Sunnova Energy International (NOVA) 10-Q 29 Oct 20 2020 Q3 Quarterly report Financial data

Cover Page

Cover Page - shares	9 Months Ended
	Sep. 30, 2020	Oct. 26, 2020
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 30, 2020
Document Transition Report	false
Entity File Number	001-38995
Entity Registrant Name	Sunnova Energy International Inc.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	30-1192746
Entity Address, Address Line One	20 East Greenway Plaza, Suite 540
Entity Address, City or Town	Houston
Entity Address, State or Province	TX
Entity Address, Postal Zip Code	77046
City Area Code	281
Local Phone Number	985-9904
Title of 12(b) Security	Common Stock, $0.0001 par value per share
Trading Symbol	NOVA
Security Exchange Name	NYSE
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		93,587,398
Entity Central Index Key	0001772695
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	Q3
Amendment Flag	false

UNAUDITED CONDENSED CONSOLIDATE

UNAUDITED CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands		Sep. 30, 2020	Dec. 31, 2019
Current assets:
Cash		$ 84,635	$ 83,485
Accounts receivable—trade, net		11,799	10,672
Accounts receivable—other		13,354	6,147
Other current assets, net of allowance of $591 and $112 as of September 30, 2020 and December 31, 2019, respectively		199,637	174,016
Total current assets		309,425	274,320
Property and equipment, net		2,172,727	1,745,060
Customer notes receivable, net of allowance of $14,177 and $979 as of September 30, 2020 and December 31, 2019, respectively		428,586	297,975
Other assets		243,548	169,712
Total assets	[1]	3,154,286	2,487,067
Current liabilities:
Accounts payable		29,288	36,190
Accrued expenses		27,944	39,544
Current portion of long-term debt		109,729	97,464
Other current liabilities		18,572	21,804
Total current liabilities		185,533	195,002
Long-term debt, net		1,795,039	1,346,419
Other long-term liabilities		162,395	127,406
Total liabilities	[1]	2,142,967	1,668,827
Commitments and contingencies (Note 14)
Redeemable noncontrolling interests		135,847	127,129
Stockholders' equity:
Common stock, 91,125,076 and 83,980,885 shares issued as of September 30, 2020 and December 31, 2019, respectively, at $0.0001 par value		9	8
Additional paid-in capital—common stock		1,198,680	1,007,751
Accumulated deficit		(476,095)	(361,824)
Total stockholders' equity		722,594	645,935
Noncontrolling interests		152,878	45,176
Total equity		875,472	691,111
Total liabilities, redeemable noncontrolling interests and equity		$ 3,154,286	$ 2,487,067
[1]	The consolidated assets as of September 30, 2020 and December 31, 2019 include $1,254,660 and $790,211, respectively, of assets of variable interest entities ("VIEs") that can only be used to settle obligations of the VIEs. These assets include cash of $12,396 and $7,347 as of September 30, 2020 and December 31, 2019, respectively; accounts receivable—trade, net of $2,719 and $1,460 as of September 30, 2020 and December 31, 2019, respectively; accounts receivable—other of $903 and $4 as of September 30, 2020 and December 31, 2019, respectively; other current assets of $131,242 and $47,606 as of September 30, 2020 and December 31, 2019, respectively; property and equipment, net of $1,094,801 and $726,415 as of September 30, 2020 and December 31, 2019, respectively; and other assets of $12,599 and $7,379 as of September 30, 2020 and December 31, 2019, respectively. The consolidated liabilities as of September 30, 2020 and December 31, 2019 include $20,227 and $13,440, respectively, of liabilities of VIEs whose creditors have no recourse to Sunnova Energy International Inc. These liabilities include accounts payable of $2,133 and $1,926 as of September 30, 2020 and December 31, 2019, respectively; accrued expenses of $603 and $35 as of September 30, 2020 and December 31, 2019, respectively; other current liabilities of $277 and $612 as of September 30, 2020 and December 31, 2019, respectively; and other long-term liabilities of $17,214 and $10,867 as of September 30, 2020 and December 31, 2019, respectively.

UNAUDITED CONDENSED CONSOLIDA_2

UNAUDITED CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands		Sep. 30, 2020	Dec. 31, 2019
Other current asset, allowance		$ 591	$ 112
Customer notes receivable, allowance		$ 14,177	$ 979
Common stock, issued (in shares)		91,125,076	83,980,885
Common stock, par value (in USD per share)		$ 0.0001	$ 0.0001
Assets	[1]	$ 3,154,286	$ 2,487,067
Cash		84,635	83,485
Accounts receivable—trade, net		11,799	10,672
Accounts receivable—other		13,354	6,147
Other current assets		199,637	174,016
Property and equipment, net		2,172,727	1,745,060
Other assets		243,548	169,712
Liabilities	[1]	2,142,967	1,668,827
Accounts payable		29,288	36,190
Accrued expenses		27,944	39,544
Other current liabilities		18,572	21,804
Other long-term liabilities		162,395	127,406
Primary beneficiary
Assets		1,254,660	790,211
Cash		12,396	7,347
Accounts receivable—trade, net		2,719	1,460
Accounts receivable—other		903	4
Other current assets		131,242	47,606
Property and equipment, net		1,094,801	726,415
Other assets		12,599	7,379
Liabilities		20,227	13,440
Accounts payable		2,133	1,926
Accrued expenses		603	35
Other current liabilities		277	612
Other long-term liabilities		$ 17,214	$ 10,867
[1]	The consolidated assets as of September 30, 2020 and December 31, 2019 include $1,254,660 and $790,211, respectively, of assets of variable interest entities ("VIEs") that can only be used to settle obligations of the VIEs. These assets include cash of $12,396 and $7,347 as of September 30, 2020 and December 31, 2019, respectively; accounts receivable—trade, net of $2,719 and $1,460 as of September 30, 2020 and December 31, 2019, respectively; accounts receivable—other of $903 and $4 as of September 30, 2020 and December 31, 2019, respectively; other current assets of $131,242 and $47,606 as of September 30, 2020 and December 31, 2019, respectively; property and equipment, net of $1,094,801 and $726,415 as of September 30, 2020 and December 31, 2019, respectively; and other assets of $12,599 and $7,379 as of September 30, 2020 and December 31, 2019, respectively. The consolidated liabilities as of September 30, 2020 and December 31, 2019 include $20,227 and $13,440, respectively, of liabilities of VIEs whose creditors have no recourse to Sunnova Energy International Inc. These liabilities include accounts payable of $2,133 and $1,926 as of September 30, 2020 and December 31, 2019, respectively; accrued expenses of $603 and $35 as of September 30, 2020 and December 31, 2019, respectively; other current liabilities of $277 and $612 as of September 30, 2020 and December 31, 2019, respectively; and other long-term liabilities of $17,214 and $10,867 as of September 30, 2020 and December 31, 2019, respectively.

UNAUDITED CONDENSED CONSOLIDA_3

UNAUDITED CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Revenue	$ 50,177	$ 36,615	$ 122,796	$ 97,942
Operating expense:
Cost of revenue—depreciation	15,113	10,942	42,120	30,820
Cost of revenue—other	1,403	1,186	5,315	2,914
Operations and maintenance	3,469	1,925	8,614	6,468
General and administrative	28,549	28,509	84,575	70,984
Other operating income	(6)	(49)	(28)	(129)
Total operating expense, net	48,528	42,513	140,596	111,057
Operating income (loss)	1,649	(5,898)	(17,800)	(13,115)
Interest expense, net	29,954	30,884	127,804	99,855
Interest expense, net—affiliates	0	701	0	4,098
Interest income	(5,999)	(3,407)	(17,299)	(8,868)
Loss on extinguishment of long-term debt, net	50,721	0	50,721	0
Loss on extinguishment of long-term debt, net—affiliates	0	0	0	10,645
Other (income) expense	91	293	(175)	827
Loss before income tax	(73,118)	(34,369)	(178,851)	(119,672)
Income tax expense	176	0	176	0
Net loss	(73,294)	(34,369)	(179,027)	(119,672)
Net income (loss) attributable to redeemable noncontrolling interests and noncontrolling interests	(9,113)	3,221	(18,513)	7,170
Net loss attributable to stockholders	(64,181)	(37,590)	(160,514)	(126,842)
Net loss attributable to common stockholders—basic	(64,181)	(37,590)	(160,514)	(151,567)
Net loss attributable to common stockholders—diluted	$ (64,181)	$ (37,590)	$ (160,514)	$ (151,567)
Net loss per share attributable to common stockholders—basic and diluted (in USD per share)	$ (0.73)	$ (0.62)	$ (1.88)	$ (5.77)
Weighted average common shares outstanding—basic and diluted (in shares)	87,768,712	60,890,129	85,276,841	26,245,493
Series A convertible preferred stock
Operating expense:
Dividends earned on convertible preferred stock	$ 0	$ 0	$ 0	$ (19,271)
Series C convertible preferred stock
Operating expense:
Dividends earned on convertible preferred stock	$ 0	$ 0	$ 0	$ (5,454)

UNAUDITED CONDENSED CONSOLIDA_4

UNAUDITED CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
CASH FLOWS FROM OPERATING ACTIVITIES
Net loss	$ (179,027)	$ (119,672)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation	47,811	34,987
Impairment and loss on disposals, net	1,768	1,236
Amortization of deferred financing costs	6,781	8,795
Amortization of debt discount	12,205	2,027
Non-cash effect of equity-based compensation plans	8,389	6,974
Non-cash payment-in-kind interest on loan	780	0
Non-cash payment-in-kind interest on loan—affiliates	0	2,716
Unrealized loss on derivatives	2,755	30,262
Unrealized (gain) loss on fair value option instruments	(165)	97
Loss on extinguishment of long-term debt, net	50,721	0
Loss on extinguishment of long-term debt, net—affiliates	0	10,645
Other non-cash items	10,566	4,637
Changes in components of operating assets and liabilities:
Accounts receivable	(2,785)	(8,006)
Other current assets	(10,688)	(11,753)
Other assets	(32,541)	(37,787)
Accounts payable	(3,274)	5,156
Accrued expenses	(8,566)	(2,455)
Other current liabilities	(2,781)	75
Long-term debt—paid-in-kind—affiliates	0	(719)
Other long-term liabilities	(3,745)	(1,753)
Net cash used in operating activities	(101,796)	(74,538)
CASH FLOWS FROM INVESTING ACTIVITIES
Purchases of property and equipment	(439,855)	(299,199)
Payments for investments and customer notes receivable	(180,725)	(104,391)
Proceeds from customer notes receivable	25,028	14,072
State utility rebates and tax credits	327	401
Other, net	950	(584)
Net cash used in investing activities	(594,275)	(389,701)
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from long-term debt	1,182,912	588,153
Payments of long-term debt	(667,670)	(318,855)
Proceeds of long-term debt from affiliates	0	15,000
Payments of long-term debt to affiliates	0	(56,236)
Payments on notes payable	(3,017)	(2,177)
Payments of deferred financing costs	(18,317)	(10,435)
Payments of debt discounts	(3,132)	(1,084)
Proceeds from issuance of common stock, net	4,269	164,695
Proceeds from equity component of debt instrument, net	73,657	0
Proceeds from issuance of convertible preferred stock, net	0	(2,510)
Contributions from redeemable noncontrolling interests and noncontrolling interests	197,360	119,372
Distributions to redeemable noncontrolling interests and noncontrolling interests	(4,484)	(6,289)
Payments of costs related to redeemable noncontrolling interests and noncontrolling interests	(4,108)	(3,155)
Other, net	(1)	(15)
Net cash provided by financing activities	757,469	486,464
Net increase in cash and restricted cash	61,398	22,225
Cash and restricted cash at beginning of period	150,291	87,046
Cash and restricted cash at end of period	211,689	109,271
Restricted cash included in other current assets	(54,096)	(16,688)
Restricted cash included in other assets	(72,958)	(41,557)
Cash at end of period	84,635	51,026
Non-cash investing and financing activities:
Change in accounts payable and accrued expenses related to purchases of property and equipment	7,603	25,576
Change in accounts payable and accrued expenses related to payments for investments and customer notes receivable	(12,429)	(6,335)
Change in accounts payable and accrued expenses related to financing costs	(972)	(485)
Transfers of inventory to property and equipment, net and customer notes receivable	38,089	1,628
Non-cash conversion of convertible senior notes for common stock	84,196	0
Supplemental cash flow information:
Cash paid for interest	69,058	48,866
Cash paid for income taxes	$ 58	$ 0

UNAUDITED CONDENSED CONSOLIDA_5

UNAUDITED CONDENSED CONSOLIDATED STATEMENTS OF REDEEMABLE NONCONTROLLING INTERESTS AND EQUITY - USD ($) $ in Thousands	Total	Cumulative-effect adjustment	Total Stockholders' Equity	Total Stockholders' EquityCumulative-effect adjustment	Convertible preferred stockSeries A and Series C Convertible Preferred Stock	Common stock	Common stockSeries A and Series B Common Stock	Additional Paid-in Capital - Convertible Preferred Stock	Additional Paid-in Capital - Common Stock	Accumulated Deficit	Accumulated DeficitCumulative-effect adjustment	Noncontrolling Interests
Redeemable noncontrolling interest, beginning balance at Dec. 31, 2018	$ 85,680
Increase (Decrease) in Redeemable Noncontrolling Interests [Roll Forward]
Net income (loss)	3,018
Contributions from redeemable noncontrolling interests and noncontrolling interests	18,030
Distributions to redeemable noncontrolling interests and noncontrolling interests	(3,652)
Costs related to redeemable noncontrolling interests and noncontrolling interests	(1,562)
Equity in subsidiaries attributable to parent	(10,125)
Other, net	2,627
Redeemable noncontrolling interest, ending balance at Mar. 31, 2019	94,016
Stockholders' equity, beginning balance (in shares) at Dec. 31, 2018					57,949,374	0	8,634,455
Stockholders' equity, beginning balance at Dec. 31, 2018	501,118		$ 501,118		$ 579	$ 0	$ 86	$ 701,326	$ 85,439	$ (286,312)		$ 0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	(38,514)		(38,514)							(38,514)
Issuance of stock, net (in shares)							2,143
Issuance of common stock	4		4						4
Repurchase of convertible preferred stock (in shares)					(13,484)
Repurchase of convertible preferred stock	(191)		(191)					(183)		(8)
Equity in subsidiaries attributable to parent	10,125		10,125							10,125
Equity-based compensation expense	281		281						281
Other, net	491		491					493		(2)
Stockholders' equity, ending balance (in shares) at Mar. 31, 2019					57,935,890	0	8,636,598
Stockholders' equity, ending balance at Mar. 31, 2019	473,314		473,314		$ 579	$ 0	$ 86	701,636	85,724	(314,711)		0
Increase (Decrease) in Redeemable Noncontrolling Interests [Roll Forward]
Net income (loss)	931
Contributions from redeemable noncontrolling interests and noncontrolling interests	32,207
Distributions to redeemable noncontrolling interests and noncontrolling interests	(1,491)
Costs related to redeemable noncontrolling interests and noncontrolling interests	(419)
Equity in subsidiaries attributable to parent	(18,297)
Other, net	600
Redeemable noncontrolling interest, ending balance at Jun. 30, 2019	107,547
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	(50,738)		(50,738)							(50,738)
Equity in subsidiaries attributable to parent	18,297		18,297							18,297
Equity-based compensation expense	713		713						713
Other, net	(1)		(1)					(1)
Stockholders' equity, ending balance (in shares) at Jun. 30, 2019					57,935,890	0	8,636,598
Stockholders' equity, ending balance at Jun. 30, 2019	441,585		441,585		$ 579	$ 0	$ 86	701,635	86,437	(347,152)		0
Increase (Decrease) in Redeemable Noncontrolling Interests [Roll Forward]
Net income (loss)	3,028
Contributions from redeemable noncontrolling interests and noncontrolling interests	17,048
Distributions to redeemable noncontrolling interests and noncontrolling interests	(1,146)
Costs related to redeemable noncontrolling interests and noncontrolling interests	(116)
Equity in subsidiaries attributable to parent	(5,105)
Other, net	(385)
Redeemable noncontrolling interest, ending balance at Sep. 30, 2019	120,871
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	(37,397)		(37,590)							(37,590)		193
Issuance of stock, net (in shares)						14,865,267
Issuance of common stock	164,392		164,392			$ 1			164,391
Non-cash exchange of Series A and Series C convertible preferred stock and Series A and Series B common stock for common stock (in shares)					(60,479,017)	69,115,618	(8,636,601)
Non-cash exchange of Series A and Series C convertible preferred stock and Series A and Series B common stock for common stock					$ (605)	$ 7	$ (86)	(734,444)	735,128
Contributions from redeemable noncontrolling interests and noncontrolling interests	52,087											52,087
Distributions to redeemable noncontrolling interests and noncontrolling interests												0
Costs related to redeemable noncontrolling interests and noncontrolling interests	(2,322)											(2,322)
Equity in subsidiaries attributable to parent	5,105		19,356							19,356		(14,251)
Stock issued during period, conversion of convertible notes (in shares)					2,543,127
Stock issued during period, conversion of convertible notes	32,834		32,834		$ 25			32,809
Equity-based compensation expense	5,980		5,980						5,980
Other, net	3		3		$ 1					2		0
Other, net (in shares)							3
Stockholders' equity, ending balance (in shares) at Sep. 30, 2019					0	83,980,885	0
Stockholders' equity, ending balance at Sep. 30, 2019	662,267		626,560		$ 0	$ 8	$ 0	$ 0	991,936	(365,384)		35,707
Redeemable noncontrolling interest, beginning balance at Dec. 31, 2019	127,129
Increase (Decrease) in Redeemable Noncontrolling Interests [Roll Forward]
Net income (loss)	1,576
Contributions from redeemable noncontrolling interests and noncontrolling interests	3,170
Distributions to redeemable noncontrolling interests and noncontrolling interests	(1,373)
Costs related to redeemable noncontrolling interests and noncontrolling interests	187
Equity in subsidiaries attributable to parent	145
Other, net	(44)
Redeemable noncontrolling interest, ending balance at Mar. 31, 2020	130,790
Stockholders' equity, beginning balance (in shares) at Dec. 31, 2019						83,980,885
Stockholders' equity, beginning balance at Dec. 31, 2019	691,111	$ (9,908)	645,935	$ (9,908)		$ 8			1,007,751	(361,824)	$ (9,908)	45,176
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	(78,580)		(71,075)							(71,075)		(7,505)
Issuance of stock, net (in shares)						45,405
Issuance of common stock	214		214						214
Contributions from redeemable noncontrolling interests and noncontrolling interests	99,172											99,172
Distributions to redeemable noncontrolling interests and noncontrolling interests												0
Costs related to redeemable noncontrolling interests and noncontrolling interests	(894)											(894)
Equity in subsidiaries attributable to parent	(145)		24,164							24,164		(24,309)
Equity-based compensation expense	2,690		2,690						2,690
Other, net	(3)											(3)
Stockholders' equity, ending balance (in shares) at Mar. 31, 2020						84,026,290
Stockholders' equity, ending balance at Mar. 31, 2020	703,657		592,020			$ 8			1,010,655	(418,643)		111,637
Increase (Decrease) in Redeemable Noncontrolling Interests [Roll Forward]
Net income (loss)	2,869
Contributions from redeemable noncontrolling interests and noncontrolling interests	0
Distributions to redeemable noncontrolling interests and noncontrolling interests	(1,211)
Costs related to redeemable noncontrolling interests and noncontrolling interests	0
Equity in subsidiaries attributable to parent	(68)
Other, net	193
Redeemable noncontrolling interest, ending balance at Jun. 30, 2020	132,573
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	(31,598)		(25,258)							(25,258)		(6,340)
Issuance of stock, net (in shares)						29,742
Issuance of common stock	558		558						558
Contributions from redeemable noncontrolling interests and noncontrolling interests	18,311											18,311
Distributions to redeemable noncontrolling interests and noncontrolling interests	(16)											(16)
Costs related to redeemable noncontrolling interests and noncontrolling interests	(604)											(604)
Equity in subsidiaries attributable to parent	68		17,358							17,358		(17,290)
Equity component of debt instrument, net	73,657		73,657						73,657
Equity-based compensation expense	3,354		3,354						3,354
Other, net	33		(1)						(1)			34
Stockholders' equity, ending balance (in shares) at Jun. 30, 2020						84,056,032
Stockholders' equity, ending balance at Jun. 30, 2020	767,420		661,688			$ 8			1,088,223	(426,543)		105,732
Increase (Decrease) in Redeemable Noncontrolling Interests [Roll Forward]
Net income (loss)	4,268
Contributions from redeemable noncontrolling interests and noncontrolling interests	279
Distributions to redeemable noncontrolling interests and noncontrolling interests	(1,111)
Equity in subsidiaries attributable to parent	(718)
Other, net	556
Redeemable noncontrolling interest, ending balance at Sep. 30, 2020	135,847
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	(77,562)		(64,181)							(64,181)		(13,381)
Issuance of stock, net (in shares)						7,069,044
Issuance of common stock	152,920		152,920			$ 1			152,919
Contributions from redeemable noncontrolling interests and noncontrolling interests	76,428											76,428
Distributions to redeemable noncontrolling interests and noncontrolling interests	(773)											(773)
Costs related to redeemable noncontrolling interests and noncontrolling interests	(1,007)											(1,007)
Equity in subsidiaries attributable to parent	718		14,629							14,629		(13,911)
Equity component of debt instrument, net	(44,808)		(44,808)						(44,808)
Equity-based compensation expense	2,345		2,345						2,345
Other, net	(209)		1						1			(210)
Stockholders' equity, ending balance (in shares) at Sep. 30, 2020						91,125,076
Stockholders' equity, ending balance at Sep. 30, 2020	$ 875,472		$ 722,594			$ 9			$ 1,198,680	$ (476,095)		$ 152,878

Description of Business and Bas

Description of Business and Basis of Presentation	9 Months Ended
	Sep. 30, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Description of Business and Basis of Presentation	Description of Business and Basis of Presentation We are a leading residential solar and energy storage service provider, serving over 98,000 customers in more than 20 United States ("U.S.") states and territories. Sunnova Energy Corporation was incorporated in Delaware on October 22, 2012 and formed Sunnova Energy International Inc. ("SEI") as a Delaware corporation on April 1, 2019. We completed our initial public offering on July 29, 2019 (our "IPO"); and in connection with our IPO, all of Sunnova Energy Corporation's ownership interests were contributed to SEI. Unless the context otherwise requires, references in this report to "Sunnova," the "Company," "we," "our," "us," or like terms, refer to SEI and its consolidated subsidiaries. We have a differentiated residential solar dealer model in which we partner with local dealers who originate, design and install our customers' solar energy systems and energy storage systems on our behalf. Our focus on our dealer model enables us to leverage our dealers' specialized knowledge, connections and experience in local markets to drive customer origination while providing our dealers with access to high quality products at competitive prices as well as technical oversight and expertise. We believe this structure provides operational flexibility , reduced exposure to labor shortages and lower fixed costs relative to our peers, furthering our competitive advantage. We provide our services through long-term residential solar service agreements with a diversified pool of high credit quality customers. Our solar service agreements typically are structured as either a legal-form lease (a "lease") of a solar energy system or energy storage system to the customer, the sale of the solar energy system's output to the customer under a power purchase agreement ("PPA") or the purchase of a solar energy system or energy storage system with financing provided by us (a "loan"). The initial term of our solar service agreements is typically either 10, 15 or 25 years, during which time we provide or arrange for ongoing services to customers, including monitoring, maintenance and warranty services. Our lease and PPA agreements typically include an opportunity for customers to renew for up to an additional 10 years, via two five-year renewal options. Customer payments and rates can be fixed for the duration of the solar service agreement or escalated at a pre-determined percentage annually. We also receive tax benefits and other incentives from leases and PPAs, a portion of which we finance through tax equity, non-recourse debt structures and hedging arrangements in order to fund our upfront costs, overhead and growth investments. Basis of Presentation The accompanying interim unaudited condensed consolidated financial statements ("interim financial statements") include our consolidated balance sheets, statements of operations, statements of redeemable noncontrolling interests and equity and statements of cash flows and have been prepared in accordance with accounting principles generally accepted in the United States of America ("GAAP") from records maintained by us. We have condensed or omitted certain information and note disclosures normally included in the financial statements prepared in accordance with GAAP pursuant to the applicable rules and regulations of the Securities and Exchange Commission ("SEC") regarding interim financial reporting. As such, these interim financial statements should be read in conjunction with our 2019 annual audited consolidated financial statements and accompanying notes included in our Annual Report on Form 10-K filed with the SEC on February 25, 2020. Our interim financial statements reflect all normal recurring adjustments necessary, in our opinion, to state fairly our financial position and results of operations for the reported periods. Amounts reported for interim periods may not be indicative of a full year period because of our continual growth, seasonal fluctuations in demand for power, timing of maintenance and other expenditures, changes in interest expense and other factors. Our interim financial statements reflect our accounts and operations and those of our subsidiaries in which we have a controlling financial interest. In accordance with the provisions of the Financial Accounting Standards Board ("FASB") Accounting Standards Codification ("ASC") 810, Consolidation , we consolidate any VIE of which we are the primary beneficiary. We form VIEs with our investors in the ordinary course of business to facilitate the funding and monetization of certain attributes associated with our solar energy systems. The typical condition for a controlling financial interest ownership is holding a majority of the voting interests of an entity; however, a controlling financial interest may also exist in entities, such as VIEs, through arrangements that do not involve controlling voting interests. ASC 810 requires a variable interest holder to consolidate a VIE if that party has (a) the power to direct the activities of the VIE that most significantly impact the VIE's economic performance and (b) the obligation to absorb losses or the right to receive benefits from the VIE that could potentially be significant to the VIE. We do not consolidate a VIE in which we have a majority ownership interest when we are not considered the primary beneficiary. We have considered the provisions within the contractual arrangements that grant us power to manage and make decisions that affect the operation of our VIEs, including determining the solar energy systems contributed to the VIEs, and the installation, operation and maintenance of the solar energy systems. We consider the rights granted to the other investors under the contractual arrangements to be more protective in nature rather than participating rights. As such, we have determined we are the primary beneficiary of our VIEs and evaluate our relationships with our VIEs on an ongoing basis to ensure we continue to be the primary beneficiary. We have eliminated all intercompany accounts and transactions in consolidation. Adoption of ASU In June 2016, the FASB issued Accounting Standards Update ("ASU") No. 2016-13, Financial Instruments—Credit Losses , which requires entities to use a forward-looking expected loss approach, referred to as the current expected credit loss ("CECL") methodology, in accordance with ASC 326, Financial Instruments—Credit Losses , instead of the incurred loss approach previously in effect when estimating the allowance for credit losses. Under CECL, financial assets measured at amortized cost are presented at the net amount expected to be collected by using an estimate of credit losses for the remaining estimated life of the financial asset based on historical experience, current conditions and reasonable and supportable forecasts. This ASU is effective for annual and interim reporting periods in 2020. In 2018 and 2019, the FASB issued the following ASUs related to ASU 2016-13: ASU No. 2018-19, Codification Improvements to Topic 326, Financial Instruments—Credit Losses , ASU 2019-05, Financial Instruments—Credit Losses: Targeted Transition Relief and ASU 2019-11, Codification Improvements to Topic 326, Financial Instruments—Credit Losses . The supplemental ASUs must be adopted simultaneously with ASU 2016-13 As of January 1, 2020 As Reported Impact of ASC Pre-ASC 326 (in thousands) Accounts receivable—trade, net $ 10,912 $ 240 $ 10,672 Other current assets 173,565 (451) 174,016 Customer notes receivable 289,191 (8,784) 297,975 Other assets 168,799 (913) 169,712 Accumulated deficit (371,732) (9,908) (361,824) Revisions We have revised our previously issued annual audited consolidated financial statements and interim financial statements to correct immaterial classification errors pertaining to the Class A members' interests in certain of our tax equity funds. We incorrectly classified the Class A members' interests as redeemable noncontrolling interests whereas these interests should have been classified as noncontrolling interests. These misclassifications impacted our consolidated balance sheets and consolidated statements of redeemable noncontrolling interests and equity. The following tables present the impact of these revisions on the financial statements: As of December 31, 2019 As Previously Revisions As (in thousands) Redeemable noncontrolling interests $ 172,305 $ (45,176) $ 127,129 Noncontrolling interests — 45,176 45,176 Redeemable Noncontrolling As Previously Revisions As As Previously Revisions As (unaudited, in thousands) June 30, 2019 $ 107,547 $ — $ 107,547 $ — $ — $ — Net income 3,221 (193) 3,028 — 193 193 Contributions from redeemable noncontrolling interests and noncontrolling interests 69,135 (52,087) 17,048 — 52,087 52,087 Distributions to redeemable noncontrolling interests (1,146) — (1,146) — — — Costs related to redeemable noncontrolling interests and noncontrolling interests (2,438) 2,322 (116) — (2,322) (2,322) Equity in subsidiaries attributable to parent (19,356) 14,251 (5,105) — (14,251) (14,251) Other, net (385) — (385) — — — September 30, 2019 $ 156,578 $ (35,707) $ 120,871 $ — $ 35,707 $ 35,707 December 31, 2019 $ 172,305 $ (45,176) $ 127,129 $ — $ 45,176 $ 45,176 Net income (loss) (5,929) 7,505 1,576 — (7,505) (7,505) Contributions from redeemable noncontrolling interests and noncontrolling interests 102,342 (99,172) 3,170 — 99,172 99,172 Distributions to redeemable noncontrolling interests (1,373) — (1,373) — — — Costs related to redeemable noncontrolling interests and noncontrolling interests (707) 894 187 — (894) (894) Equity in subsidiaries attributable to parent (24,164) 24,309 145 — (24,309) (24,309) Other, net (47) 3 (44) — (3) (3) March 31, 2020 242,427 (111,637) 130,790 — 111,637 111,637 Net income (loss) (3,471) 6,340 2,869 — (6,340) (6,340) Contributions from noncontrolling interests 18,311 (18,311) — — 18,311 18,311 Distributions to redeemable noncontrolling interests and noncontrolling interests (1,227) 16 (1,211) — (16) (16) Costs related to noncontrolling interests (604) 604 — — (604) (604) Equity in subsidiaries attributable to parent (17,359) 17,291 (68) — (17,290) (17,290) Other, net 228 (35) 193 — 34 34 June 30, 2020 $ 238,305 $ (105,732) $ 132,573 $ — $ 105,732 $ 105,732 Reclassifications Certain other prior period amounts have been reclassified to conform to the current period presentation. These reclassifications did not have a significant impact on our interim financial statements. Coronavirus ("COVID-19") Pandemic The ongoing COVID-19 pandemic has resulted in widespread adverse impacts on the global economy. Our first priority in our response to this pandemic has been the health and safety of our employees, customers and dealers. To that end, we quickly implemented preventative measures to minimize unnecessary risk of exposure, which we have continued to follow. We have experienced some resulting disruptions to our business operations as the COVID-19 pandemic has continued to spread through the states and U.S. territories in which we operate. To adjust to federal social distancing guidelines, stay-at-home orders and similar government measures, our dealers have expanded the use of digital tools and origination channels and created new methods that offset restrictions on their ability to meet with potential new customers in person. The service and installation of solar energy systems has continued during the COVID-19 pandemic. This reflects residential solar services' designation as an essential service in all of our service territories. In order to adhere to all applicable state and federal health and safety guidelines, we and our dealers have moved to a contact-free process for installers and service technicians. In addition, an increasing number of jurisdictional authorities as well as local utilities are accepting electronic submissions for permits, and inspections are being performed in many locations through video calls and other electronic means. Throughout the COVID-19 pandemic, we have seen minimal impact to our supply chain as our technicians and dealers have largely been able to successfully procure the equipment needed to service and install solar energy systems. We cannot predict the full impact the COVID-19 pandemic or the significant disruption and volatility currently being experienced in the capital markets will have on our business, cash flows, liquidity, financial condition and results of operations at this time due to numerous uncertainties. The ultimate impact will depend on future developments, including, among other things, the ultimate duration of the COVID-19 virus, the depth and duration of the economic downturn and other economic effects of the COVID-19 pandemic, the consequences of governmental and other measures designed to prevent the spread of the COVID-19 virus, actions taken by governmental authorities, customers, suppliers, dealers and other third parties, our ability and the ability of our customers, potential customers and dealers to adapt to operating in a changed environment and the timing and extent to which normal economic and operating conditions resume.

Significant Accounting Policies

Significant Accounting Policies	9 Months Ended
	Sep. 30, 2020
Accounting Policies [Abstract]
Significant Accounting Policies	Significant Accounting Policies Included below are updates to significant accounting policies disclosed in our 2019 annual audited consolidated financial statements. Use of Estimates The application of GAAP in the preparation of the interim financial statements requires us to make estimates and assumptions that affect the amounts reported in the interim financial statements and accompanying notes. We base our estimates on historical experience and on various other assumptions believed to be reasonable, the results of which form the basis for making judgments about the carrying values of assets and liabilities. Actual results could differ materially from those estimates. Accounts Receivable Accounts Receivable — Trade. Accounts receivable — trade primarily represents trade receivables from residential customers that are generally collected in the subsequent month. Accounts receivable — trade is recorded net of an allowance for credit losses, which is based on our assessment of the collectability of customer accounts. We review the allowance by considering factors such as historical experience, customer credit rating, contractual term, aging category and current economic conditions that may affect a customer's ability to pay to identify customers with potential disputes or collection issues. We write off accounts receivable when we deem them uncollectible. As of September 30, 2020, we have not experienced a significant increase in delinquent customer accounts and have not made any significant adjustments to our allowance for credit losses related to accounts receivable — trade as a result of the COVID-19 pandemic. The following table presents the changes in the allowance for credit losses recorded against accounts receivable — trade, net in the unaudited condensed consolidated balance sheets: Three Months Ended Nine Months Ended 2020 2019 2020 2019 (in thousands) Balance at beginning of period $ 773 $ 746 $ 960 $ 723 Impact of ASC 326 adoption — — (240) — Provision for current expected credit losses 458 — 1,337 — Bad debt expense — 511 — 1,149 Write off of uncollectible accounts (419) (412) (1,267) (1,076) Recoveries 17 16 39 65 Balance at end of period $ 829 $ 861 $ 829 $ 861 Accounts Receivable — Other. Accounts receivable — other primarily represents receivables related to the sale of inventory and amounts owed from dealers in a net receivable position primarily as a result of customer contract cancelations or settlement agreements. Inventory Inventory primarily represents energy storage systems, photovoltaic modules, inverters, meters and other associated equipment purchased and held for use as original parts on new solar energy systems or replacement parts on existing solar energy systems. We record inventory in other current assets in the consolidated balance sheets at the lower of cost and net realizable value. We remove these items from inventory using the weighted-average method and (a) expense to operations and maintenance expense when installed as a replacement part for a solar energy system or (b) capitalize to property and equipment when installed as an original part on a solar energy system. We evaluate our inventory reserves and write down the estimated value of excess and obsolete inventory based upon assumptions about future demand and market conditions. The following table presents the detail of inventory as recorded in other current assets in the unaudited condensed consolidated balance sheets: As of As of (in thousands) Energy storage systems and components $ 18,467 $ 33,443 Modules and inverters 91,632 10,137 Meters 912 169 Total $ 111,011 $ 43,749 As of September 30, 2020 and December 31, 2019, we recorded accrued expenses of $8.1 million and $15.2 million, respectively, for inventory purchases. Fair Value of Financial Instruments Fair value is an exit price representing the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. As such, fair value is a market-based measurement that should be determined based on assumptions market participants would use in pricing an asset or a liability. Valuation techniques used to measure fair value must maximize the use of observable inputs and minimize the use of unobservable inputs. ASC 820 establishes a three-tier fair value hierarchy, which prioritizes inputs that may be used to measure fair value as follows: • Level 1—Observable inputs that reflect unadjusted quoted market prices in active markets for identical assets or liabilities that are accessible at the measurement date. • Level 2—Observable inputs other than Level 1 prices, such as quoted market prices for similar assets or liabilities in active markets, quoted market prices in markets that are not active or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities. • Level 3—Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities. In certain cases, the inputs used to measure fair value may fall into different levels of the fair value hierarchy. In such cases, the level in the fair value hierarchy must be determined based on the lowest level input that is significant to the fair value measurement. An assessment of the significance of a particular input to the fair value measurement in its entirety requires judgment and consideration of factors specific to the asset or liability. Our financial instruments include accounts receivable, notes receivable, accounts payable, accrued expenses, long-term debt and interest rate swaps. The carrying values of accounts receivable, accounts payable and accrued expenses approximate the fair values due to the fact that they are short-term in nature (Level 1). We estimate the fair value of our customer notes receivable based on interest rates currently offered under the loan program with similar maturities and terms (Level 3). We estimate the fair value of our fixed-rate long-term debt based on interest rates currently offered for debt with similar maturities and terms (Level 3). We determine the fair values of the interest rate derivative transactions based on a discounted cash flow method using contractual terms of the transactions. The floating interest rate is based on observable rates consistent with the frequency of the interest cash flows (Level 2). See Note 6, Customer Notes Receivable, Note 7, Long-Term Debt and Note 8, Derivative Instruments. Derivative Instruments Our derivative instruments consist of interest rate swaps that are not designated as cash flow hedges or fair value hedges under accounting guidance. We use interest rate swaps to manage our net exposure to interest rate changes. We record the derivatives in other current assets, other assets, other current liabilities and other long-term liabilities, as appropriate, in the consolidated balance sheets and the changes in fair value are recorded in interest expense, net in the consolidated statements of operations. We include unrealized gains and losses on derivatives as a non-cash reconciling item in operating activities in the consolidated statements of cash flows. We include realized gains and losses on derivatives as a change in components of operating assets and liabilities in operating activities in the consolidated statements of cash flows. See Note 8, Derivative Instruments. Revenue The following table presents the detail of revenue as recorded in the unaudited condensed consolidated statements of operations: Three Months Ended Nine Months Ended 2020 2019 2020 2019 (in thousands) PPA revenue $ 19,713 $ 14,329 $ 52,268 $ 37,895 Lease revenue 13,115 10,238 36,995 29,496 Solar renewable energy certificate revenue 14,147 10,603 27,245 26,911 Loan revenue 788 418 2,021 1,152 Other revenue 2,414 1,027 4,267 2,488 Total $ 50,177 $ 36,615 $ 122,796 $ 97,942 We recognize revenue from contracts with customers as we satisfy our performance obligations at a transaction price reflecting an amount of consideration based upon an estimated rate of return. We express this rate of return as the solar rate per kilowatt hour ("kWh") in the customer contract. The amount of revenue we recognize does not equal customer cash payments because we satisfy performance obligations ahead of cash receipt or evenly as we provide continuous access on a stand-ready basis to the solar energy system. We reflect the differences between revenue recognition and cash payments received in accounts receivable, other assets or deferred revenue, as appropriate. Revenue allocated to remaining performance obligations represents contracted revenue we have not yet recognized and includes deferred revenue as well as amounts that will be invoiced and recognized as revenue in future periods. Contracted but not yet recognized revenue was approximately $1.4 billion as of September 30, 2020, of which we expect to recognize approximately 4% over the next 12 months. We do not expect the annual recognition to vary significantly over approximately the next 20 years as the vast majority of existing solar service agreements have at least 20 years remaining, given the average age of the fleet of solar energy systems under contract is less than three years. PPAs. Customers purchase electricity from us under PPAs. Pursuant to ASC 606, we recognize revenue based upon the amount of electricity delivered as determined by remote monitoring equipment at solar rates specified under the PPAs. All customers must pass our credit evaluation process. The PPAs generally have a term of 25 years with an opportunity for customers to renew for up to an additional 10 years, via two five-year renewal options. Leases . We are the lessor under lease agreements for solar energy systems and energy storage systems, which do not meet the definition of a lease under ASC 842 and are accounted for as contracts with customers under ASC 606. We recognize revenue on a straight-line basis over the contract term as we satisfy our obligation to provide continuous access to the solar energy system. All customers must pass our credit evaluation process. The lease agreements generally have a term of 25 years with an opportunity for customers to renew for up to an additional 10 years, via two five-year renewal options. We provide customers under our lease agreements a performance guarantee that each solar energy system will achieve a certain specified minimum solar energy production output, which is a significant proportion of its expected output. The specified minimum solar energy production output may not be achieved due to natural fluctuations in the weather or equipment failures from exposure and wear and tear outside of our control, among other factors. We determine the amount of the guaranteed output based on a number of different factors, including: (a) the specific site information relating to the tilt of the panels, azimuth (a horizontal angle measured clockwise in degrees from a reference direction) of the panels, size of the system, and shading on site; (b) the calculated amount of available irradiance (amount of energy for a given flat surface facing a specific direction) based on historical average weather data and (c) the calculated amount of energy output of the solar energy system. While actual irradiance levels can significantly change year over year due to natural fluctuations in the weather, we expect the levels to average out over the term of a 25-year lease and to approximate the levels used in determining the amount of the performance guarantee. Generally, weather fluctuations are the most likely reason a solar energy system may not achieve a certain specified minimum solar energy production output. If the solar energy system does not produce the guaranteed production amount, we are required to refund a portion of the previously remitted customer payments, where the repayment is calculated as the product of (a) the shortfall production amount and (b) the dollar amount (guaranteed rate) per kWh that is fixed throughout the term of the contract. These remittances of a customer's payments, if needed, are payable in January following the end of the first three years of the solar energy system's placed in service date and then every annual period thereafter. See Note 14, Commitments and Contingencies. Solar Renewable Energy Certificates. Each solar renewable energy certificate ("SREC") represents one megawatt hour (1,000 kWh) generated by a solar energy system. SRECs can be sold with or without the actual electricity associated with the renewable-based generation source. We account for the SRECs we generate from our solar energy systems as governmental incentives with no costs incurred to obtain them and do not consider those SRECs output of the underlying solar energy systems. We classify these SRECs as inventory held until sold and delivered to third parties. As we did not incur costs to obtain these governmental incentives, the inventory carrying value for the SRECs was $0 as of September 30, 2020 and December 31, 2019. We enter into economic hedges related to expected production of SRECs through forward contracts. The contracts require us to physically deliver the SRECs upon settlement. We recognize the related revenue under ASC 606 upon satisfaction of the performance obligation to transfer the SRECs to the stated counterparty. Payments are typically received within one month of transferring the SREC to the counterparty. The costs related to the sales of SRECs are generally limited to broker fees (recorded in cost of revenue—other), which are only paid in connection with certain transactions. In certain circumstances we are required to purchase SRECs on the open market to fulfill minimum delivery requirements under our forward contracts. Loans. See discussion of loan revenue in the " Loans " section below. Other Revenue. Other revenue includes certain state and utility incentives, revenue from the direct sale of energy storage systems to customers and sales of service plans. We recognize revenue from state and utility incentives in the periods in which they are earned. We recognize revenue from the direct sale of energy storage systems in the period in which the storage components are placed in service. Service plans are available to customers whose solar energy system was not originally sold by Sunnova. We recognize revenue from service plan contracts over the life of the contract, which is typically five years. Loans We offer a loan program, under which the customer finances the purchase of a solar energy system or energy storage system through a solar service agreement, typically for a term of 10, 15 or 25 years. We recognize cash payments received from customers on a monthly basis under our loan program (a) as interest income, to the extent attributable to earned interest on the contract that financed the customer's purchase of the solar energy system or energy storage system; (b) as a reduction of a note receivable on the balance sheet, to the extent attributable to a return of principal (whether scheduled or prepaid) on the contract that financed the customer's purchase of the solar energy system or energy storage system; and (c) as revenue, to the extent attributable to payments for operations and maintenance services provided by us. To qualify for the loan program, a customer must pass our credit evaluation process, which requires the customer to have a minimum FICO ® score of 650 to 720 depending on certain circumstances, and we secure the loans with the solar energy systems or energy storage systems financed. The credit evaluation process is performed once for each customer at the time the customer is entering into the solar service agreement with us. Our investments in solar energy systems and energy storage systems related to the loan program that are not yet placed in service are recorded in other assets in the consolidated balance sheets and are transferred to customer notes receivable upon being placed in service. Customer notes receivable are recorded at amortized cost, net of an allowance for credit losses (as described below), in other current assets and customer notes receivable in the consolidated balance sheets. Accrued interest receivable related to our customer notes receivable is recorded in accounts receivable—trade, net in the consolidated balance sheets. Interest income from customer notes receivable is recorded in interest income in the consolidated statements of operations. The amortized cost of our customer notes receivable is equal to the principal balance of customer notes receivable outstanding and does not include accrued interest receivable. Customer notes receivable continue to accrue interest until they are written off against the allowance, which occurs when the balance is 180 days or more past due unless the balance is in the process of collection. Customer notes receivable are considered past due one day after the due date based on the contractual terms of the loan agreement. In all cases, customer notes receivable balances are placed on a nonaccrual status or written off at an earlier date when they are deemed uncollectible. Expected recoveries do not exceed the aggregate of amounts previously written off and expected to be written off. Accrued interest receivable for customer notes receivable placed on a nonaccrual status is recorded as a reduction to interest income. Interest received on such customer notes receivable is accounted for on a cash basis until the customer notes receivable qualifies for the return to accrual status. Customer notes receivable are returned to accrual status when there is no longer any principal or interest amounts past due and future payments are reasonably assured. The allowance for credit losses is deducted from the customer notes receivable amortized cost to present the net amount expected to be collected. It is measured on a collective (pool) basis when similar risk characteristics (such as financial asset type, customer credit rating, contractual term and vintage) exist. In determining the allowance for credit losses, we identify customers with potential disputes or collection issues and consider our historical level of credit losses and current economic trends that might impact the level of future credit losses. Adjustments to historical loss information are made for differences in current loan-specific risk characteristics, such as differences in underwriting standards. Expected credit losses are estimated over the contractual term of the loan agreements, adjusted for expected prepayments when appropriate. The contractual term excludes expected extensions, renewals and modifications unless either of the following applies: (a) we have a reasonable expectation at the reporting date that a troubled debt restructuring will be executed with an individual customer or (b) the extension or renewal options are included in the original or modified contract at the reporting date and are not unconditionally cancelable by us. As of September 30, 2020, we have not experienced a significant increase in delinquent customer notes receivable and have not made any significant adjustments to our allowance for credit losses related to loans as a result of the COVID-19 pandemic. See Note 6, Customer Notes Receivable. Deferred Revenue Deferred revenue consists of amounts for which the criteria for revenue recognition have not yet been met and includes (a) down payments and partial or full prepayments from customers, (b) differences due to the timing of energy production versus billing for certain types of PPAs and (c) payments for unfulfilled performance obligations from the loan program which will be recognized on a straight-line basis over the remaining term of the respective solar service agreements. Deferred revenue was $34.0 million as of December 31, 2018. The following table presents the detail of deferred revenue as recorded in other current liabilities and other long-term liabilities in the unaudited condensed consolidated balance sheets: As of As of (in thousands) Loans $ 73,417 $ 46,958 PPAs and leases 10,162 8,895 SRECs 1,420 3,000 Total (1) $ 84,999 $ 58,853 (1) Of this amount, $2.9 million and $2.1 million is recorded in other current liabilities as of September 30, 2020 and December 31, 2019, respectively. During the nine months ended September 30, 2020 and 2019, we recognized revenue of $5.0 million and $2.3 million, respectively, from amounts recorded in deferred revenue at the beginning of the respective years. New Accounting Guidance New accounting pronouncements are issued by the FASB or other standard setting bodies and are adopted as of the specified effective date. In December 2019, the FASB issued ASU No. 2019-12, Income Taxes: Simplifying the Accounting for Income Taxes , to remove certain exceptions and clarify and amend the existing guidance. This ASU is effective for annual and interim reporting periods in 2021. We have evaluated this ASU and determined it will not have a significant impact on our consolidated financial statements and related disclosures. In March 2020, the FASB issued ASU No. 2020-03, Codification Improvements to Financial Instruments , to clarify and amend the existing guidance. The amendments in this ASU are effective either upon issuance of this ASU or for annual and interim reporting periods in 2020. We adopted this ASU in January 2020 and determined it did not have a significant impact on our consolidated financial statements and related disclosures. In March 2020, the FASB issued ASU No. 2020-04, Reference Rate Reform: Facilitation of the Effects of Reference Rate Reform on Financial Reporting , to provide temporary optional expedients and exceptions for applying GAAP to contracts, hedging relationships and other transactions affected by reference rate reform. This ASU is effective beginning in March 2020 or prospectively from a date through December 2022. We adopted this ASU in October 2020 and determined it did not have a significant impact on our consolidated financial statements and related disclosures. In August 2020, the FASB issued ASU No. 2020-06, Debt—Debt with Conversion and Other Options and Derivatives and Hedging—Contracts in Entity's Own Equity: Accounting for Convertible Instruments and Contracts in an Entity's Own Equity , to simplify the accounting for certain financial instruments with characteristics of liabilities and equity by removing the separation models for convertible debt with a cash conversion feature and convertible instruments with a beneficial conversion feature. This ASU also expands the required disclosures related to the terms and features of convertible instruments, how the instruments have been reported and information about events, conditions and circumstances that can affect how to assess the amount or timing of an entity's future cash flows related to those instruments. This ASU is effective for annual and interim reporting periods in 2022. We have not yet determined the potential impact of this ASU on our consolidated financial statements and related disclosures.

Property and Equipment

Property and Equipment	9 Months Ended
	Sep. 30, 2020
Property, Plant and Equipment [Abstract]
Property and Equipment	Property and Equipment The following table presents the detail of property and equipment, net as recorded in the unaudited condensed consolidated balance sheets: Useful Lives As of As of (in years) (in thousands) Solar energy systems 35 $ 2,131,054 $ 1,689,457 Construction in progress 167,246 143,449 Asset retirement obligations 30 33,099 26,967 Information technology systems 3 29,398 28,320 Computers and equipment 3-5 1,694 1,499 Leasehold improvements 3-6 2,705 1,014 Furniture and fixtures 7 811 735 Vehicles 4-5 2,073 1,632 Other 5-6 158 146 Property and equipment, gross 2,368,238 1,893,219 Less: accumulated depreciation (195,511) (148,159) Property and equipment, net $ 2,172,727 $ 1,745,060 Solar Energy Systems. The amounts included in the above table for solar energy systems and substantially all the construction in progress relate to our customer contracts (including PPAs and leases). These assets had accumulated depreciation of $172.6 million and $130.9 million as of September 30, 2020 and December 31, 2019, respectively.

Detail of Certain Balance Sheet

Detail of Certain Balance Sheet Captions	9 Months Ended
	Sep. 30, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Detail of Certain Balance Sheet Captions	Detail of Certain Balance Sheet Captions The following table presents the detail of other current assets as recorded in the unaudited condensed consolidated balance sheets: As of As of (in thousands) Prepaid inventory $ — $ 96,167 Inventory 111,011 43,749 Current portion of customer notes receivable 20,083 13,758 Other prepaid assets 7,428 7,380 Current portion of other notes receivable 878 982 Deferred receivables 4,636 1,506 Restricted cash 54,096 10,474 Other 1,505 — Total $ 199,637 $ 174,016 The following table presents the detail of other assets as recorded in the unaudited condensed consolidated balance sheets: As of As of (in thousands) Restricted cash $ 72,958 $ 56,332 Construction in progress - customer notes receivable 65,288 37,137 Exclusivity and other bonus arrangements with dealers, net 54,543 32,791 Straight-line revenue adjustment, net 30,949 24,852 Other 19,810 18,600 Total $ 243,548 $ 169,712 The following table presents the detail of other current liabilities as recorded in the unaudited condensed consolidated balance sheets: As of As of (in thousands) Interest payable $ 11,669 $ 14,680 Current portion of performance guarantee obligations 2,921 4,067 Current portion of lease liability 1,075 561 Deferred revenue 2,882 2,086 Other 25 410 Total $ 18,572 $ 21,804

Asset Retirement Obligations (A

Asset Retirement Obligations (ARO)	9 Months Ended
	Sep. 30, 2020
Asset Retirement Obligation Disclosure [Abstract]
Asset Retirement Obligations (ARO)	Asset Retirement Obligations ("ARO")AROs consist primarily of costs to remove solar energy system assets and costs to restore the solar energy system sites to the original condition, which we estimate based on current market rates. For each solar energy system, we recognize the fair value of the ARO as a liability and capitalize that cost as part of the cost basis of the related solar energy system. The related assets are depreciated on a straight-line basis over 30 years, which is the estimated average time a solar energy system will be installed in a location before being removed, and the related liabilities are accreted to the full value over the same period of time. We revise our estimated future liabilities based on recent actual experiences, including third party cost estimates, average size of solar energy systems and inflation rates, which we evaluate at least annually. Changes in our estimated future liabilities are recorded as either a reduction or addition in the carrying amount of the remaining unamortized asset and the ARO and either decrease or increase our depreciation and accretion expense amounts prospectively. The following table presents the changes in AROs as recorded in other long-term liabilities in the unaudited condensed consolidated balance sheets: As of September 30, 2020 2019 (in thousands) Balance at beginning of period $ 31,053 $ 20,033 Additional obligations incurred 6,179 2,980 Accretion expense 1,577 989 Other (58) (32) Balance at end of period $ 38,751 $ 23,970

Customer Notes Receivable

Customer Notes Receivable	9 Months Ended
	Sep. 30, 2020
Receivables [Abstract]
Customer Notes Receivable	Customer Notes Receivable We offer a loan program, under which the customer finances the purchase of a solar energy system or energy storage system through a solar service agreement, typically for a term of 10, 15 or 25 years. The following table presents the detail of customer notes receivable as recorded in the unaudited condensed consolidated balance sheets and the corresponding fair values: As of As of (in thousands) Customer notes receivable $ 463,436 $ 312,823 Allowance for credit losses (14,767) (1,091) Customer notes receivable, net (1) $ 448,669 $ 311,732 Estimated fair value, net $ 453,321 $ 314,222 (1) Of this amount, $20.1 million and $13.8 million is recorded in other current assets as of September 30, 2020 and December 31, 2019, respectively. The following table presents the changes in the allowance for credit losses related to customer notes receivable as recorded in the unaudited condensed consolidated balance sheets: Three Months Ended Nine Months Ended 2020 2019 2020 2019 (in thousands) Balance at beginning of period $ 13,543 $ 944 $ 1,091 $ 710 Impact of ASC 326 adoption — — 9,235 — Provision for current expected credit losses (1) 1,483 — 4,701 — Bad debt expense — 5 — 278 Write off of uncollectible accounts (258) — (258) (39) Other, net (1) — (2) — Balance at end of period $ 14,767 $ 949 $ 14,767 $ 949 (1) In addition, we recognized $61,000 and $123,000 of provision for current expected credit losses during the three and nine months ended September 30, 2020, respectively, related to our long-term receivables for our leases. As of September 30, 2020 and December 31, 2019, we invested $65.3 million and $37.1 million, respectively, in loan solar energy systems and energy storage systems not yet placed in service. For the three months ended September 30, 2020 and 2019, interest income related to our customer notes receivable was $5.9 million and $3.1 million, respectively. For the nine months ended September 30, 2020 and 2019, interest income related to our customer notes receivable was $16.9 million and $8.2 million, respectively. As of September 30, 2020 and December 31, 2019, accrued interest receivable related to our customer notes receivable was $873,000 and $869,000, respectively. As of September 30, 2020 and December 31, 2019, there were no customer notes receivable not accruing interest and thus, there was no allowance recorded for loans on nonaccrual status. For the three months ended September 30, 2020 and 2019, interest income of $0 was recognized for loans on nonaccrual status and accrued interest receivable of $9,000 and $0, respectively, was written off by reversing interest income. For the nine months ended September 30, 2020 and 2019, interest income of $0 was recognized for loans on nonaccrual status and accrued interest receivable of $9,000 and $0, respectively, was written off by reversing interest income. We consider the performance of our customer notes receivable portfolio and its impact on our allowance for credit losses. We also evaluate the credit quality based on the aging status and payment activity. The following table presents the aging of the amortized cost of customer notes receivable as of September 30, 2020: As of As of (in thousands) 1-90 days past due $ 6,546 $ 5,741 91-180 days past due 1,716 1,714 Greater than 180 days past due 5,747 3,331 Total past due 14,009 10,786 Not past due 449,427 302,037 Total $ 463,436 $ 312,823 As of September 30, 2020 and December 31, 2019, the amortized cost of our customer notes receivable more than 90 days past due but not on nonaccrual status was $7.5 million and $5.0 million, respectively. The following table presents the amortized cost by origination year of our customer notes receivable based on payment activity. Amortized Cost by Origination Year 2020 2019 2018 2017 2016 Prior Total (in thousands) Payment performance: Performing $ 168,507 $ 138,644 $ 88,587 $ 31,939 $ 19,788 $ 10,224 $ 457,689 Nonperforming (1) 84 975 1,564 1,628 1,275 221 $ 5,747 Total $ 168,591 $ 139,619 $ 90,151 $ 33,567 $ 21,063 $ 10,445 $ 463,436 (1) A nonperforming loan is a loan in which the customer is in default and has not made any scheduled principal or interest payments for 180 days or more.

Long-Term Debt

Long-Term Debt	9 Months Ended
	Sep. 30, 2020
Debt Disclosure [Abstract]
Long-Term Debt	Long-Term DebtOur subsidiaries with long-term debt include SEI, Sunnova Energy Corporation, Sunnova Asset Portfolio 4, LLC ("AP4"), Helios Issuer, LLC ("HELI"), Sunnova LAP Holdings, LLC ("LAPH"), Sunnova EZ-Own Portfolio, LLC ("EZOP"), Sunnova TEP II Holdings, LLC ("TEPIIH"), Sunnova Helios II Issuer, LLC ("HELII"), Sunnova RAYS I Issuer, LLC ("RAYSI"), Sunnova Helios III Issuer, LLC ("HELIII"), Sunnova TEP Holdings, LLC ("TEPH"), Sunnova TEP Inventory, LLC ("TEPINV"), Sunnova Sol Issuer, LLC ("SOLI"), Sunnova Helios IV Issuer, LLC ("HELIV") and Sunnova Asset Portfolio 8, LLC ("AP8"). The following table presents the detail of long-term debt, net as recorded in the unaudited condensed consolidated balance sheets: Nine Months Ended As of September 30, 2020 Year Ended As of December 31, 2019 Long-term Current Long-term Current (in thousands, except interest rates) SEI 7.75% convertible senior notes 17.41 % $ — $ — 7.75 % $ 55,000 $ — 9.75% convertible senior notes 14.39 % 160,804 — — — Paid-in-kind 780 — — — Debt discount, net (64,490) — (16,913) — Deferred financing costs, net (416) — (480) — Sunnova Energy Corporation Notes payable 8.50 % — 2,769 3.22 % — 2,428 AP4 Secured term loan 10.81 % — — 5.61 % 86,369 6,109 Debt discount, net — — (452) — Deferred financing costs, net — — (196) — HELI Solar asset-backed notes 6.59 % 205,394 6,328 6.56 % 213,632 8,673 Debt discount, net (2,445) — (3,169) — Deferred financing costs, net (4,372) — (5,586) — LAPH Secured term loan 10.11 % 10,288 371 7.71 % 41,484 1,392 Debt discount, net (152) — (401) — Deferred financing costs, net (123) — (356) — EZOP Warehouse credit facility 4.64 % 115,450 — 6.60 % 121,400 — Debt discount, net (1,618) — (2,178) — TEPIIH Revolving credit facility 19.47 % — — 6.36 % 234,650 — Debt discount, net — — (2,219) — HELII Solar asset-backed notes 5.73 % 227,574 11,707 5.77 % 241,309 13,005 Debt discount, net (44) — (49) — Deferred financing costs, net (5,277) — (5,873) — RAYSI Solar asset-backed notes 5.49 % 121,844 5,993 5.47 % 126,828 6,327 Debt discount, net (1,421) — (1,547) — Deferred financing costs, net (4,441) — (4,759) — HELIII Solar loan-backed notes 4.00 % 124,660 14,704 4.03 % 135,543 19,030 Debt discount, net (2,451) — (2,532) — Deferred financing costs, net (2,353) — (2,410) — TEPH Revolving credit facility 5.72 % 380,720 — 6.70 % 90,325 — Debt discount, net (4,051) — (645) — TEPINV Revolving credit facility 10.15 % 35,819 36,640 7.95 % 54,707 40,500 Debt discount, net (1,811) — (2,856) — Deferred financing costs, net (2,322) — (2,207) — SOLI Solar asset-backed notes 3.91 % 389,435 15,318 — — Debt discount, net (117) — — — Deferred financing costs, net (9,169) — — — HELIV Solar loan-backed notes 3.91 % 134,293 15,899 — — Debt discount, net (921) — — — Deferred financing costs, net (4,028) — — — Total $ 1,795,039 $ 109,729 $ 1,346,419 $ 97,464 Availability. As of September 30, 2020, we had $224.1 million of available borrowing capacity under our various financing arrangements, consisting of $84.5 million under the EZOP warehouse credit facility, $56.8 million under the TEPH revolving credit facility, $22.7 million under the TEPINV revolving credit facility and $60.0 million under the AP8 revolving credit facility. There was no available borrowing capacity under any of our other financing arrangements. As of September 30, 2020, we were in compliance with all debt covenants under our financing arrangements. Weighted Average Effective Interest Rates. The weighted average effective interest rates disclosed in the table above are the weighted average stated interest rates for each debt instrument plus the effect on interest expense for other items classified as interest expense, such as the amortization of deferred financing costs, amortization of debt discounts and commitment fees on unused balances for the period of time the debt was outstanding during the indicated periods. SEI Debt . In May 2020, we issued and sold an aggregate principal amount of $130.0 million of our 9.75% convertible senior notes ("9.75% convertible senior notes") in a private placement at an issue price of 95%, for an aggregate purchase price of $123.5 million. The 9.75% convertible senior notes mature in April 2025 unless earlier redeemed, repurchased or converted. We granted the investors of the 9.75% convertible senior notes an option to purchase up to an additional $60.0 million aggregate principal amount of 9.75% convertible senior notes on the same terms and conditions, and the investors exercised this option and completed the purchase of such additional 9.75% convertible senior notes in June 2020. In May 2020, we also exchanged all $55.0 million aggregate principal amount outstanding of our 7.75% convertible senior notes for an equal principal amount of our 9.75% convertible senior notes. In the third quarter of 2020, certain holders of our 9.75% convertible senior notes converted approximately $84.8 million aggregate principal amount, including accrued and unpaid interest to the date of each conversion, of our 9.75% convertible senior notes into common stock. See Note 11, Stockholders' Equity. The investors in our 9.75% convertible senior notes may, at their option, convert all or any portion of their 9.75% convertible senior notes. Upon conversion, we may satisfy our conversion obligation by paying and/or delivering, as the case may be, cash, shares of common stock, or a combination of cash and shares of common stock, at our option, subject to certain terms and conditions. The conversion rate for the 9.75% convertible senior notes is 74.0741 shares of common stock per $1,000 principal amount of 9.75% convertible senior notes, plus accrued and unpaid interest, which is equivalent to an initial conversion price (excluding interest) of approximately $13.50 per share of common stock. The conversion rate is subject to adjustment under certain circumstances in accordance with the terms of the related indenture. On and after May 14, 2023, we have the right to cause the conversion of the 9.75% convertible senior notes if certain specified conditions are met, including minimum common stock price and minimum volume conditions. At any time prior to May 14, 2022, we may, at our option, redeem for cash up to 33.33% aggregate principal amount of the then outstanding 9.75% convertible senior notes (after giving effect to any conversions on or prior to such redemption date) at a redemption price equal to 115% of aggregate principal amount of 9.75% convertible senior notes so redeemed, plus any accrued and unpaid interest to, but excluding, the redemption date, using the net cash proceeds of one or more equity offerings by us, provided the redemption occurs within 180 days of the date of the closing of such equity offering. At any time on or after May 14, 2023, we may, at our option, redeem for cash all (but not less than all) of the 9.75% convertible senior notes at the redemption price (expressed as percentages of principal amount) set forth below, plus any accrued and unpaid interest, if any, to, but excluding, the redemption date accrued and unpaid interest, if any, to, but excluding, the redemption date: Period Percentage At any time on and after May 14, 2023 but prior to May 14, 2024 115% At any time on and after May 14, 2024 110% On and after September 23, 2024, the holders of the 9.75% convertible senior notes have the option to require us to repurchase their 9.75% convertible senior notes for cash at a purchase price of 110% of the aggregate principal amount repurchased, plus accrued and unpaid interest to the date of repurchase. For accounting purposes and in accordance with GAAP, the exchange of our 7.75% convertible senior notes for our 9.75% convertible senior notes was treated as a debt modification and we separated the 9.75% convertible senior notes into liability and equity components. As of September 30, 2020, the carrying amount of the liability component for the 9.75% convertible senior notes of approximately $96.7 million (net of an unamortized debt discount of $64.5 million and unamortized issuance costs of $416,000) was determined based on a discounted cash flow analysis and a binomial lattice model. The valuation required the use of Level 3 unobservable inputs and subjective assumptions, including but not limited to, the stock price volatility and bond yield. The use of alternative market assumptions and estimation methodologies could have had an effect on these estimates of fair value. As of September 30, 2020, the carrying amount of the equity component for the 9.75% convertible senior notes of approximately $42.8 million (net of unamortized issuance costs of $653,000), representing the conversion option, was determined by deducting the carrying amount of the liability components from the principal amount of the 9.75% convertible senior notes. This difference between the principal amount of the 9.75% convertible senior notes and the liability component represents the debt discount, presented as a reduction to the 9.75% convertible senior notes in the unaudited condensed consolidated balance sheets and is amortized to interest expense, net using the effective interest method over the remaining term of the 9.75% convertible senior notes. The equity component of the 9.75% convertible senior notes is included in additional paid-in-capital—common stock in the unaudited condensed consolidated balance sheets and is not remeasured as long as it continues to meet the conditions for equity classification. AP4 Debt, TEPIIH Debt and LAPH Debt . In February 2020 , the aggregate principal amounts outstanding under the AP4 financing agreement and TEPIIH revolving credit facility of $92.0 million and $226.6 million, respectively, were fully repaid using proceeds from the SOLI Notes (as defined below), all related interest rate swaps were unwound and the debt facilities were terminated. In addition, proceeds from the SOLI Notes were used to repay $32.0 million of LAPH debt. EZOP Debt . In June 2020, proceeds from the HELIV Notes (as defined below) were used to repay $149.3 million in aggregate principal amount outstanding of EZOP debt. TEPH Debt . In March 2020, we amended the TEPH revolving credit facility to, among other things, (a) increase the maximum facility amount to $400.0 million, with all of the increased amount coming from Class A lenders on an uncommitted basis, (b) increase both the Class A and Class B interest rates by 0.40% and (c) modify the borrowing base calculation to shift a portion of the borrowing base from Class B to Class A lenders. In May 2020, we amended the TEPH revolving credit facility to, among other things, (a) increase the aggregate commitment amount from $200.0 million to $390.0 million and (b) increase the unused line fee on such committed amounts. In June 2020, we amended the TEPH revolving credit facility to, among other things, (a) increase the aggregate commitment amount from $390.0 million to $437.5 million, (b) modify the advance rates for solar energy systems and (c) modify the interest rates to an adjusted LIBOR rate plus a weighted average margin of 4.15%. SOLI Debt . In February 2020 , we pooled and transferred eligible solar energy systems and the related asset receivables into wholly-owned subsidiaries of SOLI, a special purpose entity, that issued $337.1 million in aggregate principal amount of Series 2020-1 Class A solar asset-backed notes and $75.4 million in aggregate principal amount of Series 2020-1 Class B solar asset-backed notes (collectively, the "SOLI Notes") with a maturity date of January 2055 . The SOLI Notes were issued at a discount of 0.89% for Class A and 0.85% for Class B and bear interest at an annual rate equal to 3.35% and 5.54% , respectively. The cash flows generated by the solar energy systems of SOLI's subsidiaries are used to service the quarterly principal and interest payments on the SOLI Notes and satisfy SOLI's expenses, and any remaining cash can be distributed to Sunnova Sol Depositor, LLC, SOLI's sole member. In connection with the SOLI Notes, certain of our affiliates receive a fee for managing and servicing the solar energy systems pursuant to a transaction management agreement and managing and servicing agreements. In addition, Sunnova Energy Corporation has guaranteed (a) the obligations of certain of our subsidiaries to manage and service the solar energy systems pursuant to management, servicing and transaction management agreements, (b) the managing members' obligations, in such capacity, under the related financing fund's limited liability company agreement and (c) certain of our subsidiaries' obligations to repurchase or substitute certain ineligible solar energy systems eventually sold to SOLI pursuant to the sale and contribution agreement. SOLI is also required to maintain a liquidity reserve account, a tax loss insurance proceeds account and a supplemental reserve account for the benefit of the holders of the SOLI Notes, each of which must remain funded at all times to the levels specified in the SOLI Notes. The creditors of SOLI have no recourse to our other assets except as expressly set forth in the SOLI Notes. HELIV Debt . In June 2020, we pooled and transferred eligible solar loans and the related receivables into HELIV, a special purpose entity, that issued $135.9 million in aggregate principal amount of Series 2020-A Class A solar loan-backed notes and $22.6 million in aggregate principal amount of Series 2020-A Class B solar loan-backed notes (collectively, the "HELIV Notes") with a maturity date of June 2047. The HELIV Notes were issued at a discount of 0.01% for Class A and 4.18% for Class B and bear interest at an annual rate of 2.98% and 7.25%, respectively. The cash flows generated by these solar loans are used to service the monthly principal and interest payments on the HELIV Notes and satisfy HELIV's expenses, and any remaining cash can be distributed to Sunnova Helios IV Depositor, LLC, HELIV's sole member. In connection with the HELIV Notes, certain of our affiliates receive a fee for managing and servicing the solar energy systems pursuant to management and service agreements. In addition, Sunnova Energy Corporation has guaranteed, among other things, (a) the obligations of certain of our subsidiaries to manage and service the solar energy systems pursuant to management and servicing agreements and (b) certain of our subsidiaries' obligations to repurchase or substitute certain ineligible solar loans eventually sold to HELIV pursuant to the related sale and contribution agreement. HELIV is also required to maintain a reserve account, a supplemental reserve account for equipment replacement and a capitalized interest reserve account for the benefit of the holders of the HELIV Notes, each of which must be funded at all times to the levels specified in the HELIV Notes. The creditors of HELIV have no recourse to our other assets except as expressly set forth in the HELIV Notes. AP8 Debt . In September 2020 , AP8 entered into a revolving credit facility with Banco Popular de Puerto Rico for an aggregate committed amount of $60.0 million with a maturity date of September 2023. The proceeds of the loans under the revolving credit facility, the first portion of which were not received until October 2020, are available to purchase or otherwise acquire solar loans, fund a reserve account that is required to be maintained by AP8 in accordance with the credit agreement and pay fees and expenses incurred in connection with the revolving credit facility. The amount available for borrowings at any one time under the revolving credit facility is limited to a borrowing base amount determined at each borrowing and calculated based on a specified advance rate applied to the net outstanding principal balance of the solar loans securing the revolving credit facility. Interest on the borrowings under the revolving credit facility is due monthly. Borrowings under the AP8 revolving credit facility bear interest at an annual rate of adjusted LIBOR plus an applicable margin . In connection with the AP8 revolving credit facility, certain of our affiliates receive a fee for managing and servicing the solar loan agreements and related solar energy systems pursuant to management and servicing agreements. In addition, Sunnova Energy Corporation has guaranteed (a) the manager's obligations to manage the solar loan agreements and related solar energy systems pursuant to the management agreement, (b) the servicer's obligations to service the solar loan agreements and related solar energy systems pursuant to the servicing agreement, (c) Sunnova Asset Portfolio 8 Holdings, LLC's obligations to repurchase or substitute certain ineligible solar loans sold to AP8 pursuant to certain sale and contribution agreements, (d) certain indemnification obligations related to its affiliates in connection with the AP8 revolving credit facility and (e) the obligation of AP8 under the AP8 revolving credit facility to the extent a default is caused by a misappropriation of funds or certain insolvency events relating to AP8, but does not provide a general guarantee of the creditworthiness of the assets of AP8 pledged as the collateral for the revolving credit facility. Under the limited guarantee, Sunnova Energy Corporation is subject to certain financial covenants regarding tangible net worth, working capital and restrictions on the use of proceeds from the AP8 revolving credit facility. Fair Values of Long-Term Debt . The fair values of our long-term debt and the corresponding carrying amounts are as follows: As of September 30, 2020 As of December 31, 2019 Carrying Estimated Carrying Estimated (in thousands) SEI 7.75% convertible senior notes $ — $ — $ 55,000 $ 37,964 SEI 9.75% convertible senior notes 161,584 170,114 — — Sunnova Energy Corporation notes payable 2,769 2,769 2,428 2,428 AP4 secured term loan — — 92,478 92,478 HELI solar asset-backed notes 211,722 220,307 222,305 223,895 LAPH secured term loan 10,659 10,659 42,876 42,876 EZOP warehouse credit facility 115,450 115,450 121,400 121,400 TEPIIH revolving credit facility — — 234,650 234,650 HELII solar asset-backed notes 239,281 290,893 254,314 281,850 RAYSI solar asset-backed notes 127,837 150,689 133,155 139,004 HELIII solar loan-backed notes 139,364 156,345 154,573 155,701 TEPH revolving credit facility 380,720 380,720 90,325 90,325 TEPINV revolving credit facility 72,459 72,459 95,207 95,207 SOLI solar asset-backed notes 404,753 438,874 — — HELIV solar loan-backed notes 150,192 150,794 — — Total (1) $ 2,016,790 $ 2,160,073 $ 1,498,711 $ 1,517,778 (1) Amounts exclude the net deferred financing costs and net debt discounts of $112.0 million and $54.8 million as of September 30, 2020 and December 31, 2019, respectively. For the AP4, LAPH, EZOP, TEPIIH, TEPH and TEPINV debt, the estimated fair values approximate the carrying amounts due primarily to the variable nature of the interest rates of the underlying instruments. For the notes payable, the estimated fair value approximates the carrying amount due primarily to the short-term nature of the instruments. For the convertible senior notes and the HELI, HELII, RAYSI, HELIII, SOLI and HELIV debt, we determined the estimated fair values based on a yield analysis of similar type debt.

Derivative Instruments

Derivative Instruments	9 Months Ended
	Sep. 30, 2020
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative Instruments	Derivative Instruments Interest Rate Swaps on AP4 Debt . In February 2020 , all AP4 interest rate swaps were unwound in connection with the termination of the AP4 financing agreement. See Note 7, Long-Term Debt. Interest Rate Swaps on TEPIIH Debt . In February 2020 , all TEPIIH interest rate swaps were unwound in connection with the termination of the TEPIIH revolving credit facility. See Note 7, Long-Term Debt. Interest Rate Swaps on EZOP Debt . In June 2020, EZOP unwound interest rate swaps with a notional amount of $126.1 million and recorded a realized loss of $5.8 million in connection with the repayment of the aggregate principal amount outstanding of EZOP debt. See Note 7, Long-Term Debt. The following table presents a summary of the outstanding derivative instruments: As of September 30, 2020 As of December 31, 2019 Effective Termination Fixed Aggregate Effective Termination Fixed Aggregate (in thousands, except interest rates) AP4 —% $ — March 2018 July 2020 2.338% $ 99,762 LAPH November 2018 October 2036 3.409% 10,584 November 2018 October 2036 3.409% 43,298 EZOP June 2020 - September 2029 - 0.483% - 2.620% 78,210 June 2019 - July 2029 - 1.631% - 2.620% 100,083 TEPIIH —% — September 2018 - July 2031 - 1.909% - 3.383% 225,845 TEPH September 2018 - January 2023 - 0.528% - 3.125% 202,418 September 2019 January 2023 1.620% - 1.928% 55,115 TEPINV December 2019 December 2022 2.500% 65,657 —% — Total $ 356,869 $ 524,103 The following table presents the fair value of the interest rate swaps as recorded in the unaudited condensed consolidated balance sheets: As of As of (in thousands) Other assets $ 1 $ 360 Other current liabilities — (397) Other long-term liabilities (29,931) (27,092) Total, net $ (29,930) $ (27,129) We did not designate the interest rate swaps as hedging instruments for accounting purposes. As a result, we recognize changes in fair value immediately in interest expense, net. The following table presents the impact of the interest rate swaps as recorded in the unaudited condensed consolidated statements of operations: Three Months Ended Nine Months Ended 2020 2019 2020 2019 (in thousands) Realized loss $ 665 $ 265 $ 38,668 $ 12,637 Unrealized (gain) loss (1,788) 12,813 2,755 30,262 Total $ (1,123) $ 13,078 $ 41,423 $ 42,899

Income Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2020
Income Tax Disclosure [Abstract]
Income Taxes	Income TaxesOur effective income tax rate is 0% for the three and nine months ended September 30, 2020 and 2019. Total income tax differs from the amounts computed by applying the statutory income tax rate to loss before income tax primarily as a result of our valuation allowance. We assessed whether we had any significant uncertain tax positions taken in a filed tax return, planned to be taken in a future tax return or claim, or otherwise subject to interpretation and determined there were none not more likely than not to be sustained upon examination, including resolution of any related appeals or litigation processes, based on the technical merits of the position, or prospectively approved when such approval may be sought in advance. Accordingly, we recorded no reserve for uncertain tax positions. Should a provision for any interest or penalties relative to unrecognized tax benefits be necessary, it is our policy to accrue for such in our income tax accounts. There were no such accruals as of September 30, 2020 and December 31, 2019 and we do not expect a significant change in gross unrecognized tax benefits in the next twelve months. Our tax years after 2011 remain subject to examination by the Internal Revenue Service and by the taxing authorities in the states and territories in which we operate. We conduct operations in the U.S. territories of Puerto Rico, Guam and the Commonwealth of the Northern Mariana Islands. As a result, our income tax expense includes the effects of taxes incurred in such jurisdictions where the tax code for the respective jurisdiction may have separate tax-reporting requirements. Jurisdiction-specific income taxes, in aggregate, do not adjust our effective income tax rate of 0%. In March 2020, the U.S. enacted the Coronavirus Aid, Relief, and Economic Security Act ("CARES Act"), featuring significant tax provisions and relief measures to assist individuals and businesses impacted by the economic effects of the COVID-19 pandemic. Relief measures intended to aid businesses in employee retention include payroll tax relief and a refundable tax credit for employers who retain employees during the COVID-19 pandemic. In addition, among other things, the CARES Act establishes (a) a five-year carryback of net operating losses generated in 2018, 2019 and 2020, (b) a temporary suspension of the 80% limitation on the use of net operating losses in 2018, 2019 and 2020 and (c) an increase to the adjusted taxable income limitation from 30% to 50% for business interest deductions under Section 163(j) of the U.S. Internal Revenue Code of 1986, as amended, for 2019 and 2020. We have historically maintained, and continue to maintain, a full valuation allowance against deferred tax assets. Due to our aggregate amount of net operating losses, we cannot utilize the carryback or limitation suspension provisions pertaining to the usage of net operating losses. However, the increase to the adjusted taxable income limitation for business interest deductions resulted in a decrease to our deferred tax assets for unused business interest deductions and an offsetting increase to our net operating loss carryforward. The CARES Act does not have any impact on our valuation allowance.

Redeemable Noncontrolling Inter

Redeemable Noncontrolling Interests and Noncontrolling Interests	9 Months Ended
	Sep. 30, 2020
Noncontrolling Interest [Abstract]
Redeemable Noncontrolling Interests and Noncontrolling Interests	Redeemable Noncontrolling Interests and Noncontrolling Interests In February 2020, we admitted a tax equity investor as the Class A member of Sunnova TEP IV-C, LLC ("TEPIVC"), a subsidiary of Sunnova TEP IV-C Manager, LLC, which is the Class B member of TEPIVC. The Class A member of TEPIVC made a total capital commitment of $75.0 million. In May 2020, we admitted a tax equity investor as the Class A member of Sunnova TEP IV-D, LLC ("TEPIVD"), a subsidiary of Sunnova TEP IV-D Manager, LLC, which is the Class B member of TEPIVD. The Class A member of TEPIVD made a total capital commitment of $75.0 million. In July 2020, we admitted a tax equity investor as the Class A member of Sunnova TEP IV-F, LLC ("TEPIVF"), a subsidiary of Sunnova TEP IV-F Manager, LLC, which is the Class B member of TEPIVF. The Class A member of TEPIVF made a total capital commitment of $10.0 million. In September 2020, we admitted a tax equity investor as the Class A member of Sunnova TEP IV-E, LLC ("TEPIVE"), a subsidiary of Sunnova TEP IV-E Manager, LLC, which is the Class B member of TEPIVE. The Class A member of TEPIVE made a total capital commitment of $75.0 million. The carrying values of the redeemable noncontrolling interests were equal to or greater than the redemption values as of September 30, 2020 and December 31, 2019.

Stockholders' Equity

Stockholders' Equity	9 Months Ended
	Sep. 30, 2020
Equity [Abstract]
Stockholders' Equity	Stockholders' Equity Common Stock In the third quarter of 2020, certain of the holders of our 9.75% convertible senior notes converted approximately $84.8 million aggregate principal amount, including accrued and unpaid interest to the date of each conversion, of our 9.75% convertible senior notes into 6,277,982 shares of our common stock. Such conversions resulted in a loss on extinguishment of debt under GAAP of $50.7 million for the three and nine months ended September 30, 2020 .

Equity-Based Compensation

Equity-Based Compensation	9 Months Ended
	Sep. 30, 2020
Share-based Payment Arrangement [Abstract]
Equity-Based Compensation	Equity-Based Compensation Stock Options The following table summarizes stock option activity: Number Weighted Weighted Weighted Aggregate (in thousands) Outstanding, December 31, 2019 4,304,309 $ 15.86 7.08 $ 242 Exercised (569,512) $ 12.96 $ 9,938 Forfeited (115,191) $ 19.19 $ 3.54 Outstanding, September 30, 2020 3,619,606 $ 16.21 6.16 $ 51,383 Exercisable, September 30, 2020 3,619,606 $ 16.21 6.16 $ 51,383 Vested, September 30, 2020 3,619,606 $ 16.21 6.16 $ 51,383 Non-vested, September 30, 2020 — $ — The number of stock options that vested during the three months ended September 30, 2020 and 2019 was 545,785 and 1,020,026, respectively. The number of stock options that vested during the nine months ended September 30, 2020 and 2019 was 915,501 and 1,764,125, respectively. The grant date fair value of stock options that vested during the three months ended September 30, 2020 and 2019 was $2.0 million and $3.6 million, respectively. The grant date fair value of stock options that vested during the nine months ended September 30, 2020 and 2019 was $3.2 million and $6.0 million, respectively. As of September 30, 2020, there was no unrecognized compensation expense related to stock options. Restricted Stock Units The following table summarizes restricted stock unit activity: Number of Weighted Outstanding, December 31, 2019 1,426,139 $ 11.93 Granted 1,130,312 $ 11.75 Vested (443,620) $ 11.96 Forfeited (43,703) $ 11.77 Outstanding, September 30, 2020 2,069,128 $ 11.83 The number of restricted stock units that vested during the three and nine months ended September 30, 2020 was 416,537 and 443,620, respectively. The grant date fair value of restricted stock units that vested during the three and nine months ended September 30, 2020 was $5.0 million and $5.3 million, respectively. As of September 30, 2020, there was $20.0 million of total unrecognized compensation expense related to restricted stock units, which is expected to be recognized over the weighted average period of 1.83 years.

Basic and Diluted Net Loss Per

Basic and Diluted Net Loss Per Share	9 Months Ended
	Sep. 30, 2020
Earnings Per Share [Abstract]
Basic and Diluted Net Loss Per Share	Basic and Diluted Net Loss Per Share The following table sets forth the computation of our basic and diluted net loss per share: Three Months Ended Nine Months Ended 2020 2019 2020 2019 (in thousands, except share and per share amounts) Net loss attributable to stockholders $ (64,181) $ (37,590) $ (160,514) $ (126,842) Dividends earned on Series A convertible preferred stock — — — (19,271) Dividends earned on Series C convertible preferred stock — — — (5,454) Net loss attributable to common stockholders—basic and diluted $ (64,181) $ (37,590) $ (160,514) $ (151,567) Net loss per share attributable to common stockholders—basic and diluted $ (0.73) $ (0.62) $ (1.88) $ (5.77) Weighted average common shares outstanding—basic and diluted 87,768,712 60,890,129 85,276,841 26,245,493 The following table presents the weighted average shares of common stock equivalents that were excluded from the computation of diluted net loss per share for the periods presented because including them would have been anti-dilutive: Three Months Ended Nine Months Ended 2020 2019 2020 2019 Equity-based compensation awards 6,006,791 5,277,414 6,176,162 4,693,647 Convertible preferred stock — 18,337,539 — 45,405,229 Convertible senior notes 14,970,678 — 9,839,125 —

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2020
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Legal. We are a party to a number of lawsuits, claims and governmental proceedings which are ordinary, routine matters incidental to our business. In addition, in the ordinary course of business, we periodically have disputes with dealers and customers. We do not expect the outcomes of these matters to have, either individually or in the aggregate, a material adverse effect on our financial position or results of operations. Performance Guarantee Obligations. As of September 30, 2020, we recorded $4.9 million relating to our guarantee of certain specified minimum solar energy production output under our leases and loans, of which we include $2.9 million in other current liabilities and $2.0 million in other long-term liabilities in the unaudited condensed consolidated balance sheet. As of December 31, 2019, we recorded $6.5 million relating to these guarantees, of which $4.1 million is recorded in other current liabilities and $2.4 million is recorded in other long-term liabilities in the unaudited condensed consolidated balance sheet. The changes in our aggregate performance guarantee obligations are as follows: As of September 30, 2020 2019 (in thousands) Balance at beginning of period $ 6,468 $ 6,044 Accruals for obligations issued 2,359 2,259 Settlements made in cash (3,888) (2,628) Balance at end of period $ 4,939 $ 5,675 Operating and Finance Leases . We lease real estate and certain office equipment under operating leases and certain other office equipment under finance leases. The following table presents the detail of lease expense and lease income as recorded in general and administrative expense and other operating income, respectively, in the unaudited condensed consolidated statements of operations: Three Months Ended Nine Months Ended 2020 2019 2020 2019 (in thousands) Operating lease expense $ 336 $ 344 $ 1,007 $ 914 Finance lease amortization expense — 2 2 6 Short-term lease expense 14 11 36 34 Variable lease expense 258 268 437 731 Sublease income — (18) — (55) Total $ 608 $ 607 $ 1,482 $ 1,630 The following table presents the detail of right-of-use assets and lease liabilities as recorded in other assets and other current liabilities/other long-term liabilities, respectively, in the unaudited condensed consolidated balance sheets: As of As of (in thousands) Right-of-use assets: Operating leases $ 8,997 $ 9,668 Finance leases — 5 Total right-of-use assets $ 8,997 $ 9,673 Current lease liabilities: Operating leases $ 1,075 $ 556 Finance leases — 5 Long-term leases liabilities: Operating leases 8,846 9,389 Total lease liabilities $ 9,921 $ 9,950 Other information related to leases was as follows: Nine Months Ended 2020 2019 (in thousands) Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows from operating leases $ 358 $ 819 Financing cash flows from finance leases 1 7 Right-of-use assets obtained in exchange for lease obligations: Operating leases — 8,053 Finance leases — 13 As of September 30, 2020 2019 Weighted average remaining lease term (years): Operating leases 8.69 9.68 Finance leases 0.00 0.92 Weighted average discount rate: Operating leases 3.94 % 3.94 % Finance leases — % 4.26 % Future minimum lease payments under our non-cancelable leases as of September 30, 2020 were as follows: Operating (in thousands) Remaining 2020 $ 381 2021 1,536 2022 1,559 2023 1,594 2024 1,616 2025 and thereafter 7,617 Total 14,303 Amount representing interest (2,254) Amount representing leasehold incentives (2,128) Present value of future payments 9,921 Current portion of lease liability (1,075) Long-term portion of lease liability $ 8,846 Letters of Credit . In connection with various security arrangements for an office lease, we have a letter of credit outstanding of $375,000 and $725,000 as of September 30, 2020 and December 31, 2019, respectively. The letter of credit is cash collateralized for the same amount or a lesser amount and this cash is classified as restricted cash recorded in other current assets and other assets in the unaudited condensed consolidated balance sheets. Guarantees or Indemnifications . We enter into contracts that include indemnifications and guarantee provisions. In general, we enter into contracts with indemnities for matters such as breaches of representations and warranties and covenants contained in the contract and/or against certain specified liabilities. Examples of these contracts include dealer agreements, debt agreements, asset purchases and sales agreements, service agreements and procurement agreements. We are unable to estimate our maximum potential exposure under these agreements until an event triggering payment occurs. We do not expect to make any material payments under these agreements. Dealer Commitments. As of September 30, 2020, the net unamortized balance of payments to dealers for exclusivity and other similar arrangements was $54.5 million. Under these agreements, we paid $7.7 million and $9.7 million during the three months ended September 30, 2020 and 2019, respectively, and we paid $24.4 million and $31.7 million during the nine months ended September 30, 2020 and 2019, respectively. We could be obligated to make maximum payments, excluding additional amounts payable on a per watt basis if even higher thresholds are met, as follows: Dealer (in thousands) Remaining 2020 $ 484 2021 33,312 2022 33,477 2023 10,505 2024 9,766 2025 and thereafter 1,509 Total $ 89,053 Purchase Commitments. In August 2019, we amended an agreement with a supplier in which we agreed to purchase a minimum amount of energy storage systems and components for five years. These purchases are recorded to inventory in other current assets in the consolidated balance sheets. Under this agreement, we could be obligated to make minimum purchases as follows: Purchase (in thousands) Remaining 2020 $ 3,327 2021 26,629 2022 26,810 2023 26,605 2024 19,807 2025 and thereafter — Total $ 103,178 Information Technology Commitments. We have certain long-term contractual commitments related to information technology software services and licenses. Future commitments as of September 30, 2020 were as follows: Information (in thousands) Remaining 2020 $ 1,475 2021 5,322 2022 121 2023 26 2024 26 2025 and thereafter 7 Total $ 6,977

Subsequent Events

Subsequent Events	9 Months Ended
	Sep. 30, 2020
Subsequent Events [Abstract]
Subsequent Events	Subsequent Events EZOP Debt . In October 2020, a portion of the proceeds from the AP8 revolving credit facility were used to repay $28.0 million in aggregate principal amount outstanding of EZOP debt. TEPH Debt . In October 2020, we amended the TEPH revolving credit facility to, among other things, increase the aggregate commitment amount from $437.5 million to $600.0 million. Common Stock . In October 2020, certain of the holders of our 9.75% convertible senior notes converted approximately $32.5 million aggregate principal amount, including accrued and unpaid interest to the date of each conversion, of our 9.75% convertible senior notes into 2,406,523 shares of our common stock.

Significant Accounting Polici_2

Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2020
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The accompanying interim unaudited condensed consolidated financial statements ("interim financial statements") include our consolidated balance sheets, statements of operations, statements of redeemable noncontrolling interests and equity and statements of cash flows and have been prepared in accordance with accounting principles generally accepted in the United States of America ("GAAP") from records maintained by us. We have condensed or omitted certain information and note disclosures normally included in the financial statements prepared in accordance with GAAP pursuant to the applicable rules and regulations of the Securities and Exchange Commission ("SEC") regarding interim financial reporting. As such, these interim financial statements should be read in conjunction with our 2019 annual audited consolidated financial statements and accompanying notes included in our Annual Report on Form 10-K filed with the SEC on February 25, 2020. Our interim financial statements reflect all normal recurring adjustments necessary, in our opinion, to state fairly our financial position and results of operations for the reported periods. Amounts reported for interim periods may not be indicative of a full year period because of our continual growth, seasonal fluctuations in demand for power, timing of maintenance and other expenditures, changes in interest expense and other factors. Our interim financial statements reflect our accounts and operations and those of our subsidiaries in which we have a controlling financial interest. In accordance with the provisions of the Financial Accounting Standards Board ("FASB") Accounting Standards Codification ("ASC") 810, Consolidation , we consolidate any VIE of which we are the primary beneficiary. We form VIEs with our investors in the ordinary course of business to facilitate the funding and monetization of certain attributes associated with our solar energy systems. The typical condition for a controlling financial interest ownership is holding a majority of the voting interests of an entity; however, a controlling financial interest may also exist in entities, such as VIEs, through arrangements that do not involve controlling voting interests. ASC 810 requires a variable interest holder to consolidate a VIE if that party has (a) the power to direct the activities of the VIE that most significantly impact the VIE's economic performance and (b) the obligation to absorb losses or the right to receive benefits from the VIE that could potentially be significant to the VIE. We do not consolidate a VIE in which we have a majority ownership interest when we are not considered the primary beneficiary. We have considered the provisions within the contractual arrangements that grant us power to manage and make decisions that affect the operation of our VIEs, including determining the solar energy systems contributed to the VIEs, and the installation, operation and maintenance of the solar energy systems. We consider the rights granted to the other investors under the contractual arrangements to be more protective in nature rather than participating rights. As such, we have determined we are the primary beneficiary of our VIEs and evaluate our relationships with our VIEs on an ongoing basis
New Accounting Guidance	Adoption of ASU In June 2016, the FASB issued Accounting Standards Update ("ASU") No. 2016-13, Financial Instruments—Credit Losses , which requires entities to use a forward-looking expected loss approach, referred to as the current expected credit loss ("CECL") methodology, in accordance with ASC 326, Financial Instruments—Credit Losses , instead of the incurred loss approach previously in effect when estimating the allowance for credit losses. Under CECL, financial assets measured at amortized cost are presented at the net amount expected to be collected by using an estimate of credit losses for the remaining estimated life of the financial asset based on historical experience, current conditions and reasonable and supportable forecasts. This ASU is effective for annual and interim reporting periods in 2020. In 2018 and 2019, the FASB issued the following ASUs related to ASU 2016-13: ASU No. 2018-19, Codification Improvements to Topic 326, Financial Instruments—Credit Losses , ASU 2019-05, Financial Instruments—Credit Losses: Targeted Transition Relief and ASU 2019-11, Codification Improvements to Topic 326, Financial Instruments—Credit Losses ASU 2016-13 New Accounting Guidance New accounting pronouncements are issued by the FASB or other standard setting bodies and are adopted as of the specified effective date. In December 2019, the FASB issued ASU No. 2019-12, Income Taxes: Simplifying the Accounting for Income Taxes , to remove certain exceptions and clarify and amend the existing guidance. This ASU is effective for annual and interim reporting periods in 2021. We have evaluated this ASU and determined it will not have a significant impact on our consolidated financial statements and related disclosures. In March 2020, the FASB issued ASU No. 2020-03, Codification Improvements to Financial Instruments , to clarify and amend the existing guidance. The amendments in this ASU are effective either upon issuance of this ASU or for annual and interim reporting periods in 2020. We adopted this ASU in January 2020 and determined it did not have a significant impact on our consolidated financial statements and related disclosures. In March 2020, the FASB issued ASU No. 2020-04, Reference Rate Reform: Facilitation of the Effects of Reference Rate Reform on Financial Reporting , to provide temporary optional expedients and exceptions for applying GAAP to contracts, hedging relationships and other transactions affected by reference rate reform. This ASU is effective beginning in March 2020 or prospectively from a date through December 2022. We adopted this ASU in October 2020 and determined it did not have a significant impact on our consolidated financial statements and related disclosures. In August 2020, the FASB issued ASU No. 2020-06, Debt—Debt with Conversion and Other Options and Derivatives and Hedging—Contracts in Entity's Own Equity: Accounting for Convertible Instruments and Contracts in an Entity's Own Equity , to simplify the accounting for certain financial instruments with characteristics of liabilities and equity by removing the separation models for convertible debt with a cash conversion feature and convertible instruments with a beneficial conversion feature. This ASU also expands the required disclosures related to the terms and features of convertible instruments, how the instruments have been reported and information about events, conditions and circumstances that can affect how to assess the amount or timing of an entity's future cash flows related to those instruments. This ASU is effective for annual and interim reporting periods in 2022. We have not yet determined the potential impact of this ASU on our consolidated financial statements and related disclosures.
Reclassifications	Reclassifications Certain other prior period amounts have been reclassified to conform to the current period presentation. These reclassifications did not have a significant impact on our interim financial statements.
Use of Estimates	Use of Estimates The application of GAAP in the preparation of the interim financial statements requires us to make estimates and assumptions that affect the amounts reported in the interim financial statements and accompanying notes. We base our estimates on historical experience and on various other assumptions believed to be reasonable, the results of which form the basis for making judgments about the carrying values of assets and liabilities. Actual results could differ materially from those estimates.
Accounts Receivable	Accounts Receivable Accounts Receivable — Trade. Accounts receivable — trade primarily represents trade receivables from residential customers that are generally collected in the subsequent month. Accounts receivable — Accounts Receivable — Other. Accounts receivable — other primarily represents receivables related to the sale of inventory and amounts owed from dealers in a net receivable position primarily as a result of customer contract cancelations or settlement agreements.
Inventory	InventoryInventory primarily represents energy storage systems, photovoltaic modules, inverters, meters and other associated equipment purchased and held for use as original parts on new solar energy systems or replacement parts on existing solar energy systems. We record inventory in other current assets in the consolidated balance sheets at the lower of cost and net realizable value. We remove these items from inventory using the weighted-average method and (a) expense to operations and maintenance expense when installed as a replacement part for a solar energy system or (b) capitalize to property and equipment when installed as an original part on a solar energy system. We evaluate our inventory reserves and write down the estimated value of excess and obsolete inventory based upon assumptions about future demand and market conditions.
Fair Value of Financial Instruments	Fair Value of Financial Instruments Fair value is an exit price representing the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. As such, fair value is a market-based measurement that should be determined based on assumptions market participants would use in pricing an asset or a liability. Valuation techniques used to measure fair value must maximize the use of observable inputs and minimize the use of unobservable inputs. ASC 820 establishes a three-tier fair value hierarchy, which prioritizes inputs that may be used to measure fair value as follows: • Level 1—Observable inputs that reflect unadjusted quoted market prices in active markets for identical assets or liabilities that are accessible at the measurement date. • Level 2—Observable inputs other than Level 1 prices, such as quoted market prices for similar assets or liabilities in active markets, quoted market prices in markets that are not active or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities. • Level 3—Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities.
Derivative Instruments	Derivative Instruments Our derivative instruments consist of interest rate swaps that are not designated as cash flow hedges or fair value hedges under accounting guidance. We use interest rate swaps to manage our net exposure to interest rate changes. We record the derivatives in other current assets, other assets, other current liabilities and other long-term liabilities, as appropriate, in the consolidated balance sheets and the changes in fair value are recorded in interest expense, net in the consolidated statements of operations. We include unrealized gains and losses on derivatives as a non-cash reconciling item in operating activities in the consolidated statements of cash flows. We include realized gains and losses on derivatives as a change in components of operating assets and liabilities in operating activities in the consolidated statements of cash flows. See Note 8, Derivative Instruments.
Revenue / Loans / Deferred Revenue	Revenue We recognize revenue from contracts with customers as we satisfy our performance obligations at a transaction price reflecting an amount of consideration based upon an estimated rate of return. We express this rate of return as the solar rate per kilowatt hour ("kWh") in the customer contract. The amount of revenue we recognize does not equal customer cash payments because we satisfy performance obligations ahead of cash receipt or evenly as we provide continuous access on a stand-ready basis to the solar energy system. We reflect the differences between revenue recognition and cash payments received in accounts receivable, other assets or deferred revenue, as appropriate. Revenue allocated to remaining performance obligations represents contracted revenue we have not yet recognized and includes deferred revenue as well as amounts that will be invoiced and recognized as revenue in future periods. Contracted but not yet recognized revenue was approximately $1.4 billion as of September 30, 2020, of which we expect to recognize approximately 4% over the next 12 months. We do not expect the annual recognition to vary significantly over approximately the next 20 years as the vast majority of existing solar service agreements have at least 20 years remaining, given the average age of the fleet of solar energy systems under contract is less than three years. PPAs. Customers purchase electricity from us under PPAs. Pursuant to ASC 606, we recognize revenue based upon the amount of electricity delivered as determined by remote monitoring equipment at solar rates specified under the PPAs. All customers must pass our credit evaluation process. The PPAs generally have a term of 25 years with an opportunity for customers to renew for up to an additional 10 years, via two five-year renewal options. Leases . We are the lessor under lease agreements for solar energy systems and energy storage systems, which do not meet the definition of a lease under ASC 842 and are accounted for as contracts with customers under ASC 606. We recognize revenue on a straight-line basis over the contract term as we satisfy our obligation to provide continuous access to the solar energy system. All customers must pass our credit evaluation process. The lease agreements generally have a term of 25 years with an opportunity for customers to renew for up to an additional 10 years, via two five-year renewal options. We provide customers under our lease agreements a performance guarantee that each solar energy system will achieve a certain specified minimum solar energy production output, which is a significant proportion of its expected output. The specified minimum solar energy production output may not be achieved due to natural fluctuations in the weather or equipment failures from exposure and wear and tear outside of our control, among other factors. We determine the amount of the guaranteed output based on a number of different factors, including: (a) the specific site information relating to the tilt of the panels, azimuth (a horizontal angle measured clockwise in degrees from a reference direction) of the panels, size of the system, and shading on site; (b) the calculated amount of available irradiance (amount of energy for a given flat surface facing a specific direction) based on historical average weather data and (c) the calculated amount of energy output of the solar energy system. While actual irradiance levels can significantly change year over year due to natural fluctuations in the weather, we expect the levels to average out over the term of a 25-year lease and to approximate the levels used in determining the amount of the performance guarantee. Generally, weather fluctuations are the most likely reason a solar energy system may not achieve a certain specified minimum solar energy production output. If the solar energy system does not produce the guaranteed production amount, we are required to refund a portion of the previously remitted customer payments, where the repayment is calculated as the product of (a) the shortfall production amount and (b) the dollar amount (guaranteed rate) per kWh that is fixed throughout the term of the contract. These remittances of a customer's payments, if needed, are payable in January following the end of the first three years of the solar energy system's placed in service date and then every annual period thereafter. See Note 14, Commitments and Contingencies. Solar Renewable Energy Certificates. Each solar renewable energy certificate ("SREC") represents one megawatt hour (1,000 kWh) generated by a solar energy system. SRECs can be sold with or without the actual electricity associated with the renewable-based generation source. We account for the SRECs we generate from our solar energy systems as governmental incentives with no costs incurred to obtain them and do not consider those SRECs output of the underlying solar energy systems. We classify these SRECs as inventory held until sold and delivered to third parties. As we did not incur costs to obtain these governmental incentives, the inventory carrying value for the SRECs was $0 as of September 30, 2020 and December 31, 2019. We enter into economic hedges related to expected production of SRECs through forward contracts. The contracts require us to physically deliver the SRECs upon settlement. We recognize the related revenue under ASC 606 upon satisfaction of the performance obligation to transfer the SRECs to the stated counterparty. Payments are typically received within one month of transferring the SREC to the counterparty. The costs related to the sales of SRECs are generally limited to broker fees (recorded in cost of revenue—other), which are only paid in connection with certain transactions. In certain circumstances we are required to purchase SRECs on the open market to fulfill minimum delivery requirements under our forward contracts. Loans. See discussion of loan revenue in the " Loans " section below. Other Revenue. Other revenue includes certain state and utility incentives, revenue from the direct sale of energy storage systems to customers and sales of service plans. We recognize revenue from state and utility incentives in the periods in which they are earned. We recognize revenue from the direct sale of energy storage systems in the period in which the storage components are placed in service. Service plans are available to customers whose solar energy system was not originally sold by Sunnova. We recognize revenue from service plan contracts over the life of the contract, which is typically five years. Loans We offer a loan program, under which the customer finances the purchase of a solar energy system or energy storage system through a solar service agreement, typically for a term of 10, 15 or 25 years. We recognize cash payments received from customers on a monthly basis under our loan program (a) as interest income, to the extent attributable to earned interest on the contract that financed the customer's purchase of the solar energy system or energy storage system; (b) as a reduction of a note receivable on the balance sheet, to the extent attributable to a return of principal (whether scheduled or prepaid) on the contract that financed the customer's purchase of the solar energy system or energy storage system; and (c) as revenue, to the extent attributable to payments for operations and maintenance services provided by us. To qualify for the loan program, a customer must pass our credit evaluation process, which requires the customer to have a minimum FICO ® score of 650 to 720 depending on certain circumstances, and we secure the loans with the solar energy systems or energy storage systems financed. The credit evaluation process is performed once for each customer at the time the customer is entering into the solar service agreement with us. Our investments in solar energy systems and energy storage systems related to the loan program that are not yet placed in service are recorded in other assets in the consolidated balance sheets and are transferred to customer notes receivable upon being placed in service. Customer notes receivable are recorded at amortized cost, net of an allowance for credit losses (as described below), in other current assets and customer notes receivable in the consolidated balance sheets. Accrued interest receivable related to our customer notes receivable is recorded in accounts receivable—trade, net in the consolidated balance sheets. Interest income from customer notes receivable is recorded in interest income in the consolidated statements of operations. The amortized cost of our customer notes receivable is equal to the principal balance of customer notes receivable outstanding and does not include accrued interest receivable. Customer notes receivable continue to accrue interest until they are written off against the allowance, which occurs when the balance is 180 days or more past due unless the balance is in the process of collection. Customer notes receivable are considered past due one day after the due date based on the contractual terms of the loan agreement. In all cases, customer notes receivable balances are placed on a nonaccrual status or written off at an earlier date when they are deemed uncollectible. Expected recoveries do not exceed the aggregate of amounts previously written off and expected to be written off. Accrued interest receivable for customer notes receivable placed on a nonaccrual status is recorded as a reduction to interest income. Interest received on such customer notes receivable is accounted for on a cash basis until the customer notes receivable qualifies for the return to accrual status. Customer notes receivable are returned to accrual status when there is no longer any principal or interest amounts past due and future payments are reasonably assured. The allowance for credit losses is deducted from the customer notes receivable amortized cost to present the net amount expected to be collected. It is measured on a collective (pool) basis when similar risk characteristics (such as financial asset type, customer credit rating, contractual term and vintage) exist. In determining the allowance for credit losses, we identify customers with potential disputes or collection issues and consider our historical level of credit losses and current economic trends that might impact the level of future credit losses. Adjustments to historical loss information are made for differences in current loan-specific risk characteristics, such as differences in underwriting standards. Expected credit losses are estimated over the contractual term of the loan agreements, adjusted for expected prepayments when appropriate. The contractual term excludes expected extensions, renewals and modifications unless either of the following applies: (a) we have a reasonable expectation at the reporting date that a troubled debt restructuring will be executed with an individual customer or (b) the extension or renewal options are included in the original or modified contract at the reporting date and are not unconditionally cancelable by us. As of September 30, 2020, we have not experienced a significant increase in delinquent customer notes receivable and have not made any significant adjustments to our allowance for credit losses related to loans as a result of the COVID-19 pandemic. See Note 6, Customer Notes Receivable. Deferred Revenue

Description of Business and B_2

Description of Business and Basis of Presentation (Tables)	9 Months Ended
	Sep. 30, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Schedule of new accounting pronouncements and changes in accounting principles	The following table presents the impact of the adoption of ASU No. 2016-13 on the unaudited condensed consolidated balance sheet: As of January 1, 2020 As Reported Impact of ASC Pre-ASC 326 (in thousands) Accounts receivable—trade, net $ 10,912 $ 240 $ 10,672 Other current assets 173,565 (451) 174,016 Customer notes receivable 289,191 (8,784) 297,975 Other assets 168,799 (913) 169,712 Accumulated deficit (371,732) (9,908) (361,824)
Schedule of accounting revisions	The following tables present the impact of these revisions on the financial statements: As of December 31, 2019 As Previously Revisions As (in thousands) Redeemable noncontrolling interests $ 172,305 $ (45,176) $ 127,129 Noncontrolling interests — 45,176 45,176 Redeemable Noncontrolling As Previously Revisions As As Previously Revisions As (unaudited, in thousands) June 30, 2019 $ 107,547 $ — $ 107,547 $ — $ — $ — Net income 3,221 (193) 3,028 — 193 193 Contributions from redeemable noncontrolling interests and noncontrolling interests 69,135 (52,087) 17,048 — 52,087 52,087 Distributions to redeemable noncontrolling interests (1,146) — (1,146) — — — Costs related to redeemable noncontrolling interests and noncontrolling interests (2,438) 2,322 (116) — (2,322) (2,322) Equity in subsidiaries attributable to parent (19,356) 14,251 (5,105) — (14,251) (14,251) Other, net (385) — (385) — — — September 30, 2019 $ 156,578 $ (35,707) $ 120,871 $ — $ 35,707 $ 35,707 December 31, 2019 $ 172,305 $ (45,176) $ 127,129 $ — $ 45,176 $ 45,176 Net income (loss) (5,929) 7,505 1,576 — (7,505) (7,505) Contributions from redeemable noncontrolling interests and noncontrolling interests 102,342 (99,172) 3,170 — 99,172 99,172 Distributions to redeemable noncontrolling interests (1,373) — (1,373) — — — Costs related to redeemable noncontrolling interests and noncontrolling interests (707) 894 187 — (894) (894) Equity in subsidiaries attributable to parent (24,164) 24,309 145 — (24,309) (24,309) Other, net (47) 3 (44) — (3) (3) March 31, 2020 242,427 (111,637) 130,790 — 111,637 111,637 Net income (loss) (3,471) 6,340 2,869 — (6,340) (6,340) Contributions from noncontrolling interests 18,311 (18,311) — — 18,311 18,311 Distributions to redeemable noncontrolling interests and noncontrolling interests (1,227) 16 (1,211) — (16) (16) Costs related to noncontrolling interests (604) 604 — — (604) (604) Equity in subsidiaries attributable to parent (17,359) 17,291 (68) — (17,290) (17,290) Other, net 228 (35) 193 — 34 34 June 30, 2020 $ 238,305 $ (105,732) $ 132,573 $ — $ 105,732 $ 105,732

Significant Accounting Polici_3

Significant Accounting Policies (Tables)	9 Months Ended
	Sep. 30, 2020
Accounting Policies [Abstract]
Changes in the allowance for doubtful accounts	The following table presents the changes in the allowance for credit losses recorded against accounts receivable — trade, net in the unaudited condensed consolidated balance sheets: Three Months Ended Nine Months Ended 2020 2019 2020 2019 (in thousands) Balance at beginning of period $ 773 $ 746 $ 960 $ 723 Impact of ASC 326 adoption — — (240) — Provision for current expected credit losses 458 — 1,337 — Bad debt expense — 511 — 1,149 Write off of uncollectible accounts (419) (412) (1,267) (1,076) Recoveries 17 16 39 65 Balance at end of period $ 829 $ 861 $ 829 $ 861 The following table presents the changes in the allowance for credit losses related to customer notes receivable as recorded in the unaudited condensed consolidated balance sheets: Three Months Ended Nine Months Ended 2020 2019 2020 2019 (in thousands) Balance at beginning of period $ 13,543 $ 944 $ 1,091 $ 710 Impact of ASC 326 adoption — — 9,235 — Provision for current expected credit losses (1) 1,483 — 4,701 — Bad debt expense — 5 — 278 Write off of uncollectible accounts (258) — (258) (39) Other, net (1) — (2) — Balance at end of period $ 14,767 $ 949 $ 14,767 $ 949 (1) In addition, we recognized $61,000 and $123,000 of provision for current expected credit losses during the three and nine months ended September 30, 2020, respectively, related to our long-term receivables for our leases.
Schedule of inventory	The following table presents the detail of inventory as recorded in other current assets in the unaudited condensed consolidated balance sheets: As of As of (in thousands) Energy storage systems and components $ 18,467 $ 33,443 Modules and inverters 91,632 10,137 Meters 912 169 Total $ 111,011 $ 43,749
Disaggregation of revenue	The following table presents the detail of revenue as recorded in the unaudited condensed consolidated statements of operations: Three Months Ended Nine Months Ended 2020 2019 2020 2019 (in thousands) PPA revenue $ 19,713 $ 14,329 $ 52,268 $ 37,895 Lease revenue 13,115 10,238 36,995 29,496 Solar renewable energy certificate revenue 14,147 10,603 27,245 26,911 Loan revenue 788 418 2,021 1,152 Other revenue 2,414 1,027 4,267 2,488 Total $ 50,177 $ 36,615 $ 122,796 $ 97,942
Deferred revenue schedule	The following table presents the detail of deferred revenue as recorded in other current liabilities and other long-term liabilities in the unaudited condensed consolidated balance sheets: As of As of (in thousands) Loans $ 73,417 $ 46,958 PPAs and leases 10,162 8,895 SRECs 1,420 3,000 Total (1) $ 84,999 $ 58,853 (1) Of this amount, $2.9 million and $2.1 million is recorded in other current liabilities as of September 30, 2020 and December 31, 2019, respectively.

Property and Equipment (Tables)

Property and Equipment (Tables)	9 Months Ended
	Sep. 30, 2020
Property, Plant and Equipment [Abstract]
Property and Equipment	The following table presents the detail of property and equipment, net as recorded in the unaudited condensed consolidated balance sheets: Useful Lives As of As of (in years) (in thousands) Solar energy systems 35 $ 2,131,054 $ 1,689,457 Construction in progress 167,246 143,449 Asset retirement obligations 30 33,099 26,967 Information technology systems 3 29,398 28,320 Computers and equipment 3-5 1,694 1,499 Leasehold improvements 3-6 2,705 1,014 Furniture and fixtures 7 811 735 Vehicles 4-5 2,073 1,632 Other 5-6 158 146 Property and equipment, gross 2,368,238 1,893,219 Less: accumulated depreciation (195,511) (148,159) Property and equipment, net $ 2,172,727 $ 1,745,060

Detail of Certain Balance She_2

Detail of Certain Balance Sheet Captions (Tables)	9 Months Ended
	Sep. 30, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Schedule of other current assets	The following table presents the detail of other current assets as recorded in the unaudited condensed consolidated balance sheets: As of As of (in thousands) Prepaid inventory $ — $ 96,167 Inventory 111,011 43,749 Current portion of customer notes receivable 20,083 13,758 Other prepaid assets 7,428 7,380 Current portion of other notes receivable 878 982 Deferred receivables 4,636 1,506 Restricted cash 54,096 10,474 Other 1,505 — Total $ 199,637 $ 174,016
Schedule of other assets	The following table presents the detail of other assets as recorded in the unaudited condensed consolidated balance sheets: As of As of (in thousands) Restricted cash $ 72,958 $ 56,332 Construction in progress - customer notes receivable 65,288 37,137 Exclusivity and other bonus arrangements with dealers, net 54,543 32,791 Straight-line revenue adjustment, net 30,949 24,852 Other 19,810 18,600 Total $ 243,548 $ 169,712
Schedule of other current liabilities	The following table presents the detail of other current liabilities as recorded in the unaudited condensed consolidated balance sheets: As of As of (in thousands) Interest payable $ 11,669 $ 14,680 Current portion of performance guarantee obligations 2,921 4,067 Current portion of lease liability 1,075 561 Deferred revenue 2,882 2,086 Other 25 410 Total $ 18,572 $ 21,804

Asset Retirement Obligations _2

Asset Retirement Obligations (ARO) (Tables)	9 Months Ended
	Sep. 30, 2020
Asset Retirement Obligation Disclosure [Abstract]
Schedule of changes in AROs	The following table presents the changes in AROs as recorded in other long-term liabilities in the unaudited condensed consolidated balance sheets: As of September 30, 2020 2019 (in thousands) Balance at beginning of period $ 31,053 $ 20,033 Additional obligations incurred 6,179 2,980 Accretion expense 1,577 989 Other (58) (32) Balance at end of period $ 38,751 $ 23,970

Customer Notes Receivable (Tabl

Customer Notes Receivable (Tables)	9 Months Ended
	Sep. 30, 2020
Receivables [Abstract]
Fair values of notes receivable and corresponding carrying amounts	The following table presents the detail of customer notes receivable as recorded in the unaudited condensed consolidated balance sheets and the corresponding fair values: As of As of (in thousands) Customer notes receivable $ 463,436 $ 312,823 Allowance for credit losses (14,767) (1,091) Customer notes receivable, net (1) $ 448,669 $ 311,732 Estimated fair value, net $ 453,321 $ 314,222 (1) Of this amount, $20.1 million and $13.8 million is recorded in other current assets as of September 30, 2020 and December 31, 2019, respectively.
Changes in the allowance for doubtful accounts	The following table presents the changes in the allowance for credit losses recorded against accounts receivable — trade, net in the unaudited condensed consolidated balance sheets: Three Months Ended Nine Months Ended 2020 2019 2020 2019 (in thousands) Balance at beginning of period $ 773 $ 746 $ 960 $ 723 Impact of ASC 326 adoption — — (240) — Provision for current expected credit losses 458 — 1,337 — Bad debt expense — 511 — 1,149 Write off of uncollectible accounts (419) (412) (1,267) (1,076) Recoveries 17 16 39 65 Balance at end of period $ 829 $ 861 $ 829 $ 861 The following table presents the changes in the allowance for credit losses related to customer notes receivable as recorded in the unaudited condensed consolidated balance sheets: Three Months Ended Nine Months Ended 2020 2019 2020 2019 (in thousands) Balance at beginning of period $ 13,543 $ 944 $ 1,091 $ 710 Impact of ASC 326 adoption — — 9,235 — Provision for current expected credit losses (1) 1,483 — 4,701 — Bad debt expense — 5 — 278 Write off of uncollectible accounts (258) — (258) (39) Other, net (1) — (2) — Balance at end of period $ 14,767 $ 949 $ 14,767 $ 949 (1) In addition, we recognized $61,000 and $123,000 of provision for current expected credit losses during the three and nine months ended September 30, 2020, respectively, related to our long-term receivables for our leases.
Financing receivable, past due	The following table presents the aging of the amortized cost of customer notes receivable as of September 30, 2020: As of As of (in thousands) 1-90 days past due $ 6,546 $ 5,741 91-180 days past due 1,716 1,714 Greater than 180 days past due 5,747 3,331 Total past due 14,009 10,786 Not past due 449,427 302,037 Total $ 463,436 $ 312,823
Financing receivable amortized cost of customer notes receivable	The following table presents the amortized cost by origination year of our customer notes receivable based on payment activity. Amortized Cost by Origination Year 2020 2019 2018 2017 2016 Prior Total (in thousands) Payment performance: Performing $ 168,507 $ 138,644 $ 88,587 $ 31,939 $ 19,788 $ 10,224 $ 457,689 Nonperforming (1) 84 975 1,564 1,628 1,275 221 $ 5,747 Total $ 168,591 $ 139,619 $ 90,151 $ 33,567 $ 21,063 $ 10,445 $ 463,436 (1) A nonperforming loan is a loan in which the customer is in default and has not made any scheduled principal or interest payments for 180 days or more.

Long-Term Debt (Tables)

Long-Term Debt (Tables)	9 Months Ended
	Sep. 30, 2020
Debt Disclosure [Abstract]
Schedule of long-term debt instruments	The following table presents the detail of long-term debt, net as recorded in the unaudited condensed consolidated balance sheets: Nine Months Ended As of September 30, 2020 Year Ended As of December 31, 2019 Long-term Current Long-term Current (in thousands, except interest rates) SEI 7.75% convertible senior notes 17.41 % $ — $ — 7.75 % $ 55,000 $ — 9.75% convertible senior notes 14.39 % 160,804 — — — Paid-in-kind 780 — — — Debt discount, net (64,490) — (16,913) — Deferred financing costs, net (416) — (480) — Sunnova Energy Corporation Notes payable 8.50 % — 2,769 3.22 % — 2,428 AP4 Secured term loan 10.81 % — — 5.61 % 86,369 6,109 Debt discount, net — — (452) — Deferred financing costs, net — — (196) — HELI Solar asset-backed notes 6.59 % 205,394 6,328 6.56 % 213,632 8,673 Debt discount, net (2,445) — (3,169) — Deferred financing costs, net (4,372) — (5,586) — LAPH Secured term loan 10.11 % 10,288 371 7.71 % 41,484 1,392 Debt discount, net (152) — (401) — Deferred financing costs, net (123) — (356) — EZOP Warehouse credit facility 4.64 % 115,450 — 6.60 % 121,400 — Debt discount, net (1,618) — (2,178) — TEPIIH Revolving credit facility 19.47 % — — 6.36 % 234,650 — Debt discount, net — — (2,219) — HELII Solar asset-backed notes 5.73 % 227,574 11,707 5.77 % 241,309 13,005 Debt discount, net (44) — (49) — Deferred financing costs, net (5,277) — (5,873) — RAYSI Solar asset-backed notes 5.49 % 121,844 5,993 5.47 % 126,828 6,327 Debt discount, net (1,421) — (1,547) — Deferred financing costs, net (4,441) — (4,759) — HELIII Solar loan-backed notes 4.00 % 124,660 14,704 4.03 % 135,543 19,030 Debt discount, net (2,451) — (2,532) — Deferred financing costs, net (2,353) — (2,410) — TEPH Revolving credit facility 5.72 % 380,720 — 6.70 % 90,325 — Debt discount, net (4,051) — (645) — TEPINV Revolving credit facility 10.15 % 35,819 36,640 7.95 % 54,707 40,500 Debt discount, net (1,811) — (2,856) — Deferred financing costs, net (2,322) — (2,207) — SOLI Solar asset-backed notes 3.91 % 389,435 15,318 — — Debt discount, net (117) — — — Deferred financing costs, net (9,169) — — — HELIV Solar loan-backed notes 3.91 % 134,293 15,899 — — Debt discount, net (921) — — — Deferred financing costs, net (4,028) — — — Total $ 1,795,039 $ 109,729 $ 1,346,419 $ 97,464
Debt instrument redemption	At any time on or after May 14, 2023, we may, at our option, redeem for cash all (but not less than all) of the 9.75% convertible senior notes at the redemption price (expressed as percentages of principal amount) set forth below, plus any accrued and unpaid interest, if any, to, but excluding, the redemption date accrued and unpaid interest, if any, to, but excluding, the redemption date: Period Percentage At any time on and after May 14, 2023 but prior to May 14, 2024 115% At any time on and after May 14, 2024 110%
Schedule of carrying values and estimated fair values of debt instruments	Fair Values of Long-Term Debt . The fair values of our long-term debt and the corresponding carrying amounts are as follows: As of September 30, 2020 As of December 31, 2019 Carrying Estimated Carrying Estimated (in thousands) SEI 7.75% convertible senior notes $ — $ — $ 55,000 $ 37,964 SEI 9.75% convertible senior notes 161,584 170,114 — — Sunnova Energy Corporation notes payable 2,769 2,769 2,428 2,428 AP4 secured term loan — — 92,478 92,478 HELI solar asset-backed notes 211,722 220,307 222,305 223,895 LAPH secured term loan 10,659 10,659 42,876 42,876 EZOP warehouse credit facility 115,450 115,450 121,400 121,400 TEPIIH revolving credit facility — — 234,650 234,650 HELII solar asset-backed notes 239,281 290,893 254,314 281,850 RAYSI solar asset-backed notes 127,837 150,689 133,155 139,004 HELIII solar loan-backed notes 139,364 156,345 154,573 155,701 TEPH revolving credit facility 380,720 380,720 90,325 90,325 TEPINV revolving credit facility 72,459 72,459 95,207 95,207 SOLI solar asset-backed notes 404,753 438,874 — — HELIV solar loan-backed notes 150,192 150,794 — — Total (1) $ 2,016,790 $ 2,160,073 $ 1,498,711 $ 1,517,778 (1) Amounts exclude the net deferred financing costs and net debt discounts of $112.0 million and $54.8 million as of September 30, 2020 and December 31, 2019, respectively.

Derivative Instruments (Tables)

Derivative Instruments (Tables)	9 Months Ended
	Sep. 30, 2020
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Outstanding derivative instruments	The following table presents a summary of the outstanding derivative instruments: As of September 30, 2020 As of December 31, 2019 Effective Termination Fixed Aggregate Effective Termination Fixed Aggregate (in thousands, except interest rates) AP4 —% $ — March 2018 July 2020 2.338% $ 99,762 LAPH November 2018 October 2036 3.409% 10,584 November 2018 October 2036 3.409% 43,298 EZOP June 2020 - September 2029 - 0.483% - 2.620% 78,210 June 2019 - July 2029 - 1.631% - 2.620% 100,083 TEPIIH —% — September 2018 - July 2031 - 1.909% - 3.383% 225,845 TEPH September 2018 - January 2023 - 0.528% - 3.125% 202,418 September 2019 January 2023 1.620% - 1.928% 55,115 TEPINV December 2019 December 2022 2.500% 65,657 —% — Total $ 356,869 $ 524,103
Fair value of interest rate swaps	The following table presents the fair value of the interest rate swaps as recorded in the unaudited condensed consolidated balance sheets: As of As of (in thousands) Other assets $ 1 $ 360 Other current liabilities — (397) Other long-term liabilities (29,931) (27,092) Total, net $ (29,930) $ (27,129) Three Months Ended Nine Months Ended 2020 2019 2020 2019 (in thousands) Realized loss $ 665 $ 265 $ 38,668 $ 12,637 Unrealized (gain) loss (1,788) 12,813 2,755 30,262 Total $ (1,123) $ 13,078 $ 41,423 $ 42,899

Equity-Based Compensation (Tabl

Equity-Based Compensation (Tables)	9 Months Ended
	Sep. 30, 2020
Share-based Payment Arrangement [Abstract]
Stock option activity	The following table summarizes stock option activity: Number Weighted Weighted Weighted Aggregate (in thousands) Outstanding, December 31, 2019 4,304,309 $ 15.86 7.08 $ 242 Exercised (569,512) $ 12.96 $ 9,938 Forfeited (115,191) $ 19.19 $ 3.54 Outstanding, September 30, 2020 3,619,606 $ 16.21 6.16 $ 51,383 Exercisable, September 30, 2020 3,619,606 $ 16.21 6.16 $ 51,383 Vested, September 30, 2020 3,619,606 $ 16.21 6.16 $ 51,383 Non-vested, September 30, 2020 — $ —
Restricted stock unit activity	The following table summarizes restricted stock unit activity: Number of Weighted Outstanding, December 31, 2019 1,426,139 $ 11.93 Granted 1,130,312 $ 11.75 Vested (443,620) $ 11.96 Forfeited (43,703) $ 11.77 Outstanding, September 30, 2020 2,069,128 $ 11.83

Basic and Diluted Net Loss Pe_2

Basic and Diluted Net Loss Per Share (Tables)	9 Months Ended
	Sep. 30, 2020
Earnings Per Share [Abstract]
Schedule of basic and diluted net loss per share	The following table sets forth the computation of our basic and diluted net loss per share: Three Months Ended Nine Months Ended 2020 2019 2020 2019 (in thousands, except share and per share amounts) Net loss attributable to stockholders $ (64,181) $ (37,590) $ (160,514) $ (126,842) Dividends earned on Series A convertible preferred stock — — — (19,271) Dividends earned on Series C convertible preferred stock — — — (5,454) Net loss attributable to common stockholders—basic and diluted $ (64,181) $ (37,590) $ (160,514) $ (151,567) Net loss per share attributable to common stockholders—basic and diluted $ (0.73) $ (0.62) $ (1.88) $ (5.77) Weighted average common shares outstanding—basic and diluted 87,768,712 60,890,129 85,276,841 26,245,493
Schedule of antidilutive weighted average shares	The following table presents the weighted average shares of common stock equivalents that were excluded from the computation of diluted net loss per share for the periods presented because including them would have been anti-dilutive: Three Months Ended Nine Months Ended 2020 2019 2020 2019 Equity-based compensation awards 6,006,791 5,277,414 6,176,162 4,693,647 Convertible preferred stock — 18,337,539 — 45,405,229 Convertible senior notes 14,970,678 — 9,839,125 —

Commitments and Contingencies (

Commitments and Contingencies (Tables)	9 Months Ended
	Sep. 30, 2020
Commitments and Contingencies Disclosure [Abstract]
Schedule of performance guarantee obligations	The changes in our aggregate performance guarantee obligations are as follows: As of September 30, 2020 2019 (in thousands) Balance at beginning of period $ 6,468 $ 6,044 Accruals for obligations issued 2,359 2,259 Settlements made in cash (3,888) (2,628) Balance at end of period $ 4,939 $ 5,675
Lease expense	The following table presents the detail of lease expense and lease income as recorded in general and administrative expense and other operating income, respectively, in the unaudited condensed consolidated statements of operations: Three Months Ended Nine Months Ended 2020 2019 2020 2019 (in thousands) Operating lease expense $ 336 $ 344 $ 1,007 $ 914 Finance lease amortization expense — 2 2 6 Short-term lease expense 14 11 36 34 Variable lease expense 258 268 437 731 Sublease income — (18) — (55) Total $ 608 $ 607 $ 1,482 $ 1,630 Other information related to leases was as follows: Nine Months Ended 2020 2019 (in thousands) Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows from operating leases $ 358 $ 819 Financing cash flows from finance leases 1 7 Right-of-use assets obtained in exchange for lease obligations: Operating leases — 8,053 Finance leases — 13 As of September 30, 2020 2019 Weighted average remaining lease term (years): Operating leases 8.69 9.68 Finance leases 0.00 0.92 Weighted average discount rate: Operating leases 3.94 % 3.94 % Finance leases — % 4.26 %
Lease assets and liabilities	The following table presents the detail of right-of-use assets and lease liabilities as recorded in other assets and other current liabilities/other long-term liabilities, respectively, in the unaudited condensed consolidated balance sheets: As of As of (in thousands) Right-of-use assets: Operating leases $ 8,997 $ 9,668 Finance leases — 5 Total right-of-use assets $ 8,997 $ 9,673 Current lease liabilities: Operating leases $ 1,075 $ 556 Finance leases — 5 Long-term leases liabilities: Operating leases 8,846 9,389 Total lease liabilities $ 9,921 $ 9,950
Operating lease, future minimum lease payments	Future minimum lease payments under our non-cancelable leases as of September 30, 2020 were as follows: Operating (in thousands) Remaining 2020 $ 381 2021 1,536 2022 1,559 2023 1,594 2024 1,616 2025 and thereafter 7,617 Total 14,303 Amount representing interest (2,254) Amount representing leasehold incentives (2,128) Present value of future payments 9,921 Current portion of lease liability (1,075) Long-term portion of lease liability $ 8,846
Other commitments	Dealer Commitments. As of September 30, 2020, the net unamortized balance of payments to dealers for exclusivity and other similar arrangements was $54.5 million. Under these agreements, we paid $7.7 million and $9.7 million during the three months ended September 30, 2020 and 2019, respectively, and we paid $24.4 million and $31.7 million during the nine months ended September 30, 2020 and 2019, respectively. We could be obligated to make maximum payments, excluding additional amounts payable on a per watt basis if even higher thresholds are met, as follows: Dealer (in thousands) Remaining 2020 $ 484 2021 33,312 2022 33,477 2023 10,505 2024 9,766 2025 and thereafter 1,509 Total $ 89,053
Future commitments	Purchase Commitments. In August 2019, we amended an agreement with a supplier in which we agreed to purchase a minimum amount of energy storage systems and components for five years. These purchases are recorded to inventory in other current assets in the consolidated balance sheets. Under this agreement, we could be obligated to make minimum purchases as follows: Purchase (in thousands) Remaining 2020 $ 3,327 2021 26,629 2022 26,810 2023 26,605 2024 19,807 2025 and thereafter — Total $ 103,178 Information (in thousands) Remaining 2020 $ 1,475 2021 5,322 2022 121 2023 26 2024 26 2025 and thereafter 7 Total $ 6,977

Description of Business and B_3

Description of Business and Basis of Presentation - Narrative (Details) customer in Thousands, $ in Thousands	9 Months Ended
	Sep. 30, 2020USD ($)customerrenewal_optionstate	Dec. 31, 2019USD ($)
Subsidiary, Sale of Stock [Line Items]
Number of customers | customer	98
Number of states in which entity operates (more than) | state	20
Maximum renewal term	10 years
Accounting Standards Update [Extensible List]	us-gaap:AccountingStandardsUpdate201613Member
Stockholders' equity	$ (722,594)	$ (645,935)
Impact of ASC 326 Adoption
Subsidiary, Sale of Stock [Line Items]
Stockholders' equity		$ 9,900
Lease and Power Purchase Agreement (PPA)
Subsidiary, Sale of Stock [Line Items]
Number of options to renew term | renewal_option	2
Renewal term	5 years
Minimum
Subsidiary, Sale of Stock [Line Items]
Agreement term	10 years
Median
Subsidiary, Sale of Stock [Line Items]
Agreement term	15 years
Maximum
Subsidiary, Sale of Stock [Line Items]
Agreement term	25 years

Description of Business and B_4

Description of Business and Basis of Presentation Schedule of New Accounting Pronouncement (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Jan. 01, 2020	Dec. 31, 2019
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Accounts receivable—trade, net	$ 11,799	$ 10,672	$ 10,672
Other current assets	199,637	174,016	174,016
Customer notes receivable	428,586	297,975	297,975
Other assets	243,548	169,712	169,712
Accumulated deficit	$ (476,095)	(361,824)	$ (361,824)
As Reported Under ASC 326
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Accounts receivable—trade, net		10,912
Other current assets		173,565
Customer notes receivable		289,191
Other assets		168,799
Accumulated deficit		(371,732)
Impact of ASC 326 Adoption
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Accounts receivable—trade, net		240
Other current assets		(451)
Customer notes receivable		(8,784)
Other assets		(913)
Accumulated deficit		$ (9,908)

Description of Business and B_5

Description of Business and Basis of Presentation - Revision of Interim Financials (Details) - USD ($) $ in Thousands	3 Months Ended
	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019
Stockholders' Equity Attributable to Noncontrolling Interest [Abstract]
Redeemable noncontrolling interest, beginning balance	$ 132,573	$ 130,790	$ 127,129	$ 107,547	$ 94,016	$ 85,680
Net income (loss)	4,268	2,869	1,576	3,028	931	3,018
Contributions from redeemable noncontrolling interests and noncontrolling interests	279	0	3,170	17,048	32,207	18,030
Distributions to redeemable noncontrolling interests and noncontrolling interests	(1,111)	(1,211)	(1,373)	(1,146)	(1,491)	(3,652)
Costs related to redeemable noncontrolling interests and noncontrolling interests		0	187	(116)	(419)	(1,562)
Equity in subsidiaries attributable to parent	(718)	(68)	145	(5,105)	(18,297)	(10,125)
Other, net	556	193	(44)	(385)	600	2,627
Redeemable noncontrolling interest, ending balance	135,847	132,573	130,790	120,871	107,547	94,016
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest [Abstract]
Stockholders' equity, beginning balance	767,420	703,657	691,111	441,585	473,314	501,118
Net income (loss)	(77,562)	(31,598)	(78,580)	(37,397)	(50,738)	(38,514)
Contributions from redeemable noncontrolling interests and noncontrolling interests	76,428	18,311	99,172	52,087
Distributions to redeemable noncontrolling interests and noncontrolling interests	(773)	(16)
Costs related to redeemable noncontrolling interests and noncontrolling interests	(1,007)	(604)	(894)	(2,322)
Equity in subsidiaries attributable to parent	718	68	(145)	5,105	18,297	10,125
Other, net	(209)	33	(3)	3	(1)	491
Stockholders' equity, ending balance	875,472	767,420	703,657	662,267	441,585	473,314
Noncontrolling Interests
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest [Abstract]
Stockholders' equity, beginning balance	105,732	111,637	45,176	0	0	0
Net income (loss)	(13,381)	(6,340)	(7,505)	193
Contributions from redeemable noncontrolling interests and noncontrolling interests	76,428	18,311	99,172	52,087
Distributions to redeemable noncontrolling interests and noncontrolling interests	(773)	(16)	0	0
Costs related to redeemable noncontrolling interests and noncontrolling interests	(1,007)	(604)	(894)	(2,322)
Equity in subsidiaries attributable to parent	(13,911)	(17,290)	(24,309)	(14,251)
Other, net	(210)	34	(3)	0
Stockholders' equity, ending balance	152,878	105,732	111,637	35,707	0	$ 0
As Previously Reported
Stockholders' Equity Attributable to Noncontrolling Interest [Abstract]
Redeemable noncontrolling interest, beginning balance	238,305	242,427	172,305	107,547
Net income (loss)		(3,471)	(5,929)	3,221
Contributions from redeemable noncontrolling interests and noncontrolling interests		18,311	102,342	69,135
Distributions to redeemable noncontrolling interests and noncontrolling interests		(1,227)	(1,373)	(1,146)
Costs related to redeemable noncontrolling interests and noncontrolling interests		(604)	(707)	(2,438)
Equity in subsidiaries attributable to parent		(17,359)	(24,164)	(19,356)
Other, net		228	(47)	(385)
Redeemable noncontrolling interest, ending balance		238,305	242,427	156,578	107,547
As Previously Reported | Noncontrolling Interests
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest [Abstract]
Stockholders' equity, beginning balance	0	0	0	0
Net income (loss)		0	0	0
Contributions from redeemable noncontrolling interests and noncontrolling interests		0	0	0
Distributions to redeemable noncontrolling interests and noncontrolling interests		0	0	0
Costs related to redeemable noncontrolling interests and noncontrolling interests		0	0	0
Equity in subsidiaries attributable to parent		0	0	0
Other, net		0	0	0
Stockholders' equity, ending balance		0	0	0	0
Revisions
Stockholders' Equity Attributable to Noncontrolling Interest [Abstract]
Redeemable noncontrolling interest, beginning balance	(105,732)	(111,637)	(45,176)	0
Net income (loss)		6,340	7,505	(193)
Contributions from redeemable noncontrolling interests and noncontrolling interests		(18,311)	(99,172)	(52,087)
Distributions to redeemable noncontrolling interests and noncontrolling interests		16	0	0
Costs related to redeemable noncontrolling interests and noncontrolling interests		604	894	2,322
Equity in subsidiaries attributable to parent		17,291	24,309	14,251
Other, net		(35)	3	0
Redeemable noncontrolling interest, ending balance		(105,732)	(111,637)	(35,707)	0
Revisions | Noncontrolling Interests
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest [Abstract]
Stockholders' equity, beginning balance	$ 105,732	111,637	45,176	0
Net income (loss)		(6,340)	(7,505)	193
Contributions from redeemable noncontrolling interests and noncontrolling interests		18,311	99,172	52,087
Distributions to redeemable noncontrolling interests and noncontrolling interests		(16)	0	0
Costs related to redeemable noncontrolling interests and noncontrolling interests		(604)	(894)	(2,322)
Equity in subsidiaries attributable to parent		(17,290)	(24,309)	(14,251)
Other, net		34	(3)	0
Stockholders' equity, ending balance		$ 105,732	$ 111,637	$ 35,707	$ 0

Significant Accounting Polici_4

Significant Accounting Policies - Allowance for Credit Losses (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period	$ 773	$ 746	$ 960	$ 723
Provision for current expected credit losses/Bad debt expense	458	511	1,337	1,149
Write off of uncollectible accounts	(419)	(412)	(1,267)	(1,076)
Recoveries	17	16	39	65
Balance at end of period	$ 829	$ 861	$ 829	$ 861
Accounting Standards Update [Extensible List]			us-gaap:AccountingStandardsUpdate201613Member
Impact of ASC 326 Adoption
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period			$ (240)

Significant Accounting Polici_5

Significant Accounting Policies - Inventories (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Inventory [Line Items]
Inventory	$ 111,011	$ 43,749
Energy storage systems and components
Inventory [Line Items]
Inventory	18,467	33,443
Modules and inverters
Inventory [Line Items]
Inventory	91,632	10,137
Meters
Inventory [Line Items]
Inventory	$ 912	$ 169

Significant Accounting Polici_6

Significant Accounting Policies - Narrative (Details)	9 Months Ended
	Sep. 30, 2020USD ($)renewal_optionFICO_score	Sep. 30, 2019USD ($)	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)
Disaggregation of Revenue [Line Items]
Accrued expenses for inventory purchases	$ 8,100,000		$ 15,200,000
SREC inventory	111,011,000		43,749,000
Deferred revenue	84,999,000		58,853,000	$ 34,000,000
Revenue recognized	$ 5,000,000	$ 2,300,000
PPA revenue
Disaggregation of Revenue [Line Items]
Agreement term	25 years
Renewal term	5 years
Number of options to renew term | renewal_option	2
Lease revenue
Disaggregation of Revenue [Line Items]
Agreement term	25 years
Renewal term	5 years
Number of options to renew term | renewal_option	2
Remittances of customer payments, period after placed in service date	3 years
Solar renewable energy certificate revenue
Disaggregation of Revenue [Line Items]
Typical period for receiving payment	1 month
Loan revenue
Disaggregation of Revenue [Line Items]
Deferred revenue	$ 73,417,000		46,958,000
Other revenue
Disaggregation of Revenue [Line Items]
Agreement term	5 years
Minimum
Disaggregation of Revenue [Line Items]
Agreement term	10 years
Minimum | Loan revenue
Disaggregation of Revenue [Line Items]
Agreement term	10 years
Minimum FICO score required for customer to qualify for program | FICO_score	650
Median
Disaggregation of Revenue [Line Items]
Agreement term	15 years
Median | Loan revenue
Disaggregation of Revenue [Line Items]
Agreement term	15 years
Maximum
Disaggregation of Revenue [Line Items]
Agreement term	25 years
Maximum | PPA revenue
Disaggregation of Revenue [Line Items]
Renewal term	10 years
Maximum | Lease revenue
Disaggregation of Revenue [Line Items]
Renewal term	10 years
Maximum | Loan revenue
Disaggregation of Revenue [Line Items]
Agreement term	25 years
Minimum FICO score required for customer to qualify for program | FICO_score	720
Solar Renewable Energy Certificates
Disaggregation of Revenue [Line Items]
SREC inventory	$ 0		$ 0

Significant Accounting Polici_7

Significant Accounting Policies - Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Disaggregation of Revenue [Line Items]
Revenue	$ 50,177	$ 36,615	$ 122,796	$ 97,942
PPA revenue
Disaggregation of Revenue [Line Items]
Revenue	19,713	14,329	52,268	37,895
Lease revenue
Disaggregation of Revenue [Line Items]
Revenue	13,115	10,238	36,995	29,496
Solar renewable energy certificate revenue
Disaggregation of Revenue [Line Items]
Revenue	14,147	10,603	27,245	26,911
Loan revenue
Disaggregation of Revenue [Line Items]
Revenue	788	418	2,021	1,152
Other revenue
Disaggregation of Revenue [Line Items]
Revenue	$ 2,414	$ 1,027	$ 4,267	$ 2,488

Significant Accounting Polici_8

Significant Accounting Policies - Performance Obligations (Details) $ in Billions	9 Months Ended
	Sep. 30, 2020USD ($)
Accounting Policies [Abstract]
Contracted but not yet recognized revenue	$ 1.4
Performance obligation, description of timing	We do not expect the annual recognition to vary significantly over approximately the next 20 years as the vast majority of existing solar service agreements have at least 20 years remaining
Average age of solar systems	3 years
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-10-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Contracted but not yet recognized revenue, percentage	4.00%
Contracted but not yet recognized revenue, expected timing of satisfaction	12 months

Significant Accounting Polici_9

Significant Accounting Policies - Deferred Revenue (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019	Dec. 31, 2018
Disaggregation of Revenue [Line Items]
Deferred revenue	$ 84,999	$ 58,853	$ 34,000
Deferred revenue included in other current liabilities	2,882	2,086
Loans
Disaggregation of Revenue [Line Items]
Deferred revenue	73,417	46,958
PPAs and leases
Disaggregation of Revenue [Line Items]
Deferred revenue	10,162	8,895
SRECs
Disaggregation of Revenue [Line Items]
Deferred revenue	$ 1,420	$ 3,000

Property and Equipment (Details

Property and Equipment (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2020	Dec. 31, 2019
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 2,368,238	$ 1,893,219
Less: accumulated depreciation	(195,511)	(148,159)
Property and equipment, net	$ 2,172,727	1,745,060
Solar energy systems
Property, Plant and Equipment [Line Items]
Useful Lives	35 years
Property and equipment, gross	$ 2,131,054	1,689,457
Less: accumulated depreciation	(172,600)	(130,900)
Construction in progress
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 167,246	143,449
Asset retirement obligations
Property, Plant and Equipment [Line Items]
Useful Lives	30 years
Property and equipment, gross	$ 33,099	26,967
Information technology systems
Property, Plant and Equipment [Line Items]
Useful Lives	3 years
Property and equipment, gross	$ 29,398	28,320
Computers and equipment
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 1,694	1,499
Computers and equipment | Minimum
Property, Plant and Equipment [Line Items]
Useful Lives	3 years
Computers and equipment | Maximum
Property, Plant and Equipment [Line Items]
Useful Lives	5 years
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 2,705	1,014
Leasehold improvements | Minimum
Property, Plant and Equipment [Line Items]
Useful Lives	3 years
Leasehold improvements | Maximum
Property, Plant and Equipment [Line Items]
Useful Lives	6 years
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Useful Lives	7 years
Property and equipment, gross	$ 811	735
Vehicles
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 2,073	1,632
Vehicles | Minimum
Property, Plant and Equipment [Line Items]
Useful Lives	4 years
Vehicles | Maximum
Property, Plant and Equipment [Line Items]
Useful Lives	5 years
Other
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 158	$ 146
Other | Minimum
Property, Plant and Equipment [Line Items]
Useful Lives	5 years
Other | Maximum
Property, Plant and Equipment [Line Items]
Useful Lives	6 years

Detail of Certain Balance She_3

Detail of Certain Balance Sheet Captions - Other Current Assets (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Jan. 01, 2020	Dec. 31, 2019	Sep. 30, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Prepaid inventory	$ 0		$ 96,167
Inventory	111,011		43,749
Current portion of customer notes receivable	20,083		13,758
Other prepaid assets	7,428		7,380
Current portion of other notes receivable	878		982
Deferred receivables	4,636		1,506
Restricted cash	54,096		10,474	$ 16,688
Other	1,505		0
Total	$ 199,637	$ 174,016	$ 174,016

Detail of Certain Balance She_4

Detail of Certain Balance Sheet Captions - Other Assets (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Jan. 01, 2020	Dec. 31, 2019	Sep. 30, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Restricted cash	$ 72,958		$ 56,332	$ 41,557
Construction in progress - customer notes receivable	65,288		37,137
Exclusivity and other bonus arrangements with dealers, net	54,543		32,791
Straight-line revenue adjustment, net	30,949		24,852
Other	19,810		18,600
Total	$ 243,548	$ 169,712	$ 169,712

Detail of Certain Balance She_5

Detail of Certain Balance Sheet Captions - Other Current Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Interest payable	$ 11,669	$ 14,680
Current portion of performance guarantee obligations	2,921	4,067
Current portion of lease liability	1,075	561
Deferred revenue	2,882	2,086
Other	25	410
Total	$ 18,572	$ 21,804

Asset Retirement Obligations _3

Asset Retirement Obligations (ARO) (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Asset Retirement Obligation Disclosure [Abstract]
Asset retirement obligation, useful life	30 years
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Balance at beginning of period	$ 31,053	$ 20,033
Additional obligations incurred	6,179	2,980
Accretion expense	1,577	989
Other	(58)	(32)
Balance at end of period	$ 38,751	$ 23,970

Customer Notes Receivable - Nar

Customer Notes Receivable - Narrative (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loan systems not yet placed in service	$ 65,300,000		$ 65,300,000		$ 37,100,000
Interest income	5,999,000	$ 3,407,000	17,299,000	$ 8,868,000
Customer notes receivable not accruing interest	0		0		0
Interest income for nonaccrual loans	0	0	0	0
Amortized cost	7,500,000		7,500,000		5,000,000
Customer notes receivable
Accounts, Notes, Loans and Financing Receivable [Line Items]
Interest income	5,900,000	3,100,000	16,900,000	8,200,000
Accrued investment income receivable	873,000		873,000		$ 869,000
Accrued investment income receivable, written off	$ 9,000	$ 0	$ 9,000	$ 0
Minimum
Accounts, Notes, Loans and Financing Receivable [Line Items]
Agreement term			10 years
Median
Accounts, Notes, Loans and Financing Receivable [Line Items]
Agreement term			15 years
Maximum
Accounts, Notes, Loans and Financing Receivable [Line Items]
Agreement term			25 years
Loan revenue | Minimum
Accounts, Notes, Loans and Financing Receivable [Line Items]
Agreement term			10 years
Loan revenue | Median
Accounts, Notes, Loans and Financing Receivable [Line Items]
Agreement term			15 years
Loan revenue | Maximum
Accounts, Notes, Loans and Financing Receivable [Line Items]
Agreement term			25 years

Customer Notes Receivable - Sch

Customer Notes Receivable - Schedule of Customer Notes Receivables (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Jun. 30, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Dec. 31, 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Customer notes receivable	$ 463,436		$ 312,823
Allowance for credit losses	(14,767)	$ (13,543)	(1,091)	$ (949)	$ (944)	$ (710)
Current portion of customer notes receivable	20,083		13,758
Carrying value
Accounts, Notes, Loans and Financing Receivable [Line Items]
Customer notes receivable	448,669		311,732
Estimated fair value
Accounts, Notes, Loans and Financing Receivable [Line Items]
Customer notes receivable	453,321		314,222
Customer notes receivable
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current portion of customer notes receivable	$ 20,100		$ 13,800

Customer Notes Receivable - S_2

Customer Notes Receivable - Schedule of Changes in Allowances for Credit Losses Related to Customer Notes Receivable (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Balance at beginning of period	$ 13,543	$ 944	$ 1,091	$ 710
Provision for current expected credit loss/Bad debt expense	1,483	5	4,701	278
Write off of uncollectible accounts	(258)	0	(258)	(39)
Other, net	(1)	0	(2)	0
Balance at end of period	14,767	$ 949	14,767	$ 949
Provision for expected credit losses	$ 61		$ 123
Accounting Standards Update [Extensible List]			us-gaap:AccountingStandardsUpdate201613Member
Impact of ASC 326 Adoption
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Balance at beginning of period			$ 9,235

Customer Notes Receivable - S_3

Customer Notes Receivable - Schedule of Aged Receivables (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Financing Receivable, Past Due [Line Items]
Financing receivable, past due	$ 14,009	$ 10,786
Financing receivable, not past due	449,427	302,037
Total	463,436	312,823
1-90 days past due
Financing Receivable, Past Due [Line Items]
Financing receivable, past due	6,546	5,741
91-180 days past due
Financing Receivable, Past Due [Line Items]
Financing receivable, past due	1,716	1,714
Greater than 180 days past due
Financing Receivable, Past Due [Line Items]
Financing receivable, past due	$ 5,747	$ 3,331

Customer Notes Receivable - S_4

Customer Notes Receivable - Schedule of Amortized cost of Customer Notes Receivable (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Financing Receivable, Credit Quality Indicator [Line Items]
2020	$ 168,591
2019	139,619
2018	90,151
2017	33,567
2016	21,063
Prior	10,445
Total	463,436	$ 312,823
Performing
Financing Receivable, Credit Quality Indicator [Line Items]
2020	168,507
2019	138,644
2018	88,587
2017	31,939
2016	19,788
Prior	10,224
Total	457,689
Nonperforming
Financing Receivable, Credit Quality Indicator [Line Items]
2020	84
2019	975
2018	1,564
2017	1,628
2016	1,275
Prior	221
Total	$ 5,747

Long-Term Debt - Schedule of Lo

Long-Term Debt - Schedule of Long-Term Debt (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2020	Dec. 31, 2019
Debt Instrument [Line Items]
Long-term debt, non-current	$ 1,795,039	$ 1,346,419
Long-term debt, current	$ 109,729	$ 97,464
SEI | Convertible senior notes | 7.75% convertible senior notes
Debt Instrument [Line Items]
Stated interest rate		7.75%
Weighted average effective interest rates	17.41%	7.75%
Long-term debt, gross, non-current	$ 0	$ 55,000
Long-term debt, gross, current	$ 0	0
SEI | Convertible senior notes | 9.75% convertible senior notes
Debt Instrument [Line Items]
Stated interest rate	9.75%
Weighted average effective interest rates	14.39%
Long-term debt, gross, non-current	$ 160,804	0
Paid-in-kind, noncurrent	780	0
Debt discount, net, non-current	(64,490)	(16,913)
Deferred financing costs, net, non-current	(416)	(480)
Long-term debt, gross, current	0	0
Paid-in-kind, current	0	0
Debt discount, net, current	0	0
Deferred financing costs, net, current	$ 0	$ 0
Sunnova Energy Corporation | Notes payable
Debt Instrument [Line Items]
Weighted average effective interest rates	8.50%	3.22%
Long-term debt, gross, non-current	$ 0	$ 0
Long-term debt, gross, current	2,769	2,428
AP4
Debt Instrument [Line Items]
Debt discount, net, non-current	0	(452)
Deferred financing costs, net, non-current	0	(196)
Debt discount, net, current	0	0
Deferred financing costs, net, current	$ 0	$ 0
AP4 | Secured term loan
Debt Instrument [Line Items]
Weighted average effective interest rates	10.81%	5.61%
Long-term debt, gross, non-current	$ 0	$ 86,369
Long-term debt, gross, current	0	6,109
HELI
Debt Instrument [Line Items]
Debt discount, net, non-current	(2,445)	(3,169)
Deferred financing costs, net, non-current	(4,372)	(5,586)
Debt discount, net, current	0	0
Deferred financing costs, net, current	$ 0	$ 0
HELI | Solar asset-backed notes
Debt Instrument [Line Items]
Weighted average effective interest rates	6.59%	6.56%
Long-term debt, gross, non-current	$ 205,394	$ 213,632
Long-term debt, gross, current	6,328	8,673
LAPH
Debt Instrument [Line Items]
Debt discount, net, non-current	(152)	(401)
Deferred financing costs, net, non-current	(123)	(356)
Debt discount, net, current	0	0
Deferred financing costs, net, current	$ 0	$ 0
LAPH | Secured term loan
Debt Instrument [Line Items]
Weighted average effective interest rates	10.11%	7.71%
Long-term debt, gross, non-current	$ 10,288	$ 41,484
Long-term debt, gross, current	371	1,392
EZOP
Debt Instrument [Line Items]
Debt discount, net, non-current	(1,618)	(2,178)
Debt discount, net, current	$ 0	$ 0
EZOP | Warehouse credit facility
Debt Instrument [Line Items]
Weighted average effective interest rates	4.64%	6.60%
Long-term debt, gross, non-current	$ 115,450	$ 121,400
Long-term debt, gross, current	0	0
TEPIIH
Debt Instrument [Line Items]
Debt discount, net, non-current	0	(2,219)
Debt discount, net, current	$ 0	$ 0
TEPIIH | Line of credit | Revolving credit facility
Debt Instrument [Line Items]
Weighted average effective interest rates	19.47%	6.36%
Long-term debt, gross, non-current	$ 0	$ 234,650
Long-term debt, gross, current	0	0
HELII
Debt Instrument [Line Items]
Debt discount, net, non-current	(44)	(49)
Deferred financing costs, net, non-current	(5,277)	(5,873)
Debt discount, net, current	0	0
Deferred financing costs, net, current	$ 0	$ 0
HELII | Solar asset-backed notes
Debt Instrument [Line Items]
Weighted average effective interest rates	5.73%	5.77%
Long-term debt, gross, non-current	$ 227,574	$ 241,309
Long-term debt, gross, current	11,707	13,005
RAYSI
Debt Instrument [Line Items]
Debt discount, net, non-current	(1,421)	(1,547)
Deferred financing costs, net, non-current	(4,441)	(4,759)
Debt discount, net, current	0	0
Deferred financing costs, net, current	$ 0	$ 0
RAYSI | Solar asset-backed notes
Debt Instrument [Line Items]
Weighted average effective interest rates	5.49%	5.47%
Long-term debt, gross, non-current	$ 121,844	$ 126,828
Long-term debt, gross, current	5,993	6,327
HELIII
Debt Instrument [Line Items]
Debt discount, net, non-current	(2,451)	(2,532)
Deferred financing costs, net, non-current	(2,353)	(2,410)
Debt discount, net, current	0	0
Deferred financing costs, net, current	$ 0	$ 0
HELIII | Solar loan-backed notes
Debt Instrument [Line Items]
Weighted average effective interest rates	4.00%	4.03%
Long-term debt, gross, non-current	$ 124,660	$ 135,543
Long-term debt, gross, current	14,704	19,030
TEPH
Debt Instrument [Line Items]
Debt discount, net, non-current	(4,051)	(645)
Debt discount, net, current	$ 0	$ 0
TEPH | Line of credit | Revolving credit facility
Debt Instrument [Line Items]
Weighted average effective interest rates	5.72%	6.70%
Long-term debt, gross, non-current	$ 380,720	$ 90,325
Long-term debt, gross, current	0	0
TEPINV
Debt Instrument [Line Items]
Debt discount, net, non-current	(1,811)	(2,856)
Deferred financing costs, net, non-current	(2,322)	(2,207)
Debt discount, net, current	0	0
Deferred financing costs, net, current	$ 0	$ 0
TEPINV | Line of credit | Revolving credit facility
Debt Instrument [Line Items]
Weighted average effective interest rates	10.15%	7.95%
Long-term debt, gross, non-current	$ 35,819	$ 54,707
Long-term debt, gross, current	36,640	40,500
SOLI
Debt Instrument [Line Items]
Debt discount, net, non-current	(117)	0
Deferred financing costs, net, non-current	(9,169)	0
Debt discount, net, current	0	0
Deferred financing costs, net, current	$ 0	0
SOLI | Solar asset-backed notes
Debt Instrument [Line Items]
Weighted average effective interest rates	3.91%
Long-term debt, gross, non-current	$ 389,435	0
Long-term debt, gross, current	15,318	0
HELIV
Debt Instrument [Line Items]
Debt discount, net, non-current	(921)	0
Deferred financing costs, net, non-current	(4,028)	0
Debt discount, net, current	0	0
Deferred financing costs, net, current	$ 0	0
HELIV | Solar loan-backed notes
Debt Instrument [Line Items]
Weighted average effective interest rates	3.91%
Long-term debt, gross, non-current	$ 134,293	0
Long-term debt, gross, current	$ 15,899	$ 0

Long-Term Debt - Narrative (Det

Long-Term Debt - Narrative (Details)	1 Months Ended			3 Months Ended	9 Months Ended
	Jun. 30, 2020USD ($)	May 31, 2020USD ($)$ / shares	Feb. 29, 2020USD ($)	Sep. 30, 2020USD ($)	Sep. 30, 2020USD ($)	Sep. 30, 2019USD ($)	May 30, 2020USD ($)	Mar. 31, 2020USD ($)	Dec. 31, 2019USD ($)
Debt Instrument [Line Items]
Borrowing capacity				$ 224,100,000	$ 224,100,000
Debt conversion					84,196,000	$ 0
EZOP
Debt Instrument [Line Items]
Unamortized debt discount				1,618,000	1,618,000				$ 2,178,000
Repayments of debt	$ 149,300,000
EZOP | Warehouse credit facility
Debt Instrument [Line Items]
Borrowing capacity				84,500,000	84,500,000
TEPH
Debt Instrument [Line Items]
Unamortized debt discount				4,051,000	4,051,000				645,000
TEPINV
Debt Instrument [Line Items]
Unamortized debt discount				1,811,000	1,811,000				2,856,000
Unamortized issuance costs				$ 2,322,000	$ 2,322,000				2,207,000
SEI | Convertible senior notes | At any time prior to May 14, 2022
Debt Instrument [Line Items]
Redemption price					115.00%
SEI | Convertible senior notes | At any time on and after September 23, 2024
Debt Instrument [Line Items]
Redemption price					110.00%
SEI | 9.75% convertible senior notes | Convertible senior notes
Debt Instrument [Line Items]
Principal amount of debt issued		$ 130,000,000
Stated interest rate				9.75%	9.75%
Issue price percentage		95.00%
Purchase price		$ 123,500,000
Additional principal available to purchase		$ 60,000,000
Debt conversion				$ 84,800,000
Conversion ratio		0.0740741
Conversion price (in USD per share) | $ / shares		$ 13.50
Redemption period					180 days
Long-term debt				96,700,000	$ 96,700,000
Unamortized debt discount				64,490,000	64,490,000				16,913,000
Unamortized issuance costs				416,000	416,000				$ 480,000
Carrying amount of equity component				42,800,000	42,800,000
Unamortized issuance costs, equity component				653,000	$ 653,000
SEI | 9.75% convertible senior notes | Convertible senior notes | At any time prior to May 14, 2022
Debt Instrument [Line Items]
Percentage of principal amount redeemed					33.33%
SEI | 7.75% convertible senior notes | Convertible senior notes
Debt Instrument [Line Items]
Stated interest rate									7.75%
Long-term debt exchanged		$ 55,000,000
AP4
Debt Instrument [Line Items]
Unamortized debt discount				0	$ 0				$ 452,000
Unamortized issuance costs				0	0				196,000
Repayments of debt			$ 92,000,000
TEPIIH
Debt Instrument [Line Items]
Unamortized debt discount				0	0				2,219,000
Repayments of debt			226,600,000
LAPH
Debt Instrument [Line Items]
Unamortized debt discount				152,000	152,000				401,000
Unamortized issuance costs				123,000	123,000				356,000
Repayments of debt			32,000,000
SOLI
Debt Instrument [Line Items]
Unamortized debt discount				117,000	117,000				0
Unamortized issuance costs				9,169,000	9,169,000				0
SOLI | SOLI Series 2020-1 Class A | Solar asset-backed notes
Debt Instrument [Line Items]
Principal amount of debt issued			$ 337,100,000
Stated interest rate			3.35%
Discount percent			0.89%
SOLI | SOLI Series 2020-1 Class B | Solar asset-backed notes
Debt Instrument [Line Items]
Principal amount of debt issued			$ 75,400,000
Stated interest rate			5.54%
Discount percent			0.85%
HELIV
Debt Instrument [Line Items]
Unamortized debt discount				921,000	921,000				0
Unamortized issuance costs				4,028,000	4,028,000				$ 0
HELIV | HELIV Series 2020-A Class A | Solar loan-backed notes
Debt Instrument [Line Items]
Principal amount of debt issued	$ 135,900,000
Stated interest rate	2.98%
Discount percent	0.01%
HELIV | HELIV Series 2020-A Class B | Solar loan-backed notes
Debt Instrument [Line Items]
Principal amount of debt issued	$ 22,600,000
Stated interest rate	7.25%
Discount percent	4.18%
Revolving credit facility | TEPH | Line of credit
Debt Instrument [Line Items]
Borrowing capacity				56,800,000	56,800,000
Maximum borrowing capacity		$ 390,000,000		437,500,000	$ 437,500,000		$ 200,000,000	$ 400,000,000
Revolving credit facility | TEPH | Line of credit | LIBOR
Debt Instrument [Line Items]
Basis spread on variable rate					4.15%
Revolving credit facility | TEPH | TEPH Class A | Line of credit
Debt Instrument [Line Items]
Stated interest rate, increase								0.40%
Revolving credit facility | TEPH | TEPH Class B | Line of credit
Debt Instrument [Line Items]
Stated interest rate, increase								0.40%
Revolving credit facility | TEPINV | Line of credit
Debt Instrument [Line Items]
Borrowing capacity				22,700,000	$ 22,700,000
Revolving credit facility | AP8 | Line of credit
Debt Instrument [Line Items]
Borrowing capacity				60,000,000	60,000,000
Maximum borrowing capacity				$ 60,000,000	$ 60,000,000

Long-Term Debt - Redemption Rat

Long-Term Debt - Redemption Rate (Details) - SEI - Convertible senior notes	9 Months Ended
	Sep. 30, 2020
At any time on and after May 14, 2023 but prior to May 14, 2024
Debt Instrument, Redemption [Line Items]
Redemption price	115.00%
At any time on and after May 14, 2024
Debt Instrument, Redemption [Line Items]
Redemption price	110.00%

Long-Term Debt - Schedule of Fa

Long-Term Debt - Schedule of Fair Value of Long-term Debt (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Debt Instrument [Line Items]
Net deferred financing costs and debt discounts	$ 112,000	$ 54,800
Carrying value
Debt Instrument [Line Items]
Long-term debt	2,016,790	1,498,711
Estimated fair value
Debt Instrument [Line Items]
Long-term debt	$ 2,160,073	$ 1,517,778
SEI | Convertible senior notes | 7.75% convertible senior notes
Debt Instrument [Line Items]
Stated interest rate		7.75%
SEI | Convertible senior notes | 9.75% convertible senior notes
Debt Instrument [Line Items]
Stated interest rate	9.75%
SEI | Carrying value | Convertible senior notes | 7.75% convertible senior notes
Debt Instrument [Line Items]
Long-term debt	$ 0	$ 55,000
SEI | Carrying value | Convertible senior notes | 9.75% convertible senior notes
Debt Instrument [Line Items]
Long-term debt	161,584	0
SEI | Estimated fair value | Convertible senior notes | 7.75% convertible senior notes
Debt Instrument [Line Items]
Long-term debt	0	37,964
SEI | Estimated fair value | Convertible senior notes | 9.75% convertible senior notes
Debt Instrument [Line Items]
Long-term debt	170,114	0
Sunnova Energy Corporation | Carrying value | Notes payable
Debt Instrument [Line Items]
Long-term debt	2,769	2,428
Sunnova Energy Corporation | Estimated fair value | Notes payable
Debt Instrument [Line Items]
Long-term debt	2,769	2,428
AP4 | Carrying value | Secured term loan
Debt Instrument [Line Items]
Long-term debt	0	92,478
AP4 | Estimated fair value | Secured term loan
Debt Instrument [Line Items]
Long-term debt	0	92,478
HELI | Carrying value | Solar asset-backed notes
Debt Instrument [Line Items]
Long-term debt	211,722	222,305
HELI | Estimated fair value | Solar asset-backed notes
Debt Instrument [Line Items]
Long-term debt	220,307	223,895
LAPH | Carrying value | Secured term loan
Debt Instrument [Line Items]
Long-term debt	10,659	42,876
LAPH | Estimated fair value | Secured term loan
Debt Instrument [Line Items]
Long-term debt	10,659	42,876
EZOP | Carrying value | Warehouse credit facility
Debt Instrument [Line Items]
Long-term debt	115,450	121,400
EZOP | Estimated fair value | Warehouse credit facility
Debt Instrument [Line Items]
Long-term debt	115,450	121,400
HELII | Carrying value | Solar asset-backed notes
Debt Instrument [Line Items]
Long-term debt	239,281	254,314
HELII | Estimated fair value | Solar asset-backed notes
Debt Instrument [Line Items]
Long-term debt	290,893	281,850
RAYSI | Carrying value | Solar asset-backed notes
Debt Instrument [Line Items]
Long-term debt	127,837	133,155
RAYSI | Estimated fair value | Solar asset-backed notes
Debt Instrument [Line Items]
Long-term debt	150,689	139,004
HELIII | Carrying value | Solar loan-backed notes
Debt Instrument [Line Items]
Long-term debt	139,364	154,573
HELIII | Estimated fair value | Solar loan-backed notes
Debt Instrument [Line Items]
Long-term debt	156,345	155,701
SOLI | Carrying value | Solar asset-backed notes
Debt Instrument [Line Items]
Long-term debt	404,753	0
SOLI | Estimated fair value | Solar asset-backed notes
Debt Instrument [Line Items]
Long-term debt	438,874	0
HELIV | Carrying value | Solar loan-backed notes
Debt Instrument [Line Items]
Long-term debt	150,192	0
HELIV | Estimated fair value | Solar loan-backed notes
Debt Instrument [Line Items]
Long-term debt	150,794	0
Revolving credit facility | TEPIIH | Carrying value | Line of credit
Debt Instrument [Line Items]
Long-term debt	0	234,650
Revolving credit facility | TEPIIH | Estimated fair value | Line of credit
Debt Instrument [Line Items]
Long-term debt	0	234,650
Revolving credit facility | TEPH | Carrying value | Line of credit
Debt Instrument [Line Items]
Long-term debt	380,720	90,325
Revolving credit facility | TEPH | Estimated fair value | Line of credit
Debt Instrument [Line Items]
Long-term debt	380,720	90,325
Revolving credit facility | TEPINV | Carrying value | Line of credit
Debt Instrument [Line Items]
Long-term debt	72,459	95,207
Revolving credit facility | TEPINV | Estimated fair value | Line of credit
Debt Instrument [Line Items]
Long-term debt	$ 72,459	$ 95,207

Derivative Instruments - Narrat

Derivative Instruments - Narrative (Details) - EZOP - Interest rate swap $ in Millions	1 Months Ended
	Jun. 30, 2020USD ($)
Derivative [Line Items]
Aggregate notional amount of unwound derivative	$ 126.1
Realized loss	$ 5.8

Derivative Instruments - Outsta

Derivative Instruments - Outstanding Derivative Instruments (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Interest rate swap
Derivative [Line Items]
Aggregate Notional Amount	$ 356,869	$ 524,103
AP4 | Interest rate swap one
Derivative [Line Items]
Fixed Interest Rate	0.00%	2.338%
Aggregate Notional Amount	$ 0	$ 99,762
LAPH | Interest rate swap two
Derivative [Line Items]
Fixed Interest Rate	3.409%	3.409%
Aggregate Notional Amount	$ 10,584	$ 43,298
EZOP | Interest rate swap three
Derivative [Line Items]
Aggregate Notional Amount	$ 78,210	$ 100,083
EZOP | Interest rate swap three | Minimum
Derivative [Line Items]
Fixed Interest Rate	0.483%	1.631%
EZOP | Interest rate swap three | Maximum
Derivative [Line Items]
Fixed Interest Rate	2.62%	2.62%
TEPIIH | Interest rate swap four
Derivative [Line Items]
Fixed Interest Rate	0.00%
Aggregate Notional Amount	$ 0	$ 225,845
TEPIIH | Interest rate swap four | Minimum
Derivative [Line Items]
Fixed Interest Rate		1.909%
TEPIIH | Interest rate swap four | Maximum
Derivative [Line Items]
Fixed Interest Rate		3.383%
TEPH | Interest rate swap five
Derivative [Line Items]
Aggregate Notional Amount	$ 202,418	$ 55,115
TEPH | Interest rate swap five | Minimum
Derivative [Line Items]
Fixed Interest Rate	0.528%	1.62%
TEPH | Interest rate swap five | Maximum
Derivative [Line Items]
Fixed Interest Rate	3.125%	1.928%
TEPINV | Interest rate swap six
Derivative [Line Items]
Fixed Interest Rate	2.50%	0.00%
Aggregate Notional Amount	$ 65,657	$ 0

Derivative Instruments - Balanc

Derivative Instruments - Balance Sheet (Details) - Not designated as hedging instrument - Interest rate swap - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Derivatives, Fair Value [Line Items]
Total, net	$ (29,930)	$ (27,129)
Other assets
Derivatives, Fair Value [Line Items]
Derivative asset, fair value	1	360
Other current liabilities
Derivatives, Fair Value [Line Items]
Derivative liability, fair value	0	(397)
Other long-term liabilities
Derivatives, Fair Value [Line Items]
Derivative liability, fair value	$ (29,931)	$ (27,092)

Derivative Instruments - Intere

Derivative Instruments - Interest Expense (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized (gain) loss			$ 2,755	$ 30,262
Interest rate swaps | Interest expense
Derivative Instruments, Gain (Loss) [Line Items]
Realized loss	$ 665	$ 265	38,668	12,637
Unrealized (gain) loss	(1,788)	12,813	2,755	30,262
Total	$ (1,123)	$ 13,078	$ 41,423	$ 42,899

Income Taxes - Narrative (Detai

Income Taxes - Narrative (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Effective income tax rate	0.00%	0.00%	0.00%	0.00%
Income tax penalties and interest accrued	$ 0		$ 0		$ 0

Redeemable Noncontrolling Int_2

Redeemable Noncontrolling Interests And Noncontrolling Interests (Details) - USD ($) $ in Thousands	1 Months Ended				3 Months Ended
	Sep. 30, 2020	Jul. 31, 2020	May 31, 2020	Feb. 29, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019
Noncontrolling Interest [Line Items]
Contributions from redeemable noncontrolling interests and noncontrolling interests					$ 279	$ 0	$ 3,170	$ 17,048	$ 32,207	$ 18,030
Class A members | TEPIVC
Noncontrolling Interest [Line Items]
Contributions from redeemable noncontrolling interests and noncontrolling interests				$ 75,000
Class A members | TEPIVD
Noncontrolling Interest [Line Items]
Contributions from redeemable noncontrolling interests and noncontrolling interests			$ 75,000
Class A members | TEPIVF
Noncontrolling Interest [Line Items]
Contributions from redeemable noncontrolling interests and noncontrolling interests		$ 10,000
Class A members | TEPIVE
Noncontrolling Interest [Line Items]
Contributions from redeemable noncontrolling interests and noncontrolling interests	$ 75,000

Stockholders' Equity (Details)

Stockholders' Equity (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Class of Stock [Line Items]
Non-cash issuance of convertible preferred stock relating to the reduction of debt			$ 84,196	$ 0
Debt conversion, shares issued (in shares)	6,277,982
Loss on extinguishment of debt	$ 50,721	$ 0	$ 50,721	$ 0
9.75% convertible senior notes | Convertible senior notes | SEI
Class of Stock [Line Items]
Stated interest rate	9.75%		9.75%
Non-cash issuance of convertible preferred stock relating to the reduction of debt	$ 84,800

Equity-Based Compensation - Sto

Equity-Based Compensation - Stock Option Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2020	Dec. 31, 2019
Number of Stock Options
Outstanding, beginning balance (in shares)	4,304,309
Exercised (in shares)	(569,512)
Forfeited (in shares)	(115,191)
Outstanding, ending balance (in shares)	3,619,606	4,304,309
Number of options, exercisable (in shares)	3,619,606
Number of options, vested (in shares)	3,619,606
Number of options, non-vested (in shares)	0
Weighted Average Exercise Price
Outstanding, beginning balance (in USD per share)	$ 15.86
Exercised (in USD per share)	12.96
Forfeited (in USD per share)	19.19
Outstanding, ending balance (in USD per share)	16.21	$ 15.86
Weighted average exercise price, exercisable (in USD per share)	16.21
Weighted average exercise price, vested (in USD per share)	$ 16.21
Weighted Average Remaining Contractual Term (Years)
Outstanding	6 years 1 month 28 days	7 years 29 days
Exercisable	6 years 1 month 28 days
Vested	6 years 1 month 28 days
Weighted Average Grant Date Fair Value
Forfeited (in USD per share)	$ 3.54
Non-vested (in USD per share)	$ 0
Aggregate Intrinsic Value
Outstanding, beginning balance	$ 242
Exercised	9,938
Outstanding, ending balance	51,383	$ 242
Exercisable	51,383
Vested	$ 51,383

Equity-Based Compensation - Nar

Equity-Based Compensation - Narrative (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options vested (in shares)	545,785	1,020,026	915,501	1,764,125
Stock options vested	$ 2,000,000	$ 3,600,000	$ 3,200,000	$ 6,000,000
Total unrecognized compensation expense	$ 0		$ 0
Restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock units vested (in shares)	416,537		443,620
Restricted stock units, vested	$ 5,000,000		$ 5,300,000
Unrecognized compensation expense	$ 20,000,000		$ 20,000,000
Weighted average period			1 year 9 months 29 days

Equity-Based Compensation - Res

Equity-Based Compensation - Restricted Stock Activity (Details) - $ / shares	3 Months Ended	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2020	Dec. 31, 2019
Number of Restricted Stock Units
Forfeited (in shares)		(43,703)
Weighted Average Grant Date Fair Value
Forfeited (in USD per share)		$ 11.77
Restricted stock units
Number of Restricted Stock Units
Outstanding, beginning balance (in shares)		1,426,139
Granted (in shares)		1,130,312
Vested (in shares)	(416,537)	(443,620)
Outstanding, ending balance (in shares)	2,069,128	2,069,128
Weighted Average Grant Date Fair Value
Outstanding (in USD per share)	$ 11.83	$ 11.83	$ 11.93
Granted (in USD per share)		11.75
Vested (in USD per share)		$ 11.96

Basic and Diluted Net Loss Pe_3

Basic and Diluted Net Loss Per Share - Schedule of Basic and Diluted Net Loss Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Net loss attributable to stockholders	$ (64,181)	$ (37,590)	$ (160,514)	$ (126,842)
Net loss attributable to common stockholders—basic	(64,181)	(37,590)	(160,514)	(151,567)
Net loss attributable to common stockholders—diluted	$ (64,181)	$ (37,590)	$ (160,514)	$ (151,567)
Net loss per share attributable to common stockholders—basic and diluted (in USD per share)	$ (0.73)	$ (0.62)	$ (1.88)	$ (5.77)
Weighted average common shares outstanding—basic and diluted (in shares)	87,768,712	60,890,129	85,276,841	26,245,493
Series A and Series C Convertible Preferred Stock
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Dividends earned on convertible preferred stock	$ 0	$ 0	$ 0	$ (19,271)
Series C convertible preferred stock
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Dividends earned on convertible preferred stock	$ 0	$ 0	$ 0	$ (5,454)

Basic and Diluted Net Loss Pe_4

Basic and Diluted Net Loss Per Share - Anti-Dilutive Weighted Average Shares (Details) - shares	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Equity-based compensation awards
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share (in shares)	6,006,791	5,277,414	6,176,162	4,693,647
Convertible preferred stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share (in shares)	0	18,337,539	0	45,405,229
Convertible senior notes
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share (in shares)	14,970,678	0	9,839,125	0

Commitments and Contingencies -

Commitments and Contingencies - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019	Dec. 31, 2018
Loss Contingencies [Line Items]
Current portion of performance guarantee obligations	$ 2,921		$ 2,921		$ 4,067
Letter of credit outstanding	375		375		725
Other commitment	54,500		54,500
Payments for dealer commitments	7,700	$ 9,700	24,400	$ 31,700
Performance guarantee obligations
Loss Contingencies [Line Items]
Performance guarantee obligations	4,939	$ 5,675	4,939	$ 5,675	6,468	$ 6,044
Current portion of performance guarantee obligations	2,900		2,900		4,100
Long-term portion of performance guarantee obligations	$ 2,000		$ 2,000		$ 2,400

Commitments and Contingencies_2

Commitments and Contingencies - Performance Guarantee Obligations (Details) - Performance guarantee obligations - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Performance Guarantee Obligations [Roll Forward]
Balance at beginning of period	$ 6,468	$ 6,044
Accruals for obligations issued	2,359	2,259
Settlements made in cash	(3,888)	(2,628)
Balance at end of period	$ 4,939	$ 5,675

Commitments and Contingencies_3

Commitments and Contingencies - Lease Expenses and Other Information (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Commitments and Contingencies Disclosure [Abstract]
Operating lease expense	$ 336	$ 344	$ 1,007	$ 914
Finance lease amortization expense	0	2	2	6
Short-term lease expense	14	11	36	34
Variable lease expense	258	268	437	731
Sublease income	0	(18)	0	(55)
Total	$ 608	$ 607	$ 1,482	$ 1,630

Commitments and Contingencies_4

Commitments and Contingencies - Lease Assets and Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Right-of-use assets:
Operating leases	$ 8,997	$ 9,668
Finance leases	0	5
Total right-of-use assets	8,997	9,673
Current lease liabilities:
Operating leases	1,075	556
Finance leases	0	5
Long-term leases liabilities:
Operating leases	8,846	9,389
Total lease liabilities	$ 9,921	$ 9,950

Commitments and Contingencies_5

Commitments and Contingencies - Other Lease Information (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash flows from operating leases	$ 358	$ 819
Financing cash flows from finance leases	1	7
Right-of-use assets obtained in exchange for lease obligations:
Operating leases	0	8,053
Finance leases	$ 0	$ 13
Weighted average remaining lease term (years):
Operating leases	8 years 8 months 8 days	9 years 8 months 4 days
Finance leases	0 years	11 months 1 day
Weighted average discount rate:
Operating leases	3.94%	3.94%
Finance leases	0.00%	4.26%

Commitments and Contingencies_6

Commitments and Contingencies - Future Minimum Lease Payments (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Operating Leases
Remaining 2020	$ 381
2021	1,536
2022	1,559
2023	1,594
2024	1,616
2025 and thereafter	7,617
Total	14,303
Amount representing interest	(2,254)
Amount representing leasehold incentives	(2,128)
Present value of future payments	9,921
Current portion of lease liability	(1,075)	$ (556)
Long-term portion of lease liability	$ 8,846	$ 9,389

Commitments and Contingencies_7

Commitments and Contingencies - Dealer Commitments (Details) $ in Thousands	Sep. 30, 2020USD ($)
Long-term Purchase Commitment [Line Items]
Total	$ 54,500
Long-term dealer commitments
Long-term Purchase Commitment [Line Items]
Remaining 2020	484
2021	33,312
2022	33,477
2023	10,505
2024	9,766
2025 and thereafter	1,509
Total	$ 89,053

Commitments and Contingencies_8

Commitments and Contingencies - Purchase Commitments (Details) $ in Thousands	Sep. 30, 2020USD ($)
Commitments and Contingencies Disclosure [Abstract]
Remaining 2020	$ 3,327
2021	26,629
2022	26,810
2023	26,605
2024	19,807
2025 and thereafter	0
Total	$ 103,178

Commitments and Contingencies_9

Commitments and Contingencies - Future Commitments (Details) $ in Thousands	Sep. 30, 2020USD ($)
Commitments and Contingencies Disclosure [Abstract]
Remaining 2020	$ 1,475
2021	5,322
2022	121
2023	26
2024	26
2025 and thereafter	7
Total	$ 6,977

Subsequent Events (Details)

Subsequent Events (Details) - USD ($)	1 Months Ended		3 Months Ended	9 Months Ended
	Oct. 29, 2020	Jun. 30, 2020	Sep. 30, 2020	Sep. 30, 2020	Sep. 30, 2019	May 31, 2020	May 30, 2020	Mar. 31, 2020
Subsequent Event [Line Items]
Non-cash issuance of convertible preferred stock relating to the reduction of debt				$ 84,196,000	$ 0
Debt conversion, shares issued (in shares)			6,277,982
EZOP
Subsequent Event [Line Items]
Repayments of debt		$ 149,300,000
EZOP | Subsequent Event
Subsequent Event [Line Items]
Repayments of debt	$ 28,000,000
TEPH | Line of credit | Revolving credit facility
Subsequent Event [Line Items]
Maximum borrowing capacity			$ 437,500,000	$ 437,500,000		$ 390,000,000	$ 200,000,000	$ 400,000,000
TEPH | Subsequent Event | Line of credit | Revolving credit facility
Subsequent Event [Line Items]
Maximum borrowing capacity	600,000,000
SEI | 9.75% convertible senior notes | Convertible senior notes
Subsequent Event [Line Items]
Stated interest rate			9.75%	9.75%
Non-cash issuance of convertible preferred stock relating to the reduction of debt			$ 84,800,000
SEI | Subsequent Event | 9.75% convertible senior notes | Convertible senior notes
Subsequent Event [Line Items]
Non-cash issuance of convertible preferred stock relating to the reduction of debt	$ 32,500,000
Debt conversion, shares issued (in shares)	2,406,523