 and 2021: Year ended December 31, 2023 2022 2021 Tax provision at federal statutory rate of 21% $ 3,857 $ 9,081 $ ( 77 ) State tax provision 430 998 800 Permanent differences 114 15 79 Stock compensation ( 175 ) ( 24 ) 723 162(m) compensation limitation 1,530 — 4,382 Valuation allowance — 50 12 Production tax credit ( 2,324 ) ( 2,052 ) ( 2,112 ) Return to provision — ( 20 ) ( 29 ) Deferred tax adjustments — — 383 Other ( 14 ) — — Total income tax expense $ 3,418 $ 8,048 $ 4,161 As of December 31, 2023, the tax years 2020 , 2021 and 2022 are open for examination by the IRS. Valuation Allowance The Company annually reviews its deferred tax assets for the possibility they will not be realized. A valuation allowance will be recorded if it is determined more than a 50% likelihood exists that a deferred tax asset will not be realized. A $ 3,950 valuation allowance exists at December 31, 2023, which represents the Company’s deferred tax assets that are not expected to be realized. The balance at December 31, 2022, was also $ 3,950 . Uncertain Tax Position The calculation of the Company’s tax liabilities involves dealing with uncertainties in the application of complex tax laws and regulations in both federal and state jurisdictions. ASC 740 states that a tax benefit from an uncertain tax position may be recognized when it is more likely than not that the position will be sustained upon examination, including resolutions of any related appeals or litigation processes, on the basis of each situation’s technical merits. At this point in time the Company is not aware of any tax positions taken that would give rise to recording an uncertain tax position. As such, the Company has not recorded any liability for unrecognized tax benefits as of December 31, 2023 or 2022. The Company records interest and penalties as a component of income tax expense. However, as there are no unrecognized tax benefits for the years ended December 31, 2023 and December 31, 2022, the Company has no penalties or interest accrued at December 31, 2023 and 2022, respectively.

Share-Based Compensation

Share-Based Compensation	12 Months Ended
	Dec. 31, 2023
Share-Based Payment Arrangement [Abstract]
Share-Based Compensation	NOTE 15—SHARE-BASED COMPENSATION In January 2021, Montauk Renewables undertook the Reorganization Transactions which resulted in the Company owning all of the assets and entities (excluding Montauk USA) through which MNK’s business and operations were conducted. As a result of the Distribution, the options outstanding under MNK’s Employee Share Appreciation Rights Scheme (the “SAR Plan”) were cancelled. The Company recorded $ 2,050 of accelerated compensation expense in its consolidated statements of operations within general and administrative expenses in connection with the cancellation of the options under the SAR Plan for the year ended December 31, 2021. The board of directors of Montauk Renewables adopted the Montauk Renewables, Inc. Equity and Incentive Compensation Plan (“MRI EICP”) in January 2021. Following the closing of the IPO, the board of directors of Montauk Renewables approved the grant of non-qualified stock options, restricted stock units and restricted share awards to the employees of Montauk Renewables and its subsidiaries in January 2021. In connection with the restricted share awards, the officers of the Company made elections under Section 83(b) of the Code. Pursuant to such elections, the Company withheld 950,214 shares of common stock from such awards at a price of $ 11.38 per share from such awards. The Company records and reports restricted shares and restricted stock units when vested and in the case of options, when such awards are settled in the Company’s common stock. Stock compensation expense related to these awards was $ 1,723 , $ 6,979 and $ 9,474 for the years ended December 31, 2023, 2022 and 2021, respectively. In connection with a May 2021 asset acquisition, 1,250,000 restricted share awards (“RS Awards”) were granted to two employees that were hired by the Company in connection with such acquisition. The RS Awards were to vest over a five-year period and subject to the achievement of time and performance-based vesting criteria over such period. In May 2022, the RS Awards were amended to remove the performance-based vesting criteria and will only be subject to time-based vesting requirements over a five-year period. The awards were revalued at $ 15,500 . Stock compensation expense related to the two awards was $ 4,908 , $ 2,863 and $ 0 for the year ended December 31, 2023, 2022 and 2021, respectively. In April 2023, the board of directors of the Company approved the grant of non-qualified stock options to the executive officers of the Company, which vest ratably over a period of three to five years. In September 2023, the board of directors approved the grant of non-qualified stock options to a new executive officer of the Company, which also vest ratably over a period of three to five years. Stock compensation expense related to these awards was $ 1,692 for the year ended December 31, 2023. The restricted shares, restricted stock units and option awards are subject to vesting schedules and are subject to the terms and conditions of the MRI EICP and related award agreements including, in the case of the restricted share awards, each officer having made an election under Section 83(b) of the Code. The Company recorded $ 10,813 of compensation expense in its consolidated statements of operations within general and administrative expenses for the year ended December 31, 2021 in connection with the withheld 950,214 shares associated with the Section 83(b) elections. Options granted under the MRI EICP allow the recipient to receive the Company’s common stock equal to the appreciation in the fair market value of the Company’s common stock between the grant date and the exercise and settlement of options into shares as of the exercise date(s). The fair value of the MRI EICP options was estimated using the Black-Scholes option pricing model with the following weighted-average assumptions (no dividends were expected): September 2023 Awards Options awarded 225,000 Risk-free interest rate 4.44 %- 4.65 % Expected volatility 71 %- 73 % Expected option life (in years) 3.5 - 5.5 Grant-date fair value $ 5.72 April 2023 Awards Options awarded 2,100,000 Risk-free interest rate 3.71 %- 3.97 % Expected volatility 78 %- 80 % Expected option life (in years) 3.5 - 5.5 Grant-date fair value $ 4.25 January 2021 Awards Options awarded 950,214 Risk-free interest rate 0.5 % Expected volatility 32 % Expected option life (in years) 5.5 Grant-date fair value $ 3.44 The following table summarizes the restricted shares, restricted stock units and options outstanding under the MRI EICP for the years ended December 31, 2023, 2022 and 2021: Restricted Shares Restricted Stock Units Options Number of Weighted Number of Weighted Number of Weighted End of period - December 31, 2021 2,569,613 $ 10.08 377,984 $ 10.23 950,214 $ 11.38 Beginning of period - January 1, 2022 2,569,613 $ 10.08 377,984 $ 10.23 950,214 $ 11.38 Granted 1,250,000 12.40 — — — — Vested ( 541,312 ) 11.38 ( 97,984 ) 10.49 ( 950,214 ) 11.38 Forfeited ( 1,250,000 ) 9.04 — — — — End of period - December 31, 2022 2,028,301 $ 11.80 280,000 $ 10.13 — $ — Beginning of period - January 1, 2023 2,028,301 $ 11.80 280,000 $ 10.13 — $ — Granted — — — — 2,325,000 7.04 Vested ( 316,228 ) 11.38 ( 50,000 ) 10.09 — — Forfeited ( 73,395 ) 11.38 ( 80,000 ) 10.23 — — End of period - December 31, 2023 1,638,678 $ 11.91 150,000 $ 10.09 2,325,000 $ 7.04 As of December 31, 2023 none of the 950,214 vested options have been exercised. Unrecognized MRI EICP compensation expense for awards the Company expects to vest as of December 31, 2023, was $ 18,158 and will be recognized over approximately 5 years.

Defined Contribution Plan

Defined Contribution Plan	12 Months Ended
	Dec. 31, 2023
Retirement Benefits [Abstract]
Defined Contribution Plan	NOTE 16—DEFINED CONTRIBUTION PLAN The Company maintains a 401(k) defined contribution plan for eligible employees. The Company matches 50 % of an employee’s deferrals up to 4 %. The Company also contributes 3 % of eligible employee’s compensation expense as a safe harbor contribution. The matching contributions vest ratably over four years of service, while the safe harbor contributions vest immediately. Incurred expense related to the 401(k) plan was approximately $ 640 , $ 589 and $ 502 for the years ended December 31, 2023, 2022 and 2021, respectively.

Related Party Transactions

Related Party Transactions	12 Months Ended
	Dec. 31, 2023
Related Party Transactions [Abstract]
Related Party Transactions	NOTE 17—RELATED-PARTY TRANSACTIONS Related Party Loan On January 26, 2021, the Company entered into a Loan Agreement and Secured Promissory Note (the “Initial Promissory Note”) with Montauk Holdings Limited (“MNK”). MNK is currently an affiliate of the Company and certain of the Company’s directors are also directors of MNK. Pursuant to the Initial Promissory Note, the Company advanced a cash loan of $ 5,000 to MNK for MNK to pay its dividend's tax liability arising from the Reorganization Transactions under the South African Income Tax Act, 1962 (Act No. 58 of 1962), as amended (the “South African Income Tax Act”). On February 22, 2021, the Company and MNK entered into an Amended and Restated Promissory Note (the “Amended Promissory Note”) to increase the principal amount of the loan to a total of $ 7,140 , in the aggregate, on December 22, 2021 entered into the Second Amended and Restated Loan Agreement and Secured Promissory Note (the “Second Amended Promissory Note”) to increase the principal amount of the loan to a total of $ 8,940 , in the aggregate, and on December 22, 2022 entered into the First Amendment of the Second Amended and Restated Loan Agreement and Secured Promissory Note (the “First Amendment of Second Amended Promissory Note”) to amend the maturity date to June 30, 2023, and on June 21, 2023 entered into the Third Amended and Restated Loan Agreement and Secured Promissory Note (the "Third Amended and Restated Loan Agreement and Secured Promissory Note") to increase the principal amount of the loan to a total of $ 10,040 , in the aggregate and extend the maturity date of the loan to December 31, 2023 and on December 27, 2023 entered into the Fourth Amended and Restated Loan Agreement and Secured Promissory Note to extend the maturity date of the loan to December 31, 2033 each in accordance with the Company’s obligations set forth in the transaction implementation agreement entered into by and among the Company, MNK and the other party thereto, dated November 6, 2020, and amended on January 14, 2021. The "Third Amended and Restated Loan Agreement and Secured Promissory Note" increased the security interest of the Company from 800,000 shares of the common stock of the Company owned by MNK to 976,623 shares of the Company. MNK is required to use the proceeds of any such sale of the shares to repay the note. The Amended Promissory Note has default provisions where MNK will deliver any unsold shares of the Company back to the Company to satisfy repayment of the note. Under applicable guidance for variable interest entities in ASC 810, Consolidation, the Company determined that MNK is a variable interest entity. The Company concluded that it is not the primary beneficiary of the variable interest entity, as the Company does not have a controlling financial interest and does not have the power to direct the activities that most significantly impact the economic performance of MNK. Accordingly, the Company concluded that presentation of the Amended Promissory Note as a related party receivable remains appropriate. The maximum exposure to loss is limited to the Promissory Note principal and accrued interest, which totaled $ 10,138 and $ 9,000 as of December 31, 2023 and 2022, respectively. MNK was delisted from the JSE on January 26, 2021. The MNK Board of Directors and Shareholders held its annual general meeting in March 2023 and voted to take MNK private. Related Party Reimbursements Periodically the Company will reimburse MNK and HCI Managerial Services Proprietary Limited, the administrator for the Company’s secondarily listed Johannesburg Stock Exchange trading symbol, for expenses incurred on behalf of the Company. Amounts reimbursed were $ 156 , $ 68 and $ 813 for the years ended December 31, 2023, 2022 and 2021, respectively. $ 11 and $ 26 were owed as of December 31, 2023 and 2022, respectively.

Segment Information

Segment Information	12 Months Ended
	Dec. 31, 2023
Segment Reporting [Abstract]
Segment Information	NOTE 18—SEGMENT INFORMATION The Company’s reportable segments for the years ended December 31, 2023, 2022, and 2021 are Renewable Natural Gas and Renewable Electricity Generation. Renewable Natural Gas includes the production of RNG. Renewable Electricity Generation includes generation of electricity at biogas-to-electricity plants. The corporate entity is not determined to be an operating segment but is discretely disclosed for purposes of reconciliation of the Company’s consolidated financial statements. The following table is consistent with the manner in which the chief operating decision maker evaluates the performance of each segment and allocates the Company’s resources. In the following tables “RNG” refers to Renewable Natural Gas and “REG” refer to Renewable Electricity Generation. For the year ended December 31, 2023 RNG REG Corporate Total Total revenue $ 156,455 $ 18,449 $ — $ 174,904 Net income (loss) 59,271 ( 572 ) ( 43,751 ) 14,948 EBITDA 74,991 4,621 ( 34,335 ) 45,277 Adjusted EBITDA (1) 75,859 4,749 ( 34,157 ) 46,451 Total assets 176,951 73,369 99,918 350,238 Capital expenditures 41,325 21,682 84 63,091 (1) 2023 EBITDA Reconciliation The following table is a reconciliation of the Company’s reportable segments’ net income from continuing operations to Adjusted EBITDA for the year ended December 31, 2023: For the year ended December 31, 2023 RNG REG Corporate Total Net income (loss) $ 59,271 $ ( 572 ) $ ( 43,751 ) $ 14,948 Depreciation, depletion and amortization 15,720 5,193 245 21,158 Interest expense — — 5,753 5,753 Income tax expense — — 3,418 3,418 EBITDA $ 74,991 $ 4,621 $ ( 34,335 ) $ 45,277 Impairment loss 777 125 — 902 Net loss on sale of assets 91 3 — 94 Transaction costs — — 178 178 Adjusted EBITDA $ 75,859 $ 4,749 $ ( 34,157 ) $ 46,451 For the year ended December 31, 2022 RNG REG Corporate Total Total revenue $ 196,218 $ 17,170 $ ( 7,829 ) $ 205,559 Net income (loss) 94,330 ( 6,756 ) ( 52,380 ) 35,194 EBITDA 109,297 ( 1,297 ) ( 42,266 ) 65,734 Adjusted EBITDA (2) 110,510 1,918 ( 41,890 ) 70,538 Total assets 151,998 53,255 127,063 332,316 Capital expenditures 16,667 5,033 577 22,277 (2) 2022 EBITDA Reconciliation The following table is a reconciliation of the Company’s reportable segments’ net income from continuing operations to Adjusted EBITDA for the year ended December 31, 2022: For the year ended December 31, 2022 RNG REG Corporate Total Net income (loss) $ 94,330 $ ( 6,756 ) $ ( 52,380 ) $ 35,194 Depreciation, depletion and amortization 14,967 5,443 290 20,700 Interest expense — — 1,792 1,792 Income tax expense — 16 8,032 8,048 EBITDA $ 109,297 $ ( 1,297 ) $ ( 42,266 ) $ 65,734 Impairment loss 1,135 3,526 191 4,852 Net loss (gain) on sale of assets 78 ( 311 ) — ( 233 ) Transaction costs — — 185 185 Adjusted EBITDA $ 110,510 $ 1,918 $ ( 41,890 ) $ 70,538 For the year ended December 31, 2021 RNG REG Corporate Total Total revenue $ 131,803 $ 15,449 $ 875 $ 148,127 Net income (loss) 49,387 ( 3,129 ) ( 50,786 ) ( 4,528 ) EBITDA 66,549 2,399 ( 43,518 ) 25,430 Adjusted EBITDA (3) 67,812 3,149 ( 43,012 ) 27,949 Total assets 150,472 57,980 78,028 286,480 Capital expenditures 7,647 2,296 43 9,986 (3) 2021 EBITDA Reconciliation The following table is a reconciliation of the Company’s reportable segments’ net income from continuing operations to Adjusted EBITDA for the year ended December 31, 2021: For the year ended December 31, 2021 RNG REG Corporate Total Net income (loss) $ 49,387 $ ( 3,129 ) $ ( 50,786 ) $ ( 4,528 ) Depreciation, depletion and amortization 17,162 5,528 179 22,869 Interest expense — — 2,928 2,928 Income tax expense — — 4,161 4,161 EBITDA $ 66,549 $ 2,399 $ ( 43,518 ) $ 25,430 Impairment loss 441 750 — 1,191 Net loss on sale of assets 822 — — 822 Transaction costs — — 352 352 Loss on extinguishment of debt — — 154 154 Adjusted EBITDA $ 67,812 $ 3,149 $ ( 43,012 ) $ 27,949 For the years ended December 31, 2023, 2022 and 2021, three, two and two customers, respectively, made up greater than 10% of our total revenues. For the year ended December 31, 2023 RNG REG Corporate Total Customer A 22.0 % — — 22.0 % Customer B 11.7 % — — 11.7 % Customer C 11.7 % — — 11.7 % For the year ended December 31, 2022 RNG REG Corporate Total Customer A 32.0 % — — 32.0 % Customer B 17.0 % — — 17.0 % For the year ended December 31, 2021 RNG REG Corporate Total Customer A 13.1 % — — 13.1 % Customer B 12.4 % — — 12.4 %

Leases

Leases	12 Months Ended
	Dec. 31, 2023
Leases [Abstract]
Leases	NOTE 19—LEASES The Company leases office space and other office equipment under operating lease arrangements (with initial terms greater than twelve months), expiring in various years through 2033. These leases have been entered into to better enable the Company to conduct business operations. Office space is leased to provide adequate workspace for all employees in Pittsburgh, Pennsylvania and Houston, Texas. Office space and office equipment agreements that exceed 12 months are accounted for as operating leases in accordance with ASC 842, Leases. The Company also leases safety equipment for the various operational sites in the United States. The term of certain equipment exceeds twelve months and is accordingly classified as a finance lease under ASC 842. The finance leases expire in 2024 and were entered into in order to provide a safe work environment for operational employees. The Company determines if an arrangement is, or contains, a lease at inception based on whether that contract conveys the right to control the use of an identified asset in exchange for consideration for a period of time. For all operating lease arrangements, the Company presents at the commencement date: a lease liability, which is a lessee’s obligation to make lease payments arising from a lease, measured on a discounted basis; and a right-of-use asset, which is an asset that represents the lessee’s right to use, or control the use of, a specified asset for the lease term. The Company has elected, as a practical expedient, not to separate non-lease components from lease components, and instead account for each separate component as a single lease component for all lease arrangements, as lessee. In addition, the Company has elected, as a practical expedient, not to apply lease recognition requirements to short-term lease arrangements, generally those with a lease term of less than twelve months, for all classes of underlying assets. In determination of the lease term, the Company considers the likelihood of lease renewal options and lease termination provisions. The Company uses its incremental borrowing rate, as the basis to calculate the present value of future lease payments, at lease commencement. The incremental borrowing rate represents the rate of interest a lessee would have to pay to borrow an amount equal to the total lease payments on a collateralized basis over a similar term in a similar economic environment. As of December 31, 2023, there were no leases entered into which have not yet commenced and that would entitle the Company to significant rights or create additional obligations. The total lease cost included in our consolidated financial statements statement of operations for the years ended December 31, 2023, 2022 and 2021 were $ 695 , $ 412 , and $ 349 , respectively. Leases with an initial term of 12 months or less are not recorded on the Consolidated Balance Sheet and the lease expense for those leases is recognized on a straight-line basis. The short-term lease expense for the years ended December 31, 2023, 2022 and 2021 were approximately $ 1,182 , $ 895 and $ 494 , respectively. Supplemental information related to operating lease arrangements was as follows as of and for the year ended December 31, 2023, 2022 and 2021: Year ended December 31, 2023 2022 2021 Cash paid for amounts included in the measurement of $ 431 $ 385 $ 304 Weighted average remaining lease term (in years) 5.24 5.87 1.03 Weighted average discount rate 5.00 % 5.00 % 5.00 % Future minimum lease payments for the years ending December 31, are as follows: Year Ending 2024 $ 611 2025 624 2026 573 2027 583 2028 594 Thereafter 2,714 Imputed interest ( 1,146 ) Total $ 4,553 Supplemental information related to finance lease arrangements was as follows: Year ended December 31, 2023 2022 Cash paid for amounts included in the measurement of $ 79 $ 50 Weighted average remaining lease term (in years) 3.54 1.25 Weighted average discount rate 5.00 % 5.00 % Future minimum finance lease payments are as follows: Year Ending 2024 $ 27 2025 1 2026 1 2027 1 2028 1 Thereafter 10 Imputed interest ( 5 ) Total $ 36

Income (Loss) Per Share

Income (Loss) Per Share	12 Months Ended
	Dec. 31, 2023
Earnings Per Share [Abstract]
Income (Loss) Per Share	Note 21—INCOME (LOSS) PER SHARE Basic and diluted income (loss) per share was computed using the following common share data for the years ended December 31, 2023, 2022 and 2021, respectively: Year ended December 31, 2023 2022 2021 Net income (loss) $ 14,948 $ 35,194 $ ( 4,528 ) Basic weighted-average shares outstanding 141,727,905 141,238,851 141,015,213 Dilutive effect of share-based awards 423,735 1,340,538 — Diluted weighted-average shares outstanding 142,151,640 142,579,389 141,015,213 Basic income (loss) per share $ 0.11 $ 0.25 $ ( 0.03 ) Diluted income (loss) per share $ 0.11 $ 0.25 $ ( 0.03 ) As a result of incurring a net loss for the year ended December 31, 2021, 3,897,811 potential antidilutive shares were excluded from the above loss per share calculation.

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2023
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	NOTE 20—COMMITMENTS AND CONTINGENCIES Concentrations A substantial portion of the Company’s revenues are generated from five locations in 2023, 2022, and 2021, each in separate areas of the country. For the years ended December 31, 2023, 2022 and 2021, excluding the impact of derivative instruments, approximately 68 %, 72 % and 76 %, respectively, of operating revenues were derived from these locations. In addition, five customers make up approximately 71 % and 69 % of trade receivables as of December 31, 2023 and December 31, 2022, respectively. Environmental The Company is subject to a variety of environmental laws and regulations governing discharges to the air and water, as well as the handling, storage and disposing of hazardous or waste materials. The Company believes its operations currently comply in all material respects with all environmental laws and regulations applicable to its business. However, there can be no assurance that environmental requirements will not change in the future or that the Company will not incur significant costs to comply with such requirements. Contingencies The Company, from time to time, may be involved in litigation. At December 31, 2023, management does not believe there are any matters outstanding that would have a material adverse effect on the Company’s financial position or results of operations.

Subsequent Events

Subsequent Events	12 Months Ended
	Dec. 31, 2023
Subsequent Events [Abstract]
Subsequent Events	NOTE 22—SUBSEQUENT EVENTS Subsequent Events The Company evaluated its December 31, 2023 consolidated financial statements through the date the financial statements were issued. The Company is not aware of any subsequent events which would require recognition or disclosure in the consolidated financial statements, except for the matters discussed below. On February 18, 2024, for one of its renewable electrical sites, the Company entered into a bill of sale, assignment and assumption agreement to sell its rights to the existing fuel supply agreement and property back to the site host in advance of the fuel supply agreement termination date. The agreement will transfer all rights, titles, interests and landfill improvements back to the site host. The Company received proceeds of $ 1,000 and will no longer have any obligation to decommission or remove any machinery or equipment at the site. The site is reported within the Company’s REG segment and the consideration received is in excess of the carrying value of the assets. The effective date of the sale, assignment and assumption agreement is October 1, 2024. In connection with the bill of sale, assignment and assumption agreement, the Company entered into agreements with the same site host to extend the fuel supply agreements at two RNG sites for an additional five years .

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2023
Accounting Policies [Abstract]
Principles of Consolidation	Principles of Consolidation The historical consolidated financial information included reflects the historical results of operations and financial position of Montauk USA through January 4, 2021 when MNK sold the membership interest of Montauk USA. The consolidated financial statements of Montauk USA became the Company’s historical financial statements following the IPO. Certain historical financial information included relates to periods prior to the Reorganization Transactions. All intercompany balances and transactions have been eliminated in consolidation. The Company utilizes the equity method of accounting for companies where its ownership is greater than 50 % and significant but controlling interest does not exist.
Retrospective Presentation of Ownership Related to the Reorganization Transactions	Retrospective Presentation of Ownership Related to the Reorganization Transactions As discussed in Note 1, as a result of the Reorganization Transactions, the Company acquired the assets and entities (excluding Montauk USA) which were previously owned by MNK. As part of the Reorganization Transactions, a 1: 1 pro rata distribution of shares of the Company’s common stock was made to holders of MNK’s ordinary shares. The Reorganization Transactions resulted in a pro rata distribution whereby the ownership of the Company after the Reorganization Transactions was identical to the ownership of MNK prior to the Reorganization Transaction and was therefore akin to a common control transaction. All member’s equity in the financial statements and notes have been retrospectively adjusted to give effect to the Distribution, as if such pro rata distribution on a 1: 1 basis occurred as of all pre-IPO periods presented, including periods presented on the Consolidated Balance Sheets, Consolidated Statements of Operations, Consolidated Statements of Stockholders’ and Member’s Equity and notes to the Consolidated Financial Statements contained herein.
Reclassifications	Reclassifications Certain prior period amounts have been reclassified to conform to the current period financial statement presentation. These reclassifications had no effect on the previously reported total assets, total liabilities, stockholders’ equity, results of operations or cash flows
Segment Reporting	Segment Reporting The Company reports segment information in three segments: RNG, Renewable Electricity Generation and Corporate. This is consistent with the internal reporting provided to the chief operating decision maker who evaluates operating results and performance. The aforementioned business services and offerings described in Note 1 are grouped and defined by management as two distinct operating segments: RNG and Renewable Electricity Generation. Below is a description of the Company’s operating segments and other activities. The RNG segment represents the sale of gas sold at fixed-price contracts, counterparty share RNG volumes and applicable Environmental Attributes. This business unit represents the majority of the revenues generated by the Company. The Renewable Electricity Generation segment represents the sale of captured electricity and applicable Environmental Attributes. Corporate & Other relates to additional discrete financial information for the corporate function. It is primarily used as a shared service center for maintaining functions such as executive, accounting, treasury, legal, human resources, tax, environmental, engineering and other operations functions not otherwise allocated to a segment. As such, the corporate entity is not determined to be an operating segment but is discretely disclosed for purposes of reconciliation to the Company’s consolidated financial statements.
Use of Estimates	Use of Estimates The preparation of financial statements, in conformity with accounting principles generally accepted in the United States (“GAAP”), requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates.
Cash, Cash Equivalents and Restricted Cash	Cash, Cash Equivalents and Restricted Cash Cash and cash equivalents include highly liquid investments with maturity dates of three months or less from the date of purchase and are recorded at cost. The Company may hold cash in excess of federally insured limits. Restricted cash is classified as current or non-current based on the terms of the underlying agreements and represents cash held as deposits, cash held in escrow and cash collateral for financial letters of credit.
Accounts and Other Receivables	Accounts and Other Receivables Accounts and other receivables on the Consolidated Balance Sheets represent outstanding billings for goods and services delivered to customers on an unsecured basis as well as reimbursable expenses. In evaluating its allowance for doubtful accounts for accounts receivable, the Company performs ongoing reviews of its outstanding receivables to determine if any amounts are uncollectible and adjusts the allowance for doubtful accounts accordingly.
Property, Plant and Equipment	Property, Plant and Equipment Property, plant and equipment purchases are stated at cost. Depreciation and amortization are based on costs less estimated salvage values, primarily using the straight-line method over the estimated useful lives or, if applicable, the term of the related gas rights agreements or power purchase agreements, whichever is shorter. Maintenance and repairs are expensed as incurred. Major improvements that extend the useful lives of property are capitalized. The estimated useful lives of the Company’s property, plant and equipment reflect the expected consumption of the economic benefit of these assets as noted in the following table: Buildings and improvements 5 - 30 years Machinery and equipment 1 - 43 years Gas mineral rights 15 - 25 years $ 313 and $ 332 in insurance proceeds were received for the years ended December 31, 2022 and 2021, respectively, related to an engine failure at an RNG Facility. These insurance proceeds are included in Gain on insurance proceeds for the years ended December 31, 2022 and 2021, respectively within the Consolidated Statements of Operations.
Goodwill and Intangible Assets	Goodwill and Intangible Assets Goodwill is the cost of an acquisition less the fair value of the identified net assets of the acquired business. Separately identifiable intangible assets are recorded at their fair values upon acquisition. The Company accounts for its intangible assets in accordance with ASC 350, Intangibles—Goodwill and Other (“ASC 350”). Finite-lived intangible assets include interconnections, customer contracts and trade names & trademarks. The interconnection intangible asset is the exclusive right to utilize an interconnection line between the operating plant and a utility substation to transmit produced natural gas and electricity. Included in that right is full maintenance provided on this line by the utility. Intangible assets with finite useful lives are amortized on a straight-line basis over their estimated useful life as depicted in the chart below. Indefinite intangible assets are not amortized and include emission allowances and land use rights. The estimated useful lives of separately identified intangible assets are as follows: Interconnection 10 - 25 years Customer contracts 2 - 15 years Emissions allowances Indefinite Land use rights Indefinite
Assets Held for Sale	Assets Held for Sale Assets classified as held for sale are reported at the lower of their carrying value or fair value less costs to sell. Assets are classified as held for sale if their carrying amounts will be recovered through a sale transaction, rather than through continued use. This condition is met only when the sale is highly probable and the assets are available for immediate sale in their present condition, subject only to terms that are usual and customary for sales of such assets. Management must be committed to a sale, which should be expected to qualify for recognition as a completed sale within one year from the date of classification as held for sale and actions required to complete the plan of sale indicate that it is unlikely that significant changes to the plan will be made or that the plan will be withdrawn. Impairment losses on initial classification as held-for-sale are recognized in the Consolidated Statement of Operations. Assets classified as held for sale are no longer depreciated or amortized.
Leases	Leases The Company assesses leases in accordance with ASU 2016-02, Leases, (“ASU 2016-02”). This ASU requires lessees to recognize a right-of-use asset and lease liability on the Consolidated Balance Sheet for leases classified as either operating or finance leases. For leases with a term of 12 months or less, a lessee is permitted to make an accounting policy election by class of underlying asset not to recognize a right-of-use asset and lease liability. Additionally, when measuring assets and liabilities arising from a lease, optional payments should be included only if the lessee is reasonably certain to exercise an option to extend the lease, exercise a purchase option, or not exercise an option to terminate the lease. A right-of-use asset represents an entity’s right to use the underlying asset for the lease term, and a lease liability represents an entity’s obligation to make lease payments. The measurement, recognition and presentation of expenses and cash flows arising from leases by a lessee remains the same. The Company has included further lease disclosures in Note 19.
Long-lived Asset Impairment	Long-lived Asset Impairment In accordance with ASC 360, Property, plant, equipment and intangible assets with finite useful lives are evaluated for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. Recoverability of assets to be held and used is measured by comparing the carrying amount of an asset or asset group to future undiscounted cash flows expected to be generated by the asset or asset group. Such estimates are based on certain assumptions, which are subject to uncertainty and may materially differ from actual results. If such assets are considered to be impaired, the impairment to be recognized is measured by the amount by which the carrying amount of the assets exceeds the fair value of the assets. A summary of impairment losses on tangible and intangible assets for the year ended December 31, 2023, 2022 and 2021 is included in Note 3.
Indefinite-Lived Asset Impairment	Indefinite-Lived Asset Impairment Indefinite-lived intangible assets are required to be evaluated for impairment at least annually or whenever events or changes in circumstances indicate that the carrying value of the asset may not be recoverable. The evaluation of impairment under ASC 350 requires the use of projections, estimates and assumptions as to the future performance of the Company’s operations, including anticipated future revenues, expected operating costs and the discount factor used. Actual results may differ from projections. If such indefinite-lived assets are considered to be impaired, the impairment to be recognized is measured by the amount by which the carrying amount of the assets exceeds the fair value of the assets.
Asset Retirement Obligations	Asset Retirement Obligations The Company accounts for asset retirement obligations as required under ASC 410, Asset Retirement and Environmental Obligations, (“ASC 410”). ASC 410 requires the fair value of a liability for an asset retirement obligation be recognized in the period in which the legal obligation arises, with the associated discounted asset retirement costs being capitalized as a part of the carrying amount of the long-lived asset and the annual accretion expense recorded in operations. The Company has recorded in the consolidated financial statements estimates for asset retirement obligations related to the decommissioning and removal requirements for specific gas processing and distribution assets, as required by their associated gas rights agreements.
Revenue	Revenue The Company recognizes revenue in accordance with ASC 606, Revenue from Contracts with Customers (“ASC 606”) . Revenue from the Company’s point in time product sales is recognized when products are transferred, or services are invoiced and control transferred. Revenue from the Company’s product and service sales provided under long-term agreements is recognized as the Company transfers control of the product or renders service to its customers, which approximates the time when the customer is invoiced. The Company has presented the disclosures required by ASC 606 in Note 4.
Income Taxes	Income Taxes The Company is treated as a corporation for income tax purposes. Therefore, income taxes are accounted for under the liability method on a consolidated basis by the Company and its consolidated subsidiaries in accordance with ASC 740, Income Taxes (“ASC 740”). Deferred tax assets and liabilities are determined based on differences between financial reporting and tax bases of assets and liabilities and are measured using the enacted tax rates and laws. The provision for income taxes includes federal and state income taxes. The Company recognizes the financial statement benefit of a tax position only after determining the relevant tax authority would more-likely-than-not sustain the position following an audit. For tax positions meeting the more-likely-than-not threshold, the amount recognized in the consolidated financial statements is the largest benefit that has a greater than 50 percent likelihood of being realized upon ultimate settlement with the relevant tax authority. The Company recognizes accrued interest and penalties related to unrecognized tax benefits in income tax expense.
Derivative Instruments	Derivative Instruments The Company applies the provisions of ASC 815, Derivatives and Hedging, (“ASC 815”). ASC 815 requires each derivative instrument to be recorded in the Consolidated Balance Sheets at its fair value. Changes in a derivative instrument’s fair value are recognized currently in earnings.
Fair Value of Financial Instruments	Fair Value of Financial Instruments The Company employs varying methods and assumptions in estimating the fair value of each class of financial instruments for which it is practical to estimate fair value. For cash and cash equivalents, receivables and payables, the carrying amounts approximate fair value due to the short maturity of these instruments. For long-term debt, the carrying amounts approximate fair value as the interest rates obtained by the Company approximate the prevailing interest rates available to the Company for similar instruments. In accordance with ASC 820, Fair Value Measurement (“ASC 820”), a hierarchy is established which requires an entity to maximize the use of observable inputs and minimize the use of unobservable inputs when measuring fair value. The hierarchy defines three levels of inputs that may be used to measure fair value: Level 1—Unadjusted quoted prices in active markets for identical unrestricted assets and liabilities that the reporting entity has the ability to access at the measurement date. Level 2—Inputs other than quoted prices included within Level 1 that are observable for the assets and liabilities or can be corroborated with observable market data for substantially the entire contractual term of the assets or liabilities. Level 3—Unobservable inputs that reflect the entity’s own assumptions about the assumptions market participants would use in the pricing of the assets or liabilities and are consequently not based on market activity but rather through particular valuation techniques. The Company uses the fair value methodology to value the assets and liabilities recorded at fair value, including the Company’s asset retirement obligations and earn out liability. The values of the Level 2 interest rate derivatives were determined using a model, which incorporates market inputs including the implied forward interest rate yield curve for the same period as the future interest rate swap settlement. The Company has also considered both its own credit risk and counterparty credit risk in determining fair value and determined these adjustments were insignificant for the years ended December 31, 2023 and 2022. The Company’s asset retirement obligations are recorded at fair value at the time the liability is incurred if a reasonable estimate of fair value can be made. Fair value is determined by calculating the estimated present value of the cost to retire the asset as determined by qualified engineers, based on currently available information and inflation estimates and is considered a Level 3 measurement. The Company’s earn-out liability fair value is determined by calculating the estimated present value of future obligations based on currently available information and the discount factor used and is considered a Level 3 measurement. A summary of changes in the fair values of the Company’s Level 3 instruments, attributable to asset retirement obligations and the earn out liability, for the years ended December 31, 2023 and 2022 is included in Note 11.
Renewable Identification Numbers ("RIN")	Renewable Identification Numbers (“RINs”) The Company generates D3 RINs through its production and sale of RNG used for transportation purposes as prescribed under the Federal Renewable Fuel Standard. The RINs that the Company generates as government incentives through its renewable operating projects can be separated and sold as credits independent from the energy produced and not a result of physical attributes of the Company’s production. Therefore, no cost is allocated to the RIN when it is generated. Revenue is recognized on these Environmental Attributes when there is an agreement in place to monetize the credits at an agreed upon price with a customer and transfer of control has occurred. Realized prices for Environmental Attributes monetized in a year may not correspond directly to index prices due to the forward selling of commitments. The Company had 0.1 and 0.7 million RINs generated and unsold as of December 31, 2023 and 2022, respectively. Renewable Energy Credits (“RECs”) The Company generates RECs through its production and sale of landfill methane into renewable electric energy as prescribed by the State of California Renewables Portfolio Standard or the EPA. The RECs that the Company generates as government incentives through its renewable operating projects are able to be separated and sold as credits independent from the electricity produced and not a result of physical attributes of the Company’s production. Therefore, no cost is allocated to the REC when it is generated. Revenue is recognized on these Environmental Attributes when there is an agreement in place to monetize the credits at an agreed upon price with a customer and transfer of control has occurred.
Equity-Based Compensation	Equity-Based Compensation The Company accounts for equity-based compensation under the provisions of ASC 718, Compensation—Stock Compensation, (“ASC 718”). ASC 718 requires compensation costs related to share-based payment transactions, measured based on the fair value of the instruments issued, be recognized in the consolidated financial statements over the requisite service period of the award. Stock options are initially measured on the grant date using the Black-Scholes valuation model, which requires the use of subjective assumptions related to the expected stock price volatility, term, risk-free interest rate and dividend yield. For restricted stock shares, the Company determines the grant date fair value based on the closing market price of the stock on the date of the grant.
Employee Benefits	Employee Benefits Leave entitlement Employee entitlements to annual leave are recognized when they accrue to employees. An accrual is made for the estimated liability to the employees for annual leave up to the financial year end date. This liability is included in “Accrued liabilities” in the Consolidated Balance Sheets. Bonus Plans The Company recognizes a liability and an expense for incentive compensation bonuses awarded based on the achievement of Company and personnel goals where contractually obliged or where there is a past practice that has created a constructive obligation. An accrual is maintained for the appropriate proportion of the expected bonuses which would become payable at year end.
Recently Issued Accounting Standards	Recently Adopted Accounting Standards In August 2020, the FASB issued ASU 2020-06, Debt: Debt with Conversion and Other Options (Subtopic 470-20) and Derivatives and Hedging—Contracts in Entity’s Own Equity (Subtopic 815-40), which simplifies the accounting for convertible instruments and contracts in an entity’s own equity. This guidance is effective for annual reporting periods beginning after December 15, 2021, including interim periods within those years, with early adoption permitted only as of annual reporting periods beginning after December 15, 2020. The ASU does not have a material impact on the Company’s consolidated financial statements or related financial statement disclosures. In June 2016, the FASB issued Accounting Standards Update 2016-13, Measurement of Credit Losses on Financial Instruments (“ASU 2016-13”). This ASU and subsequent amendments are codified as Accounting Standards Codification Topic 326, Financial Instruments—Credit Losses (“ASC 326”). Application of ASC 326 was effective for SEC Issuers (excluding smaller reporting companies) for fiscal years beginning after December 15, 2019. Adoption for smaller reporting companies, emerging growth companies and nonpublic entities was deferred due to the COVID-19 pandemic and was required for fiscal years beginning after December 15, 2022. The ASU did not have a material impact on the Company’s consolidated financial statements or related financial statement disclosures. Recently Issued Accounting Standards In March 2020, the FASB issued ASU No. 2020-04, Reference Rate Reform (Topic 848), which provides optional expedients and exceptions to the current guidance on contract modifications and hedging relationships to ease the financial reporting burdens of the expected market transition from London Interbank Offered Rate (“LIBOR”) and other interbank offered rates to alternative reference rates. The guidance was effective upon issuance and may be applied prospectively to contract modifications made and hedging relationships entered into or evaluated on or before December 31, 2022. The FASB included a sunset provision within Topic 848 based on expectations of when the LIBOR would cease being published. The sunset provision has been amended from December 31, 2022, to December 31, 2024, after which entities will no longer be permitted to apply the relief in Topic 848. The Company’s current debt agreement bears interest at the Bloomberg Short-Term Bank Yield Index Rate plus an applicable margin. LIBOR is no longer utilized as a reference rate. In November 2023, the FASB issued ASU No. 2023-07, Segment Reporting (Topic 280): Improvements to Reportable Segments. The amendments in 2023-07 aim to improve reportable segment disclosure requirements, primarily through enhanced disclosures about significant segment expenses. ASU 2023-07 is effective for the Company's Annual Report on Form 10-K for the year ended December 31, 2024, and subsequent interim periods, with early adoption permitted. The Company is currently evaluating the impact of this standard on its consolidated financial statements. In December 2023, the FASB issued ASU No. 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures. The amendments in 2023-09 aim to enhance the transparency and decision usefulness of income tax disclosures. ASU 2023-09 is effective for the Company's Annual Report on Form 10-K for the year ended December 31, 2025, with early adoption permitted. The Company is currently evaluating the impact of this standard on its consolidated financial statements.

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2023
Accounting Policies [Abstract]
Summary of useful lives of property plant and equipment	The estimated useful lives of the Company’s property, plant and equipment reflect the expected consumption of the economic benefit of these assets as noted in the following table: Buildings and improvements 5 - 30 years Machinery and equipment 1 - 43 years Gas mineral rights 15 - 25 years
Summary of Useful Lives of Intangible Assets Other than Goodwill	The estimated useful lives of separately identified intangible assets are as follows: Interconnection 10 - 25 years Customer contracts 2 - 15 years Emissions allowances Indefinite Land use rights Indefinite

Revenues from Contracts with _2

Revenues from Contracts with Customers (Tables)	12 Months Ended
	Dec. 31, 2023
Revenue from Contract with Customer [Abstract]
Summary of Company's Revenue by Major Source	The following tables display the Company’s disaggregated revenue by major source, excluding realized and unrealized gains or losses under the Company’s gas hedge program, based on product type and timing of transfer of goods and services for the years ended December 31, 2023, 2022 and 2021: Year ended December 31, 2023 Goods transferred at a point in time Goods transferred over time Total Major goods/Service line: Natural gas commodity $ 977 $ 29,230 $ 30,207 Natural gas environmental attributes 125,874 — 125,874 Electric commodity — 11,301 11,301 Electric environmental attributes 7,522 — 7,522 $ 134,373 $ 40,531 $ 174,904 Operating segment: RNG $ 126,851 $ 29,230 $ 156,081 REG 7,522 11,301 18,823 $ 134,373 $ 40,531 $ 174,904 Year ended December 31, 2022 Goods transferred at a point in time Goods transferred over time Total Major goods/Service line: Natural gas commodity $ 2,053 $ 50,845 $ 52,898 Natural gas environmental attributes 143,025 — 143,025 Electric commodity — 10,449 10,449 Electric environmental attributes 7,016 — 7,016 $ 152,094 $ 61,294 $ 213,388 Operating segment: RNG $ 145,078 $ 50,845 $ 195,923 REG 7,016 10,449 17,465 $ 152,094 $ 61,294 $ 213,388 Year ended December 31, 2021 Goods transferred at a point in time Goods transferred over time Total Major goods/Service line: Natural gas commodity $ 15,178 $ 32,143 $ 47,321 Natural gas environmental attributes 84,906 — 84,906 Electric commodity — 9,692 9,692 Electric environmental attributes 6,208 — 6,208 $ 106,292 $ 41,835 $ 148,127 Operating segment: RNG $ 100,084 $ 32,143 $ 132,227 REG 6,208 9,692 15,900 $ 106,292 $ 41,835 $ 148,127

Accounts and Other Receivables

Accounts and Other Receivables (Tables)	12 Months Ended
	Dec. 31, 2023
Receivables, Net, Current [Abstract]
Schedule of Accounts and Other Receivables	Accounts and other receivables consist of the following as of December 31, 2023 and 2022: December 31, 2023 December 31, 2022 Accounts receivables $ 12,557 $ 7,148 Other receivables 148 57 Reimbursable expenses 47 17 Accounts and other receivables, net $ 12,752 $ 7,222

Property, Plant and Equipment_2

Property, Plant and Equipment, Net (Tables)	12 Months Ended
	Dec. 31, 2023
Property, Plant and Equipment [Abstract]
Summary of Property Plant and Equipment	Property, plant and equipment consists of the following as of December 31, 2023 and 2022: December 31, 2023 December 31, 2022 Land $ 748 $ 595 Buildings and improvements 30,329 29,268 Machinery and equipment 255,421 247,631 Gas mineral rights 35,526 34,526 Construction work in progress 67,747 20,745 Total $ 389,771 $ 332,765 Less: Accumulated depreciation and amortization ( 175,482 ) ( 156,819 ) Property, plant & equipment, net $ 214,289 $ 175,946

Goodwill And Intangible Asset_2

Goodwill And Intangible Assets, Net (Tables)	12 Months Ended
	Dec. 31, 2023
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Intangible Assets	Intangible assets consist of the following as of December 31, 2023 and December 31, 2022: December 31, 2023 December 31, 2022 Goodwill $ 60 $ 60 Intangible assets with indefinite lives: Land use rights 329 329 Total intangible assets with indefinite lives: $ 329 $ 329 Intangible assets with finite lives: Interconnection, net of accumulated amortization 3,847 and $ 3,107 $ 14,584 $ 11,686 Customer contracts, net of accumulated 17,254 and $ 17,022 3,448 3,680 Total intangible assets with finite lives: $ 18,032 $ 15,366 Total Goodwill and Intangible assets $ 18,421 $ 15,755
Summary of finite-lived intangible assets future amortization expense	Amortization expense for customer contracts and interconnection the next five years is as follows: Customer Inter- Year ending Contracts connections 2024 $ 231 $ 740 2025 230 740 2026 230 740 2027 230 740 2028 230 740 Thereafter 2,297 10,884

Asset Retirement Obligations (T

Asset Retirement Obligations (Tables)	12 Months Ended
	Dec. 31, 2023
Asset Retirement Obligation Disclosure [Abstract]
Summary of Activity Associated with Asset Retirement Obligations	The following table summarizes the activity associated with asset retirement obligations of the Company for the years ended December 31, 2023, 2022 and 2021: Year ended December 31, 2023 2022 2021 Asset retirement obligations—beginning of period $ 5,493 $ 5,301 $ 5,689 Accretion expense 407 296 ( 160 ) Decommissioning — ( 104 ) ( 228 ) Asset retirement obligations—end of period $ 5,900 $ 5,493 $ 5,301

Derivative Instruments (Tables)

Derivative Instruments (Tables)	12 Months Ended
	Dec. 31, 2023
Derivative Instrument Detail [Abstract]
Summary of Cash Received (Paid) on Derivative Instrument	As a result of the hedging strategy employed, the Company had the following cash received (paid) on derivatives in the Consolidated Statements of Operations for the years ended December 31, 2023, 2022 and 2021: Year ended December 31, Derivative Instrument Location 2023 2022 2021 Commodity contracts: Cash paid on derivatives Operating revenue $ — $ ( 7,829 ) $ — Interest rate swaps Interest expense ( 560 ) 2,652 1,422 Net gain (loss) $ ( 560 ) $ ( 5,177 ) $ 1,422

Fair Value of Financial Instr_2

Fair Value of Financial Instruments (Tables)	12 Months Ended
	Dec. 31, 2023
Fair Value Disclosures [Abstract]
Summary of Assets and Liabilities that are Measured at Fair Value on a Recurring Basis	December 31, 2023 Level 1 Level 2 Level 3 Total Interest rate swap derivative asset $ — $ 1,255 $ — $ 1,255 Asset retirement obligations — — ( 5,900 ) ( 5,900 ) Pico earn-out liability — — ( 5,109 ) ( 5,109 ) $ — $ 1,255 $ ( 11,009 ) $ ( 9,754 ) December 31, 2022 Level 1 Level 2 Level 3 Total Interest rate swap derivative asset $ — $ 1,815 $ — $ 1,815 Asset retirement obligations — — ( 5,493 ) ( 5,493 ) Pico earn-out liability — — ( 3,843 ) ( 3,843 ) $ — $ 1,815 $ ( 9,336 ) $ ( 7,521 )

Accrued Liabilities (Tables)

Accrued Liabilities (Tables)	12 Months Ended
	Dec. 31, 2023
Payables and Accruals [Abstract]
Summary of Accrued Liabilities	The Company’s accrued liabilities consists of the following as of December 31, 2023 and December 31, 2022: December 31, 2023 December 31, 2022 Accrued expenses $ 3,983 $ 3,221 Payroll and related benefits 2,355 1,561 Royalty 3,897 7,836 Utility 1,653 1,605 Accrued interest 827 794 Other 74 73 Accrued liabilities $ 12,789 $ 15,090

Debt (Tables)

Debt (Tables)	12 Months Ended
	Dec. 31, 2023
Debt Disclosure [Abstract]
Summary of Company Debt	The Company’s debt consists of the following as of December 31, 2023 and December 31, 2022: December 31, 2023 December 31, 2022 Term loans $ 64,000 $ 72,000 Less: current principal maturities ( 8,000 ) ( 8,000 ) Less: debt issuance costs (on long-term debt) ( 386 ) ( 495 ) Long-term debt $ 55,614 $ 63,505 Current portion of long-term debt 7,886 7,870 Total debt $ 63,500 $ 71,375
Summary of annual principal maturities of long-term debt	Year ending Amount 2024 $ 8,000 2025 12,000 2026 44,000 Total $ 64,000

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2023
Income Tax Disclosure [Abstract]
Schedule of Components of Income Tax Provision	The following table details the components of the Company’s income tax provision (benefit) for the years ended December 31, 2023, 2022 and 2021: Year ended December 31, 2023 2022 2021 Current expense (benefit): Federal $ 1,006 $ 321 $ — State 536 1,109 ( 91 ) $ 1,542 $ 1,430 $ ( 91 ) Deferred expense: Federal $ 1,869 $ 6,446 $ 3,368 State 7 172 884 $ 1,876 $ 6,618 $ 4,252 Income tax expense $ 3,418 $ 8,048 $ 4,161 The following table details the components of the Company’s income tax provision for the years ended December 31, 2023, 2022 and 2021: Year ended December 31, 2023 2022 2021 Tax provision at federal statutory rate of 21% $ 3,857 $ 9,081 $ ( 77 ) State tax provision 430 998 800 Permanent differences 114 15 79 Stock compensation ( 175 ) ( 24 ) 723 162(m) compensation limitation 1,530 — 4,382 Valuation allowance — 50 12 Production tax credit ( 2,324 ) ( 2,052 ) ( 2,112 ) Return to provision — ( 20 ) ( 29 ) Deferred tax adjustments — — 383 Other ( 14 ) — — Total income tax expense $ 3,418 $ 8,048 $ 4,161
Schedule Of Deferred Tax Assets And Liabilities	The following table illustrates the deferred tax assets and liabilities as of December 31, 2023 and December 31, 2022: December 31, 2023 December 31, 2022 Deferred tax assets: Net operating loss carry forwards $ 4,107 $ 6,744 Federal tax credits 13,042 13,691 Book reserves 1,473 1,368 Intangible asset amortization 5,799 6,701 Stock compensation 1,370 1,087 Impairment 306 — Total deferred tax assets 26,097 29,591 Less: valuation analysis ( 3,950 ) ( 3,950 ) Net deferred tax assets $ 22,147 $ 25,641 Deferred tax liabilities: Property depreciation $ ( 20,048 ) $ ( 21,683 ) Other ( 23 ) ( 6 ) Total deferred tax liabilities ( 20,071 ) ( 21,689 ) Net deferred tax assets 2,076 3,952

Share-Based Compensation (Table

Share-Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2023
Share-Based Payment Arrangement [Abstract]
Summary of Fair Value of MRI EICP Options and Valuation Assumptions	September 2023 Awards Options awarded 225,000 Risk-free interest rate 4.44 %- 4.65 % Expected volatility 71 %- 73 % Expected option life (in years) 3.5 - 5.5 Grant-date fair value $ 5.72 April 2023 Awards Options awarded 2,100,000 Risk-free interest rate 3.71 %- 3.97 % Expected volatility 78 %- 80 % Expected option life (in years) 3.5 - 5.5 Grant-date fair value $ 4.25 January 2021 Awards Options awarded 950,214 Risk-free interest rate 0.5 % Expected volatility 32 % Expected option life (in years) 5.5 Grant-date fair value $ 3.44
Summary of Outstanding Activity of Options,Restricted Stock and Restricted Stock Units under MRI EICP	The following table summarizes the restricted shares, restricted stock units and options outstanding under the MRI EICP for the years ended December 31, 2023, 2022 and 2021: Restricted Shares Restricted Stock Units Options Number of Weighted Number of Weighted Number of Weighted End of period - December 31, 2021 2,569,613 $ 10.08 377,984 $ 10.23 950,214 $ 11.38 Beginning of period - January 1, 2022 2,569,613 $ 10.08 377,984 $ 10.23 950,214 $ 11.38 Granted 1,250,000 12.40 — — — — Vested ( 541,312 ) 11.38 ( 97,984 ) 10.49 ( 950,214 ) 11.38 Forfeited ( 1,250,000 ) 9.04 — — — — End of period - December 31, 2022 2,028,301 $ 11.80 280,000 $ 10.13 — $ — Beginning of period - January 1, 2023 2,028,301 $ 11.80 280,000 $ 10.13 — $ — Granted — — — — 2,325,000 7.04 Vested ( 316,228 ) 11.38 ( 50,000 ) 10.09 — — Forfeited ( 73,395 ) 11.38 ( 80,000 ) 10.23 — — End of period - December 31, 2023 1,638,678 $ 11.91 150,000 $ 10.09 2,325,000 $ 7.04

Segment Information (Tables)

Segment Information (Tables)	12 Months Ended
	Dec. 31, 2023
Segment Reporting [Abstract]
Summary of Reconciliation of the Company's Reportable Segments' Net Income from Continuing Operations	The following table is consistent with the manner in which the chief operating decision maker evaluates the performance of each segment and allocates the Company’s resources. In the following tables “RNG” refers to Renewable Natural Gas and “REG” refer to Renewable Electricity Generation. For the year ended December 31, 2023 RNG REG Corporate Total Total revenue $ 156,455 $ 18,449 $ — $ 174,904 Net income (loss) 59,271 ( 572 ) ( 43,751 ) 14,948 EBITDA 74,991 4,621 ( 34,335 ) 45,277 Adjusted EBITDA (1) 75,859 4,749 ( 34,157 ) 46,451 Total assets 176,951 73,369 99,918 350,238 Capital expenditures 41,325 21,682 84 63,091 (1) 2023 EBITDA Reconciliation The following table is a reconciliation of the Company’s reportable segments’ net income from continuing operations to Adjusted EBITDA for the year ended December 31, 2023: For the year ended December 31, 2023 RNG REG Corporate Total Net income (loss) $ 59,271 $ ( 572 ) $ ( 43,751 ) $ 14,948 Depreciation, depletion and amortization 15,720 5,193 245 21,158 Interest expense — — 5,753 5,753 Income tax expense — — 3,418 3,418 EBITDA $ 74,991 $ 4,621 $ ( 34,335 ) $ 45,277 Impairment loss 777 125 — 902 Net loss on sale of assets 91 3 — 94 Transaction costs — — 178 178 Adjusted EBITDA $ 75,859 $ 4,749 $ ( 34,157 ) $ 46,451 For the year ended December 31, 2022 RNG REG Corporate Total Total revenue $ 196,218 $ 17,170 $ ( 7,829 ) $ 205,559 Net income (loss) 94,330 ( 6,756 ) ( 52,380 ) 35,194 EBITDA 109,297 ( 1,297 ) ( 42,266 ) 65,734 Adjusted EBITDA (2) 110,510 1,918 ( 41,890 ) 70,538 Total assets 151,998 53,255 127,063 332,316 Capital expenditures 16,667 5,033 577 22,277 (2) 2022 EBITDA Reconciliation The following table is a reconciliation of the Company’s reportable segments’ net income from continuing operations to Adjusted EBITDA for the year ended December 31, 2022: For the year ended December 31, 2022 RNG REG Corporate Total Net income (loss) $ 94,330 $ ( 6,756 ) $ ( 52,380 ) $ 35,194 Depreciation, depletion and amortization 14,967 5,443 290 20,700 Interest expense — — 1,792 1,792 Income tax expense — 16 8,032 8,048 EBITDA $ 109,297 $ ( 1,297 ) $ ( 42,266 ) $ 65,734 Impairment loss 1,135 3,526 191 4,852 Net loss (gain) on sale of assets 78 ( 311 ) — ( 233 ) Transaction costs — — 185 185 Adjusted EBITDA $ 110,510 $ 1,918 $ ( 41,890 ) $ 70,538 For the year ended December 31, 2021 RNG REG Corporate Total Total revenue $ 131,803 $ 15,449 $ 875 $ 148,127 Net income (loss) 49,387 ( 3,129 ) ( 50,786 ) ( 4,528 ) EBITDA 66,549 2,399 ( 43,518 ) 25,430 Adjusted EBITDA (3) 67,812 3,149 ( 43,012 ) 27,949 Total assets 150,472 57,980 78,028 286,480 Capital expenditures 7,647 2,296 43 9,986 (3) 2021 EBITDA Reconciliation The following table is a reconciliation of the Company’s reportable segments’ net income from continuing operations to Adjusted EBITDA for the year ended December 31, 2021: For the year ended December 31, 2021 RNG REG Corporate Total Net income (loss) $ 49,387 $ ( 3,129 ) $ ( 50,786 ) $ ( 4,528 ) Depreciation, depletion and amortization 17,162 5,528 179 22,869 Interest expense — — 2,928 2,928 Income tax expense — — 4,161 4,161 EBITDA $ 66,549 $ 2,399 $ ( 43,518 ) $ 25,430 Impairment loss 441 750 — 1,191 Net loss on sale of assets 822 — — 822 Transaction costs — — 352 352 Loss on extinguishment of debt — — 154 154 Adjusted EBITDA $ 67,812 $ 3,149 $ ( 43,012 ) $ 27,949
Summary of Revenue by Major Customers	For the years ended December 31, 2023, 2022 and 2021, three, two and two customers, respectively, made up greater than 10% of our total revenues. For the year ended December 31, 2023 RNG REG Corporate Total Customer A 22.0 % — — 22.0 % Customer B 11.7 % — — 11.7 % Customer C 11.7 % — — 11.7 % For the year ended December 31, 2022 RNG REG Corporate Total Customer A 32.0 % — — 32.0 % Customer B 17.0 % — — 17.0 % For the year ended December 31, 2021 RNG REG Corporate Total Customer A 13.1 % — — 13.1 % Customer B 12.4 % — — 12.4 %

Leases (Tables)

Leases (Tables)	12 Months Ended
	Dec. 31, 2023
Leases [Abstract]
Summary of Supplemental information Related to Operating Lease	Supplemental information related to operating lease arrangements was as follows as of and for the year ended December 31, 2023, 2022 and 2021: Year ended December 31, 2023 2022 2021 Cash paid for amounts included in the measurement of $ 431 $ 385 $ 304 Weighted average remaining lease term (in years) 5.24 5.87 1.03 Weighted average discount rate 5.00 % 5.00 % 5.00 %
Summary of Future Minimum Operating Lease Payments	Future minimum lease payments for the years ending December 31, are as follows: Year Ending 2024 $ 611 2025 624 2026 573 2027 583 2028 594 Thereafter 2,714 Imputed interest ( 1,146 ) Total $ 4,553
Summary of Supplemental information Related to Finance Leases	Supplemental information related to finance lease arrangements was as follows: Year ended December 31, 2023 2022 Cash paid for amounts included in the measurement of $ 79 $ 50 Weighted average remaining lease term (in years) 3.54 1.25 Weighted average discount rate 5.00 % 5.00 %
Summary of Future Minimum Finance Lease Payments	Future minimum finance lease payments are as follows: Year Ending 2024 $ 27 2025 1 2026 1 2027 1 2028 1 Thereafter 10 Imputed interest ( 5 ) Total $ 36

Income (Loss) Per Share (Tables

Income (Loss) Per Share (Tables)	12 Months Ended
	Dec. 31, 2023
Earnings Per Share [Abstract]
Schedule of Basic and Diluted Income (Loss) Per Share	Basic and diluted income (loss) per share was computed using the following common share data for the years ended December 31, 2023, 2022 and 2021, respectively: Year ended December 31, 2023 2022 2021 Net income (loss) $ 14,948 $ 35,194 $ ( 4,528 ) Basic weighted-average shares outstanding 141,727,905 141,238,851 141,015,213 Dilutive effect of share-based awards 423,735 1,340,538 — Diluted weighted-average shares outstanding 142,151,640 142,579,389 141,015,213 Basic income (loss) per share $ 0.11 $ 0.25 $ ( 0.03 ) Diluted income (loss) per share $ 0.11 $ 0.25 $ ( 0.03 )

Description of Business - Addit

Description of Business - Additional Information (Detail) $ / shares in Units, $ in Thousands		12 Months Ended
	Jan. 26, 2021 USD ($) $ / shares shares	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)
Number of years of experience		30 years
Number of current operations		15
Percent of greenhouse gas reduction requirement		60%
Sale of stock, Number of shares issued in transaction | shares	2,702,500
Sale of stock, price per share | $ / shares	$ 8.5
Sale of stock, Consideration received on transaction	$ 22,971
Principal amount of loan	$ 10,040	$ 10,138	$ 0

Summary of Significant Accoun_4

Summary of Significant Accounting Policies - Additional Information (Detail) Numbers in Millions	12 Months Ended
	Dec. 31, 2023 Numbers ReportableSegments	Dec. 31, 2022 Numbers
Accounting Policies [Line Items]
Exchange of shares of the company's common stock	1
Pro rata exchange occurred as of all pre-IPO periods presented	1
Number of reportable segments | ReportableSegments	3
Renewable identification numbers unsold | Numbers	0.1	0.7
Minimum [Member]
Accounting Policies [Line Items]
Percentage of equity method investment where significant but controlling interest does not exist	50%

Summary of Significant Accoun_5

Summary of Significant Accounting Policies - Summary of Useful Lives of Property Plant and Equipment (Detail)	Dec. 31, 2023
Buildings and improvements [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and equipment, Useful life	5 years
Buildings and improvements [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and equipment, Useful life	30 years
Machinery and equipment [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and equipment, Useful life	1 year
Machinery and equipment [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and equipment, Useful life	43 years
Gas mineral rights [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and equipment, Useful life	15 years
Gas mineral rights [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and equipment, Useful life	25 years

Summary of Significant Accoun_6

Summary of Significant Accounting Policies - Summary of Useful Lives of Property Plant and Equipment (Detail) (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Renewable Natural Gas [Member] | Gain on Insurance Proceeds [Member]
Accounting Policies [Line Items]
Loss Contingency, Receivable, Proceeds	$ 313	$ 332

Summary of Significant Accoun_7

Summary of Significant Accounting Policies - Summary of Useful Lives of Intangible Assets Other than Goodwill (Detail)	12 Months Ended
	Dec. 31, 2023
Land Use Rights [Member]
Disclosure Details Of Useful Lives Of Intangible Assets Other Than Goodwill [LineItems]
Useful lives of intangible assets other than goodwill	Indefinite
Interconnection [Member]
Disclosure Details Of Useful Lives Of Intangible Assets Other Than Goodwill [LineItems]
Intangible asset useful life	15 years
Interconnection [Member] | Minimum [Member]
Disclosure Details Of Useful Lives Of Intangible Assets Other Than Goodwill [LineItems]
Intangible asset useful life	10 years
Interconnection [Member] | Maximum [Member]
Disclosure Details Of Useful Lives Of Intangible Assets Other Than Goodwill [LineItems]
Intangible asset useful life	25 years
Customer Contracts [Member]
Disclosure Details Of Useful Lives Of Intangible Assets Other Than Goodwill [LineItems]
Intangible asset useful life	15 years
Customer Contracts [Member] | Minimum [Member]
Disclosure Details Of Useful Lives Of Intangible Assets Other Than Goodwill [LineItems]
Intangible asset useful life	2 years
Customer Contracts [Member] | Maximum [Member]
Disclosure Details Of Useful Lives Of Intangible Assets Other Than Goodwill [LineItems]
Intangible asset useful life	15 years
Emission Allowances [Member]
Disclosure Details Of Useful Lives Of Intangible Assets Other Than Goodwill [LineItems]
Useful lives of intangible assets other than goodwill	Indefinite

Asset Impairment - Additional I

Asset Impairment - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Impairment loss	$ 902	$ 4,852	$ 1,191
Impairment of long lived assets to be disposed of			0
Impairment, Long-Lived Asset, Held-for-Use, Statement of Income or Comprehensive Income [Extensible Enumeration]		Impairment loss
Computer Software And Hardware [Member]
Impairment loss		$ 191
Customer Contracts [Member]
Impairment loss		27
Renewable Electricity Generation Site [Member]
Impairment loss	125	2,133
Renewable Electricity Generation Site [Member] | North Carolina Facility [Member]
Impairment loss		1,393
Renewable Natural Gas [Member]
Impairment loss	$ 777	1,135	441
Renewable Natural Gas [Member] | Psa Media [Member]
Impairment loss		$ 1,108
Renewable Natural Gas and Renewable Electricity Generation [Member]
Impairment loss			$ 1,191

Revenues from Contracts with _3

Revenues from Contracts with Customers - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Revenue from Contract with Customer, Segment Benchmark [Member] | Goods transferred over time [Member] | Renewable Natural Gas and Renewable Electricity Generation [Member] | Customer Concentration Risk [Member] | Renewable Energy [Member]
Disaggregation of Revenue [Line Items]
Revenue Performance obligation satisfied to segments, Percentage	23%	29%	28%
Revenue Benchmark [Member] | Product Concentration Risk [Member] | Counter Party Sharing Arrangement [Member]
Disaggregation of Revenue [Line Items]
Revenue Performance obligation satisfied to segments, Percentage		1%	10%
Revenue from Contract with Customer, Product and Service Benchmark [Member] | Goods transferred at a point in time [Member] | Product Concentration Risk [Member] | Electric Environmental Attributes [Member]
Disaggregation of Revenue [Line Items]
Revenue Performance obligation satisfied to segments, Percentage	77%	71%	72%

Revenues from Contracts with _4

Revenues from Contracts with Customers - Summary of Company's Revenue by Major Source (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	$ 174,904	$ 213,388	$ 148,127
RNG [Member]
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	156,081	195,923	132,227
REG [Member]
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	18,823	17,465	15,900
Natural Gas Commodity [Member]
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	30,207	52,898	47,321
Natural Gas Environmental Attributes [Member]
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	125,874	143,025	84,906
Electric Commodity [Member]
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	11,301	10,449	9,692
Electric Environmental Attributes [Member]
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	7,522	7,016	6,208
Goods transferred at a point in time [Member]
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	134,373	152,094	106,292
Goods transferred at a point in time [Member] | RNG [Member]
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	126,851	145,078	100,084
Goods transferred at a point in time [Member] | REG [Member]
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	7,522	7,016	6,208
Goods transferred at a point in time [Member] | Natural Gas Commodity [Member]
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	977	2,053	15,178
Goods transferred at a point in time [Member] | Natural Gas Environmental Attributes [Member]
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	125,874	143,025	84,906
Goods transferred at a point in time [Member] | Electric Environmental Attributes [Member]
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	7,522	7,016	6,208
Goods transferred over time [Member]
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	40,531	61,294	41,835
Goods transferred over time [Member] | RNG [Member]
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	29,230	50,845	32,143
Goods transferred over time [Member] | REG [Member]
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	11,301	10,449	9,692
Goods transferred over time [Member] | Natural Gas Commodity [Member]
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	29,230	50,845	32,143
Goods transferred over time [Member] | Electric Commodity [Member]
Disaggregation of Revenue [Line Items]
Revenues from Contracts with Customers	$ 11,301	$ 10,449	$ 9,692

Accounts and Other Receivable_2

Accounts and Other Receivables - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Receivables, Net, Current [Abstract]
Provision for accounts receivable and credit loss expense	$ 0	$ 0	$ 0

Accounts and Other Receivable_3

Accounts and Other Receivables - Schedule of Accounts and Other Receivables (Detail) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Receivables, Net, Current [Abstract]
Accounts receivables	$ 12,557	$ 7,148
Other receivables	148	57
Reimbursable expenses	47	17
Accounts and other receivables, net	$ 12,752	$ 7,222

Assets Held For Sale -Additiona

Assets Held For Sale -Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Impairment of long lived assets to be disposed of		$ 0
Sale of allowances credits	$ 1,088
Nitrogen Oxide (NOx) Credits [Member]
Asset held for sale		$ 777
Gain on sale of intangible assets	$ 311

Property, Plant and Equipment_3

Property, Plant and Equipment, Net - Summary of Property Plant and Equipment (Detail) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	$ 389,771	$ 332,765
Less: Accumulated depreciation and amortization	(175,482)	(156,819)
Property, Plant & Equipment, Net	214,289	175,946
Land [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	748	595
Buildings and improvements [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	30,329	29,268
Machinery and equipment [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	255,421	247,631
Gas mineral rights [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	35,526	34,526
Construction work in progress [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	$ 67,747	$ 20,745

Property, Plant and Equipment_4

Property, Plant and Equipment, Net - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Property, Plant and Equipment [Line Items]
Depreciation expense	$ 19,624	$ 19,251	$ 19,617
Impairment of long lived assets to be disposed of			0
Impairment, Long-Lived Asset, Held-for-Use, Statement of Income or Comprehensive Income [Extensible Enumeration]		Impairment loss
Impairment loss	902	$ 4,852	1,191
Capital expenditures	63,091	22,277	9,986
Gas mineral rights [Member]
Property, Plant and Equipment [Line Items]
Adjustment for amortization	489	515	$ 1,828
Computer Software And Hardware [Member]
Property, Plant and Equipment [Line Items]
Impairment loss	191
Renewable Electricity Generation [Member]
Property, Plant and Equipment [Line Items]
Impairment loss	125	2,089
Renewable Electricity Generation [Member] | North Carolina Facility [Member]
Property, Plant and Equipment [Line Items]
Impairment loss		1,393
Renewable Electricity Generation [Member] | Psa Media [Member]
Property, Plant and Equipment [Line Items]
Impairment loss		$ 1,108
Renewable Natural Gas [Member]
Property, Plant and Equipment [Line Items]
Impairment loss	777
Renewable Natural Gas and Renewable Electricity Generation [Member]
Property, Plant and Equipment [Line Items]
Impairment loss	$ 1,191

Goodwill And Intangible Asset_3

Goodwill And Intangible Assets, Net - Schedule of Intangible Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Schedule Of Intangible Assets And Goodwill [Line Items]
Goodwill	$ 60	$ 60
Indefinite-Lived Intangible Assets (Excluding Goodwill) [Abstract]
Indefinite-Lived Intangible Assets (Excluding Goodwill)	329	329
Finite-Lived Intangible Assets, Net [Abstract]
Finite-Lived Intangible Assets, Net	18,032	15,366
Total Goodwill and Intangible Assets	18,421	15,755
Interconnection [Member]
Finite-Lived Intangible Assets, Net [Abstract]
Finite-Lived Intangible Assets, Net	14,584	11,686
Customer Contracts [Member]
Finite-Lived Intangible Assets, Net [Abstract]
Finite-Lived Intangible Assets, Net	3,448	3,680
Land Use Rights [Member]
Indefinite-Lived Intangible Assets (Excluding Goodwill) [Abstract]
Indefinite-Lived Intangible Assets (Excluding Goodwill)	$ 329	$ 329

Goodwill And Intangible Asset_4

Goodwill And Intangible Assets, Net - Schedule of Intangible Assets (Parenthetical) (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Interconnection [Member]
Schedule Of Intangible Assets And Goodwill [Line Items]
Finite lived intangible assets accumulated amortization	$ 3,847	$ 3,107
Customer Contracts [Member]
Schedule Of Intangible Assets And Goodwill [Line Items]
Finite lived intangible assets accumulated amortization	$ 17,254	$ 17,022

Goodwill And Intangible Asset_5

Goodwill And Intangible Assets, Net - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Finite-Lived Intangible Assets [Line Items]
Amortization expense	$ 972	$ 887	$ 1,424
Impairment, Intangible Asset, Finite-Lived, Statement of Income or Comprehensive Income [Extensible Enumeration]		Asset Impairment Charges
Impairment of intangible assets		$ 71
Renewable Electricity Generation [Member]
Finite-Lived Intangible Assets [Line Items]
Impairment of intangible assets		44
Renewable Natural Gas [Member]
Finite-Lived Intangible Assets [Line Items]
Impairment of intangible assets		$ 27
Customer Contracts [Member]
Finite-Lived Intangible Assets [Line Items]
Finite lived intangible asset useful life	15 years
Interconnection [Member]
Finite-Lived Intangible Assets [Line Items]
Finite lived intangible asset useful life	15 years

Goodwill And Intangible Asset_6

Goodwill And Intangible Assets, Net - Summary of finite-lived intangible assets future amortization expense (Detail) $ in Thousands	Dec. 31, 2023 USD ($)
Customer Contracts [Member]
Finite Lived Intangible Assets Future Amortization Expense [Line Items]
2024	$ 231
2025	230
2026	230
2027	230
2028	230
Thereafter	2,297
Interconnection [Member]
Finite Lived Intangible Assets Future Amortization Expense [Line Items]
2024	740
2025	740
2026	740
2027	740
2028	740
Thereafter	$ 10,884

Asset Retirement Obligations -

Asset Retirement Obligations - Summary of Activity Associated with Asset Retirement Obligations (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Asset Retirement Obligation Disclosure [Abstract]
Asset retirement obligations - beginning of period	$ 5,493	$ 5,301	$ 5,689
Accretion of asset retirement obligation	407	296	(160)
Decommissioning	0	(104)	(228)
Asset retirement obligations - end of period	$ 5,900	$ 5,493	$ 5,301

Derivative Instruments - Summar

Derivative Instruments - Summary of Cash Received (Paid) on Derivative Instrument (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Derivative [Line Items]
Cash paid on derivatives	$ (560)	$ (5,177)	$ 1,422
Net gain (loss)	$ (560)	$ (5,177)	$ 1,422
Derivative, Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]	Net Income (Loss)	Net Income (Loss)	Net Income (Loss)
Commodity contract [Member]
Derivative [Line Items]
Cash paid on derivatives	$ 0	$ (7,829)	$ 0
Net gain (loss)	0	(7,829)	0
Interest rate swap [Member]
Derivative [Line Items]
Cash paid on derivatives	(560)	2,652	1,422
Net gain (loss)	$ (560)	$ 2,652	$ 1,422

Fair Value of Financial Instr_3

Fair Value of Financial Instruments - Summary of Assets and Liabilities Measured at Fair Value on a Recurring Basis (Detail) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Asset retirement obligations	$ (5,900)	$ (5,493)	$ (5,301)	$ (5,689)
Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest rate swap derivative asset	1,255	1,815
Asset retirement obligations	(5,900)	(5,493)
Pico earn-out liability	(5,109)	(3,843)
Fair Value, Net Asset (Liability)	(9,754)	(7,521)
Fair Value, Recurring [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest rate swap derivative asset	0	0
Asset retirement obligations	0	0
Pico earn-out liability	0	0
Fair Value, Net Asset (Liability)	0	0
Fair Value, Recurring [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest rate swap derivative asset	1,255	1,815
Asset retirement obligations	0	0
Pico earn-out liability	0	0
Fair Value, Net Asset (Liability)	1,255	1,815
Fair Value, Recurring [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest rate swap derivative asset	0	0
Asset retirement obligations	(5,900)	(5,493)
Pico earn-out liability	(5,109)	(3,843)
Fair Value, Net Asset (Liability)	$ (11,009)	$ (9,336)

Accrued Liabilities - Summary o

Accrued Liabilities - Summary of Accrued Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Payables and Accruals [Abstract]
Accrued expenses	$ 3,983	$ 3,221
Payroll and related benefits	2,355	1,561
Royalty	3,897	7,836
Utility	1,653	1,605
Accrued interest	827	794
Other	74	73
Accrued liabilities	$ 12,789	$ 15,090

Debt - Summary of Company Debt

Debt - Summary of Company Debt (Detail) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Long-Term Debt, by Current and Noncurrent [Abstract]
Term loans	$ 64,000	$ 72,000
Less: current principal maturities	(8,000)	(8,000)
Less: debt issuance costs (on long-term debt)	(386)	(495)
Long-Term Debt	55,614	63,505
Current portion of long-term debt	7,886	7,870
Total debt	$ 63,500	$ 71,375

Debt - Additional Information (

Debt - Additional Information (Detail) - USD ($) $ in Thousands			12 Months Ended
	Dec. 21, 2021	Sep. 12, 2019	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Extinguishment of Debt [Line Items]
Debt interest rate			6.11%	4.12%
Debt Issuance Costs, Net			$ 326
Debt Issuance Costs, capitalized			1,701
Amortized debt issuance expense			367	$ 412	$ 483
Long-term debt			55,614	$ 63,505
Payment of debt modification charges			2,027
Term Loans [Member]
Extinguishment of Debt [Line Items]
Long-term debt			64,000
Revolving Credit Facility [Member]
Extinguishment of Debt [Line Items]
Line of Credit Facility, Current Borrowing Capacity			117,495
Letter of Credit [Member]
Extinguishment of Debt [Line Items]
Line of Credit Facility, Maximum Amount Outstanding During Period			$ 2,505
MEH [Member] | Second Amendment [Member]
Extinguishment of Debt [Line Items]
Line of Credit		$ 80,000
Repayment of long term debt		38,250
MEH [Member] | Fourth Amendment [Member]
Extinguishment of Debt [Line Items]
Line of Credit Facility, Current Borrowing Capacity	$ 120,000
Long-term debt	80,000
MEH [Member] | Term Loans [Member]
Extinguishment of Debt [Line Items]
Debt Instrument, Periodic Payment, Principal		$ 2,500
MEH [Member] | Term Loans [Member] | Through Two Thousand And Twenty Four [Member]
Extinguishment of Debt [Line Items]
Debt Instrument, Periodic Payment, Principal	2,000
MEH [Member] | Term Loans [Member] | From Two Thousand And Twenty Five And Upto Two Thousand And Twetny Six [Member]
Extinguishment of Debt [Line Items]
Debt Instrument, Periodic Payment, Principal	3,000
Debt Instrument, Periodic Payment Terms, Balloon Payment to be Paid	$ 32,000

Debt - Summary of annual princi

Debt - Summary of annual principal maturities of long-term debt (Detail) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Summary of annual principal maturities of long - term debt
2024	$ 8,000
2025	12,000
2026	44,000
Total	$ 64,000	$ 72,000

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - USD ($) $ in Thousands		12 Months Ended
	Mar. 11, 2021	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Income Tax [Line Items]
Stock compensation	$ 1,000	$ (175)	$ (24)	$ 723
Deferred Tax Assets, Valuation Allowance		3,950	3,950
Unrecognized tax benefits		0	0
Unrecognized tax benefits income tax penalties and interest accrued		$ 0	$ 0
Tax Year 2020 [Member] | Internal Revenue Service (IRS) [Member]
Income Tax [Line Items]
Years subject to examination by income tax		2020
Tax Year 2021 [Member] | Internal Revenue Service (IRS) [Member]
Income Tax [Line Items]
Years subject to examination by income tax		2021
Tax Year 2022 [Member] | Internal Revenue Service (IRS) [Member]
Income Tax [Line Items]
Years subject to examination by income tax		2022
Domestic Country [Member]
Income Tax [Line Items]
Net operating losses carry forward		$ 12,986
Domestic Country [Member] | 2026 [Member]
Income Tax [Line Items]
Tax credit carry forward		$ 13,042
Tax credit carry forward period period of expiry		20 years
State and Local Jurisdiction [Member] | 2026 [Member]
Income Tax [Line Items]
Net operating losses carry forward		$ 18,059

Income Taxes - Schedule of Comp

Income Taxes - Schedule of Components of Income Tax Provision Benefit (Detail) - USD ($) $ in Thousands		12 Months Ended
	Mar. 11, 2021	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Current expense (benefit):
Federal		$ 1,006	$ 321	$ 0
State		536	1,109	(91)
Current expense (benefit)		1,542	1,430	(91)
Deferred expense
Federal		1,869	6,446	3,368
State		7	172	884
Deferred expense (benefit)		1,876	6,618	4,252
Total income tax expense		3,418	8,048	4,161
Tax provision at federal statutory rate of 21%		3,857	9,081	(77)
State tax provision		430	998	800
Permanent differences		114	15	79
Stock compensation	$ 1,000	(175)	(24)	723
162(m) compensation limitation		1,530	0	4,382
Valuation allowance			50	12
Production tax credit		(2,324)	(2,052)	(2,112)
Return to provision			(20)	(29)
Deferred tax adjustments			0	383
Other		$ (14)	$ 0	$ 0

Income Taxes - Schedule Of Defe

Income Taxes - Schedule Of Deferred Tax Assets And Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Deferred tax assets:
Net operating loss carry forwards	$ 4,107	$ 6,744
Federal tax credits	13,042	13,691
Book reserves	1,473	1,368
Intangible asset amortization	5,799	6,701
Stock compensation	1,370	1,087
Impairment	306	0
Total deferred tax assets	26,097	29,591
Less: valuation analysis	(3,950)	(3,950)
Net deferred tax assets	22,147	25,641
Deferred tax liabilities:
Property depreciation	(20,048)	(21,683)
Other	(23)	(6)
Total deferred tax liabilities	(20,071)	(21,689)
Net Deferred tax assets	$ 2,076	$ 3,952

Share-Based Compensation - Summ

Share-Based Compensation - Summary of Fair Value of MRI EICP Options and Valuation Assumptions (Detail)	12 Months Ended
	Dec. 31, 2023 $ / shares shares
MRI EICP September 2023 Awards [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Options awarded | shares	225,000
Grant-date fair value | $ / shares	$ 5.72
MRI EICP September 2023 Awards [Member] | Maximum [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Risk-free interest rate	4.65%
Expected volatility, maximum	73%
Expected option life	5 years 6 months
MRI EICP September 2023 Awards [Member] | Minimum [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Risk-free interest rate	4.44%
Expected volatility, minimum	71%
Expected option life	3 years 6 months
MRI EICP April 2023 Awards [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Options awarded | shares	2,100,000
Grant-date fair value | $ / shares	$ 4.25
MRI EICP April 2023 Awards [Member] | Maximum [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Risk-free interest rate	3.97%
Expected volatility, maximum	80%
Expected option life	5 years 6 months
MRI EICP April 2023 Awards [Member] | Minimum [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Risk-free interest rate	3.71%
Expected volatility, minimum	78%
Expected option life	3 years 6 months
MRI EICP January 2023 Awards [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Options awarded | shares	950,214
Risk-free interest rate	0.50%
Expected volatility	32%
Expected option life	5 years 6 months
Grant-date fair value | $ / shares	$ 3.44

Share-Based Compensation - Su_2

Share-Based Compensation - Summary of Outstanding Activity of Options,Restricted Stock and Restricted Stock Units under MRI EICP (Detail) - MRI EICP September 2023 Awards [Member] - $ / shares	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Restricted Shares [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Number of Shares, Beginning of period	2,028,301	2,569,613
Number of Shares, Granted	0	1,250,000
Number of Shares, Vested	(316,228)	(541,312)
Number of Shares, Forfeited	(73,395)	(1,250,000)
Number of Shares, End of period	1,638,678	2,028,301
Weighted Average Grant Date Fair Value, Beginning of period	$ 11.8	$ 10.08
Weighted Average Grant Date Fair Value, Granted	0	12.4
Weighted Average Grant Date Fair Value, Vested	11.38	11.38
Weighted Average Grant Date Fair Value, Forfeited	11.38	9.04
Weighted Average Grant Date Fair Value, End of period	$ 11.91	$ 11.8
Restricted Stock Units [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Number of Shares, Beginning of period	280,000	377,984
Number of Shares, Granted	0	0
Number of Shares, Vested	(50,000)	(97,984)
Number of Shares, Forfeited	(80,000)	0
Number of Shares, End of period	150,000	280,000
Weighted Average Grant Date Fair Value, Beginning of period	$ 10.13	$ 10.23
Weighted Average Grant Date Fair Value, Granted	0	0
Weighted Average Grant Date Fair Value, Vested	10.09	10.49
Weighted Average Grant Date Fair Value, Forfeited	10.23	0
Weighted Average Grant Date Fair Value, End of period	$ 10.09	$ 10.13
Employee Stock Option
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Number of Shares, Beginning of period	0	950,214
Number of Shares, Granted	2,325,000	0
Number of Shares, Vested	0	(950,214)
Number of Shares, Forfeited	0	0
Number of Shares, End of period	2,325,000	0
Weighted Average Grant Date Fair Value, Beginning of period	$ 0	$ 11.38
Weighted Average Grant Date Fair Value, Granted	7.04	0
Weighted Average Grant Date Fair Value, Vested	0	11.38
Weighted Average Grant Date Fair Value, Forfeited	0	0
Weighted Average Grant Date Fair Value, End of period	$ 7.04	$ 0

Share-Based Compensation - Addi

Share-Based Compensation - Additional Information (Detail) $ / shares in Units, $ in Thousands			12 Months Ended
	May 31, 2022 USD ($)	Jan. 31, 2021 $ / shares shares	Dec. 31, 2023 USD ($) Employees shares	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($) shares
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-based compensation			$ 8,318	$ 9,836	$ 22,419
Stock Appreciation Rights (SARs) | General and Administrative Expense [Member]
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Share based compensation expense					$ 2,050
MRI EICP September 2023 Awards [Member]
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Common stock shares withheld | shares		950,214	950,214
Exercise price of common stock | $ / shares		$ 11.38
Stock-based compensation			$ 18,158
Unrecognised compensation expense recognised, Period			5 years
MRI EICP September 2023 Awards [Member] | Section 83 (B) [Member]
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Common stock shares withheld | shares					950,214
MRI EICP September 2023 Awards [Member] | General and Administrative Expense [Member] | Section 83 (B) [Member]
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Share based compensation expense					$ 10,813
Non-Qualified Stock Options [Member]
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-based compensation			$ 1,692
Restricted Stock [Member]
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-based compensation			$ 1,723	6,979	9,474
Share-Based Compensation Arrangement by Share-Based Payment Award, Maximum Number of Shares Per Employee | shares			1,250,000
Number of employees | Employees			2
Time Based Restricted Stock Awards [Member]
Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-based compensation			$ 4,908	$ 2,863	$ 0
Share-Based compensation arrangement by share-Based payment award, equity instruments other than options, revalued amount	$ 15,500

Defined Contribution Plan - Add

Defined Contribution Plan - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Defined Benefit Plan Disclosure [Line Items]
Defined contribution plan, employer matching contribution, percent of match	50%
Defined contribution plan, employer matching contribution, percent of employees' gross pay	4%
Defined contribution plan, cost	$ 640	$ 589	$ 502
Safe Harbor Contribution [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined contribution plan, maximum annual contributions per employee, percent	3%
Defined contribution plan, employer matching contribution, vesting period	4 years

Related Party Transactions - Ad

Related Party Transactions - Additional Information (Detail) - USD ($) $ in Thousands		12 Months Ended
	Jan. 26, 2021	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 22, 2022	Dec. 22, 2021
Related Party Transaction [Line Items]
Debt Instrument Collateral Shares		976,623
Debt Instrument Collateral Shares		800,000
Related Party
Related Party Transaction [Line Items]
Notes receivable from related parties current		$ 10,040			$ 8,940	$ 7,140
Variable interest entity maximum exposure to loss amount		10,138	$ 9,000
MNK [Member] | Loans Advanced To Related Parties [Member]
Related Party Transaction [Line Items]
Payment towards advances to related parties	$ 5,000
MNK And Hosken Consolidated Investments Limited [Member]
Related Party Transaction [Line Items]
Reimbursments received from related party		156	68	$ 813
MNK And Hosken Consolidated Investments Limited [Member] | Related Party
Related Party Transaction [Line Items]
Due to related party		$ 11	$ 26

Segment Information - Summary o

Segment Information - Summary of Reconciliation of the Company's Reportable Segments' Net Income from Continuing Operations (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023		Dec. 31, 2022		Dec. 31, 2021
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Total revenue	$ 174,904		$ 205,559		$ 148,127
Net income (loss)	14,948		35,194		(4,528)
Depreciation, depletion and amortization	21,158		20,700		22,869
Interest expense	5,753		1,792		2,928
Income tax expense	3,418		8,048		4,161
EBITDA	45,277		65,734		25,430
Impairment loss	902		4,852		1,191
Net loss (gain) on sale of assets	94		(233)		822
Transaction costs	178		185		352
Loss on extinguishment of debt	0		0		154
Adjusted EBITDA	46,451	[1]	70,538	[2]	27,949	[3]
Total assets	350,238		332,316		286,480
Capital expenditures	63,091		22,277		9,986
RNG [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Total revenue	156,455		196,218		131,803
Net income (loss)	59,271		94,330		49,387
Depreciation, depletion and amortization	15,720		14,967		17,162
EBITDA	74,991		109,297		66,549
Impairment loss	777		1,135		441
Net loss (gain) on sale of assets	91		78		822
Adjusted EBITDA	75,859	[1]	110,510	[2]	67,812	[3]
Total assets	176,951		151,998		150,472
Capital expenditures	41,325		16,667		7,647
REG [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Total revenue	18,449		17,170		15,449
Net income (loss)	(572)		(6,756)		(3,129)
Depreciation, depletion and amortization	5,193		5,443		5,528
Income tax expense			16
EBITDA	4,621		(1,297)		2,399
Impairment loss	125		3,526		750
Net loss (gain) on sale of assets	3		(311)
Adjusted EBITDA	4,749	[1]	1,918	[2]	3,149	[3]
Total assets	73,369		53,255		57,980
Capital expenditures	21,682		5,033		2,296
Corporate [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Total revenue			(7,829)		875
Net income (loss)	(43,751)		(52,380)		(50,786)
Depreciation, depletion and amortization	245		290		179
Interest expense	5,753		1,792		2,928
Income tax expense	3,418		8,032		4,161
EBITDA	(34,335)		(42,266)		(43,518)
Impairment loss			191
Transaction costs	178		185		352
Loss on extinguishment of debt					154
Adjusted EBITDA	(34,157)	[1]	(41,890)	[2]	(43,012)	[3]
Total assets	99,918		127,063		78,028
Capital expenditures	$ 84		$ 577		$ 43
[1] 2023 EBITDA Reconciliation 2022 EBITDA Reconciliation 2021 EBITDA Reconciliation

Segment Information - Summary_2

Segment Information - Summary of Revenue by Major Customers (Detail) - Customer Concentration Risk [Member] - Revenue Benchmark [Member]	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Customer A [Member]
Revenue, Major Customer [Line Items]
Concentration risk, percentage	22%	32%	13.10%
Customer B [Member]
Revenue, Major Customer [Line Items]
Concentration risk, percentage	11.70%	17%	12.40%
Customer C [Member]
Revenue, Major Customer [Line Items]
Concentration risk, percentage	11.70%
RNG [Member] | Customer A [Member]
Revenue, Major Customer [Line Items]
Concentration risk, percentage	22%	32%	13.10%
RNG [Member] | Customer B [Member]
Revenue, Major Customer [Line Items]
Concentration risk, percentage	11.70%	17%	12.40%
RNG [Member] | Customer C [Member]
Revenue, Major Customer [Line Items]
Concentration risk, percentage	11.70%

Leases - Summary of Supplementa

Leases - Summary of Supplemental information Related to Operating Lease (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Leases [Abstract]
Cash paid for amounts included in the measurement of operating lease liabilities	$ 431	$ 385	$ 304
Weighted average remaining lease term (in years)	5 years 2 months 26 days	5 years 10 months 13 days	1 year 10 days
Weighted average discount rate	5%	5%	5%

Leases - Summary of Future Mini

Leases - Summary of Future Minimum Operating Lease Payments (Detail) $ in Thousands	Dec. 31, 2023 USD ($)
Leases [Abstract]
2024	$ 611
2025	624
2026	573
2027	583
2028	594
Therafter	2,714
Imputed interest	(1,146)
Total	$ 4,553

Leases - Summary of Supplemen_2

Leases - Summary of Supplemental Information Related To Finance Leases (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Leases [Abstract]
Cash paid for amounts included in the measurement of financing lease liabilities	$ 79	$ 50
Weighted average remaining lease term (in years)	3 years 6 months 14 days	1 year 3 months
Weighted average discount rate	5%	5%

Leases - Summary of Future Mi_2

Leases - Summary of Future Minimum Finance Lease Payments (Detail) $ in Thousands	Dec. 31, 2023 USD ($)
Finance Lease, Liability, to be Paid, Fiscal Year Maturity [Abstract]
2024	$ 27
2025	1
2026	1
2027	1
2028	1
Thereafter	10
Imputed interest	(5)
Total	$ 36

Leases - Additional Information

Leases - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Leases [Abstract]
Lease Cost	$ 695	$ 412	$ 349
short term lease expense	$ 1,182	$ 895	$ 494

Commitment and Contingencies -

Commitment and Contingencies - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Revenue from Contract with Customer Benchmark [Member] | Geographic Concentration Risk [Member] | Five Geographical Locations [Member]
Loss Contingencies [Line Items]
Revenue Performance obligation satisfied to segments, Percentage	68%	72%	76%
Accounts Receivable [Member] | Customer Concentration Risk [Member] | Five Customers [Member]
Loss Contingencies [Line Items]
Revenue Performance obligation satisfied to segments, Percentage	71%	69%

Quarterly Financial Data (Unaud

Quarterly Financial Data (Unaudited) - Schedule Of Quarterly Financial Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Quarterly Financial Data [Abstract]
Operating Income (Loss)	$ 23,640	$ 44,566	$ 3,335
Net Income (Loss)	$ 14,948	$ 35,194	$ (4,528)

Quarterly Financial Data (Una_2

Quarterly Financial Data (Unaudited) - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Quarterly Financial Information Line Items
Gain on insurance proceeds	$ 0	$ 313	$ 332

Income (Loss) Per Share - Sched

Income (Loss) Per Share - Schedule of Basic and Diluted Income (Loss) Per Share (Detail) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Earnings Per Share [Abstract]
Net income (loss)	$ 14,948	$ 35,194	$ (4,528)
Basic weighted-average shares outstanding	141,727,905	141,238,851	141,015,213
Dilutive effect of share-based awards	423,735	1,340,538	0
Diluted weighted-average shares outstanding	142,151,640	142,579,389	141,015,213
Basic income (loss) per share	$ 0.11	$ 0.25	$ (0.03)
Diluted income (loss) per share	$ 0.11	$ 0.25	$ (0.03)

Income (Loss) Per Share - Addit

Income (Loss) Per Share - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2021 shares
Earnings Per Share [Abstract]
Antidilutive excluded from diluted net loss per share	3,897,811

Subsequent Events - Additional

Subsequent Events - Additional Information (Detail) - Subsequent Event [Member] $ in Thousands	Feb. 18, 2024 USD ($) Numbers
Subsequent Event [Line Items]
Proceeds received | $	$ 1,000
Agreements extended term	5 years
RNG [Member]
Subsequent Event [Line Items]
Number of operating sites | Numbers	2