TerraForm Power NY (TERP) 10-Q 9 Nov 17 2017 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2017	Oct. 31, 2017
Document and Entity Information [Abstract]
Entity Registrant Name	TerraForm Power, Inc.
Entity Central Index Key	1,599,947
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Document Type	10-Q
Document Period End Date	Sep. 30, 2017
Document Fiscal Year Focus	2,017
Document Fiscal Period Focus	Q3
Amendment Flag	false
Entity Common Stock, Shares Outstanding		148,224,429

Unaudited Condensed Consolidate

Unaudited Condensed Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Operating revenues, net	$ 153,430	$ 178,118	$ 474,932	$ 519,336
Operating costs and expenses:
Cost of operations	41,859	32,820	108,402	94,534
Cost of operations - affiliate	1,199	7,149	10,224	22,898
General and administrative expenses	21,664	26,510	99,644	64,750
General and administrative expenses - affiliate	2,192	2,943	6,893	10,614
Acquisition and related costs	0	0	0	2,743
Impairment of renewable energy facilities	0	0	1,429	0
Depreciation, accretion and amortization expense	61,830	57,988	186,039	178,026
Total operating costs and expenses	128,744	127,410	412,631	373,565
Operating income	24,686	50,708	62,301	145,771
Other expenses (income):
Interest expense, net	70,232	72,818	206,749	243,111
Gain on sale of renewable energy facilities	0	0	(37,116)	0
(Gain) loss on foreign currency exchange, net	(1,078)	3,913	(5,695)	4,161
Loss on receivables - affiliate	0	0	0	845
Other (income) expenses, net	(7,015)	548	(4,882)	692
Total other expenses, net	62,139	77,279	159,056	248,809
Loss before income tax (benefit) expense	(37,453)	(26,571)	(96,755)	(103,038)
Income tax (benefit) expense	(2,633)	1,140	(4,982)	3,115
Net loss	(34,820)	(27,711)	(91,773)	(106,153)
Less: Net income attributable to redeemable non-controlling interests	6,803	4,642	18,162	16,374
Less: Net loss attributable to non-controlling interests	(15,077)	(6,182)	(59,045)	(74,968)
Net loss attributable to Class A common stockholders	$ (26,546)	$ (26,171)	$ (50,890)	$ (47,559)
Class A common stock
Weighted average number of shares:
Class A common stock - Basic and diluted (in shares)	92,352	90,860	92,228	89,140
Loss per share:
Class A common stock - Basic and diluted (in dollars per share)	$ (0.31)	$ (0.29)	$ (0.62)	$ (0.53)

Unaudited Condensed Consolidat3

Unaudited Condensed Consolidated Statements of Comprehensive (Loss) Income - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Statement of Comprehensive Income [Abstract]
Net loss	$ (34,820)	$ (27,711)	$ (91,773)	$ (106,153)
Foreign currency translation adjustments:
Net unrealized gain (loss) arising during the period	6,535	(6,158)	12,136	(2,442)
Reclassification of net realized loss (gain) into earnings	0	0	14,741	0
Hedging activities:
Net unrealized gain (loss) arising during the period	17,338	14,258	27,960	(32,348)
Reclassification of net realized (gain) loss into earnings	94	3,164	(527)	15,667
Other comprehensive income (loss), net of tax	23,967	11,264	54,310	(19,123)
Total comprehensive loss	(10,853)	(16,447)	(37,463)	(125,276)
Less comprehensive income (loss) attributable to non-controlling interests:
Net income attributable to redeemable non-controlling interests	6,803	4,642	18,162	16,374
Net loss attributable to non-controlling interests	(15,077)	(6,182)	(59,045)	(74,968)
Foreign currency translation adjustments	1,967	(2,165)	1,250	(668)
Hedging activities	6,799	7,015	18,638	(6,151)
Comprehensive income (loss) attributable to non-controlling interests	492	3,310	(20,995)	(65,413)
Comprehensive loss attributable to Class A common stockholders	$ (11,345)	$ (19,757)	$ (16,468)	$ (59,863)

Unaudited Condensed Consolidat4

Unaudited Condensed Consolidated Statements of Comprehensive (Loss) Income (Parenthetical) - USD ($) $ in Millions	May 11, 2017	Sep. 30, 2017	Sep. 30, 2016
Gain on sale of renewable energy facilities | United Kingdom
Reclassification of net realized loss (gain) into earnings		$ 23.6
Interest Expense
Reclassification of net realized loss (gain) into earnings	$ 0.4
Interest Expense | United Kingdom
Reclassification of net realized loss (gain) into earnings			$ 15.9

Unaudited Condensed Consolidat5

Unaudited Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Current assets:
Cash and cash equivalents	$ 462,846	$ 565,333
Restricted cash	126,083	114,950
Accounts receivable, net	104,841	89,461
Prepaid expenses and other current assets	62,550	61,749
Assets held for sale	0	61,523
Total current assets	756,320	893,016
Renewable energy facilities, net, including consolidated variable interest entities of $3,309,214 and $3,434,549 in 2017 and 2016, respectively	4,854,303	4,993,251
Intangible assets, net, including consolidated variable interest entities of $836,290 and $875,095 in 2017 and 2016, respectively	1,096,416	1,142,112
Deferred financing costs, net	4,585	7,798
Other assets	133,539	114,863
Restricted cash	26,080	2,554
Non-current assets held for sale	0	552,271
Total assets	6,871,243	7,705,865
Current liabilities:
Current portion of long-term debt and financing lease obligations, including consolidated variable interest entities of $156,621 and $594,442 in 2017 and 2016, respectively	716,728	2,212,968
Accounts payable, accrued expenses and other current liabilities, including consolidated variable interest entities of $42,555 and $37,760 in 2017 and 2016, respectively	145,276	125,596
Deferred revenue	17,992	18,179
Due to SunEdison and affiliates, net	15,775	16,692
Liabilities related to assets held for sale	0	21,798
Total current liabilities	895,771	2,395,233
Long-term debt and financing lease obligations, less current portion, including consolidated variable interest entities of $781,464 and $375,726 in 2017 and 2016, respectively	2,864,666	1,737,946
Deferred revenue, less current portion	44,669	55,793
Deferred income taxes	32,889	27,723
Asset retirement obligations, including consolidated variable interest entities of $95,596 and $92,213 in 2017 and 2016, respectively	150,743	148,575
Other long-term liabilities	33,261	31,470
Non-current liabilities related to assets held for sale	0	410,759
Total liabilities	4,021,999	4,807,499
Redeemable non-controlling interests	198,031	180,367
Stockholders' equity:
Preferred stock, $0.01 par value per share, 50,000,000 shares authorized, no shares issued	0	0
Additional paid-in capital	1,480,584	1,467,108
Accumulated deficit	(285,330)	(234,440)
Accumulated other comprehensive income	57,334	22,912
Treasury stock, 362,018 and 253,687 shares in 2017 and 2016, respectively	(5,381)	(4,025)
Total TerraForm Power, Inc. stockholders' equity	1,248,617	1,252,957
Non-controlling interests	1,402,596	1,465,042
Total stockholders' equity	2,651,213	2,717,999
Total liabilities, redeemable non-controlling interests and stockholders' equity	6,871,243	7,705,865
Class A common stock
Stockholders' equity:
Common stock	928	920
Class B common stock
Stockholders' equity:
Common stock	482	482
Class B1 common stock
Stockholders' equity:
Common stock	$ 0	$ 0

Unaudited Condensed Consolidat6

Unaudited Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Noncurrent Assets:
Renewable energy facilities, net	$ 4,854,303	$ 4,993,251
Intangible assets, net	1,096,416	1,142,112
Current liabilities:
Current portion of long-term debt and financing lease obligations	716,728	2,212,968
Accounts payable, accrued expenses and other current liabilities	145,276	125,596
Noncurrent liabilities:
Long-term debt and financing lease obligations, less current portion	2,864,666	1,737,946
Asset retirement obligations	$ 150,743	$ 148,575
Stockholders' equity:
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized (in shares)	50,000,000	50,000,000
Preferred stock, shares issued (in shares)	0	0
Common stock, shares outstanding (in shares)	140,610,906
Treasury stock (in shares)	362,018	253,687
Consolidated Variable Interest Entities
Noncurrent Assets:
Renewable energy facilities, net	$ 3,309,214	$ 3,434,549
Intangible assets, net	836,290	875,095
Current liabilities:
Current portion of long-term debt and financing lease obligations	156,621	594,442
Accounts payable, accrued expenses and other current liabilities	42,555	37,760
Noncurrent liabilities:
Long-term debt and financing lease obligations, less current portion	781,464	375,726
Asset retirement obligations	$ 95,596	$ 92,213
Class A common stock
Stockholders' equity:
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	850,000,000	850,000,000
Common stock, shares issued (in shares)	92,770,614	92,476,776
Common stock, shares outstanding (in shares)	92,408,596	92,223,089
Class B common stock
Stockholders' equity:
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	140,000,000	140,000,000
Common stock, shares issued (in shares)	48,202,310	48,202,310
Common stock, shares outstanding (in shares)	48,202,310	48,202,310
Class B1 common stock
Stockholders' equity:
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	260,000,000	260,000,000
Common stock, shares issued (in shares)	0	0

Unaudited Condensed Consolidat7

Unaudited Condensed Consolidated Statement of Stockholders' Equity - 9 months ended Sep. 30, 2017 - USD ($) $ in Thousands		Total	Class A Common Stock Issued	Class B Common Stock Issued	Total	Common StockClass A Common Stock Issued	Common StockClass B Common Stock Issued	Additional Paid-in Capital	Accumulated Deficit	Accumulated Other Comprehensive Income	Common Stock Held in Treasury	Non-controlling Interests	Capital	Accumulated Deficit	Accumulated Other Comprehensive (Loss) Income
Beginning balance (in shares) at Dec. 31, 2016			92,223,089	48,202,310		92,477,000	48,202,000				(254,000)
Beginning balance at Dec. 31, 2016		$ 2,717,999			$ 1,252,957	$ 920	$ 482	$ 1,467,108	$ (234,440)	$ 22,912	$ (4,025)	$ 1,465,042	$ 1,792,295	$ (312,847)	$ (14,406)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation (in shares)						294,000					(108,000)
Stock-based compensation		3,670			3,670	$ 8		5,018			$ (1,356)
Net loss	[1]	(109,935)			(50,890)				(50,890)			(59,045)		(59,045)
Net SunEdison investment		9,466			6,224			6,224				3,242	3,242
Other comprehensive income		54,310			34,422					34,422		19,888			19,888
Sale of membership interests and contributions from non-controlling interests in renewable energy facilities		6,935										6,935	6,935
Distributions to non-controlling interests in renewable energy facilities		(15,790)										(15,790)	(15,790)
Deconsolidation of non-controlling interest in renewable energy facility		(8,713)										(8,713)	(8,713)
Accretion of redeemable non-controlling interest		(6,729)			(6,729)			(6,729)	0
Equity reallocation		$ 0			8,963			8,963				(8,963)	(8,963)
Ending balance (in shares) at Sep. 30, 2017		140,610,906	92,408,596	48,202,310		92,771,000	48,202,000				(362,000)
Ending balance at Sep. 30, 2017		$ 2,651,213			$ 1,248,617	$ 928	$ 482	$ 1,480,584	$ (285,330)	$ 57,334	$ (5,381)	$ 1,402,596	$ 1,769,006	$ (371,892)	$ 5,482
[1]	Excludes $18,162 of net income attributable to redeemable non-controlling interests

Unaudited Condensed Consolidat8

Unaudited Condensed Consolidated Statement of Stockholders' Equity (Parenthetical) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Statement of Stockholders' Equity [Abstract]
Net income attributable to redeemable non-controlling interests	$ 6,803	$ 4,642	$ 18,162	$ 16,374

Unaudited Condensed Consolidat9

Unaudited Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Cash flows from operating activities:
Net loss	$ (91,773)	$ (106,153)
Adjustments to reconcile net loss to net cash provided by operating activities:
Depreciation, accretion and amortization expense	186,039	178,026
Amortization of favorable and unfavorable rate revenue contracts, net	29,459	30,128
Gain on sale of renewable energy facilities	(37,116)	0
Impairment of renewable energy facilities	1,429	0
Amortization of deferred financing costs and debt discounts	19,729	19,579
Unrealized loss on U.K. interest rate swaps	2,425	35,840
Unrealized (gain) loss on commodity contract derivatives, net	(1,244)	5,006
Recognition of deferred revenue	(11,510)	(9,508)
Stock-based compensation expense	7,049	3,857
Unrealized (gain) loss on foreign currency exchange, net	(5,275)	6,349
Loss on extinguishment of debt	2,518	0
Loss on receivables - affiliate	0	845
Deferred taxes	5,166	3,014
Other, net	5,978	2,287
Changes in assets and liabilities:
Accounts receivable	(18,860)	(30,502)
Prepaid expenses and other current assets	(4,997)	(11,827)
Accounts payable, accrued expenses and other current liabilities	(758)	10,035
Deferred revenue	199	2,457
Other, net	3,907	5,483
Net cash provided by operating activities	92,365	144,916
Cash flows from investing activities:
Capital expenditures	(7,472)	(41,698)
Proceeds from sale of renewable energy facilities, net of cash and restricted cash disposed	183,235	0
Proceeds from renewable energy state rebate	15,542	0
Proceeds from reimbursable interconnection costs	8,079	0
Acquisitions of renewable energy facilities from third parties, net of cash and restricted cash acquired	0	(4,064)
Net cash provided by (used in) investing activities	199,384	(45,762)
Cash flows from financing activities:
Borrowings of non-recourse long-term debt	79,835	3,980
Principal payments and prepayments on non-recourse long-term debt	(199,481)	(122,597)
Revolver repayments	(275,000)	0
Sale of membership interests and contributions from non-controlling interests in renewable energy facilities	6,935	15,501
Distributions to non-controlling interests in renewable energy facilities	(23,017)	(19,365)
Net SunEdison investment	7,436	37,200
Due to SunEdison and affiliates, net	(3,097)	(29,036)
Debt financing fees	(10,228)	(12,958)
Other financing activities	(1,030)	0
Net cash used in financing activities	(417,647)	(127,275)
Net decrease in cash, cash equivalents and restricted cash	(125,898)	(28,121)
Net change in cash, cash equivalents and restricted cash classified within assets held for sale	54,806	(54,731)
Effect of exchange rate changes on cash, cash equivalents and restricted cash	3,264	(5,933)
Cash, cash equivalents and restricted cash at beginning of period	682,837	793,033
Cash, cash equivalents and restricted cash at end of period	615,009	704,248
Supplemental Disclosures:
Cash paid for interest	182,021	183,577
Cash paid for income taxes	$ 0	$ 0

Nature of Operations and Basis

Nature of Operations and Basis of Presentation	9 Months Ended
	Sep. 30, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Nature of Operations and Basis of Presentation	NATURE OF OPERATIONS AND BASIS OF PRESENTATION Nature of Operations As of September 30, 2017, TerraForm Power, Inc. ("TerraForm Power") and its subsidiaries (together with TerraForm Power, the "Company") was a controlled affiliate of SunEdison, Inc. (together with its consolidated subsidiaries excluding the Company and TerraForm Global, Inc. and its subsidiaries, "SunEdison"). TerraForm Power is a holding company and its sole asset is an equity interest in TerraForm Power, LLC ("Terra LLC"), which through its subsidiaries owns and operates renewable energy facilities that have long-term contractual arrangements to sell the electricity generated by these facilities to third parties. The related green energy certificates, ancillary services and other environmental attributes generated by these facilities are also sold to third parties. TerraForm Power is the managing member of Terra LLC and operates, controls and consolidates the business affairs of Terra LLC. As a result of the consummation of the Merger (as discussed and defined below) on October 16, 2017, a change of control of TerraForm Power occurred, and Orion US Holdings 1 L.P. ("Orion Holdings"), which is an affiliate of Brookfield Asset Management Inc. (“Brookfield”), now holds 51% of the voting securities of TerraForm Power. As a result of the Merger closing, TerraForm Power is no longer a controlled affiliate of SunEdison, Inc. and is now a controlled affiliate of Brookfield. The Consummation of the Brookfield Sponsorship Transaction and of the Settlement with SunEdison On April 21, 2016, SunEdison Inc. and certain of its domestic and international subsidiaries (the "SunEdison Debtors") voluntarily filed for protection under Chapter 11 of the U.S. Bankruptcy Code (the "SunEdison Bankruptcy"). In response to SunEdison’s financial and operating difficulties, the Company initiated a process for the exploration and evaluation of potential strategic alternatives for the Company, including potential transactions to secure a new sponsor or sell the Company, and a process to settle claims with SunEdison. This process resulted in the Company's entry into a definitive merger and sponsorship transaction agreement (the “Merger Agreement”) on March 6, 2017 with Orion Holdings and BRE TERP Holdings Inc. ("Merger Sub"), a wholly-owned subsidiary of Orion Holdings, which are affiliates of Brookfield. At the same time, the Company and SunEdison also entered into a settlement agreement (the “Settlement Agreement”) and a voting and support agreement (the “Voting and Support Agreement”), among other things, to facilitate the closing of the Merger and the settlement of claims between the Company and SunEdison. On October 6, 2017, the Merger Agreement was approved by the holders of a majority of the outstanding Class A shares of TerraForm Power, excluding SunEdison, Orion Holdings, any of their respective affiliates or any person with whom any of them has formed (and not terminated) a “group” (as such term is defined in the Securities Exchange Act of 1934, as amended) and by the holders of a majority of the total voting power of the outstanding shares of the Company’s common stock entitled to vote on the transaction. With these votes, all conditions to the merger transaction contemplated by the Merger Agreement were satisfied. On October 16, 2017, Merger Sub merged with and into TerraForm Power (the “Merger”), with TerraForm Power continuing as the surviving corporation in the Merger. Immediately following the consummation of the Merger, there were 148,224,429 Class A shares of TerraForm Power outstanding and Orion Holdings holds 51% of such shares. In addition, pursuant to the Merger Agreement, at or prior to the effective time of the Merger, the Company and Orion Holdings (or one of its affiliates), among other parties, entered into a suite of agreements providing for sponsorship arrangements, including a master services agreement, relationship agreement, governance agreement and a sponsor line of credit (the "Sponsorship Agreements"), as are more fully described in Note 15 . Related Parties and Note 6 . Long-term Debt . Immediately prior to the effective time of the Merger, pursuant to the Settlement Agreement, SunEdison exchanged all of the Class B units held by SunEdison or any of its controlled affiliates in Terra LLC for 48,202,310 Class A shares of TerraForm Power, and as a result of such exchange, all shares of Class B common stock of TerraForm Power held by SunEdison or any of its controlled affiliates were automatically redeemed and retired. Pursuant to the Settlement Agreement, immediately following such exchange, the Company issued to SunEdison additional Class A shares such that immediately prior to the effective time of the Merger, SunEdison and certain of its affiliates held an aggregate number of Class A shares equal to 36.9% of the Company’s fully diluted share count. SunEdison and certain of its affiliates also transferred all of the outstanding incentive distribution rights (“IDRs”) of Terra LLC held by SunEdison or certain of its affiliates to BRE Delaware, Inc. (the "Brookfield IDR Holder") at the effective time of the Merger. Under the Settlement Agreement, upon the consummation of the Merger, all agreements between the Company and the SunEdison Debtors were deemed rejected, subject to certain limited exceptions, without further liability, claims or damages on the part of the Company. The settlements, mutual release and certain other terms and conditions of the Settlement Agreement also became effective upon the consummation of the Merger. Refer to Note 15 . Related Parties for further discussion. Going Concern In its Form 10-K for the year ended December 31, 2016 and its Forms 10-Q for each of the quarters ended March 31, 2017 and June 30, 2017, the Company disclosed there was substantial doubt about its ability to continue as a going concern. While the financial statements accompanying those filings and the accompanying unaudited condensed consolidated financial statements were prepared on a going concern basis, the matters disclosed in those filings raised substantial doubt about our ability to continue as a going concern as a result of the SunEdison Bankruptcy and the related impacts on the Company, including the Company’s historic reliance on SunEdison, defaults under project-level financing arrangements and the potential for creditors or other stakeholders of SunEdison to petition the court to substantively consolidate the Company’s assets and liabilities into the SunEdison bankruptcy estate. Since the date of the SunEdison Bankruptcy, the Company has implemented significant measures to mitigate its impact on the Company. We no longer believe the SunEdison Bankruptcy and the related impacts raise substantial doubt about our ability to continue as a going concern for the following reasons: • Prior to the SunEdison Bankruptcy, we relied almost exclusively on the personnel, management and administration services provided by or under the direction of SunEdison. Since the date of the SunEdison Bankruptcy, we have substantially reduced our reliance on SunEdison by transitioning the asset management, operations and maintenance of our renewable energy facilities in-house or to third parties, by hiring directly our own employees and contractors and by establishing our own information technology systems. While we continue to receive a limited scope of transition services from SunEdison, we are working to complete this transition and would be in a position to implement contingency plans or replace those services should the need arise. As a result, we believe we are in a position to operate the business of the Company on a stand-alone basis. • The Company experienced covenant defaults under most of our financing arrangements in 2016 and 2017, mainly because of delays in the delivery of project-level audited financial statements and the delay in the filing of the Company’s audited annual financial statements for 2015 and 2016. The Company has completed filing of 2015 and 2016 audited annual financial statements and all of its project-level audited financial statements for fiscal year 2016 as of the date hereof. The Company is working to obtain waivers for late delivery of project-level audited financial statements that were delivered after the grace period expired. In addition, in a number of cases the SunEdison Bankruptcy resulted in defaults because SunEdison Debtors were serving as operations and maintenance ("O&M") and asset management services providers or as guarantors under relevant contracts. We have been working diligently with our lenders to cure or waive instances of default primarily through the retention of replacement service providers. The amount of restricted cash associated with the aforementioned defaults that cannot be distributed from the projects as of the date of the issuance of these financial statements is $23 million and is not needed for the Company to meet its cash flow needs. We expect to obtain waivers for these defaults before the end of the year and do not expect these defaults to affect our ability to meet our liquidity requirements and meet corporate credit facility covenants. • Finally, during the course of the SunEdison Bankruptcy there was a risk that an interested party in the SunEdison Bankruptcy could request that the assets and liabilities of the Company be substantively consolidated with SunEdison. In March of 2017, the Company entered into the Settlement Agreement and the Voting and Support Agreement with the SunEdison Debtors, both of which have been approved by the United States Bankruptcy Court for the Southern District of New York (the "Bankruptcy Court"). Mutual releases between the Company and the SunEdison Debtors have now become effective, and as a result, the vast majority of contracts between the Company and SunEdison Debtors have been terminated. In addition, SunEdison received additional shares in the Company in connection with the consummation of the sponsorship transaction with Brookfield. SunEdison’s plan of reorganization has been confirmed by the Bankruptcy Court and includes the closing of the sponsorship transaction with Brookfield as a critical part of its emergence strategy. Because of these developments, we believe it is now a remote possibility that the Bankruptcy Court would order substantive consolidation of the Company with the SunEdison Debtors. Basis of Presentation The accompanying unaudited condensed consolidated financial statements have been prepared in accordance with the Securities and Exchange Commission’s ("SEC") regulations for interim financial information. Accordingly, they do not include all of the information and notes required by U.S. generally accepted accounting principles ("U.S. GAAP") for complete financial statements. The financial statements should be read in conjunction with the accounting policies and other disclosures as set forth in the notes to the Company’s annual financial statements for the year ended December 31, 2016 , filed with the SEC on Form 10-K on July 21, 2017. Interim results are not necessarily indicative of results for a full year. In the opinion of management, the accompanying unaudited condensed consolidated financial statements contain all material adjustments consisting of normal and recurring accruals necessary to present fairly the Company's financial position as of September 30, 2017 , the results of operations and comprehensive (loss) income for the three and nine months ended September 30, 2017 and 2016 and cash flows for the nine months ended September 30, 2017 and 2016. Use of Estimates In preparing the unaudited condensed consolidated financial statements, the Company used estimates and assumptions that affect the reported amounts of assets and liabilities and the disclosure of contingent assets and liabilities as of the date of the financial statements. Such estimates also affect the reported amounts of revenues, expenses and cash flows during the reporting period. To the extent there are material differences between the estimates and actual results, the Company's future results of operations would be affected. Recent Accounting Developments In May 2014, the Financial Accounting Standards Board ("FASB") issued ASU No. 2014-09, Revenue from Contracts with Customers (Topic 606) , which requires an entity to recognize the amount of revenue to which it expects to be entitled for the transfer of promised goods or services to customers. ASU No. 2014-09 will replace most existing revenue recognition guidance in U.S. GAAP when it becomes effective. In March 2016, the FASB issued ASU No. 2016-08, Revenue from Contracts with Customers (Topic 606), Principal versus Agent Considerations (Reporting Revenue Gross versus Net) , which clarifies how to apply the implementation guidance on principal versus agent considerations related to the sale of goods or services to a customer as updated by ASU No. 2014-09. ASU No. 2014-09 and ASU No. 2016-08 will become effective for the Company on January 1, 2018. Early application is permitted but not before January 1, 2017. ASU No. 2014-09 and ASU No. 2016-08 permit the use of either the retrospective or modified retrospective method. The Company is working through an adoption plan which includes the evaluation of revenue contracts compared to the new standards and evaluating the impact of the new standards on the Company's consolidated financial statements and related disclosures. The Company does not plan to adopt these standards prior to January 1, 2018. In February 2016, the FASB issued ASU No. 2016-02, Leases (Topic 842) , which primarily changes the lessee's accounting for operating leases by requiring recognition of lease right-of-use assets and lease liabilities. This standard is effective for annual reporting periods beginning after December 15, 2018, with early adoption permitted. The Company is currently evaluating the effect of ASU No. 2016-02 on its consolidated financial statements. In March 2016, the FASB issued ASU No. 2016-09, Compensation - Stock Compensation (Topic 718) . This update was issued as part of the FASB's simplification initiative and affects all entities that issue share-based payment awards to their employees. The amendments in this update cover such areas as the recognition of excess tax benefits and deficiencies, the classification of those excess tax benefits on the statement of cash flows, an accounting policy election for forfeitures, the amount an employer can withhold to cover income taxes and still qualify for equity classification and the classification of those taxes paid on the statement of cash flows. This update is effective for annual and interim periods beginning after December 15, 2016, with early adoption permitted if all provisions are adopted within the same period. The Company adopted ASU No. 2016-09 as of January 1, 2017, which did not result in any material adjustments to the Company's consolidated financial statements and related disclosures. In March 2016, the FASB issued ASU No. 2016-06, Derivatives and Hedging (Topic 815) , which clarifies that determining whether the economic characteristics of a put or call are clearly and closely related to its debt host requires only an assessment of the four-step decision sequence outlined in FASB ASC paragraph 815-15-25-24. Additionally, entities are not required to separately assess whether the contingency itself is clearly and closely related. This standard is effective for annual and interim periods beginning after December 15, 2016, with early adoption permitted. The amendments in this update should be applied on a modified retrospective basis. The adoption of ASU No. 2016-06 as of January 1, 2017 did not have an impact on the Company's consolidated financial statements. In March 2016, the FASB issued ASU No. 2016-07, Investments - Equity Method and Joint Ventures (Topic 323) . The amendments of ASU No. 2016-07 eliminate the requirement that when an investment qualifies for use of the equity method as a result of an increase in the level of ownership interest or degree of influence, an investor must adjust the investment, results of operations and retained earnings retroactively on a step-by-step basis as if the equity method had been in effect during all previous periods that the investment had been held. The amendments require that the equity method investor add the cost of acquiring the additional interest in the investee to the current basis of the investor's previously held interest and adopt the equity method of accounting with no retroactive adjustment to the investment. In addition, ASU No. 2016-07 requires that an entity that has an available-for-sale equity security that becomes qualified for the equity method of accounting recognize through earnings the unrealized holding gain or loss in accumulated other comprehensive income at the date the investment becomes qualified for use of the equity method. The guidance in ASU No. 2016-07 is effective for fiscal years beginning after December 15, 2016, and interim periods within those annual periods. The adoption of ASU No. 2016-07 is required to be applied prospectively and early adoption is permitted. The Company evaluated this standard and determined that it did not have an impact on its consolidated financial statements as it does not have any equity method investments. In August 2016, the FASB issued ASU No. 2016-15, Statement of Cash Flows (Topic 230), Classification of Certain Cash Receipts and Cash Payments . The amendments of ASU No. 2016-15 were issued to address eight specific cash flow issues for which stakeholders have indicated to the FASB that a diversity in practice existed in how entities were presenting and classifying these items in the statement of cash flows. The issues addressed by ASU No. 2016-15 include but are not limited to the classification of debt prepayment and debt extinguishment costs, payments made for contingent consideration for a business combination, proceeds from the settlement of insurance proceeds, distributions received from equity method investees and separately identifiable cash flows and the application of the predominance principle. The amendments of ASU No. 2016-15 are effective for public entities for fiscal years beginning after December 15, 2017 and interim periods in those fiscal years. Early adoption is permitted, including adoption in an interim fiscal period with all amendments adopted in the same period. The adoption of ASU No. 2016-15 is required to be applied retrospectively. The Company is currently evaluating the impact of the standard on its consolidated statements of cash flows. In October 2016, the FASB issued ASU No. 2016-16, Income Taxes (Topic 740), Intra-Entity Transfers of Assets Other Than Inventory . The amendments of ASU No. 2016-16 were issued to improve the accounting for the income tax consequences of intra-entity transfers of assets other than inventory. Current GAAP prohibits the recognition of current and deferred income taxes for an intra-entity asset transfer until the asset has been sold to an outside party which has resulted in diversity in practice and increased complexity within financial reporting. The amendments of ASU No. 2016-16 would require an entity to recognize the income tax consequences of an intra-entity transfer of an asset other than inventory when the transfer occurs and do not require new disclosure requirements. The amendments of ASU No. 2016-16 are effective for annual reporting periods beginning after December 15, 2017, and interim periods within those annual periods. Early adoption is permitted and the adoption of ASU No. 2016-16 should be applied on a modified retrospective basis through a cumulative-effect adjustment directly to retained earnings as of the beginning of the period of adoption. The Company does not expect this standard to have an impact on its consolidated financial statements. In October 2016, the FASB issued ASU No. 2016-17, Consolidation (Topic 810), Interests Held through Related Parties That Are under Common Control . ASU No. 2016-17 updates ASU No. 2015-02. Under the amendments, a single decision maker is not required to consider indirect interests held through related parties that are under common control with the single decision maker to be the equivalent of direct interests in their entirety. Instead, a single decision maker is required to include those interests on a proportionate basis consistent with indirect interests held through other related parties. ASU No. 2016-17 is effective for annual reporting periods beginning after December 15, 2016, and interim periods within those annual periods, with early adoption permitted. The adoption of ASU No. 2016-17 as of January 1, 2017 did not have an impact on the Company's consolidated financial statements. In November 2016, the FASB issued ASU No. 2016-18, Statement of Cash Flows (Topic 320), Restricted Cash, a Consensus of the FASB Emerging Issues Task Force . The amendments require that a statement of cash flows explain the change during the period in the total of cash, cash equivalents and amounts generally described as restricted cash or restricted cash equivalents. Therefore, amounts generally described as restricted cash and restricted cash equivalents should be included with cash and cash equivalents when reconciling the beginning-of-period and end-of-period total amounts shown on the statement of cash flows. ASU No. 2016-18 is effective for fiscal years beginning after December 15, 2017 and interim periods within those fiscal years. Early adoption is permitted and the adoption of ASU No. 2016-18 will be applied retrospectively. The Company elected to early adopt ASU No. 2016-18 during the second quarter of 2017 and has revised its unaudited condensed consolidated statement of cash flows for the nine months ended September 30, 2016. Net cash used in investing activities for the nine months ended September 30, 2016 decreased by $57.7 million as a result of the adoption of this standard. The sum of the Company's cash and cash equivalents of $565.3 million , current portion of restricted cash of $114.9 million and non-current portion of restricted cash of $2.6 million reported within the unaudited condensed consolidated balance sheet as of December 31, 2016 equals the beginning balance of cash, cash equivalents and restricted cash of $682.8 million shown in the unaudited condensed consolidated statement of cash flows for the nine months ended September 30, 2017. The sum of the Company's cash and cash equivalents of $462.8 million , current portion of restricted cash of $126.1 million and non-current portion of restricted cash of $26.1 million reported within the unaudited condensed consolidated balance sheet as of September 30, 2017 equals the ending balance of cash, cash equivalents and restricted cash of $615.0 million shown in the unaudited condensed consolidated statement of cash flows for the nine months ended September 30, 2017. The Company had $54.7 million of restricted cash classified within assets held for sale as of September 30, 2016 (with no comparable amount as of December 31, 2015) and thus had to add this reclassification amount to the net change in cash, cash equivalents and restricted cash classified within assets held for sale line reported in the unaudited condensed consolidated statement of cash flows for the nine months ended September 30, 2016 to reconcile the change in the beginning and end-of-period cash, cash equivalents and restricted cash. The Company's restricted cash balances during 2016 also included amounts related to its renewable energy facilities located in the United Kingdom (the "U.K.") and Canada, which resulted in a $5.3 million change in the effect of exchange rate changes on cash, cash equivalents and restricted cash line reported in the unaudited condensed consolidated statement of cash flows for the nine months ended September 30, 2016. In December 2016, the FASB issued ASU No. 2016-19, Technical Corrections and Improvements . The amendments cover a wide range of topics in the Accounting Standards Codification, covering differences between original guidance and the Accounting Standards Codification, guidance clarification and reference corrections, simplification and minor improvements. The adoption of ASU No. 2016-19 is effective for annual periods, including interim periods within those annual periods, beginning after December 15, 2016. The Company evaluated this standard and determined that it did not have an impact on its consolidated financial statements. In December 2016, the FASB issued ASU No. 2016-20, Technical Corrections and Improvements to Topic 606, Revenue from Contracts with Customers . The amendments in this update are of a similar nature to the items typically addressed in ASU 2016-19, Technical Corrections and Improvements . However, the FASB decided to issue a separate update for technical corrections and improvements to Topic 606 and other Topics amended by ASU No. 2014-09 to increase stakeholders’ awareness of the proposals and to expedite improvements to ASU No. 2014-09. The adoption of ASU No. 2016-20 is effective for annual reporting periods beginning after December 15, 2017, including interim reporting periods within those annual periods. Early adoption is permitted only as of annual reporting periods beginning after December 15, 2016, including interim reporting periods within that reporting period. The Company is currently evaluating the effect of this standard on its consolidated financial statements. In January 2017, the FASB issued ASU No. 2017-01, Business Combinations (Topic 805), Clarifying the Definition of a Business . The amendment seeks to clarify the definition of a business with the objective of adding guidance to assist entities with evaluating whether transactions should be accounted for as acquisitions (or disposals) of assets or businesses. The definition of a business affects many areas of accounting including acquisitions, disposals, goodwill and consolidation. The adoption of ASU No. 2017-01 is effective for annual periods beginning after December 15, 2017, including interim periods within those periods. The amendments should be applied prospectively on or after the effective dates. Accordingly, the adoption will not have an effect on the Company's historical financial statements. The Company is currently evaluating the effect of this standard on future consolidated financial statements. In January 2017, the FASB issued ASU No. 2017-04, Intangibles - Goodwill and Other (Topic 350), Simplifying the Test for Goodwill Impairment. The amendment simplifies the accounting for goodwill impairment by removing Step 2 of the current test, which requires calculation of a hypothetical purchase price allocation. Under the revised guidance, goodwill impairment will be measured as the amount by which a reporting unit’s carrying value exceeds its fair value, not to exceed the carrying amount of goodwill (currently Step 1 of the two step impairment test). Entities will continue to have the option to perform a qualitative assessment to determine if a quantitative impairment test is necessary. The standard is effective January 1, 2020, with early adoption permitted, and must be adopted on a prospective basis. This updated guidance is not currently expected to impact the Company's financial reporting as the Company does not have any goodwill. In February 2017, the FASB issued ASU No. 2017-05, Other Income - Gains and Losses from the Derecognition of Nonfinancial Assets (Subtopic 610-20): Clarifying the Scope of Asset Derecognition Guidance and Accounting for Partial Sales of Nonfinancial Assets . This ASU is meant to clarify the scope of ASC Subtopic 610-20, Other Income - Gains and Losses from the Derecognition of Nonfinancial Assets and to add guidance for partial sales of nonfinancial assets. ASU No. 2017-05 is to be applied using a full retrospective method or a modified retrospective method as outlined in the guidance and is effective at the same time as ASU No. 2014-09. Further, the Company is required to adopt ASU No. 2017-05 at the same time that it adopts the guidance in ASU No. 2014-09. The Company is currently evaluating the effect of this standard on its consolidated financial statements. In May 2017, the FASB issued ASU No. 2017-09, Compensation - Stock Compensation (Topic 718): Scope of Modification Accounting . The amendment clarifies when changes to the terms or conditions of a share-based payment award must be accounted for as a modification. The new guidance is expected to reduce diversity in practice and result in fewer changes to the terms of an award being accounted for as a modification. Changes to the terms or conditions of a share-based payment award that do not impact the fair value of the award, vesting conditions and the classification as an equity or liability instrument will not need to be assessed under modification accounting. The guidance is effective for annual periods, and interim periods within those annual periods, beginning after December 15, 2017. The amendments in this update should be applied prospectively to an award modified on or after the adoption date. Accordingly, the adoption will not have an effect on the Company's historical financial statements. The Company is currently evaluating the effect of this standard on future consolidated financial statements. In August 2017, the FASB issued ASU No. 2017-12, Derivatives and Hedging (Topic 815): Targeted Improvements to Accounting for Hedging Activities . This ASU amends the hedge accounting model to enable entities to better portray the economics of their risk management activities in the financial statements and simplifies the application of hedge accounting in certain situations. ASU No. 2017-12 is effective for annual periods, and interim periods within those annual periods, beginning after December 15, 2018, with early adoption permitted. The Company is currently evaluating the effect of this standard on its consolidated financial statements.

Assets Held for Sale

Assets Held for Sale	9 Months Ended
	Sep. 30, 2017
Discontinued Operations and Disposal Groups [Abstract]
Assets Held for Sale	ASSETS HELD FOR SALE U.K. Portfolio Sale The Company commenced a sale of substantially all of its portfolio of solar power plants located in the U.K. through a broad based sales process pursuant to a plan approved by management during 2016 ( 24 operating projects for sale representing 365.0 MW, the "U.K. Portfolio"), and it was determined that this portfolio met the criteria to be classified as held for sale during the first quarter of 2016. As a result, the Company classified the assets and liabilities of this portfolio as held for sale as of December 31, 2016 (refer to the table below) and measured each at the lower of carrying value or fair value less cost to sell. As discussed below, the Company closed on the sale of these facilities in the second quarter of 2017. The Company's analysis indicated that the fair value less costs to sell exceeded the carrying value of the assets for each period the portfolio was classified as held for sale. On May 11, 2017, the Company announced that TerraForm Power Operating, LLC ("Terra Operating LLC") completed its previously announced sale of the U.K. Portfolio to Vortex Solar UK Limited, a renewable energy platform managed by the private equity arm of EFG Hermes, an investment bank. Terra Operating LLC received approximately $214.1 million of proceeds from the sale, which was net of transaction expenses of $3.9 million and distributions taken from the U.K. Portfolio after announcement and before closing of the sale. The Company also disposed of $14.8 million of cash and cash equivalents and $21.8 million of restricted cash as a result of the sale. The proceeds were used for the reduction of the Company's indebtedness as discussed in Note 6 . Long-term Debt . The sale also resulted in a reduction in the Company's non-recourse project debt by approximately GBP 301 million at the U.K. Portfolio level. The Company recognized a gain on the sale of $37.1 million in the second quarter of 2017 which is reflected within gain on sale of renewable energy facilities in the unaudited condensed consolidated statement of operations for the nine months ended September 30, 2017. The Company has retained 11.1 MW of solar assets in the U.K., which are not held for sale. Residential Portfolio Sale The Company also began exploring a sale of substantially all of its portfolio of residential rooftop solar assets located in the United States ( 11.4 MW of assets as described below) through a strategic sales process in 2016, and it was determined that these assets met the criteria to be classified as held for sale during the fourth quarter of 2016. As a result, the Company classified the related assets and liabilities as held for sale as of December 31, 2016 (refer to the table below) and measured each at the lower of carrying value or fair value less costs to sell. The Company's analysis indicated that the carrying value of the assets exceeded the fair value less costs to sell, and thus an impairment charge of $15.7 million was recognized in the fourth quarter of 2016. The Company also recorded a $3.3 million charge in the third quarter of 2016 within cost of operations due to the decision to abandon certain residential construction in progress assets that were not completed by SunEdison as a result of the SunEdison Bankruptcy. On March 14, 2017, Enfinity SPV Holdings 2, LLC, a subsidiary of the Company, entered into a membership interest purchase and sale agreement with Greenbacker Residential Solar II, LLC for the sale of 100% of the membership interests of Enfinity Colorado DHA 1, LLC, a Colorado limited liability company that owns and operates 2.5 MW of solar installations situated on the roof of public housing units located in Colorado and owned by the Denver Housing Authority. The transaction closed on March 31, 2017, and the Company received proceeds of $1.1 million in the beginning of the second quarter of 2017. The Company also disposed of $0.8 million of restricted cash as a result of the sale. There was no additional loss recognized during 2017 as a result of this sale. In addition, the Company entered into a membership interest purchase and sale agreement with Greenbacker Residential Solar II, LLC on June 12, 2017 for the sale of 100% of the membership interests of TerraForm Resi Solar Manager, LLC, a subsidiary of the Company, which owns and operates 8.9 MW of rooftop solar installations. The transaction closed on June 30, 2017, and the Company received total proceeds of $6.0 million in the third quarter of 2017. The Company also disposed of $0.6 million of cash and cash equivalents in the second quarter of 2017 as a result of the sale. There was no additional loss recognized during 2017 as a result of this sale. The Company sold its remaining 0.3 MW of residential assets (that were not classified as held for sale as of December 31, 2016) during the third quarter of 2017. These assets did not meet the criteria for held for sale classification in the second quarter of 2017 but the Company determined that certain impairment indicators were present and as a result recognized an impairment charge of $1.4 million during the second quarter which is reflected within impairment of renewable energy facilities in the unaudited condensed consolidated statement of operations for the nine months ended September 30, 2017. There was no additional loss recognized during the third quarter as a result of the sale. The following table summarizes the major classes of assets and liabilities which are classified as held for sale on the Company's unaudited condensed consolidated balance sheet as of December 31, 2016. As discussed above, the Company closed on the sale of these renewable energy facilities in the first half of 2017. As of December 31, 2016 (In thousands) U.K. Portfolio Residential Portfolio Total Assets held for sale: Restricted cash $ 53,604 $ 1,202 $ 54,806 Accounts receivable, net 4,952 300 5,252 Prepaid expenses and other current assets 1,295 170 1,465 Total current assets held for sale 59,851 1,672 61,523 Renewable energy facilities, net 529,154 19,534 548,688 Intangible assets, net 1,480 — 1,480 Other assets 2,103 — 2,103 Total non-current assets held for sale 532,737 19,534 552,271 Total assets held for sale $ 592,588 $ 21,206 $ 613,794 Liabilities related to assets held for sale: Current portion of long-term debt $ 14,510 $ 175 $ 14,685 Accounts payable, accrued expenses and other current liabilities 5,980 245 6,225 Deferred revenue — 10 10 Due to SunEdison and affiliates, net 692 186 878 Total current liabilities related to assets held for sale 21,182 616 21,798 Long-term debt, less current portion 349,687 4,190 353,877 Deferred revenue, less current portion — 246 246 Asset retirement obligations 39,563 287 39,850 Other long-term liabilities 16,786 — 16,786 Total non-current liabilities related to assets held for sale 406,036 4,723 410,759 Total liabilities related to assets held for sale $ 427,218 $ 5,339 $ 432,557

Renewable Energy Facilities

Renewable Energy Facilities	9 Months Ended
	Sep. 30, 2017
Property, Plant and Equipment [Abstract]
Renewable Energy Facilities	RENEWABLE ENERGY FACILITIES Renewable energy facilities, net consists of the following: (In thousands) September 30, December 31, Renewable energy facilities in service, at cost $ 5,379,726 $ 5,354,883 Less accumulated depreciation - renewable energy facilities (526,213 ) (364,756 ) Renewable energy facilities in service, net 4,853,513 4,990,127 Construction in progress - renewable energy facilities 790 3,124 Total renewable energy facilities, net $ 4,854,303 $ 4,993,251 Depreciation expense related to renewable energy facilities was $53.4 million and $160.0 million for the three and nine months ended September 30, 2017 , respectively, as compared to $48.1 million and $148.5 million for the same periods in the prior year. Construction in progress represents costs incurred to complete the construction of the facilities in the Company's current portfolio that were acquired from SunEdison. All construction in progress costs are stated at SunEdison's historical cost. As of December 31, 2016 , the Company reclassified $548.7 million from renewable energy facilities, net to non-current assets held for sale in the unaudited condensed consolidated balance sheet. There was no similar reclassification as of September 30, 2017 as the sale of these renewable energy facilities closed in the first half of 2017 (see Note 2. Assets Held for Sale ).

Intangibles

Intangibles	9 Months Ended
	Sep. 30, 2017
Goodwill and Intangible Assets Disclosure [Abstract]
Intangibles	INTANGIBLES The following table presents the gross carrying amount, accumulated amortization and net book value of intangibles as of September 30, 2017 : (In thousands, except weighted average amortization period) Weighted Average Amortization Period Gross Carrying Amount Accumulated Amortization Net Book Value Favorable rate revenue contracts 15 years $ 720,109 $ (92,139 ) $ 627,970 In-place value of market rate revenue contracts 19 years 521,798 (67,022 ) 454,776 Favorable rate land leases 17 years 15,800 (2,130 ) 13,670 Total intangible assets, net $ 1,257,707 $ (161,291 ) $ 1,096,416 Unfavorable rate revenue contracts 7 years $ 35,086 $ (14,744 ) $ 20,342 Unfavorable rate O&M contracts 2 years 5,000 (2,240 ) 2,760 Unfavorable rate land lease 15 years 1,000 (148 ) 852 Total intangible liabilities, net $ 41,086 $ (17,132 ) $ 23,954 The following table presents the gross carrying amount, accumulated amortization and net book value of intangibles as of December 31, 2016 : (In thousands, except weighted average amortization period) Weighted Average Amortization Period Gross Carrying Amount Accumulated Amortization Net Book Value Favorable rate revenue contracts 16 years $ 714,758 $ (57,634 ) $ 657,124 In-place value of market rate revenue contracts 20 years 518,003 (47,284 ) 470,719 Favorable rate land leases 18 years 15,800 (1,531 ) 14,269 Total intangible assets, net $ 1,248,561 $ (106,449 ) $ 1,142,112 Unfavorable rate revenue contracts 7 years $ 35,086 $ (10,541 ) $ 24,545 Unfavorable rate O&M contracts 3 years 5,000 (1,302 ) 3,698 Unfavorable rate land lease 16 years 1,000 (107 ) 893 Total intangible liabilities, net $ 41,086 $ (11,950 ) $ 29,136 The Company has intangible assets related to revenue contracts, representing long-term power purchase agreements ("PPAs") and renewable energy certificate ("REC") agreements, and favorable rate land leases that were obtained through acquisitions. The revenue contract intangible assets are comprised of favorable rate PPAs and REC agreements and the in-place value of market rate PPAs. The Company also has intangible liabilities related to unfavorable rate PPAs and REC agreements, unfavorable rate O&M contracts and an unfavorable rate land lease, which are classified within other long-term liabilities in the unaudited condensed consolidated balance sheets. These intangible assets and liabilities are amortized on a straight-line basis over the remaining lives of the agreements, which range from 1 to 27 years as of September 30, 2017 . Amortization expense related to favorable rate revenue contracts is reflected in the unaudited condensed consolidated statements of operations as a reduction of operating revenues, net. Amortization related to unfavorable rate revenue contracts is reflected in the unaudited condensed consolidated statements of operations as an increase to operating revenues, net. During the three and nine months ended September 30, 2017 , net amortization expense related to favorable and unfavorable rate revenue contracts resulted in a reduction of operating revenues, net of $10.0 million and $29.5 million , respectively, as compared to a $9.8 million and $30.1 million reduction of operating revenues, net for the same periods in the prior year. Amortization expense related to the in-place value of market rate revenue contracts is reflected in the unaudited condensed consolidated statements of operations within depreciation, accretion and amortization expense. During the three and nine months ended September 30, 2017 , amortization expense related to the in-place value of market rate revenue contracts was $6.4 million and $19.4 million , respectively, as compared to $7.0 million and $20.8 million for the same periods in the prior year. Amortization expense related to favorable rate land leases is reflected in the unaudited condensed consolidated statements of operations within cost of operations. Amortization related to the unfavorable rate land lease and unfavorable rate O&M contracts is reflected in the unaudited condensed consolidated statements of operations as a reduction of cost of operations. During the three and nine months ended September 30, 2017 , net amortization related to favorable and unfavorable rate land leases and unfavorable rate O&M contracts resulted in a reduction of cost of operations of $0.1 million and $0.4 million , respectively, as compared to a $0.2 million and $0.6 million increase to cost of operations for the same periods in the prior year.

Variable Interest Entities

Variable Interest Entities	9 Months Ended
	Sep. 30, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Variable Interest Entities	VARIABLE INTEREST ENTITIES The Company consolidates variable interest entities ("VIEs") in renewable energy facilities when the Company is the primary beneficiary. The VIEs own and operate renewable energy facilities in order to generate contracted cash flows. The VIEs were funded through a combination of equity contributions from the owners and non-recourse project-level debt. As a result of the Company's sale of TerraForm Resi Solar Manager, LLC, a subsidiary of the Company that owned and operated 8.9 MW of residential rooftop solar installations, during the second quarter of 2017, the related assets and liabilities of this variable interest entity were deconsolidated (see Note 2. Assets Held for Sale ). No other VIEs were deconsolidated during the nine months ended September 30, 2017 and 2016 . The carrying amounts and classification of the consolidated VIEs’ assets and liabilities included in the Company's unaudited condensed consolidated balance sheets are as follows: (In thousands) September 30, December 31, Current assets $ 172,183 $ 191,244 Non-current assets 4,222,425 4,351,635 Total assets $ 4,394,608 $ 4,542,879 Current liabilities $ 202,451 $ 638,452 Non-current liabilities 930,187 514,464 Total liabilities $ 1,132,638 $ 1,152,916 The amounts shown in the table above exclude intercompany balances that are eliminated upon consolidation. All of the assets in the table above are restricted for settlement of the VIE obligations, and all of the liabilities in the table above can only be settled by using VIE resources. As a result of the consummation of the Merger and change of control of TerraForm Power that occurred on October 16, 2017 as discussed in Note 1. Nature of Operations and Basis of Presentation , the Company will perform an updated consolidation assessment in the fourth quarter of 2017.

Long-term Debt

Long-term Debt	9 Months Ended
	Sep. 30, 2017
Debt Disclosure [Abstract]
Long-term Debt	LONG-TERM DEBT Long-term debt consists of the following: (In thousands, except rates) September 30, December 31, Interest Type Interest Rate (%) 1 Financing Type Corporate-level long-term debt 2 : Senior Notes due 2023 $ 950,000 $ 950,000 Fixed 6.38 Senior notes Senior Notes due 2025 300,000 300,000 Fixed 6.63 Senior notes Revolver 277,000 552,000 Variable 4.02 Revolving loan Non-recourse long-term debt 3 : Permanent financing 1,986,317 2,078,009 Blended 4 5.89 5 Term debt / Senior notes Financing lease obligations 118,194 123,930 Imputed 5.62 5 Financing lease obligations Total principal due for long-term debt and financing lease obligations 3,631,511 4,003,939 5.93 5 Unamortized discount, net (15,105 ) (13,620 ) Deferred financing costs, net (35,012 ) (39,405 ) Less current portion of long-term debt and financing lease obligations 6 (716,728 ) (2,212,968 ) Long-term debt and financing lease obligations, less current portion 7 $ 2,864,666 $ 1,737,946 ——— (1) As of September 30, 2017 . (2) Corporate-level debt represents debt issued by Terra Operating LLC and guaranteed by Terra LLC and certain subsidiaries of Terra Operating LLC other than certain non-recourse subsidiaries as defined in the relevant debt agreements. (3) Non-recourse debt represents debt issued by subsidiaries with no recourse to Terra LLC, Terra Operating LLC or guarantors of the Company's corporate-level debt, other than limited or capped contingent support obligations, which in aggregate are not considered to be material to the Company's business and financial condition. (4) Includes variable rate debt and fixed rate debt. As of September 30, 2017 , 50% of this balance had a variable interest rate and the other 50% of this balance had a fixed interest rate. The Company has entered into interest rate swap agreements to fix the interest rates of certain variable rate permanent financing non-recourse debt (see Note 8 . Derivatives ). (5) Represents the weighted average interest rate as of September 30, 2017 . (6) As of December 31, 2016, the Company reclassified $14.7 million from current portion of long-term debt and financing lease obligations to current liabilities related to assets held for sale in the unaudited condensed consolidated balance sheet. There was no similar reclassification as of September 30, 2017 as the sale of the related renewable energy facilities closed in the first half of 2017 (see Note 2. Assets Held for Sale ). (7) As of December 31, 2016, the Company reclassified $353.9 million from long-term debt and financing lease obligations, less current portion to non-current liabilities related to assets held for sale in the unaudited condensed consolidated balance sheet. There was no similar reclassification as of September 30, 2017 as the sale of the related renewable energy facilities closed in the first half of 2017 (see Note 2. Assets Held for Sale ). Corporate-level Long-term Debt Revolver In conjunction with a consent agreement that Terra Operating LLC entered into in September of 2016 with the Administrative Agent and other parties to the Revolver, which provided consent for the cross-collateralization of certain utility-scale assets located in Canada owned by subsidiaries of the Company, and as a result of the Company's election in February of 2017 to increase the principal amount of the credit facility described in the " Canada project-level financing " section below, Terra Operating LLC repaid an additional $5.0 million of Revolver indebtedness on March 6, 2017 and permanently reduced the revolving commitments and borrowing capacity by such amount. The terms of the Revolver require the Company to provide audited annual financial statements within 90 days after the end of the fiscal year, with a 10 -business day cure period. On April 5, 2017 and April 26, 2017, Terra Operating LLC entered into a tenth amendment and an eleventh amendment, respectively, to the terms of the Revolver, which collectively provided that the date on which the Company must deliver to the Administrative Agent and other parties to the Revolver its annual financial statements and accompanying audit report with respect to fiscal year 2016 would be extended to the earlier of (a) July 15, 2017 and (b) the tenth business day prior to the date on which the failure to deliver such financial statements would constitute an event of default under the indenture dated as of January 28, 2015 (as supplemented) with respect to the Senior Notes due 2023 (the "2023 Indenture"). As discussed below, an event of default would not have occurred under the 2023 Indenture until July 31, 2017. The Company's Form 10-K for the year ended December 31, 2016 was filed within the 10 -business day cure period that commenced on July 15, 2017, and consequently no event of default occurred under the Revolver with respect to the 2016 10-K filing. The amendment also extended the due date for delivery to the Administrative Agent and other parties to the Revolver for the Company's financial statements and accompanying information with respect to the fiscal quarter ended March 31, 2017 to July 31, 2017 and with respect to the fiscal quarters ending June 30, 2017 and September 30, 2017 to the date that is 75 days after the end of each such fiscal quarter, with a 10 -business day cure period for each quarterly deliverable. The eleventh amendment also amended the Debt Service Coverage Ratio (as defined therein) applicable to the fourth quarter of 2016 and first, second and third quarters of 2017 from 1.75 :1.00 to 1.50 :1.00 and amended the Leverage Ratio (as defined therein) applicable to the fourth quarter of 2016 from 6.00 :1.00 to 6.50 :1.00 and applicable to the first, second and third quarters of 2017 from 5.75 :1.00 to 6.50 :1.00. In addition, the amendment amended the definitions of Debt Service Coverage Ratio and Leverage Ratio to provide for, in each case, certain pro forma treatment of the repayment or refinancing of Non-Recourse Project Indebtedness (as defined therein) net of any new Non-Recourse Project Indebtedness incurred in connection with any such refinancing. Per the terms of the eleventh amendment, Terra Operating LLC agreed to prepay $50.0 million of revolving loans outstanding under the Revolver and permanently reduce the revolving commitments and borrowing capacity by such amount. This amount was repaid on May 3, 2017. The Company recognized a $0.6 million charge during the nine months ended September 30, 2017 as a result of this reduction in borrowing capacity for the Revolver and corresponding write-off of a portion of the unamortized deferred financing costs, which is reflected within interest expense, net in the unaudited condensed consolidated statement of operations. On July 25, 2017, Terra Operating LLC repaid an additional $150.0 million of Revolver indebtedness, a portion of which was paid using proceeds the Company received from the sale of the U.K. Portfolio as discussed in Note 2. Assets Held for Sale . There was no reduction in revolving commitments and borrowing capacity as a result of this repayment. On August 10, 2017, the Company entered into a twelfth amendment to the terms of the Revolver which further extended the due dates for delivery to the Administrative Agent and other parties to the Revolver for the Company's financial statements and accompanying information with respect to the first quarter of 2017 to August 30, 2017, the second quarter of 2017 to September 30, 2017 and the third quarter of 2017 to December 15, 2017. In addition, the Administrative Agent and requisite lenders waived all defaults or events of default existing as of or prior to the effective date of the twelfth amendment, and the consequences thereof, in connection with a failure to comply with the covenants requiring the delivery of the financial statements and accompanying information with respect to the first quarter of 2017. The Company filed its Form 10-Q for the first quarter of 2017 prior to August 30, 2017 and filed its Form 10-Q for the second quarter of 2017 prior to September 30, 2017, and consequently no event of default occurred under the Revolver with respect to financial statement delivery for the first and second quarter of 2017. As discussed below, the Company terminated the Revolver prior to the due date for the third quarter financial statements. Per the terms of the twelfth amendment, Terra Operating LLC agreed to permanently reduce the revolving commitments under the Revolver by $50.0 million . The Company recognized a $0.5 million charge during the three and nine months ended September 30, 2017 as a result of this reduction in borrowing capacity for the Revolver and corresponding write-off of a portion of the unamortized deferred financing costs, which is reflected within interest expense, net in the unaudited condensed consolidated statements of operations. As of September 30, 2017, the total borrowing capacity under the Revolver was $520.0 million . There was no additional payment of principal on the Revolver made in connection with this commitment reduction. On September 27, 2017, Terra Operating LLC repaid an additional $70.0 million of Revolver indebtedness, reducing the amount of revolving loans outstanding to $277.0 million . There was no reduction in revolving commitments and borrowing capacity as a result of this repayment. On October 17, 2017, concurrently with its entry into the New Revolver (as defined and described below), Terra Operating LLC terminated the Revolver and repaid the outstanding loan amount of $277.0 million , using $27.0 million of cash on hand and $250.0 million of borrowings drawn under the New Revolver. There were no prepayment penalties incurred in connection with the termination of the Revolver. New Revolver On October 17, 2017, Terra Operating LLC entered into a new senior secured revolving credit facility (the “New Revolver”). The New Revolver consists of a revolving credit facility in an initial amount of $450.0 million (available for revolving loans and letters of credit). The New Revolver matures on the four -year anniversary of the closing date of such facility. Each of Terra Operating LLC’s existing and subsequently acquired or organized domestic restricted subsidiaries (excluding non-recourse subsidiaries) and Terra LLC are or will become guarantors under the New Revolver. $250.0 million of revolving loans were initially drawn and used to repay a portion of the outstanding borrowings under the existing Revolver as discussed above. All outstanding amounts under the New Revolver will bear interest at a rate per annum equal to, at Terra Operating LLC’s option, either (i) a base rate plus a margin ranging between 1.25% to 2.00% or (ii) a reserve adjusted Eurodollar rate plus a margin ranging between 2.25% to 3.00% . In addition to paying interest on outstanding principal under the New Revolver, the Company will be required to pay a standby fee in respect of the unutilized commitments thereunder, payable quarterly in arrears. This standby fee will range between 0.375% and 0.50% per annum. The New Revolver provides for voluntary prepayments, in whole or in part, subject to notice periods. There are no prepayment penalties or premiums other than customary breakage costs. The New Revolver contains customary affirmative covenants and negative covenants, subject to exceptions, by Terra LLC, Terra Operating LLC and certain of Terra Operating LLC’s subsidiaries, including covenants related to financial statements and other reports (including notices of default) and a maximum leverage ratio that will be tested quarterly. Pursuant to the terms of the New Revolver, a default of more than $75.0 million of indebtedness (other than non-recourse indebtedness, and indebtedness under the Sponsor Line Agreement (as defined and discussed below) as it is an obligation of TerraForm Power), including under the 2023 Indenture and the indenture dated as of July 17, 2015 (as supplemented) with respect to the Senior Notes due 2025 (the "2025 Indenture"), would result in a cross-default under the New Revolver that would permit the lenders holding more than 50% of the aggregate exposure under the New Revolver to accelerate any outstanding principal amount of loans, terminate any outstanding letter of credit and terminate the outstanding commitments under the New Revolver. The New Revolver, each guarantee and any interest rate, currency hedging or hedging of REC obligations of Terra Operating LLC or any guarantor owed to the administrative agent, any arranger or any lender under the New Revolver is secured by first priority security interests in (i) all of Terra Operating LLC’s, each guarantor’s and certain unencumbered non-recourse subsidiaries’ assets, (ii) 100% of the capital stock of each of Terra Operating LLC and its domestic restricted subsidiaries and 65% of the capital stock of Terra Operating LLC’s foreign restricted subsidiaries and (iii) all intercompany debt. Notwithstanding the foregoing, collateral under the New Revolver excludes the capital stock of non-recourse subsidiaries. As of November 8, 2017, the New Revolver is secured equally and ratably with the Company's new senior secured term loan described below. Senior Notes due 2023 and Senior Notes due 2025 The Senior Notes due 2023 and the Senior Notes due 2025 require the Company to timely file with the SEC, or make publicly available, audited annual financial statements and unaudited quarterly financial statements no later than 60 days following the date required by the SEC's rules and regulations (including extensions thereof). The Company has a 90 -day grace period from the date a notice of default is deemed to be duly given to Terra Operating LLC in accordance with the Senior Notes due 2023 and the Senior Notes due 2025 . On May 2, 2017, Terra Operating LLC received a notice from the trustee of an event of default for failure to deliver 2016 audited annual financial statements and thus had until July 31, 2017 to deliver its 2016 audited financial statements before an event of default would occur under the 2023 Indenture and the 2025 Indenture. However, the Form 10-K for the year ended December 31, 2016 was filed with the SEC within the grace period for delivery, and consequently no event of default occurred with respect to the 2016 10-K filing. On July 11, 2017, Terra Operating LLC received a notice from the trustee of an event of default for failure to comply with its obligation to timely furnish the Company's Form 10-Q for the first quarter of 2017. However, the Company's Form 10-Q for the first quarter of 2017 was filed within the 90 -day grace period that commenced on July 11, 2017, and consequently no event of default occurred with respect to the Form 10-Q for the first quarter of 2017. The Company filed its Form 10-Q for the second quarter of 2017 and this Form 10-Q for the third quarter of 2017 prior to the initial respective deadline under the 2023 Indenture and the 2025 Indenture. The closing of the Merger would have triggered a change in control under the 2023 Indenture and the 2025 Indenture. The 2023 Indenture and the 2025 Indenture require the Company to make an offer to repurchase the Senior Notes issued under the respective indentures at 101% of the applicable principal amount, plus accrued and unpaid interest and additional interest, if any, to the repurchase date following a change in control. However, on August 11, 2017, the Company announced the successful completion of a solicitation of consents from holders of record as of 5:00 p.m., New York City time, on August 1, 2017 of its Senior Notes due 2023 and its Senior Notes due 2025 to obtain a waiver of the requirement to make an offer to repurchase the Senior Notes issued under the respective indentures upon the occurrence of a change of control that would result from the consummation of the Merger. Terra Operating LLC received validly delivered and unrevoked consents from the holders of a majority of the aggregate principal amount of each series of the Senior Notes outstanding as of the record date and paid a consent fee to each consenting holder of $1.25 per $1,000 principal amount of such series of the Senior Notes for which such holder delivered its consent. The payment of this additional $1.5 million fee to the lenders was accounted for as a debt modification and capitalized as an additional debt discount, which will be amortized proportionately over the respective maturities of the Senior Notes as part of the new effective yield. In addition to the change of control waiver, Terra Operating LLC also received consents to effect on the closing date of the Merger certain amendments to the 2023 Indenture and the 2025 Indenture. As a result, on October 16, 2017, Terra Operating LLC entered into a sixth supplemental indenture to the 2023 Indenture and a fifth supplemental indenture to the 2025 Indenture that amended the definition of "Permitted Holder" under the respective indentures (which is referred to in the definition of change of control) to replace the references to "the Sponsor" therein with "Brookfield Asset Management Inc. (or its successors and assigns)." Upon the closing of the Merger, Terra Operating LLC was also obligated to pay a success fee of $1.25 per $1,000 principal amount of each series of the Senior Notes for which such consenting holder delivered its consent. Pursuant to the terms of the 2023 Indenture and the 2025 Indenture, a default of more than $75.0 million of indebtedness (other than non-recourse indebtedness and indebtedness under the Sponsor Line Agreement (as defined and discussed below) as it is an obligation of TerraForm Power), including under the New Revolver, that is (i) caused by a failure to pay principal of, or interest or premium, if any, on such indebtedness prior to the expiration of the grace period provided in such indebtedness on the date of such default or (ii) results in the acceleration of such indebtedness would give the trustee under the respective Indentures or the holders of at least 25% in the aggregate principal amount of the then outstanding senior notes under the respective Indentures the right to accelerate any outstanding principal amount of loans, terminate any outstanding letter of credit and terminate the outstanding commitments under the respective Indentures. Sponsor Line Agreement On October 16, 2017, TerraForm Power entered into a credit agreement (the “Sponsor Line Agreement”) with Brookfield and one of its affiliates. The Sponsor Line Agreement establishes a $500.0 million secured revolving credit facility and provides for the lenders to commit to make LIBOR loans to the Company during a period not to exceed three years from the effective date of the Sponsor Line Agreement (subject to acceleration for certain specified events). The Company may only use the revolving credit facility to fund all or a portion of certain funded acquisitions or growth capital expenditures. The Sponsor Line Agreement will terminate, and all obligations thereunder will become payable, no later than October 16, 2022. Borrowings under the Sponsor Line Agreement will bear interest at a rate per annum equal to a LIBOR rate determined by reference to the costs of funds for U.S. dollar deposits for the interest period relevant to such borrowing adjusted for certain additional costs, in each case plus 3.00% per annum. In addition to paying interest on outstanding principal under the Sponsor Line Agreement, the Company will be required to pay a standby fee of 0.50% per annum in respect of the unutilized commitments thereunder, payable quarterly in arrears. TerraForm Power will be permitted to voluntarily reduce the unutilized portion of the commitment amount and repay outstanding loans under the Sponsor Line Agreement at any time without premium or penalty, other than customary “breakage” costs. TerraForm Power’s obligations under the Sponsor Line Agreement are secured by first-priority security interests in substantially all assets of TerraForm Power, including 100% of the capital stock of Terra LLC, in each case subject to certain exclusions set forth in the credit documentation governing the Sponsor Line Agreement. The Sponsor Line Agreement contains a number of covenants that, among other things and subject to certain exceptions, restrict TerraForm Power’s ability to enter into swap contracts, sell or otherwise dispose of all or substantially all its assets or to engage in certain businesses. The Sponsor Line Agreement also contains certain customary affirmative covenants and events of default. If an event of default, as specified in the Sponsor Line Agreement, shall occur and be continuing, the Company may be required to repay all amounts outstanding under the Sponsor Line Agreement. An event of default under the New Revolver, 2023 Indenture or 2025 Indenture would trigger an event of default under the Sponsor Line Agreement. Senior Secured Term Loan On November 8, 2017, Terra Operating LLC entered into a 5 -year $350.0 million senior secured term loan, which was primarily used to repay outstanding borrowings under the non-recourse portfolio term loan discussed under the Non-recourse Portfolio Term Loan Prepayments section below, prior to the date a change of control default would have occurred. This term loan bears interest at a rate per annum equal to LIBOR plus a margin of 2.75% and is secured equally and ratably with the New Revolver. Non-recourse Long-term Debt Indirect subsidiaries of the Company have incurred long-term non-recourse debt obligations with respect to the renewable energy facilities that those subsidiaries own directly or indirectly. The indebtedness of these subsidiaries is typically secured by the renewable energy facility's assets (mainly the renewable energy facility) or equity interests in such renewable energy facilities with no recourse to TerraForm Power, Terra LLC or Terra Operating LLC other than limited or capped contingent support obligations, which in aggregate are not considered to be material to the Company's business and financial condition. In connection with these financings and in the ordinary course of its business, the Company and its subsidiaries observe formalities and operating procedures to maintain each of their separate existence and can readily identify each of their separate assets and liabilities as separate and distinct from each other. As a result, these subsidiaries are legal entities that are separate and distinct from TerraForm Power, Terra LLC, Terra Operating LLC and the guarantors under the New Revolver, the Senior Notes due 2023, the Senior Notes due 2025 and the Sponsor Line Agreement. Canada project-level financing On November 2, 2016, certain of the Company's subsidiaries entered into a new non-recourse loan financing in an aggregate principal amount of $120.0 million Canadian dollars ("CAD"), including a CAD $6.9 million letter of credit, secured by approximately 59 MW of utility-scale solar power plants located in Canada that are owned by the Company's subsidiaries. On February 28, 2017, the Company increased the principal amount of the credit facility by an additional CAD $113.9 million (including an additional CAD $6.7 million letter of credit), increasing the total facility to CAD $233.9 million . The proceeds of this additional financing were used for general corporate purposes and to pay down an additional $5.0 million on the Revolver as described above. Non-recourse Portfolio Term Loan Prepayments The Company had a non-recourse portfolio term loan that was secured by indirect equity interests in approximately 1,104.3 MW of the Company's renewable energy facilities, consisting of assets acquired from Invenergy Wind Global LLC (together with its subsidiaries, "Invenergy Wind") and certain other renewable energy facilities acquired from SunEdison. The loan was to mature in January 15, 2019 to the extent the Company exercised its extension options. The Company exercised the first two extension options in January and July of 2017, respectively. In June of 2017, the Company agreed to make a $100.0 million prepayment for this loan in connection with obtaining (i) a waiver to extend the 2016 audited project financial statement deadline under the loan agreement and (ii) a waiver of the change of control default that would arise under this loan agreement as a result of the Merger until, in the case of the change of control waiver, the date that is the earlier of three months following the closing of the Merger and March 31, 2018. This prepayment was made using a portion of the proceeds the Company received from the sale of the U.K. Portfolio as discussed in Note 2. Assets Held for Sale . On September 27, 2017, the Company made an additional $30.0 million prepayment for this loan. The Company recognized a $1.4 million charge during the nine months ended September 30, 2017 as a result of these prepayments and corresponding write-off of a proportionate amount of the unamortized debt discount and deferred financing costs, which is reflected within interest expense, net in the unaudited condensed consolidated statement of operations. This term loan had an outstanding principal balance of $337.9 million as of September 30, 2017. In October of 2017, the Company made $37.6 million of additional prepayments. On November 8, 2017, the Company repaid the remaining principal balance using borrowings from the $350.0 million senior secured term loan that Terra Operating LLC entered into on November 8, 2017 as discussed in the Senior Secured Term Loan section above. Non-recourse Debt Defaults Historically, a SunEdison Debtor was a party to or guarantor of a material project agreement, such as asset management or O&M contracts, for most of the Company's non-recourse financing arrangements. As a result of the SunEdison Bankruptcy and delays in delivery of 2015 audited financial statements for the Company and/or certain project-level subsidiaries, among other things, the Company experienced defaults under most of its non-recourse financing agreements in 2016. During the course of 2016 and to date in 2017, the Company cured or obtained waivers or temporary forbearances with respect to most of these defaults and has substantially transitioned the project-level services provided by SunEdison Debtors to third parties or in-house to a Company affiliate; however, certain of these defaults persist. Moreover, the Company experienced additional defaults under most of the same non-recourse financing agreements in 2017 as the result of the failure to timely complete Company and/or project-level audits. The Company filed its Form 10-K for the year ended December 31, 2016 on July 21, 2017 and has completed all project-level audits for fiscal year 2016 as of the date hereof. The Company has also substantially delivered all outstanding project-level quarterly reporting deliverables for 2017 and is working to complete the remaining deliverables and seeking to obtain waivers for late delivery of project-level financial statements that were delivered after the grace period expired. For certain of these defaults, the corresponding contractual grace periods already expired as of the respective financial statement issuance date or the Company could not assert that it was probable that the violation would be cured within any remaining grace periods. In addition, while the Company has been actively negotiating with the lenders to obtain waivers, the lenders have not currently waived or subsequently lost the right to demand repayment for more than one year from the balance sheet date with respect to these defaults. As these defaults occurred prior to the issuance of the financial statements for the nine months ended September 30, 2017 and for the year ended December 31, 2016, $545.2 million and $1.6 billion of the Company's non-recourse long-term indebtedness, net of unamortized debt discounts and deferred financing costs, was reclassified to current in the unaudited condensed consolidated balance sheets as of September 30, 2017 and December 31, 2016, respectively, as the Company accounts for debt in default as of the date the financial statements are issued in the same manner as if the default existed as of the balance sheet date. Amortization of deferred financing costs and debt discounts continue to be amortized over the maturities of the respective financing agreements as before the violations, as the Company believes there is a reasonable likelihood that it will be able to successfully negotiate a waiver with the lenders and/or cure the defaults based on (i) its past history of obtaining waivers and/or forbearance agreements with lenders, (ii) the nature and existence of active negotiations between the Company and the respective lenders to secure a waiver, (iii) ongoing efforts to provide quarterly financial statement deliverables to cure certain of the defaults, (iv) the Company's timely servicing of these debt instruments and (v) as no non-recourse financing has been accelerated to date and no project-level lender has notified the Company of such lenders election to enforce project security interests. As a result of these defaults, the Company also reclassified $51.2 million and $65.3 million of long-term restricted cash to current as of September 30, 2017 and December 31, 2016, respectively, consistent with the corresponding debt classification, as the restrictions that required the cash balances to be classified as long-term restricted cash were driven by the financing agreements. As of September 30, 2017 and December 31, 2016, $60.0 million and $67.1 million , respectively, of cash and cash equivalents was also reclassified to current restricted cash as the cash balances were subject to distribution restrictions related to debt defaults that existed as of the respective balance sheet date. $33.8 million of the December 31, 2016 reclassification amount was reclassified from current restricted cash to assets held for sale as it related to the portfolios discussed in Note 2. Assets Held for Sale . There was no similar reclassification to assets held for sale for the September 30, 2017 reclassification amount as the sale of the related renewable energy facilities closed in the first half of 2017. Refer to Note 8 . Derivatives for discussion of corresponding interest rate swap reclassifications to current as a result of these defaults. Maturities The aggregate contractual payments of long-term debt due after September 30, 2017 , including financing lease obligations and excluding amortization of debt discounts, premiums and deferred financing costs, as stated in the financing agreements, are as follows: (In thousands) Remainder of 2017 1 2018 2019 2020 2021 2 Thereafter Total Maturities of long-term debt as of September 30, 2017 3 $ 99,146 $ 111,620 $ 391,330 $ 101,867 $ 355,118 $ 2,572,430 $ 3,631,511 ——— (1) Includes $27.0 million of Revolver indebtedness that was repaid with cash on hand in the fourth quarter of 2017 as discussed above. Also includes $37.6 million of prepayments made in the fourth quarter of 2017 for the Company's non-recourse portfolio term loan as discussed above under Non-recourse Portfolio Term Loan Prepayments . (2) Includes $250.0 million of Revolver indebtedness, which was refinanced with the New Revolver in the fourth quarter of 2017 as discussed above. Management does not intend to repay these borrowings within a year from the balance sheet date with the use of working capital and the New Revolver does not mature until 2021. (3) Represents the contractual principal payment due dates for the Company's long-term debt and does not reflect the reclassification of $545.2 million of long-term debt to current as a result of debt defaults under certain of the Company's non-recourse financing arrangements.

Income Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2017
Income Tax Disclosure [Abstract]
Income Taxes	INCOME TAXES The income tax provision consisted of the following: Three Months Ended September 30, Nine Months Ended September 30, (In thousands, except effective tax rate) 2017 2016 2017 2016 Loss before income tax (benefit) expense $ (37,453 ) $ (26,571 ) $ (96,755 ) $ (103,038 ) Income tax (benefit) expense (2,633 ) 1,140 (4,982 ) 3,115 Effective tax rate 7.0 % (4.3 )% 5.1 % (3.0 )% As of September 30, 2017 , TerraForm Power owned 65.8% of Terra LLC and consolidated the results of Terra LLC through its controlling interest. The Company recorded SunEdison's 34.2% ownership of Terra LLC as a non-controlling interest in the financial statements. Terra LLC is treated as a partnership for income tax purposes. As such, the Company recorded income tax on its 65.8% of Terra LLC's taxable income and SunEdison recorded income tax on its 34.2% share of Terra LLC's taxable income. For the three and nine months ended September 30, 2017 and 2016, the overall effective tax rate was different than the statutory rate of 35% primarily due to the recording of a valuation allowance on certain tax benefits attributed to the Company, loss allocated to non-controlling interests and the effect of state taxes. As of September 30, 2017 , most jurisdictions were in a net deferred tax asset position. A valuation allowance is recorded against the deferred tax assets primarily because of the history of losses in those jurisdictions. As of September 30, 2017, the Company had not identified any uncertain tax positions for which a liability was required.

Derivatives

Derivatives	9 Months Ended
	Sep. 30, 2017
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivatives	DERIVATIVES As part of the Company’s risk management strategy, the Company has entered into derivative instruments which include interest rate swaps, foreign currency contracts and commodity contracts to mitigate interest rate, foreign currency and commodity price exposure. If the Company elects to do so and if the instrument meets the criteria specified in ASC 815, Derivatives and Hedging , the Company designates its derivative instruments as cash flow hedges. The Company enters into interest rate swap agreements in order to hedge the variability of expected future cash interest payments. Foreign currency contracts are used to reduce risks arising from the change in fair value of certain foreign currency denominated assets and liabilities. The objective of these practices is to minimize the impact of foreign currency fluctuations on operating results. The Company also enters into commodity contracts to economically hedge price variability inherent in electricity sales arrangements. The objectives of the commodity contracts are to minimize the impact of variability in spot electricity prices and stabilize estimated revenue streams. The Company does not use derivative instruments for speculative purposes. As of September 30, 2017 and December 31, 2016 , fair values of the following derivative instruments were included in the balance sheet captions indicated below: Fair Value of Derivative Instruments Hedging Contracts Derivatives Not Designated as Hedges (In thousands) Interest Rate Swaps Commodity Contracts Interest Rate Swaps Foreign Currency Contracts Commodity Contracts Gross Amounts of Assets/Liabilities Recognized Gross Amounts Offset in Consolidated Balance Sheet Net Amounts in Consolidated Balance Sheet As of September 30, 2017 Prepaid expenses and other current assets $ — $ 11,191 $ — $ 82 $ 13,765 $ 25,038 $ (82 ) $ 24,956 Other assets 3,611 86,517 — — 19,305 109,433 — 109,433 Total assets $ 3,611 $ 97,708 $ — $ 82 $ 33,070 $ 134,471 $ (82 ) $ 134,389 Accounts payable, accrued expenses and other current liabilities $ 9,049 $ — $ 242 $ 110 $ — $ 9,401 $ (82 ) $ 9,319 Other long-term liabilities 129 — 489 — — 618 — 618 Total liabilities $ 9,178 $ — $ 731 $ 110 $ — $ 10,019 $ (82 ) $ 9,937 As of December 31, 2016 Prepaid expenses and other current assets $ 1,150 $ 3,664 $ — $ 953 $ 12,028 $ 17,795 $ — $ 17,795 Other assets 411 62,474 — 460 25,167 88,512 — 88,512 Total assets $ 1,561 $ 66,138 $ — $ 1,413 $ 37,195 $ 106,307 $ — $ 106,307 Accounts payable, accrued expenses and other current liabilities $ 10,689 $ — $ 814 $ — $ — $ 11,503 $ — $ 11,503 Liabilities related to assets held for sale — — 4,041 — — 4,041 — 4,041 Other long-term liabilities 47 — — — — 47 — 47 Non-current liabilities related to assets held for sale — — 16,786 — — 16,786 — 16,786 Total liabilities $ 10,736 $ — $ 21,641 $ — $ — $ 32,377 $ — $ 32,377 As of September 30, 2017 and December 31, 2016 , notional amounts for derivative instruments consisted of the following: Notional Amount as of (In thousands) September 30, 2017 December 31, 2016 Derivatives designated as hedges: Interest rate swaps (USD) 405,183 433,874 Interest rate swaps (CAD) 156,713 84,713 Commodity contracts (MWhs) 15,941 16,988 Derivatives not designated as hedges: Interest rate swaps (USD) 13,788 14,681 Interest rate swaps (GBP) — 222,018 Foreign currency contracts (CAD) 15,175 25,075 Commodity contracts (MWhs) 1,117 1,407 The Company has elected to present net derivative assets and liabilities on the balance sheet as a right to setoff exists. For interest rate swaps, the Company either nets derivative assets and liabilities on a trade-by-trade basis or nets them in accordance with a master netting arrangement if such an arrangement exists with the counterparties. Foreign currency contracts are netted by currency in accordance with a master netting arrangement. The Company has a master netting arrangement for its commodity contracts for which no amounts were netted as of September 30, 2017 as each of the commodity contracts were in a gain position. Gains and losses on derivatives not designated as hedges for the three and nine months ended September 30, 2017 and 2016 consisted of the following: Location of Loss (Gain) in the Statements of Operations Three Months Ended September 30, Nine Months Ended September 30, (In thousands) 2017 2016 2017 2016 Interest rate swaps Interest expense, net $ 27 $ 5,127 $ 3,219 $ 36,583 Foreign currency contracts Loss on foreign currency exchange, net 457 (73 ) 1,017 (905 ) Commodity contracts Operating revenues, net (1,371 ) (3,095 ) (7,062 ) (11,009 ) During the second quarter of 2016, the Company discontinued hedge accounting for interest rate swaps that were previously designated as cash flow hedges of the forecasted interest payments pertaining to variable rate project debt in the U.K. Portfolio. Hedge accounting was prospectively discontinued for interest payments occurring before the anticipated sale date of June 2017, and for periods beyond that, the amounts accumulated in other comprehensive income were fully reclassified into earnings during the second quarter of 2016. As discussed in Note 2 . Assets Held for Sale , the Company consummated the sale of the U.K. Portfolio on May 11, 2017. As part of the sale agreement, Vortex Solar UK Limited assumed the debt and the associated interest rate swaps. As of the date of the sale, the remaining amount accumulated in other comprehensive income of $0.4 million was reclassified into earnings and the fair value liability of the interest rate swaps of $23.4 million is reflected in the unaudited condensed consolidated statements of operations within gain on sale of renewable energy facilities for the nine months ended September 30, 2017. As the sale occurred prior to the third quarter of 2017, there was no interest expense related to these interest rate swaps for the three months ended September 30, 2017. The interest expense amounts reflected in the table above for the other periods presented primarily pertains to these interest rate swaps. Gains and losses recognized related to interest rate swaps and commodity contracts designated as cash flow hedges for the three and nine months ended September 30, 2017 and 2016 consisted of the following: Three Months Ended September 30, Gain (Loss) Recognized in Other Comprehensive Income (Effective Portion) net of taxes 1 Location of Amount Reclassified from Accumulated Other Comprehensive Income into Income (Effective Portion) Amount of (Gain) Loss Reclassified from Accumulated Other Comprehensive Income into Income (Effective Portion) 2 Amount of (Gain) Loss Recognized in Income (Ineffective Portion and Amount Excluded from Effectiveness Testing) (In thousands) 2017 2016 2017 2016 2017 2016 Interest rate swaps $ 1,353 $ 798 Interest expense, net $ 519 $ 3,114 $ (315 ) $ (17 ) Commodity contracts 15,985 13,460 Operating revenues, net (425 ) 50 (5,316 ) 382 Total $ 17,338 $ 14,258 $ 94 $ 3,164 $ (5,631 ) $ 365 ———— (1) Net of tax expense of $0.3 million and $0.8 million attributed to interest rate swaps and commodity contracts during the three months ended September 30, 2017, respectively. There were no taxes attributed to derivatives designated as cash flow hedges during the three months ended September 30, 2016. (2) Net of tax benefit of $0.7 million and tax expense of $0.7 million attributed to interest rate swaps and commodity contracts during the three months ended September 30, 2017, respectively. There were no taxes attributed to derivatives designated as cash flow hedges during the three months ended September 30, 2016. Nine Months Ended September 30, Gain (Loss) Recognized in Other Comprehensive Income (Effective Portion) net of taxes 1 Location of Amount Reclassified from Accumulated Other Comprehensive Income into Income (Effective Portion) Amount of (Gain) Loss Reclassified from Accumulated Other Comprehensive Income into Income (Effective Portion) 2 Amount of (Gain) Loss Recognized in Income (Ineffective Portion and Amount Excluded from Effectiveness Testing) (In thousands) 2017 2016 2017 2016 2017 2016 Interest rate swaps $ (1,899 ) $ (39,547 ) Interest expense, net $ 3,163 $ 9,743 $ (963 ) $ 474 Commodity contracts 29,859 7,199 Operating revenues, net (3,690 ) (9,997 ) (5,340 ) 3,465 Total $ 27,960 $ (32,348 ) $ (527 ) $ (254 ) $ (6,303 ) $ 3,939 ———— (1) Net of tax benefit of $0.2 million and tax expense of $2.9 million attributed to interest rate swaps and commodity contracts during the nine months ended September 30, 2017, respectively. There were no taxes attributed to derivatives designated as cash flow hedges during the nine months ended September 30, 2016. (2) Net of tax benefit of $2.4 million and tax expense of $2.8 million attributed to interest rate swaps and commodity contracts during the nine months ended September 30, 2017, respectively. There were no taxes attributed to derivatives designated as cash flow hedges during the nine months ended September 30, 2016. As of September 30, 2017 and December 31, 2016 , the Company had posted letters of credit in the amount of $15.0 million and $18.0 million , respectively, as collateral related to certain commodity contracts. Certain derivative contracts contain provisions providing the counterparties a lien on specific assets as collateral. There was no cash collateral received or pledged as of September 30, 2017 and December 31, 2016 related to the Company's derivative transactions. Derivatives Designated as Hedges Interest Rate Swaps The Company has interest rate swap agreements to hedge variable rate non-recourse debt. These interest rate swaps qualify for hedge accounting and were designated as cash flow hedges. Under the interest rate swap agreements, the renewable energy facilities pay a fixed rate and the counterparties to the agreements pay a variable interest rate. The amounts deferred in other comprehensive income and reclassified into e arnings during the three and nine months ended September 30, 2017 and 2016 related to the interest rate swaps are provided in the tables above. The loss expected to be reclassified into earnings over the next twelve months is approximately $2.8 million . The maximum term of outstanding interest rate swaps designated as hedges is 17 years. As discussed in Note 6 . Long-term Debt , the Company experienced defaults under certain of its non-recourse financing agreements prior to the issuance of the financial statements for the nine months ended September 30, 2017 and for the year ended December 31, 2016. As the Company's interest rate swap agreements contain cross-default provisions, $5.1 million and $4.8 million of related liabilities have been reclassified to current as of September 30, 2017 and December 31, 2016, respectively. The Company is actively working with the counterparties to cure these defaults and obtain waivers as necessary. The Company does not currently expect any changes to the underlying cash flows as a result of these defaults and thus has determined that there is no impact to the swaps' qualification for hedge accounting and designation as cash flow hedges. Commodity Contracts The Company has long-dated physically delivered commodity contracts that hedge variability in cash flows associated with the sales of power from certain renewable energy facilities located in Texas. These commodity contracts qualify for hedge accounting and are designated as cash flow hedges. Accordingly, the effective portions of the change in fair value of these derivatives are reported in accumulated other comprehensive income and subsequently reclassified to earnings in the periods when the hedged transactions affect earnings. Any ineffective portions of the derivatives’ change in fair value are recognized currently in earnings. The amounts deferred in other comprehensive income and reclassified into earnings during the three and nine months ended September 30, 2017 and 2016 related to the commodity contracts are provided in the ta bles above. The gain expected to be reclassified into earnings over the next twelve months is approximately $9.9 million . The maximum term of outstanding commodity contracts designated as hedges is 12 years. Derivatives Not Designated as Hedges Interest Rate Swaps The Company has interest rate swap agreements that economically hedge the cash flows for non-recourse debt. These interest rate swaps pay a fixed rate and the counterparties to the agreements pay a variable interest rate. The changes in fair value are recorded in interest expense, net in the unaudited condensed consolidated statements of operations as these hedges are not accounted for under hedge accounting. As discussed in Note 6 . Long-term Debt , the Company experienced defaults under certain of its non-recourse financing agreements. As the Company's interest rate swap agreements contain cross-default provisions, $0.5 million of related liabilities were reclassified to current as of December 31, 2016. There was no similar reclassification for these interest rate swaps as of September 30, 2017 as the defaults under the corresponding financing agreements were cured and/or waived prior to the issuance of the financial statements. As of December 31, 2016, the Company reclassified $4.0 million of current derivative liabilities to liabilities related to assets held for sale and $16.8 million of non-current derivative liabilities to non-current liabilities related to assets held for sale. These pertain to interest rate swap agreements for the U.K. Portfolio that were previously designated as cash flow hedges. There was no similar reclassification to assets held for sale for the September 30, 2017 reclassification amount as the sale of the related renewable energy facilities closed in the first half of 2017. The Company discontinued hedge accounting for these interest rate swaps during the second quarter of 2016 and the changes in fair value were recorded through earnings. Foreign Currency Contracts The Company has foreign currency contracts in order to economically hedge its exposure to foreign currency fluctuations. The settlement of these hedges occurs on a quarterly basis through maturity. As these hedges are not accounted for under hedge accounting, the changes in fair value are recorded in (gain) loss on foreign currency exchange, net in the unaudited condensed consolidated statements of operations. Commodity Contracts The Company has commodity contracts in order to economically hedge commodity price variability inherent in certain electricity sales arrangements. If the Company sells electricity to an independent system operator market and there is no PPA available, it may enter into a commodity contract to hedge all or a portion of their estimated revenue stream. These commodity contracts require periodic settlements in which the Company receives a fixed-price based on specified quantities of electricity and pays the counterparty a variable market price based on the same specified quantity of electricity. As these hedges are not accounted for under hedge accounting, the changes in fair value are recorded in operating revenues net, in the unaudited condensed consolidated statements of operations.

Fair Value of Financial Instrum

Fair Value of Financial Instruments	9 Months Ended
	Sep. 30, 2017
Fair Value Disclosures [Abstract]
Fair Value of Financial Instruments	FAIR VALUE OF FINANCIAL INSTRUMENTS The fair value of assets and liabilities are determined using either unadjusted quoted prices in active markets (Level 1) or pricing inputs that are observable (Level 2) whenever that information is available and using unobservable inputs (Level 3) to estimate fair value only when relevant observable inputs are not available. The Company uses valuation techniques that maximize the use of observable inputs. Assets and liabilities are classified in their entirety based on the lowest priority level of input that is significant to the fair value measurement. Where observable inputs are available for substantially the full term of the asset or liability, the instrument is categorized in Level 2. If the inputs into the valuation are not corroborated by market data, in such instances, the valuation for these contracts is established using techniques including extrapolation from or interpolation between actively traded contracts as well as calculation of implied volatilities. When such inputs have a significant impact on the measurement of fair value, the instrument is categorized as Level 3. The Company regularly evaluates and validates the inputs used to determine fair value of Level 3 contracts by using pricing services to support the underlying market price of the commodity. The Company uses a discounted cash flow valuation technique to fair value its derivative assets and liabilities. The primary inputs in the valuation models for commodity contracts are market observable forward commodity curves and risk-free discount rates and to a lesser degree credit spreads and volatilities. The primary inputs into the valuation of interest rate swaps and foreign currency contracts are forward interest rates, foreign currency exchange rates, and to a lesser degree credit spreads. Recurring Fair Value Measurements The following table summarizes the financial instruments measured at fair value on a recurring basis classified in the fair value hierarchy (Level 1, 2 or 3) based on the inputs used for valuation in the unaudited condensed consolidated balance sheets: (In thousands) As of September 30, 2017 As of December 31, 2016 Assets Level 1 Level 2 Level 3 Total Level 1 Level 2 Level 3 Total Interest rate swaps $ — $ 3,611 $ — $ 3,611 $ — $ 1,561 $ — $ 1,561 Commodity contracts — 33,070 97,708 130,778 — 37,195 66,138 103,333 Foreign currency contracts — — — — — 1,413 — 1,413 Total derivative assets $ — $ 36,681 $ 97,708 $ 134,389 $ — $ 40,169 $ 66,138 $ 106,307 Liabilities Interest rate swaps $ — $ 9,909 $ — $ 9,909 $ — $ 32,377 $ — $ 32,377 Foreign currency contracts — 28 — 28 — — — — Total derivative liabilities $ — $ 9,937 $ — $ 9,937 $ — $ 32,377 $ — $ 32,377 The Company's interest rate swaps, commodity contracts not designated as hedges and foreign currency contracts are considered Level 2, since all significant inputs are corroborated by market observable data. The Company's commodity contracts designated as hedges are considered Level 3 as they contain significant unobservable inputs. There were no transfers in or out of Level 1, Level 2 and Level 3 during the nine months ended September 30, 2017 . The following table reconciles the changes in the fair value of derivative instruments classified as Level 3 in the fair value hierarchy for the nine months ended September 30, 2017 and 2016: Three Months Ended September 30, Nine Months Ended September 30, (In thousands) 2017 2016 2017 2016 Beginning balance $ 76,790 $ 43,763 $ 66,138 $ 63,154 Realized and unrealized gains (losses): Included in other comprehensive income (loss) 15,601 13,511 26,229 (2,798 ) Included in operating revenues, net 6,407 (433 ) 11,831 6,532 Settlements (1,090 ) 50 (6,490 ) (9,997 ) Balance as of September 30 $ 97,708 $ 56,891 $ 97,708 $ 56,891 The significant unobservable inputs used in the valuation of the Company's commodity contracts categorized as Level 3 of the fair value hierarchy as of September 30, 2017 are as follows: (In thousands, except range) Fair Value as of September 30, 2017 Transaction Type Assets Liabilities Valuation Technique Unobservable Inputs Range Commodity contracts - power $ 97,708 $ — Discounted cash flow Forward price (per MWh) $ 13.4 - $ 72.5 Option model Volatilities 3.0 % - 6.7 % The sensitivity of the Company's fair value measurements to increases (decreases) in the significant unobservable inputs is as follows: Significant Unobservable Input Position Impact on Fair Value Measurement Increase (decrease) in forward price Forward sale Decrease (increase) Increase (decrease) in implied volatilities Purchase option Increase (decrease) The Company measures the sensitivity of the fair value of its Level 3 commodity contracts to potential changes in commodity prices using a mark-to-market analysis based on the current forward commodity prices and estimates of the price volatility. An increase in power forward prices will produce a mark-to-market loss, while a decrease in prices will result in a mark-to-market gain. Fair Value of Debt The carrying amount and estimated fair value of the Company's long-term debt as of September 30, 2017 and December 31, 2016 is as follows: As of September 30, 2017 As of December 31, 2016 (In thousands) Carrying Amount Fair Value Carrying Amount Fair Value Long-term debt, including current portion $ 3,581,394 $ 3,733,007 $ 3,950,914 $ 4,080,397 The fair value of the Company's long-term debt, except the senior notes was determined using inputs classified as Level 2 and a discounted cash flow approach using market rates for similar debt instruments. The fair value of the senior notes is based on market price information which is classified as a Level 1 input. They are measured using the last available trades at the end of each respective fiscal period. The fair value of the Senior Notes due 2023 and Senior Notes due 2025 were 104.25% and 107.00% of face value as of September 30, 2017 , respectively, and 101.38% and 103.75% of face value as of December 31, 2016, respectively.

Stockholders' Equity

Stockholders' Equity	9 Months Ended
	Sep. 30, 2017
Equity [Abstract]
Stockholders' Equity	STOCKHOLDERS' EQUITY As of September 30, 2017 , the following shares of TerraForm Power were outstanding: Share Class: Shares Outstanding Shareholder(s) Class A common stock 92,408,596 * Class B common stock 48,202,310 SunEdison Total Shares 140,610,906 ——— * Class A common stockholders are comprised of public and private investors, executive officers, management and personnel who provide services to the Company. Shares of Class A common stock outstanding exclude 362,018 shares of common stock held in treasury. The total par value of Class A common stock reflected on the unaudited condensed consolidated balance sheet and unaudited condensed consolidated statement of stockholders' equity as of September 30, 2017 includes the shares of stock held in treasury. Merger Consummation and SunEdison Settlement Agreement As discussed in Note 1. Nature of Operations and Basis of Presentation , on October 16, 2017, pursuant to the Merger Agreement, dated as of March 6, 2017, Merger Sub merged with and into TerraForm Power, with TerraForm Power continuing as the surviving corporation in the Merger. Immediately following the consummation of the Merger, there were 148,224,429 Class A shares of TerraForm Power outstanding and Orion Holdings holds 51% of such shares. As a result of the Merger closing, TerraForm Power is no longer a controlled affiliate of SunEdison, Inc. and is now a controlled affiliate of Brookfield. Immediately prior to the effective time of the Merger, TerraForm Power declared the payment of a special cash dividend (the "Special Dividend") in the amount of $1.94 per fully diluted share, which included the Company’s issued and outstanding Class A shares, Class A shares issued to SunEdison pursuant to the Settlement Agreement (more fully described below) and Class A shares underlying outstanding restricted stock units and restricted stock awards of the Company under the Company’s long-term incentive plan. At the effective time of the Merger, each share of Class A common stock of TerraForm Power issued and outstanding immediately prior to the effective time of the Merger, with the exception of certain excluded shares, was converted into the right to, at the holder’s election and subject to proration as described below, either (i) receive $9.52 per Class A Share, in cash, without interest (the “Per Share Cash Consideration”) or (ii) retain one share of Class A common stock, par value $0.01 per share, of the surviving corporation (the “Per Share Stock Consideration,” and, together with the Per Share Cash Consideration, without duplication, the “Per Share Merger Consideration”). Issued and outstanding shares included shares issued in connection with the SunEdison Settlement Agreement as more fully described below and shares underlying outstanding restricted stock units and restricted stock awards of the Company under the Company's long-term incentive plan. At the effective time of the Merger, any vesting conditions applicable to any Company restricted stock unit and restricted stock award outstanding immediately prior to the effective time of the Merger under the Company’s long-term incentive plan were automatically and without any required action on the part of the holder, deemed to be satisfied in full, and such Company restricted stock unit and restricted stock award were canceled and converted into the right to receive the Per Share Merger Consideration, including the election of the Per Share Stock Consideration or the Per Share Cash Consideration in respect of each share (in the case of restricted stock units subject to performance conditions, with such conditions deemed satisfied at “target” levels), less any tax withholdings. The Per Share Stock Consideration was subject to proration in the event that the aggregate number of Class A Shares for which an election to receive the Per Share Stock Consideration exceeded 49% of the TerraForm Power fully diluted share count (the “Maximum Stock Consideration Shares”). Additionally, the Per Share Cash Consideration was subject to proration in the event that the aggregate number of Class A shares for which an election to receive the Per Share Cash Consideration exceeded the TerraForm Power fully diluted share count minus (i) the Maximum Stock Consideration Shares, (ii) any Class A shares currently held by affiliates of Brookfield, and (iii) any shares for which the holders seek appraisal under Delaware law. Based on the results of the consideration election, the elections of the Per Share Stock Consideration were oversubscribed and the proration ratio was 62.6% , which meant that stockholders electing to receive 100% of their merger consideration in stock retained 62.6% of their Class A shares in the Merger and received cash consideration in respect of 37.4% of their shares. Prior to the consummation of the Merger, SunEdison was the indirect holder of 100% of the shares of Class B common stock of TerraForm Power and held approximately 83.9% of the combined total voting power of the holders of TerraForm Power’s Class A common stock and Class B common stock. As contemplated by the Merger Agreement and in satisfaction of its obligations under the Settlement Agreement, SunEdison exchanged, effective immediately prior to the effective time of the Merger, all of the Class B units of Terra LLC held by it or any of its controlled affiliates for 48,202,310 Class A shares of TerraForm Power. As a result of and following completion of the exchange, all of the issued and outstanding shares of Class B common stock of TerraForm Power were automatically redeemed and retired. Pursuant to the Settlement Agreement, immediately following such exchange, the Company issued to SunEdison additional Class A shares such that immediately prior to the effective time of the Merger, SunEdison and certain of its affiliates held an aggregate number of Class A shares equal to 36.9% of TerraForm Power’s fully diluted share count. On October 16, 2017, in connection with the consummation of the Merger, the Company entered into a registration rights agreement (the “SunEdison Registration Rights Agreement”) with SunEdison, Inc., SunEdison Holdings Corporation (“SHC”) and SUNE ML 1, LLC (“SML1"). The SunEdison Registration Rights Agreement governs the rights of SunEdison, Inc., SHC, SML1 and certain permitted assigns with respect to the registration for resale of Class A shares held by them immediately following the Merger.

Stock-based Compensation

Stock-based Compensation	9 Months Ended
	Sep. 30, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock-based Compensation	STOCK-BASED COMPENSATION The Company has equity incentive plans that provide for the award of incentive and nonqualified stock options, restricted stock awards ("RSAs") and restricted stock units ("RSUs") to personnel and directors who provide services to the Company, including personnel and directors who also provide services to SunEdison, Inc. and TerraForm Global, Inc. The maximum contractual term of an award is ten years from the date of grant. As of September 30, 2017 , an aggregate of 3,819,392 shares of Class A common stock were available for issuance under these plans. Upon exercise of stock options or the vesting of the RSUs, the Company will issue shares that have been previously authorized to be issued. Historically, stock-based compensation costs related to equity awards in the Company's stock were allocated to the Company, SunEdison, Inc. and TerraForm Global, Inc. based on the relative percentage of time that the personnel and directors spent providing services to the respective companies. As of January 1, 2017, the Company hired certain former employees of SunEdison who provided dedicated services to the Company. The amount of stock-based compensation expense related to equity awards in the Company's stock which has been awarded to the Company's employees was $1.0 million and $4.3 million during the three and nine months ended September 30, 2017, respectively, as compared to $0.8 million and $2.1 million for the same periods in the prior year, and is reflected in the unaudited condensed consolidated statements of operations within general and administrative expenses. The total amount of stock-based compensation cost related to equity awards in the Company's stock which has been allocated to SunEdison, Inc. and TerraForm Global, Inc. was $0.2 million and $0.7 million for the three and nine months ended September 30, 2017, respectively, as compared to $0.9 million and $2.5 million for the same periods in the prior year and is recognized as a distribution to SunEdison within Net SunEdison investment on the unaudited condensed consolidated statement of stockholders' equity with no impact to the Company's unaudited condensed consolidated statements of operations. Similarly, stock-based compensation costs related to equity awards in the stock of SunEdison, Inc. and TerraForm Global, Inc. awarded to employees of the Company are allocated to the Company. The amount of stock-based compensation expense related to equity awards in the stock of SunEdison, Inc. and TerraForm Global, Inc. that was allocated to the Company was $0.8 million and $2.7 million for the three and nine months ended September 30, 2017, respectively, as compared to $0.6 million and $1.8 million for the same periods in the prior year and is reflected in the unaudited condensed consolidated statements of operations within general and administrative expenses - affiliate and has been treated as an equity contribution from SunEdison within Net SunEdison investment on the unaudited condensed consolidated statement of stockholders' equity. Restricted Stock Awards RSAs provide the holder with immediate voting rights, but are restricted in all other respects until vested. Upon a termination of employment for any reason, any unvested shares of Class A common stock held by the terminated participant will be forfeited. All unvested RSAs are paid dividends and distributions. There were no unvested RSAs as of September 30, 2017 . The following table presents information regarding outstanding RSAs as of September 30, 2017 and changes during the period then ended: Number of RSAs Outstanding Weighted-Average Grant-Date Fair Value Per Share Aggregate Intrinsic Value (in millions) Balance at January 1, 2017 366,195 $ 8.51 Vested (366,195 ) 8.51 Balance as of September 30, 2017 — $ — $ — No RSAs were granted during the nine months ended September 30, 2017 or 2016. As of September 30, 2017, there was no unrecognized compensation cost in relation to outstanding RSAs. Restricted Stock Units RSUs will not entitle the holders to voting rights and holders of the RSUs will not have any right to receive dividends or distributions. The following table presents information regarding outstanding RSUs as of September 30, 2017 and changes during the period then ended: Number of RSUs Outstanding Aggregate Intrinsic Value (in millions) Weighted Average Remaining Balance at January 1, 2017 1,622,953 Granted 517,594 Vested (293,838 ) Forfeited (618,961 ) Balance as of September 30, 2017 1,227,748 $ 16.2 1.1 As of September 30, 2017, the Company had $8.0 million of total unrecognized compensation cost related to RSUs. The weighted-average fair value of RSUs on the date of grant was $12.22 and $11.05 for the nine months ended September 30, 2017 and 2016, respectively. As discussed below under Merger Consummation , all TerraForm Power unvested equity awards vested upon the change of control that occurred in the fourth quarter of 2017. Stock Options As of September 30, 2017 , there was no unrecognized compensation cost in relation to outstanding stock options. Merger Consummation As discussed in Note 1. Nature of Operations and Basis of Presentation , on October 16, 2017, TerraForm Power consummated the Merger with certain affiliates of Brookfield. Pursuant to the TerraForm Power 2014 Second Amended and Restated Long-Term Incentive Plan, the Merger resulted in a change of control causing all unvested equity awards to vest. As a result, the Company expects to recognize a $7.0 million stock-based compensation charge in the fourth quarter of 2017 within general and administrative expenses, which is net of forfeitures that occurred in October of 2017. The Company also expects to recognize an estimated $1.6 million charge within general and administrative expenses - affiliate in the fourth quarter related to allocated stock-based compensation costs for equity awards in the stock of TerraForm Global, Inc. that vested upon the change of control of TerraForm Power.

Loss Per Share

Loss Per Share	9 Months Ended
	Sep. 30, 2017
Earnings Per Share [Abstract]
Loss Per Share	LOSS PER SHARE Loss per share is based upon the weighted average shares outstanding. Net loss attributable to Class A common stockholders is adjusted by the amount of deemed dividends related to the accretion of redeemable non-controlling interest and the amount of dividends paid on Class A shares and participating RSAs. Unvested RSAs that contain non-forfeitable rights to dividends are treated as participating securities and are included in the loss per share computation using the two-class method, to the extent that there are undistributed earnings available as such securities do not participate in losses. Basic and diluted loss per share of the Company's Class A common stock for the three and nine months ended September 30, 2017 and 2016 was calculated as follows: Three Months Ended September 30, Nine Months Ended September 30, (In thousands, except per share amounts) 2017 2016 2017 2016 Basic and diluted loss per share: Net loss attributable to Class A common stockholders $ (26,546 ) $ (26,171 ) $ (50,890 ) $ (47,559 ) Less: accretion of redeemable non-controlling interest (2,316 ) — (6,729 ) — Less: dividends paid on Class A shares and participating RSAs — — — — Undistributed loss attributable to Class A shares $ (28,862 ) $ (26,171 ) $ (57,619 ) $ (47,559 ) Weighted average basic and diluted Class A shares outstanding 1 92,352 90,860 92,228 89,140 Basic and diluted loss per share $ (0.31 ) $ (0.29 ) $ (0.62 ) $ (0.53 ) ——— (1) The computation for diluted loss per share of the Company's Class A common stock for the three and nine months ended September 30, 2017 excludes 1,227,748 of potentially dilutive unvested RSUs because the effect would have been anti-dilutive. The computation for diluted loss per share of the Company's Class A common stock for the three and nine months ended September 30, 2016 excludes 459,800 of potentially dilutive unvested RSAs and 1,823,063 of potentially dilutive unvested RSUs because the effect would have been anti-dilutive.

Non-controlling Interests

Non-controlling Interests	9 Months Ended
	Sep. 30, 2017
Noncontrolling Interest [Abstract]
Non-controlling Interests	NON-CONTROLLING INTERESTS Non-controlling Interests Non-controlling interests represent the portion of net assets in consolidated entities that are not owned by the Company. The following table presents the non-controlling interest balances reported in stockholders’ equity in the unaudited condensed consolidated balance sheets as of September 30, 2017 and December 31, 2016 : (In thousands) September 30, 2017 December 31, 2016 SunEdison's non-controlling interest in Terra LLC $ 648,765 $ 660,799 Non-controlling interests in renewable energy facilities 753,831 804,243 Total non-controlling interests $ 1,402,596 $ 1,465,042 As of September 30, 2017 , TerraForm Power owned 65.8% of Terra LLC and consolidated the results of Terra LLC through its controlling interest, with SunEdison's 34.2% interest shown as a non-controlling interest. As a result of the Company's sale of TerraForm Resi Solar Manager, LLC, a subsidiary of the Company that owned and operated 8.9 MW of residential rooftop solar installations, during the second quarter of 2017 (see Note 2. Assets Held for Sale ), the amount of non-controlling interest in this entity of $8.7 million was deconsolidated. Redeemable Non-controlling Interests Non-controlling interests in subsidiaries that are redeemable either at the option of the holder or at fixed and determinable prices at certain dates are classified as redeemable non-controlling interests in subsidiaries between liabilities and stockholders' equity in the unaudited condensed consolidated balance sheets. The redeemable non-controlling interests in subsidiaries balance is determined using the hypothetical liquidation at book value method for the VIE funds or allocation of share of income or losses in other subsidiaries subsequent to initial recognition; however, the non-controlling interests balance cannot be less than the estimated redemption value. The Company recorded a $6.7 million adjustment during the nine months ended September 30, 2017 to the value of the Invenergy Wind redeemable non-controlling interest, reflecting the excess of the future redemption value over its carrying amount at the balance sheet date based on SEC guidance in ASC 480-10-S99-3A. The Company accretes the redemption value of the redeemable non-controlling interest over the redemption period using the straight-line method. Accretion adjustments to the carrying value of this redeemable non-controlling interest are recorded against additional paid-in capital. There were no similar adjustments recorded during the nine months ended September 30, 2016. The following table presents the activity of the redeemable non-controlling interests balance for the nine months ended September 30, 2017 : Redeemable Non-controlling Interests (In thousands) Capital Retained Earnings Total Balance as of December 31, 2016 $ 153,490 $ 26,877 $ 180,367 Distributions (7,227 ) — (7,227 ) Accretion of redeemable non-controlling interest 6,729 — 6,729 Net income — 18,162 18,162 Balance as of September 30, 2017 $ 152,992 $ 45,039 $ 198,031 As discussed in Note 15 . Related Parties , as part of the Settlement Agreement, the option agreement between Terra LLC and Sun Edison LLC with respect to Invenergy Wind's remaining 9.9% interest in certain subsidiaries of the Company was rejected as of the effectiveness of the settlement which occurred upon the consummation of the Merger with affiliates of Brookfield on October 16, 2017. As a result, the Company does not expect to be obligated to perform on its option agreement, and as of October 16, 2017, the Invenergy Wind non-controlling interest is no longer considered redeemable.

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2017
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	COMMITMENTS AND CONTINGENCIES Letters of Credit The Company's customers, vendors and regulatory agencies often require the Company to post letters of credit in order to guarantee performance under relevant contracts and agreements. The Company is also required to post letters of credit to secure obligations under various swap agreements and leases and may, from time to time, decide to post letters of credit in lieu of cash deposits in reserve accounts under certain financing arrangements. The amount that can be drawn under some of these letters of credit may be increased from time to time subject to the satisfaction of certain conditions. As of September 30, 2017 , the Company had outstanding letters of credit under the Revolver of $62.0 million and outstanding project-level letters of credit of $148.9 million . As of the date hereof, the Company is in the process of replacing letters of credit issued by the letter of credit issuing banks under the Revolver, which was terminated on October 17, 2017, with letters of credit issued under the New Revolver. Outstanding letters of credit will remain effective in accordance with their terms until they are replaced or expire. Guarantee Agreements The Company and its subsidiaries have provided guarantees to certain of its institutional tax equity investors and financing parties in connection with its tax equity financing transactions. These guarantees do not guarantee the returns targeted by the tax equity investors or financing parties, but rather support any potential indemnity payments payable under the tax equity agreements, including related to management of tax partnerships and recapture of tax credits or renewable energy grants in connection with transfers of the Company’s direct or indirect ownership interests in the tax partnerships to entities that are not qualified to receive those tax benefits. The Company and its subsidiaries have also provided guarantees in connection with acquisitions of third party assets or to support project contractual obligations, including renewable energy credit sales agreements. The Company and its subsidiaries have also provided other capped or limited contingent guarantees and other support obligations with respect to certain project-level indebtedness. Commitments to Acquire Renewable Energy Facilities As of September 30, 2017 , the Company did not have any open commitments to acquire renewable energy facilities from third parties or SunEdison, other than as described with respect to the Invenergy Wind Option Agreements (as discussed and defined in Note 15 . Related Parties ). Under the Settlement Agreement with SunEdison, the option agreement between Terra LLC and Sun Edison LLC was rejected as of the effectiveness of the settlement which occurred upon the consummation of the Merger with affiliates of Brookfield on October 16, 2017. As a result, the Company does not expect to be obligated to perform on its option agreement. Legal Proceedings The Company is not a party to any material legal proceedings other than various administrative and regulatory proceedings arising in the ordinary course of the Company's business or as described below. While the Company cannot predict with certainty the ultimate resolution of such proceedings or other claims asserted against the Company, certain of the claims, if adversely concluded, could result in substantial damages or other relief. Securities Class Action On April 4, 2016, a securities class action under federal securities laws (Chamblee v. TerraForm Power, Inc., et al., Case No. 1:16-cv-00981-JFM) (the "Chamblee Class Action") was filed in the United States District Court for the District of Maryland against the Company and two of its former officers ( one of which was also a director of the Company) asserting claims under Section 10(b) and 20(a) of the Securities and Exchange Act of 1934 and SEC Rule 10b-5 on behalf of a putative class. The complaint alleges that the defendants made materially false and misleading statements regarding the Company’s business, operational and compliance policies, including with respect to disclosures regarding SunEdison’s internal controls and the Company's reliance on SunEdison. An amended complaint was filed on September 26, 2016 and a former officer and director of the Company were added as defendants. On October 4, 2016, the Judicial Panel on Multidistrict Litigation transferred this matter to the U.S. District Court for the Southern District of New York (SDNY) for consolidated or coordinated pretrial proceedings. On December 19, 2016, an initial case management conference was held in the multidistrict litigation proceedings in the SDNY. The Court entered an order requiring all parties to the multidistrict litigation to mediate and entered a partial stay of all proceedings through March 31, 2017. On March 24, 2017, the plaintiffs filed an amended complaint adding three additional directors and officers of the Company as defendants, as well as additional factual allegations. On June 9, 2017, the Company filed a motion to dismiss the case. After mediation, the parties agreed in principle to a settlement of $14.8 million on behalf of a putative settlement class containing all persons and entities that purchased or otherwise acquired the publicly traded securities of the Company between July 18, 2014 and March 15, 2016, expressly conditioned on, among other things, funding of the settlement by the Company’s directors’ and officers’ liability insurance providers to the satisfaction of the Company. As of the date hereof, the parties have agreed that $13.63 million of the settlement will be covered by the Company’s directors’ and officers’ liability insurance providers. On September 11, 2017, the Bankruptcy Court granted approval of the use of $13.63 million of proceeds to fund the settlement (see Note 15 . Related Parties for further discussion). The Company, the Company’s directors’ and officers’ liability insurance providers and the Company’s co-defendants are in the process of finalizing documentation governing the use of the $13.63 million of proceeds from the insurance. On September 14, 2017, the U.S. District Court for the SDNY preliminarily approved the settlement and provided the Company with an express termination right in the event that the settlement is not timely funded with proceeds from the directors’ and officers’ liability insurance. A hearing on final approval of the settlement is scheduled for January 31, 2018. If a final resolution is achieved on the settlement, the Company's contribution to the settlement amount, net of the amount to be covered by insurance, would be $1.13 million . The Company reserved $1.13 million for its estimated probable loss related to this complaint as of December 31, 2016, which is the amount the Company would be prepared to fund the settlement out of its own funds. If the conditional settlement offer fails for any reason, including because the insurers do not make the requisite contribution to the settlement amount, the Company would continue to vigorously contest this claim. The Company has agreed to issue additional shares of Class A common stock to Orion Holdings for no additional consideration in respect of the Company’s net losses, such as out-of-pocket losses, damages, costs, fees and expenses, upon the final resolution of the Chamblee Class Action. The Company and TerraForm Global, Inc. have entered into an agreement pursuant to which TerraForm Global, Inc. has agreed to indemnify and reimburse the Company for certain costs, fees and expenses related to the defense or settlement of the Chamblee Class Action that are not covered by insurance (excluding the $1.13 million settlement contribution). As a result, as of the date hereof, the Company does not expect to incur any material fees or expenses (excluding the $1.13 million settlement contribution) in connection with the Chamblee Class Action that would not be covered by insurance or indemnified and reimbursed by TerraForm Global, Inc. Claim relating to First Wind Acquisition On May 27, 2016, D.E. Shaw Composite Holdings, L.L.C. and Madison Dearborn Capital Partners IV, L.P., as the representatives of the sellers (the “First Wind Sellers”) filed an amended complaint for declaratory judgment against the Company and Terra LLC in the Supreme Court of the State of New York alleging breach of contract with respect to the Purchase and Sale Agreement, dated as of November 17, 2014 (the “FW Purchase Agreement”) between, among others, SunEdison, the Company and Terra LLC and the First Wind Sellers. The amended complaint alleges that Terra LLC and SunEdison became jointly obligated to make $231.0 million in earn-out payments in respect of certain development assets SunEdison acquired from the First Wind Sellers under the FW Purchase Agreement, when those payments were purportedly accelerated by SunEdison's bankruptcy and by the resignations of two SunEdison employees. The amended complaint further alleges that the Company, as guarantor of certain Terra LLC obligations under the FW Purchase Agreement, is liable for this sum. The defendants filed a motion to dismiss the amended complaint on July 5, 2016, on the ground that, among other things, SunEdison is a necessary party to this action. The plaintiffs filed an opposition to the motion to dismiss on August 22, 2016. The defendants filed their reply on September 12, 2016. A hearing on the motion to dismiss took place on January 24, 2017. The Company is awaiting a decision on the motion to dismiss. No activity or proceedings have taken place in the lawsuit since the January 24, 2017 hearing. On March 30, 2017, the Company filed a motion in the Bankruptcy Court seeking discovery against D.E. Shaw Composite Holdings, L.L.C. and Madison Dearborn Capital Partners IV, L.P. in connection with the litigation brought by the First Wind Sellers described above. A hearing on the motion was held on April 20, 2017. On June 16, 2017, the Bankruptcy Court denied the motion. As of the date hereof, the Company has not been granted discovery in connection with the litigation brought by the First Wind Sellers described above. The Company cannot predict the impact on this litigation of any information that may become available if discovery is ultimately permitted to be undertaken by the defendants or the plaintiffs. The Company has agreed to issue additional shares of Class A common stock to Orion Holdings for no additional consideration in respect of the Company’s net losses, such as out-of-pocket losses, damages, costs, fees and expenses, upon the final resolution of the litigation brought by the First Wind Sellers described above. The amount, if any, of additional shares of Class A common stock to be issued to Orion Holdings will be determined based on a formula as described in greater detail in the Company’s Definitive Proxy Statement filed on Schedule 14A with the SEC on September 6, 2017. As of the date hereof, the Company is unable to predict the quantum of any net losses arising from the litigation brought by the First Wind Sellers described above or the number of additional shares, if any, that may be required to be issued to Orion Holdings pursuant to the terms of the Merger Agreement in connection with any such final resolution. The issuance of additional shares to Orion Holdings would dilute the holdings of the Company's common stockholders and may negatively affect the value of the Company's common stock. The Company believes the First Wind Sellers’ allegation is without merit and will contest the claim and allegations vigorously. However, the Company cannot predict with certainty the ultimate resolution of any proceedings brought in connection with such a claim. Whistleblower Complaint By Francisco Perez Gundin On May 18, 2016, the Company’s former Director and Chief Operating Officer, Francisco Perez Gundin (“Perez”), filed a complaint against the Company, TerraForm Global, Inc. and certain individuals, with the United States Department of Labor. The complaint alleges that the defendants engaged in a retaliatory termination of Mr. Perez's employment after he allegedly voiced concerns to SunEdison’s Board of Directors about public representations made by SunEdison officers regarding SunEdison’s liquidity position, and after he allegedly voiced his opposition to transactions that he alleges were self-interested and which he alleges SunEdison forced on the Company. He alleges that the Company participated in SunEdison’s retaliatory termination by constructively terminating his position as Chief Operating Officer of the Company in connection with SunEdison’s constructive termination of his employment. He seeks lost wages, bonuses, benefits, and other money that he alleges that he would have received if he had not been subjected to the allegedly retaliatory termination. The Company's Position Statement in response to the complaint was filed in October of 2016. On February 21, 2017, Mr. Perez filed Gundin v. TerraForm Global, Inc. et al. against TerraForm Power, TerraForm Global, Inc. and certain individuals as defendants in the United States District Court for the District of Maryland. The complaint asserts claims for retaliation, breach of the implied covenant of good faith and fair dealing and promissory estoppel based on the same allegation in Mr. Perez's Department of Labor complaint. On March 15, 2017, the Company filed notice with the Judicial Panel on Multidistrict Litigation to transfer this action to the Southern District of New York where the Chamblee Class Action and other cases not involving the Company relating to the SunEdison Bankruptcy are being tried. The plaintiff did not oppose the transfer, which was approved by the Judicial Panel on Multidistrict Litigation. On November 6, 2017, TerraForm Power and the other defendants filed a motion to dismiss Mr. Perez's complaint. The Company has agreed to issue additional shares of Class A common stock to Orion Holdings for no additional consideration in respect of the Company’s net losses, such as out-of-pocket losses, damages, costs, fees and expenses, upon the final resolution of the litigation brought by Mr. Perez described above. The amount, if any, of additional shares of Class A common stock to be issued to Orion Holdings will be determined based on a formula as described in greater detail in the Company’s Definitive Proxy Statement filed on Schedule 14A with the SEC on September 6, 2017. As of the date hereof, the Company is unable to predict the quantum of any net losses arising from the litigation brought by Mr. Perez described above or the number of additional shares, if any, that may be required to be issued to Orion Holdings pursuant to the terms of the Merger Agreement in connection with any such final resolution. The issuance of additional shares to Orion Holdings would dilute the holdings of the Company's common stockholders and may negatively affect the value of the Company's common stock. The Company reserved for its estimated loss related to this complaint as of December 31, 2016, which was not considered material to the Company's consolidated results of operations. However, the Company is unable to predict with certainty the ultimate resolution of these proceedings. Whistleblower Complaint By Carlos Domenech Zornoza On May 10, 2016, the Company’s former Director and Chief Executive Officer, Carlos Domenech Zornoza (“Domenech”), filed a complaint against the Company, TerraForm Global, Inc. and certain individuals, with the United States Department of Labor. The complaint alleges that the defendants engaged in a retaliatory termination of Mr. Domenech’s employment on November 20, 2015 after he allegedly voiced concerns to SunEdison’s Board of Directors about public representations made by SunEdison officers regarding SunEdison’s liquidity position, and after he allegedly voiced his opposition to transactions that he alleges were self-interested and which he alleges SunEdison forced on the Company. He alleges that the Company participated in SunEdison’s retaliatory termination by terminating his position as Chief Executive Officer of the Company in connection with SunEdison’s termination of his employment. He seeks lost wages, bonuses, benefits, and other money that he alleges that he would have received if he had not been subjected to the allegedly retaliatory termination. The Company's Position Statement in response to the complaint was filed in October of 2016. On February 21, 2017, Mr. Domenech filed Domenech Zornoza v. TerraForm Global, Inc. et. al against TerraForm Power, TerraForm Global, Inc. and certain individuals as defendants in the United States District Court for the District of Maryland. The complaint asserts claims for retaliation, breach of the implied covenant of good faith and fair dealing and promissory estoppel based on the same allegations in Mr. Domenech's Department of Labor complaint. On March 15, 2017, the Company filed notice with the Judicial Panel on Multidistrict Litigation to transfer this action to the Southern District of New York where the Chamblee Class Action and other cases not involving the Company relating to the SunEdison Bankruptcy are being tried. The plaintiff opposed the transfer. However, the transfer was approved by the Judicial Panel on Multidistrict Litigation. On November 6, 2017, TerraForm Power and the other defendants filed a motion to dismiss Mr. Domenech's complaint. The Company has agreed to issue additional shares of Class A common stock to Orion Holdings for no additional consideration in respect of the Company’s net losses, such as out-of-pocket losses, damages, costs, fees and expenses, upon the final resolution of the litigation brought by Mr. Domenech described above. The amount, if any, of additional shares of Class A common stock to be issued to Orion Holdings will be determined based on a formula as described in greater detail in the Company’s Definitive Proxy Statement filed on Schedule 14A with the SEC on September 6, 2017. As of the date hereof, the Company is unable to predict the quantum of any net losses arising from the litigation brought by Mr. Domenech described above or the number of additional shares, if any, that may be required to be issued to Orion Holdings pursuant to the terms of the Merger Agreement in connection with any such final resolution. The issuance of additional shares to Orion Holdings would dilute the holdings of the Company's common stockholders and may negatively affect the value of the Company's common stock. The Company reserved for its estimated loss related to this complaint as of December 31, 2016, which was not considered material to the Company's consolidated results of operations. However, the Company is unable to predict with certainty the ultimate resolution of these proceedings. Eastern Maine Electric Cooperative Litigation On November 21, 2016, the Penobscot County Maine Superior Court entered judgment in the amount of $13.6 million against First Wind Holdings, LLC (“First Wind”), an indirect subsidiary of SunEdison, Inc., and several subsidiaries of the Company. The plaintiff filed judgment liens against the defendants which will stay outstanding through the appeals process. The action involved a claimed breach of contract arising out of a contract between First Wind and Eastern Maine Electric Cooperative, Inc. (“EMEC”), under which First Wind, on behalf of itself and its then wholly-owned subsidiaries, agreed to negotiate a definitive agreement to transfer to EMEC a portion of a transmission line. The transmission line is owned, in part, by one of the Company's subsidiaries, and is the sole means of transmitting power from the Rollins, Stetson I and Stetson II wind farms. The subsidiaries that own these wind farms and the transmission line were acquired by the Company as part of the Company's acquisition of certain of the operating assets of First Wind Holdings. The Company believes all the defendants acted in good faith and the Company’s subsidiaries that are defendants in the action intend to continue to vigorously contest the allegations and have filed an appeal of the verdict with the Maine Supreme Judicial Court. The judgment was for money damages and, if upheld on appeal, would not be expected to result in a loss of the use of the transmission line by the Company's subsidiaries. The amount of the judgment has been accrued for since December of 2015. Threatened Avoidance Actions On November 7, 2016, the unsecured creditors’ committee in the SunEdison Bankruptcy filed a motion with the Bankruptcy Court seeking standing to assert against the Company, on behalf of SunEdison, avoidance claims arising from payments and other intercompany transactions between the Company and SunEdison dating back to the Company’s initial public offering and including drop-down transactions involving the sale of renewable energy facilities by SunEdison to the Company. The Company’s objection to the standing motion was filed on November 29, 2016. As described in Note 1. Nature of Operations and Basis of Presentation and Note 15 . Related Parties , the Company and SunEdison entered into the Settlement Agreement pursuant to which the Company and SunEdison released these claims and substantially all other intercompany claims between the Company and SunEdison upon the consummation of the Merger with affiliates of Brookfield on October 16, 2017. Therefore, any claims with respect to these avoidance actions have been released.

Related Parties

Related Parties	9 Months Ended
	Sep. 30, 2017
Related Party Transactions [Abstract]
Related Parties	RELATED PARTIES As discussed in Note 1. Nature of Operations and Basis of Presentation , as of September 30, 2017, TerraForm Power was a controlled affiliate of SunEdison, Inc. TerraForm Power is a holding company and its sole asset is an equity interest in Terra LLC, which through its subsidiaries owns and operates renewable energy facilities that have long-term contractual arrangements to sell the electricity generated by these facilities to third parties. The related green energy certificates, ancillary services and other environmental attributes generated by these facilities are also sold to third parties. TerraForm Power is the managing member of Terra LLC and operates, controls and consolidates the business affairs of Terra LLC. As a result of the consummation of the Merger on October 16, 2017, a change of control of TerraForm Power occurred, and Orion Holdings, which is an affiliate of Brookfield, now holds 51% of the voting securities of TerraForm Power. As a result of the Merger closing, TerraForm Power is no longer a controlled affiliate of SunEdison, Inc. and is now a controlled affiliate of Brookfield. SunEdison Bankruptcy and Settlement with SunEdison During the SunEdison Bankruptcy, SunEdison did not perform substantially as obligated under its agreements with the Company, including under its sponsor arrangement and certain O&M and asset management arrangements. In order to mitigate any adverse effects of this non-performance, the Company undertook a strategic initiative to transition away from SunEdison as a sponsor, including establishing a stand-alone corporate structure and seeking to retain third party or in-house solutions for project-level asset management and O&M. This transition away from SunEdison is expected to be complete in the fourth quarter of 2017. As discussed in Note 1. Nature of Operations and Basis of Presentation , TerraForm Power entered into the Settlement Agreement with SunEdison on March 6, 2017. The Settlement Agreement was approved by the Bankruptcy Court and the effectiveness of the settlements, mutual intercompany releases and certain other terms and conditions occurred upon the consummation of the Merger with affiliates of Brookfield on October 16, 2017. The effectiveness of these Settlement Agreement provisions has resolved claims between TerraForm Power and SunEdison, including, among other things, claims of SunEdison against the Company for alleged fraudulent and preferential transfers and claims of the Company against SunEdison, including those outlined in the initial proof of claim filed by the Company in the SunEdison Bankruptcy on September 25, 2016 and on October 7, 2016. Under the Settlement Agreement, all such claims have been mutually released, and any agreements between SunEdison Debtors and SunEdison parties to the Settlement Agreement on the one hand and the Company on the other hand have been deemed rejected, subject to certain limited exceptions, without further liability, claims or damages on the part of the Company. Upon the effectiveness of this mutual release, the agreements with SunEdison described below were deemed rejected (other than the insurance allocation agreements and the corporate-level transition services agreement which is expected to be extended through the end of the fourth quarter of 2017 with respect to certain information technology services as discussed below). Management Services Agreement Historically, general and administrative expenses - affiliate primarily represented costs incurred by SunEdison for services provided to the Company pursuant to the management services agreement ("MSA"). Pursuant to the MSA, SunEdison agreed to provide or arrange for other service providers to provide management and administrative services including legal, accounting, tax, treasury, project finance, information technology, insurance, employee benefit costs, communications, human resources and procurement to the Company. As consideration for the services provided, the Company agreed to pay SunEdison a base management fee as follows: (i) 2.5% of the Company's cash available for distribution in 2015 , 2016 , and 2017 (not to exceed $4.0 million in 2015, $7.0 million in 2016 or $9.0 million in 2017), and (ii) an amount equal to SunEdison's or other service provider's actual cost in 2018 and thereafter. Subsequent to the SunEdison Bankruptcy, SunEdison continued to provide some management and administrative services to the Company, including employee compensation and benefit costs, human resources, information technology and communications, but stopped providing (or reimbursing the Company for) other services pursuant to the MSA. Costs for services that SunEdison stopped providing or reimbursing the Company for are included within general and administrative expenses in the unaudited condensed consolidated statements of operations. Further, as discussed under the Transition Services Agreement section below, the Company entered into a corporate-level transition services agreement with SunEdison on September 7, 2017 that retroactively applied to transition services provided from and after February 1, 2017. The services that SunEdison continued to provide under the MSA are covered under this corporate-level transition services agreement since February 1, 2017, and as a result general and administrative expenses - affiliate for 2017 primarily represents amounts incurred by the Company under this transition services agreement with SunEdison. General and administrative expenses - affiliate were $2.2 million and $6.9 million for the three and nine months ended September 30, 2017 , respectively, and were $2.9 million and $10.6 million , respectively, during the same periods in 2016, as reported in the unaudited condensed consolidated statements of operations. As discussed above, pursuant to the Settlement Agreement entered into with SunEdison, and upon the consummation of the Merger with affiliates of Brookfield on October 16, 2017, the MSA was rejected without further liability, claims or damages on the part of the Company. The Company expects to extend the effectiveness of the corporate-level transition services agreement with respect to information technology services through the end of November 2017. O&M and Asset Management Services O&M services, as well as asset management services, have historically been provided to the Company substantially by SunEdison pursuant to contractual agreements. The Company has been in the process of transitioning away from SunEdison for these services and this transition is substantially complete as of the date hereof. As described below, the Company entered into certain transition services agreements with SunEdison in 2017 with respect to these services to facilitate this transition. Total costs incurred for O&M and asset management services from SunEdison were $1.2 million and $10.2 million during the three and nine months ended September 30, 2017 , respectively, and were $7.1 million and $22.9 million , respectively, during the same periods in 2016. These costs are reported as cost of operations - affiliate in the unaudited condensed consolidated statements of operations. Transition Services Agreements In the first half of 2017, the Company entered into certain transition services agreements with SunEdison with respect to project-level O&M and asset management services provided by SunEdison. These transition services agreements allowed the Company, among other things, to hire employees of SunEdison that were performing these project-level services for the Company. These transition services agreements also allowed the Company to terminate project-level asset management and O&M services on 10 days advance notice. Under these agreements, the Company agreed to indemnify SunEdison for certain losses and liabilities to the extent SunEdison failed to perform services under existing services contracts as a result of the transition of SunEdison employees to the Company. SunEdison also continued to provide certain project related services for a transitional period. $1.9 million was incurred and paid to SunEdison in the first quarter of 2017 in connection with these project-level transition services agreements and is included in the cost of operations - affiliate amount for the nine months ended September 30, 2017 discussed above. There were no material incremental fees directly paid to SunEdison in connection with these project-level transition services agreements subsequent to the first quarter, as the Company hired a substantial number of the SunEdison employees that were performing the services covered under these agreements in the second quarter of 2017. On September 7, 2017, the Company entered into a corporate-level transition services agreement with SunEdison. Pursuant to the terms of this agreement, SunEdison continued to provide the Company, on an interim basis, certain services that SunEdison historically provided the Company. These services included, without limitation, services related to information technology, tax, human resources, treasury, finance and controllership. The Company paid SunEdison certain monthly fees in exchange for SunEdison's provision of the transition services. In addition to the services provided by SunEdison, the corporate-level transition services agreement contemplated that the Company would provide certain services to SunEdison. These specific services were determined based on the needs of the parties, and were charged at rates consistent with past practice. This transition service agreement, and the parties' obligations thereunder, applied retroactively to transition services provided from and after February 1, 2017. The Company expects to extend the effectiveness of this agreement with respect to certain information technology services through the end of the fourth quarter of 2017. Engineering, Procurement and Construction Contracts and Module Warranties SunEdison served as the prime construction contractor for most of the Company's renewable energy facilities acquired from SunEdison pursuant to engineering, procurement and construction contracts with the Company's project-level subsidiaries. These contracts are generally fixed price, turn-key construction contracts that include workmanship and other warranties with respect to the design and construction of the facilities that survive for a period of time after the completion of construction. These contracts or related contracts (including O&M agreements) also often include production or availability guarantees with respect to the output or availability of the facility that survive completion of construction. Moreover, the Company also generally obtained solar module warranties from SunEdison, including workmanship warranties and output guarantees, for those solar facilities that the Company acquired from SunEdison that utilized SunEdison modules. Third party insurance has been procured by SunEdison to back-stop payment of warranty claims for SunEdison modules purchased from January of 2011 through January of 2017. During the first quarter of 2017, the Company received $7.0 million from SunEdison in satisfaction of outstanding claims made under engineering, procurement and construction contracts, of which $4.8 million related to the Company's renewable energy facility located in Chile and compensated the relevant project company as the facility's performance during the warranty period was below that guaranteed by an affiliate of SunEdison under the applicable EPC contract. These receipts were treated as equity contributions from SunEdison within Net SunEdison investment on the unaudited condensed consolidated statement of stockholders' equity for the nine months ended September 30, 2017 . As discussed above, pursuant to the Settlement Agreement entered into with SunEdison, and upon the consummation of the Merger with affiliates of Brookfield on October 16, 2017, these construction and related contracts were rejected without further liability, claims or damages on the part of the Company. Amended Interest Payment Agreement On January 28, 2015, Terra LLC and Terra Operating LLC entered into an amended and restated interest payment agreement (the “Amended Interest Payment Agreement”) with SunEdison. Pursuant to the Amended Interest Payment Agreement, SunEdison agreed to pay amounts equal to a portion of each scheduled interest payment of the Senior Notes due 2023, beginning with the first scheduled interest payment on August 1, 2015, and continuing through the scheduled interest payment on August 1, 2017. The Company received an $8.0 million equity contribution from SunEdison pursuant to the Amended Interest Payment Agreement during the first quarter of 2016, which was accrued for as of the end of 2015. As of the first quarter of 2016, the Company had received a cumulative amount of $24.0 million under the Amended Interest Payment Agreement and initial interest payment agreement from SunEdison with $24.0 million of scheduled payments due in future periods. The Company has not received any payments from SunEdison pursuant to the Amended Interest Payment Agreement since the first quarter of 2016. As discussed above, pursuant to the Settlement Agreement entered into with SunEdison, and upon the consummation of the Merger with affiliates of Brookfield on October 16, 2017, the Amended Interest Payment Agreement was rejected without further liability, claims or damages on the part of the Company. Support Agreement and Intercompany Agreement The Company entered into a project support agreement with SunEdison (the "Support Agreement") on July 23, 2014, which provided the Company the option to purchase additional renewable energy facilities from SunEdison. The Support Agreement also provided the Company a right of first offer with respect to certain other renewable energy facilities. During the first quarter of 2016, the Company acquired renewable energy facilities with a combined nameplate capacity of 19.2 MW from SunEdison under the Support Agreement. The Company paid SunEdison $39.0 million for the acquisition of these facilities, of which $9.7 million was paid in the first quarter of 2016 and $29.3 million was paid in the third quarter of 2016. The Company has not acquired any renewable energy facilities from SunEdison since the first quarter of 2016. In connection with the Company's acquisition of certain operating renewable energy facilities from First Wind in January of 2015, the Company and SunEdison entered into an agreement (the "Intercompany Agreement") pursuant to which the Company was granted the option to purchase additional renewable energy facilities in the First Wind pipeline from SunEdison. The Company has not acquired any renewable energy facilities from SunEdison under the Intercompany Agreement since the fourth quarter of 2015. As discussed above, pursuant to the Settlement Agreement entered into with SunEdison, and upon the consummation of the Merger with affiliates of Brookfield on October 16, 2017, the Support Agreement and Intercompany Agreement were rejected without further liability, claims or damages on the part of the Company. The Company continues to maintain a call right over 0.5 GW (net) of operating wind power plants that are owned by a warehouse vehicle that was owned and arranged by SunEdison (the "AP Warehouse"). SunEdison sold its equity interest in the AP Warehouse to an unaffiliated third party. Insurance Allocation Agreements The Company, TerraForm Global, Inc., SunEdison and certain of their respective directors and officers shared $150.0 million of directors’ and officers’ liability insurance policies that covered the period from July 15, 2015 to July 14, 2016 (the “D&O Insurance”). SunEdison and the independent directors of SunEdison (the “SUNE D&O Parties”) entered into an agreement, dated March 27, 2017 and amended on June 7, 2017, with the Company, TerraForm Global, Inc., their respective current directors (as of that date) and certain of their respective current officers (as of that date) (the “YieldCo D&O Parties”) related to the D&O Insurance. Among other things, this agreement provides that: (i) the YieldCo D&O Parties consent to a $32.0 million payment to SunEdison from the D&O Insurance in connection with the settlement of claims proposed to be brought by the unsecured creditors’ committee in the SunEdison Bankruptcy under a motion in the SunEdison Bankruptcy case for derivative standing; (ii) for a specified period of time, the SUNE D&O Parties and the YieldCo D&O Parties agree to cooperate in trying to reach settlements of certain lawsuits pending against the YieldCo D&O Parties arising from a variety of alleged prepetition actions and transactions, including, but not limited to, the initial public offering of TerraForm Global, Inc. and other securities transactions, and SunEdison agrees to consent to such proposed settlements to be funded by up to $32.0 million from the D&O Insurance; and (iii) for a specified period of time, SunEdison, its independent directors, the Company and TerraForm Global, Inc. will not assert certain payment priority provisions of the D&O Insurance. The agreement was approved by the Bankruptcy Court on June 28, 2017. On August 31, 2017, the Company, TerraForm Global, Inc., SunEdison and certain of their respective current and former directors and officers entered into a second agreement related to the D&O insurance, which the Company refers to as the second D&O insurance allocation agreement. Among other things, the second D&O insurance allocation agreement provided that: (i) no party to the second D&O insurance allocation agreement would object to the settlement of the Chamblee Class Action (as discussed in Note 14. Commitments and Contingencies ) with the use of $13.63 million of the D&O insurance; (ii) no party to the second D&O insurance allocation agreement would object to the settlement of the derivative action on behalf of TerraForm Global, Inc. captioned Aldridge v. Blackmore, et al., No. 12196-CB (Del. Ch.), with the use of $20.0 million of the D&O insurance; (iii) TerraForm Global, Inc. would have the full and exclusive right to an additional $20.0 million of the remaining limit of the D&O insurance for use in its sole discretion; (iv) the Company and TerraForm Global, Inc. would also have access to an additional D&O insurance payment of $0.4 million for defense costs; (v) SunEdison’s current and former directors and officers would have the full and exclusive rights to the remaining limits of the D&O insurance; and (vi) all parties to the second D&O insurance allocation agreement waived any right they might otherwise have under the D&O insurance to request or instruct the insurers to defer or stop any insurance payments to which the Company is entitled under the second insurance allocation agreement. On September 11, 2017, the Bankruptcy Court granted approval of the second D&O insurance allocation. In connection with the second D&O insurance allocation agreement, the Company and TerraForm Global, Inc. entered into an agreement pursuant to which TerraForm Global, Inc. agreed to indemnify and reimburse the Company for certain legal costs and expenses related to the defense or settlement of the Chamblee Class Action that are not covered by the D&O insurance. In addition to the insurance allocation agreements, from time to time, the Company agreed to orders or stipulations with SunEdison and TerraForm Global, Inc. in connection with the SunEdison Bankruptcy related to, among other things, insurance proceeds, interim operating protocols, bankruptcy filing protocols and other matters. Due to SunEdison and affiliates, net All amounts incurred by the Company and not paid as of the balance sheet date for asset management, O&M and transition services received from SunEdison are reported as a payable to SunEdison, and services provided to SunEdison under the transition services agreement that SunEdison has not paid for as of the balance sheet date are recorded as a receivable from SunEdison. Additionally, amounts owed to the Company from TerraForm Global, Inc. as discussed below are recorded as a receivable from TerraForm Global, Inc. As of September 30, 2017 and December 31, 2016 , the Company had a net payable to SunEdison and its affiliates of $15.8 million and $16.7 million , respectively, which is reported as Due to SunEdison and affiliates, net in the unaudited condensed consolidated balance sheets. As a result of the SunEdison Bankruptcy, the Company recognized a $0.8 million loss within loss on receivables - affiliate in the unaudited condensed consolidated statement of operations for the nine months ended September 30, 2016 related to recording a bad debt reserve for outstanding receivables from the SunEdison Debtors. Arrangements with TerraForm Global In January 2017, the Company entered into a Use and Occupancy Agreement with TerraForm Global, LLC, pursuant to which the Company granted a license to use its office space in Bethesda, Maryland that is leased by the Company and is the shared corporate headquarters of the Company and TerraForm Global, Inc. until the earlier to occur of June 30, 2018 and the termination of the underlying lease. TerraForm Global, LLC has agreed to pay the Company for one-third of the rent and other amounts due to the landlord under the underlying lease, which is expected to be equal to an aggregate of $0.8 million in 2017, and certain additional service fees. For the nine months ended September 30, 2017, $0.6 million was charged to TerraForm Global, LLC under this agreement. In addition, certain employees of the Company during the nine months ended September 30, 2017, provided general management services to TerraForm Global, Inc., and a portion of the costs associated with such employees during that time was allocated to TerraForm Global, Inc. As of September 30, 2017, the cost charged to TerraForm Global, Inc. for these services was $0.6 million . As of September 30, 2017 and December 31, 2016 , the Company had a net receivable from TerraForm Global, Inc. of $2.7 million and $0.8 million , respectively, which is reported within Due to SunEdison and affiliates, net in the unaudited condensed consolidated balance sheets. Incentive Distribution Rights Immediately prior to the completion of the IPO on July 23, 2014, Terra LLC entered into the Amended and Restated Operating Agreement of Terra LLC which granted SunEdison 100% of the IDRs of Terra LLC. IDRs represent the right to receive increasing percentages ( 15.0% , 25.0% and 50.0% ) of Terra LLC’s quarterly distributions after the Class A Units, Class B units, and Class B1 units of Terra LLC have received quarterly distributions in an amount equal to $0.2257 per unit (the "Minimum Quarterly Distribution") and the target distribution levels have been achieved. SunEdison has held 100% of the IDRs since the completion of the IPO. As of September 30, 2017 and December 31, 2016 , there were no Class B1 units of Terra LLC outstanding. There were no payments for IDRs made by the Company during the three and nine months ended September 30, 2017 and 2016 . As discussed in Note 1. Nature of Operations and Basis of Presentation , SunEdison transferred all of the outstanding IDRs of Terra LLC held by SunEdison or certain of its affiliates to Brookfield IDR Holder at the effective time of the Merger, and the Company and Brookfield IDR Holder entered into an amended and restated limited liability company agreement of Terra LLC as discussed below under Brookfield Sponsorship Transaction . Commitments to Acquire Renewable Energy Facilities from SunEdison As of September 30, 2017 , the Company did not have any open commitments to acquire renewable energy facilities from SunEdison, other than as discussed and defined directly below with respect to the Invenergy Wind Option Agreements. In connection with the Company's acquisition of certain operating wind power plants from Invenergy Wind in December of 2015, Sun Edison LLC, a wholly owned subsidiary of SunEdison, acting as intermediary, entered into certain option arrangements with Invenergy Wind for its remaining 9.9% interest in the acquired companies that are located in the U.S. (the "Invenergy Wind Interest"). Simultaneously, Terra LLC entered into a back to back option agreement with Sun Edison LLC on substantially identical terms (collectively the "Option Agreements"). The Option Agreements effectively permit (i) Terra LLC to exercise a call option to purchase the Invenergy Wind Interest over a 180 -day period beginning on September 30, 2019, and (ii) Invenergy Wind to exercise a put option with respect to the Invenergy Wind Interest over a 180 -day period beginning on September 30, 2018. The exercise prices of the put and call options described above would be based on the determination of the fair market value of the Invenergy Wind Interest at the time the relevant option is exercised, subject to certain minimum and maximum thresholds set forth in the Option Agreements. As part of the Settlement Agreement, with certain limited exceptions, all agreements, including the Option Agreement between Terra LLC and Sun Edison LLC, were rejected as of the effectiveness of the settlement, which occurred upon the consummation of the Merger with affiliates of Brookfield on October 16, 2017. As a result, the Company does not expect to be obligated to perform on its Option Agreement. Brookfield Sponsorship Transaction As discussed in Note 1. Nature of Operations and Basis of Presentation , pursuant to the Merger Agreement, at or prior to the effective time of the Merger that occurred on October 16, 2017, the Company and Orion Holdings (or one of its affiliates), among other parties, entered into a suite of agreements providing for sponsorship arrangements, as are more fully described below. Brookfield Master Services Agreements In connection with the consummation of the Merger, the Company entered into a master services agreement with Brookfield and certain affiliates of Brookfield (collectively, the "MSA Providers") pursuant to which the MSA Providers provide certain management and administrative services to the Company, including the provision of strategic and investment management services. As consideration for the services provided or arranged for by Brookfield and certain of its affiliates pursuant to the master services agreement, the Company will pay a base management fee on a quarterly basis that will be paid in arrears and calculated as follows: • for each of the first four quarters following the closing date of the Merger, a fixed component of $2.5 million per quarter (subject to proration for the quarter including the closing date of the Merger) plus 0.3125% of the market capitalization value increase for such quarter; • for each of the next four quarters, a fixed component of $3.0 million per quarter plus 0.3125% of the market capitalization value increase for such quarter; and • thereafter, a fixed component of $3.75 million per quarter plus 0.3125% of the market capitalization value increase for such quarter. For purposes of calculating the quarterly payment of the base management fee, the term market capitalization value increase means, for any quarter, the increase in value of the Company’s market capitalization for such quarter, calculated by multiplying the number of outstanding shares of Class A common stock as of the last trading day of such quarter by the difference between (x) the volume-weighted average trading price of a share of Class A common stock for the trading days in such quarter and (y) $9.52 . If the difference between (x) and (y) in the market capitalization value increase calculation for a quarter is a negative number, then the market capitalization value increase is deemed to be zero. Relationship Agreement In connection with the consummation of the Merger, the Company entered into a relationship agreement (the "Relationship Agreement") with Brookfield, which governs certain aspects of the relationship between Brookfield and the Company. Pursuant to the Relationship Agreement, Brookfield agrees that the Company will serve as the primary vehicle through which Brookfield and certain of its affiliates will own operating wind and solar assets in North America and Western Europe and that Brookfield will provide, subject to certain terms and conditions, the Company with a right of first offer on certain operating wind and solar assets that are located in such countries and developed by persons sponsored by or under the control of Brookfield. Governance Agreement In connection with the consummation of the Merger, the Company entered into a governance agreement (the “Governance Agreement”) with Orion Holdings and any controlled affiliate of Brookfield (other than the Company and its controlled affiliates) that by the terms of the Governance Agreement from time to time becomes a party thereto. The Governance Agreement establishes certain rights and obligations of the Company and controlled affiliates of Brookfield that own voting securities of the Company relating to the governance of the Company and the relationship between such affiliates of Brookfield and the Company and its controlled affiliates. Brookfield Registration Rights Agreement The Company also entered into a registration rights agreement (the “Brookfield Registration Rights Agreement”) on October 16, 2017 with Orion Holdings. The Brookfield Registration Rights Agreement governs Orion Holdings’ and the Company’s rights and obligations with respect to the registration for resale of all or a part of the Class A shares that Orion Holdings now holds following the Merger. New Terra LLC Agreement As discussed above, SunEdison transferred all of the outstanding IDRs of Terra LLC held by SunEdison or certain of its affiliates to Brookfield IDR Holder at the effective time of the Merger, and the Company and Brookfield IDR Holder entered into an amended and restated limited liability company agreement of Terra LLC (the “New Terra LLC Agreement”). The New Terra LLC Agreement, among other things, resets the IDR thresholds of Terra LLC to establish a first distribution threshold of $0.93 per share of Class A common stock and a second distribution threshold of $1.05 per share of Class A common stock. As a result of this amendment and restatement, amounts distributed from Terra LLC will be distributed on a quarterly basis as follows: • first, to the Company in an amount equal to the Company’s outlays and expenses for such quarter; • second, to holders of Class A units, until an amount has been distributed to such holders of Class A units that would result, after taking account of all taxes payable by the Company in respect of the taxable income attributable to such distribution, in a distribution to holders of shares of Class A common stock of $0.93 per share (subject to adjustment for distributions, combinations or subdivisions of shares of Class A common stock) if such amount were distributed to all holders of shares of Class A common stock; • third, 15% to the holders of the IDRs and 85% to the holders of Class A units until a further amount has been distributed to holders of Class A units in such quarter that would result, after taking account of all taxes payable by the Company in respect of the taxable income attributable to such distribution, in a distribution to holders of shares of Class A common stock of an additional $0.12 per share (subject to adjustment for distributions, combinations or subdivisions of shares of Class A common stock) if such amount were distributed to all holders of shares of Class A common stock; and • thereafter, 75% to holders of Class A units and 25% to holders of the IDRs.

Segment Reporting

Segment Reporting	9 Months Ended
	Sep. 30, 2017
Segment Reporting [Abstract]
Segment Reporting	SEGMENT REPORTING The Company has two reportable segments: Solar and Wind. These segments comprise the Company's entire portfolio of renewable energy facility assets and are determined based on the management approach. This approach designates the internal reporting used by management for making decisions and assessing performance as the source of the reportable segments. The Company’s operating segments consist of Distributed Generation, North America Utility and International Utility that are aggregated into the Solar reportable segment and Northeast Wind, Central Wind and Hawaii Wind that are aggregated into the Wind reportable segment. The operating segments have been aggregated as they have similar economic characteristics and meet all of the aggregation criteria. Corporate expenses include general and administrative expenses, acquisition costs, interest expense on corporate-level indebtedness, stock-based compensation and depreciation, accretion and amortization expense. All net operating revenues for the three and nine months ended September 30, 2017 and 2016 were earned by the Company's reportable segments from external customers in the United States (including Puerto Rico), Canada, the United Kingdom and Chile. The following table reflects summarized financial information concerning the Company’s reportable segments for the three and nine months ended September 30, 2017 and 2016 : Three Months Ended September 30, 2017 Three Months Ended September 30, 2016 (In thousands) Solar Wind Corporate Total Solar Wind Corporate Total Operating revenues, net $ 107,256 $ 46,174 $ — $ 153,430 $ 125,644 $ 52,474 $ — $ 178,118 Depreciation, accretion and amortization expense 27,418 33,937 475 61,830 29,243 28,400 345 57,988 Other operating costs and expenses 20,047 26,833 20,034 66,914 19,613 25,520 24,289 69,422 Interest expense, net 14,850 22,435 32,947 70,232 22,020 20,637 30,161 72,818 Other non-operating (income) expenses, net (854 ) (42 ) (7,197 ) (8,093 ) 2,206 11 2,244 4,461 Income tax (benefit) expense 1 — — (2,633 ) (2,633 ) — — 1,140 1,140 Net income (loss) $ 45,795 $ (36,989 ) $ (43,626 ) $ (34,820 ) $ 52,562 $ (22,094 ) $ (58,179 ) $ (27,711 ) Nine Months Ended September 30, 2017 Nine Months Ended September 30, 2016 (In thousands) Solar Wind Corporate Total Solar Wind Corporate Total Operating revenues, net $ 274,742 $ 200,190 $ — $ 474,932 $ 314,379 $ 204,957 $ — $ 519,336 Depreciation, accretion and amortization expense 82,093 101,992 1,954 186,039 90,137 87,402 487 178,026 Other operating costs and expenses 51,871 76,775 97,946 226,592 57,745 73,014 64,780 195,539 Interest expense, net 54,373 64,664 87,712 206,749 89,365 64,366 89,380 243,111 Gain on sale of renewable energy facilities (37,116 ) — — (37,116 ) — — — — Other non-operating (income) expenses, net (1,768 ) 581 (9,390 ) (10,577 ) 975 230 4,493 5,698 Income tax (benefit) expense 1 — — (4,982 ) (4,982 ) — — 3,115 3,115 Net income (loss) $ 125,289 $ (43,822 ) $ (173,240 ) $ (91,773 ) $ 76,157 $ (20,055 ) $ (162,255 ) $ (106,153 ) Balance Sheet Total assets 2 $ 2,926,805 $ 3,535,306 $ 409,132 $ 6,871,243 $ 3,595,387 $ 3,609,471 $ 501,007 $ 7,705,865 ——— (1) Income tax (benefit) expense is not allocated to the Company's Solar and Wind segments. (2) Represents total assets as of September 30, 2017 and December 31, 2016 , respectively.

Other Comprehensive Income (Los

Other Comprehensive Income (Loss)	9 Months Ended
	Sep. 30, 2017
Equity [Abstract]
Other Comprehensive Income (Loss)	OTHER COMPREHENSIVE INCOME (LOSS) The following table presents the changes in each component of accumulated other comprehensive income, net of tax, for the nine months ended September 30, 2017 : (In thousands) Foreign Currency Translation Adjustments Hedging Activities Accumulated Other Comprehensive Income Balance as of December 31, 2016 $ (22,133 ) $ 45,045 $ 22,912 Net unrealized gain arising during the period (net of tax expense of $5,921) 12,136 27,960 40,096 Reclassification of net realized loss (gain) into earnings: Interest expense, net (net of tax benefit of $2,401) — 3,163 3,163 Operating revenues, net (net of tax expense of $2,801) — (3,690 ) (3,690 ) Gain on sale of renewable energy facilities (net of tax benefit of $8,858) 1 14,741 — 14,741 Other comprehensive income 26,877 27,433 54,310 Accumulated other comprehensive income 4,744 72,478 77,222 Less: Other comprehensive income attributable to non-controlling interests 1,250 18,638 19,888 Balance as of September 30, 2017 $ 3,494 $ 53,840 $ 57,334 ——— (1) Represents reclassification of the accumulated foreign currency translation loss for the U.K. Portfolio, as the Company's sale of this portfolio closed in the second quarter of 2017 as discussed in Note 2. Assets Held for Sale . The following tables present each component of other comprehensive income (loss) and the related tax effects for the three and nine months ended September 30, 2017 and 2016 : Three Months Ended September 30, 2017 2016 (In thousands) Before Tax Tax Effect Net of Tax Before Tax Tax Effect Net of Tax Foreign currency translation adjustments: Net unrealized gain (loss) arising during the period $ 6,944 $ (409 ) $ 6,535 $ (6,158 ) $ — $ (6,158 ) Hedging activities: Net unrealized gain (loss) arising during the period 18,370 (1,032 ) 17,338 14,258 — 14,258 Reclassification of net realized loss (gain) into earnings 100 (6 ) 94 3,164 — 3,164 Other comprehensive income (loss) $ 25,414 $ (1,447 ) 23,967 $ 11,264 $ — 11,264 Less: Other comprehensive income attributable to non-controlling interests, net of tax 8,766 4,850 Other comprehensive income attributable to Class A common stockholders $ 15,201 $ 6,414 Nine Months ended September 30, 2017 2016 (In thousands) Before Tax Tax Effect Net of Tax Before Tax Tax Effect Net of Tax Foreign currency translation adjustments: Net unrealized gain (loss) arising during the period $ 15,376 $ (3,240 ) $ 12,136 $ (2,442 ) $ — $ (2,442 ) Reclassification of net realized loss (gain) into earnings 1 23,599 (8,858 ) 14,741 — — — Hedging activities: Net unrealized gain (loss) arising during the period 30,641 (2,681 ) 27,960 (32,348 ) — (32,348 ) Reclassification of net realized (gain) loss into earnings 2 (927 ) 400 (527 ) 15,667 — 15,667 Other comprehensive income (loss) $ 68,689 $ (14,379 ) 54,310 $ (19,123 ) $ — (19,123 ) Less: Other comprehensive income (loss) attributable to non-controlling interests, net of tax 19,888 (6,819 ) Other comprehensive income (loss) attributable to Class A common stockholders $ 34,422 $ (12,304 ) ——— (1) Represents reclassification of the accumulated foreign currency translation loss for the U.K. Portfolio, as the Company's sale of this portfolio closed in the second quarter of 2017 as discussed in Note 2. Assets Held for Sale. The before tax amount of $23.6 million was recognized within gain on sale of renewable energy facilities in the unaudited condensed consolidated statement of operations for the nine months ended September 30, 2017. (2) Includes $15.9 million loss reclassification for the nine months ended September 30, 2016 that occurred subsequent to the Company's discontinuation of hedge accounting in the second quarter of 2016 for interest rate swaps within the U.K. Portfolio as discussed in Note 8 . Derivatives . As discussed above, the Company's sale of the U.K. Portfolio closed in the second quarter of 2017.

Nature of Operations and Basi27

Nature of Operations and Basis of Presentation (Policies)	9 Months Ended
	Sep. 30, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	The accompanying unaudited condensed consolidated financial statements have been prepared in accordance with the Securities and Exchange Commission’s ("SEC") regulations for interim financial information. Accordingly, they do not include all of the information and notes required by U.S. generally accepted accounting principles ("U.S. GAAP") for complete financial statements. The financial statements should be read in conjunction with the accounting policies and other disclosures as set forth in the notes to the Company’s annual financial statements for the year ended December 31, 2016 , filed with the SEC on Form 10-K on July 21, 2017. Interim results are not necessarily indicative of results for a full year. In the opinion of management, the accompanying unaudited condensed consolidated financial statements contain all material adjustments consisting of normal and recurring accruals necessary to present fairly the Company's financial position as of September 30, 2017 , the results of operations and comprehensive (loss) income for the three and nine months ended September 30, 2017 and 2016 and cash flows for the nine months ended September 30, 2017 and 2016.
Use of Estimates	In preparing the unaudited condensed consolidated financial statements, the Company used estimates and assumptions that affect the reported amounts of assets and liabilities and the disclosure of contingent assets and liabilities as of the date of the financial statements. Such estimates also affect the reported amounts of revenues, expenses and cash flows during the reporting period. To the extent there are material differences between the estimates and actual results, the Company's future results of operations would be affected.
Recent Accounting Developments	In May 2014, the Financial Accounting Standards Board ("FASB") issued ASU No. 2014-09, Revenue from Contracts with Customers (Topic 606) , which requires an entity to recognize the amount of revenue to which it expects to be entitled for the transfer of promised goods or services to customers. ASU No. 2014-09 will replace most existing revenue recognition guidance in U.S. GAAP when it becomes effective. In March 2016, the FASB issued ASU No. 2016-08, Revenue from Contracts with Customers (Topic 606), Principal versus Agent Considerations (Reporting Revenue Gross versus Net) , which clarifies how to apply the implementation guidance on principal versus agent considerations related to the sale of goods or services to a customer as updated by ASU No. 2014-09. ASU No. 2014-09 and ASU No. 2016-08 will become effective for the Company on January 1, 2018. Early application is permitted but not before January 1, 2017. ASU No. 2014-09 and ASU No. 2016-08 permit the use of either the retrospective or modified retrospective method. The Company is working through an adoption plan which includes the evaluation of revenue contracts compared to the new standards and evaluating the impact of the new standards on the Company's consolidated financial statements and related disclosures. The Company does not plan to adopt these standards prior to January 1, 2018. In February 2016, the FASB issued ASU No. 2016-02, Leases (Topic 842) , which primarily changes the lessee's accounting for operating leases by requiring recognition of lease right-of-use assets and lease liabilities. This standard is effective for annual reporting periods beginning after December 15, 2018, with early adoption permitted. The Company is currently evaluating the effect of ASU No. 2016-02 on its consolidated financial statements. In March 2016, the FASB issued ASU No. 2016-09, Compensation - Stock Compensation (Topic 718) . This update was issued as part of the FASB's simplification initiative and affects all entities that issue share-based payment awards to their employees. The amendments in this update cover such areas as the recognition of excess tax benefits and deficiencies, the classification of those excess tax benefits on the statement of cash flows, an accounting policy election for forfeitures, the amount an employer can withhold to cover income taxes and still qualify for equity classification and the classification of those taxes paid on the statement of cash flows. This update is effective for annual and interim periods beginning after December 15, 2016, with early adoption permitted if all provisions are adopted within the same period. The Company adopted ASU No. 2016-09 as of January 1, 2017, which did not result in any material adjustments to the Company's consolidated financial statements and related disclosures. In March 2016, the FASB issued ASU No. 2016-06, Derivatives and Hedging (Topic 815) , which clarifies that determining whether the economic characteristics of a put or call are clearly and closely related to its debt host requires only an assessment of the four-step decision sequence outlined in FASB ASC paragraph 815-15-25-24. Additionally, entities are not required to separately assess whether the contingency itself is clearly and closely related. This standard is effective for annual and interim periods beginning after December 15, 2016, with early adoption permitted. The amendments in this update should be applied on a modified retrospective basis. The adoption of ASU No. 2016-06 as of January 1, 2017 did not have an impact on the Company's consolidated financial statements. In March 2016, the FASB issued ASU No. 2016-07, Investments - Equity Method and Joint Ventures (Topic 323) . The amendments of ASU No. 2016-07 eliminate the requirement that when an investment qualifies for use of the equity method as a result of an increase in the level of ownership interest or degree of influence, an investor must adjust the investment, results of operations and retained earnings retroactively on a step-by-step basis as if the equity method had been in effect during all previous periods that the investment had been held. The amendments require that the equity method investor add the cost of acquiring the additional interest in the investee to the current basis of the investor's previously held interest and adopt the equity method of accounting with no retroactive adjustment to the investment. In addition, ASU No. 2016-07 requires that an entity that has an available-for-sale equity security that becomes qualified for the equity method of accounting recognize through earnings the unrealized holding gain or loss in accumulated other comprehensive income at the date the investment becomes qualified for use of the equity method. The guidance in ASU No. 2016-07 is effective for fiscal years beginning after December 15, 2016, and interim periods within those annual periods. The adoption of ASU No. 2016-07 is required to be applied prospectively and early adoption is permitted. The Company evaluated this standard and determined that it did not have an impact on its consolidated financial statements as it does not have any equity method investments. In August 2016, the FASB issued ASU No. 2016-15, Statement of Cash Flows (Topic 230), Classification of Certain Cash Receipts and Cash Payments . The amendments of ASU No. 2016-15 were issued to address eight specific cash flow issues for which stakeholders have indicated to the FASB that a diversity in practice existed in how entities were presenting and classifying these items in the statement of cash flows. The issues addressed by ASU No. 2016-15 include but are not limited to the classification of debt prepayment and debt extinguishment costs, payments made for contingent consideration for a business combination, proceeds from the settlement of insurance proceeds, distributions received from equity method investees and separately identifiable cash flows and the application of the predominance principle. The amendments of ASU No. 2016-15 are effective for public entities for fiscal years beginning after December 15, 2017 and interim periods in those fiscal years. Early adoption is permitted, including adoption in an interim fiscal period with all amendments adopted in the same period. The adoption of ASU No. 2016-15 is required to be applied retrospectively. The Company is currently evaluating the impact of the standard on its consolidated statements of cash flows. In October 2016, the FASB issued ASU No. 2016-16, Income Taxes (Topic 740), Intra-Entity Transfers of Assets Other Than Inventory . The amendments of ASU No. 2016-16 were issued to improve the accounting for the income tax consequences of intra-entity transfers of assets other than inventory. Current GAAP prohibits the recognition of current and deferred income taxes for an intra-entity asset transfer until the asset has been sold to an outside party which has resulted in diversity in practice and increased complexity within financial reporting. The amendments of ASU No. 2016-16 would require an entity to recognize the income tax consequences of an intra-entity transfer of an asset other than inventory when the transfer occurs and do not require new disclosure requirements. The amendments of ASU No. 2016-16 are effective for annual reporting periods beginning after December 15, 2017, and interim periods within those annual periods. Early adoption is permitted and the adoption of ASU No. 2016-16 should be applied on a modified retrospective basis through a cumulative-effect adjustment directly to retained earnings as of the beginning of the period of adoption. The Company does not expect this standard to have an impact on its consolidated financial statements. In October 2016, the FASB issued ASU No. 2016-17, Consolidation (Topic 810), Interests Held through Related Parties That Are under Common Control . ASU No. 2016-17 updates ASU No. 2015-02. Under the amendments, a single decision maker is not required to consider indirect interests held through related parties that are under common control with the single decision maker to be the equivalent of direct interests in their entirety. Instead, a single decision maker is required to include those interests on a proportionate basis consistent with indirect interests held through other related parties. ASU No. 2016-17 is effective for annual reporting periods beginning after December 15, 2016, and interim periods within those annual periods, with early adoption permitted. The adoption of ASU No. 2016-17 as of January 1, 2017 did not have an impact on the Company's consolidated financial statements. In November 2016, the FASB issued ASU No. 2016-18, Statement of Cash Flows (Topic 320), Restricted Cash, a Consensus of the FASB Emerging Issues Task Force . The amendments require that a statement of cash flows explain the change during the period in the total of cash, cash equivalents and amounts generally described as restricted cash or restricted cash equivalents. Therefore, amounts generally described as restricted cash and restricted cash equivalents should be included with cash and cash equivalents when reconciling the beginning-of-period and end-of-period total amounts shown on the statement of cash flows. ASU No. 2016-18 is effective for fiscal years beginning after December 15, 2017 and interim periods within those fiscal years. Early adoption is permitted and the adoption of ASU No. 2016-18 will be applied retrospectively. The Company elected to early adopt ASU No. 2016-18 during the second quarter of 2017 and has revised its unaudited condensed consolidated statement of cash flows for the nine months ended September 30, 2016. Net cash used in investing activities for the nine months ended September 30, 2016 decreased by $57.7 million as a result of the adoption of this standard. The sum of the Company's cash and cash equivalents of $565.3 million , current portion of restricted cash of $114.9 million and non-current portion of restricted cash of $2.6 million reported within the unaudited condensed consolidated balance sheet as of December 31, 2016 equals the beginning balance of cash, cash equivalents and restricted cash of $682.8 million shown in the unaudited condensed consolidated statement of cash flows for the nine months ended September 30, 2017. The sum of the Company's cash and cash equivalents of $462.8 million , current portion of restricted cash of $126.1 million and non-current portion of restricted cash of $26.1 million reported within the unaudited condensed consolidated balance sheet as of September 30, 2017 equals the ending balance of cash, cash equivalents and restricted cash of $615.0 million shown in the unaudited condensed consolidated statement of cash flows for the nine months ended September 30, 2017. The Company had $54.7 million of restricted cash classified within assets held for sale as of September 30, 2016 (with no comparable amount as of December 31, 2015) and thus had to add this reclassification amount to the net change in cash, cash equivalents and restricted cash classified within assets held for sale line reported in the unaudited condensed consolidated statement of cash flows for the nine months ended September 30, 2016 to reconcile the change in the beginning and end-of-period cash, cash equivalents and restricted cash. The Company's restricted cash balances during 2016 also included amounts related to its renewable energy facilities located in the United Kingdom (the "U.K.") and Canada, which resulted in a $5.3 million change in the effect of exchange rate changes on cash, cash equivalents and restricted cash line reported in the unaudited condensed consolidated statement of cash flows for the nine months ended September 30, 2016. In December 2016, the FASB issued ASU No. 2016-19, Technical Corrections and Improvements . The amendments cover a wide range of topics in the Accounting Standards Codification, covering differences between original guidance and the Accounting Standards Codification, guidance clarification and reference corrections, simplification and minor improvements. The adoption of ASU No. 2016-19 is effective for annual periods, including interim periods within those annual periods, beginning after December 15, 2016. The Company evaluated this standard and determined that it did not have an impact on its consolidated financial statements. In December 2016, the FASB issued ASU No. 2016-20, Technical Corrections and Improvements to Topic 606, Revenue from Contracts with Customers . The amendments in this update are of a similar nature to the items typically addressed in ASU 2016-19, Technical Corrections and Improvements . However, the FASB decided to issue a separate update for technical corrections and improvements to Topic 606 and other Topics amended by ASU No. 2014-09 to increase stakeholders’ awareness of the proposals and to expedite improvements to ASU No. 2014-09. The adoption of ASU No. 2016-20 is effective for annual reporting periods beginning after December 15, 2017, including interim reporting periods within those annual periods. Early adoption is permitted only as of annual reporting periods beginning after December 15, 2016, including interim reporting periods within that reporting period. The Company is currently evaluating the effect of this standard on its consolidated financial statements. In January 2017, the FASB issued ASU No. 2017-01, Business Combinations (Topic 805), Clarifying the Definition of a Business . The amendment seeks to clarify the definition of a business with the objective of adding guidance to assist entities with evaluating whether transactions should be accounted for as acquisitions (or disposals) of assets or businesses. The definition of a business affects many areas of accounting including acquisitions, disposals, goodwill and consolidation. The adoption of ASU No. 2017-01 is effective for annual periods beginning after December 15, 2017, including interim periods within those periods. The amendments should be applied prospectively on or after the effective dates. Accordingly, the adoption will not have an effect on the Company's historical financial statements. The Company is currently evaluating the effect of this standard on future consolidated financial statements. In January 2017, the FASB issued ASU No. 2017-04, Intangibles - Goodwill and Other (Topic 350), Simplifying the Test for Goodwill Impairment. The amendment simplifies the accounting for goodwill impairment by removing Step 2 of the current test, which requires calculation of a hypothetical purchase price allocation. Under the revised guidance, goodwill impairment will be measured as the amount by which a reporting unit’s carrying value exceeds its fair value, not to exceed the carrying amount of goodwill (currently Step 1 of the two step impairment test). Entities will continue to have the option to perform a qualitative assessment to determine if a quantitative impairment test is necessary. The standard is effective January 1, 2020, with early adoption permitted, and must be adopted on a prospective basis. This updated guidance is not currently expected to impact the Company's financial reporting as the Company does not have any goodwill. In February 2017, the FASB issued ASU No. 2017-05, Other Income - Gains and Losses from the Derecognition of Nonfinancial Assets (Subtopic 610-20): Clarifying the Scope of Asset Derecognition Guidance and Accounting for Partial Sales of Nonfinancial Assets . This ASU is meant to clarify the scope of ASC Subtopic 610-20, Other Income - Gains and Losses from the Derecognition of Nonfinancial Assets and to add guidance for partial sales of nonfinancial assets. ASU No. 2017-05 is to be applied using a full retrospective method or a modified retrospective method as outlined in the guidance and is effective at the same time as ASU No. 2014-09. Further, the Company is required to adopt ASU No. 2017-05 at the same time that it adopts the guidance in ASU No. 2014-09. The Company is currently evaluating the effect of this standard on its consolidated financial statements. In May 2017, the FASB issued ASU No. 2017-09, Compensation - Stock Compensation (Topic 718): Scope of Modification Accounting . The amendment clarifies when changes to the terms or conditions of a share-based payment award must be accounted for as a modification. The new guidance is expected to reduce diversity in practice and result in fewer changes to the terms of an award being accounted for as a modification. Changes to the terms or conditions of a share-based payment award that do not impact the fair value of the award, vesting conditions and the classification as an equity or liability instrument will not need to be assessed under modification accounting. The guidance is effective for annual periods, and interim periods within those annual periods, beginning after December 15, 2017. The amendments in this update should be applied prospectively to an award modified on or after the adoption date. Accordingly, the adoption will not have an effect on the Company's historical financial statements. The Company is currently evaluating the effect of this standard on future consolidated financial statements. In August 2017, the FASB issued ASU No. 2017-12, Derivatives and Hedging (Topic 815): Targeted Improvements to Accounting for Hedging Activities . This ASU amends the hedge accounting model to enable entities to better portray the economics of their risk management activities in the financial statements and simplifies the application of hedge accounting in certain situations. ASU No. 2017-12 is effective for annual periods, and interim periods within those annual periods, beginning after December 15, 2018, with early adoption permitted. The Company is currently evaluating the effect of this standard on its consolidated financial statements.
Earnings (Loss) Per Share	Loss per share is based upon the weighted average shares outstanding. Net loss attributable to Class A common stockholders is adjusted by the amount of deemed dividends related to the accretion of redeemable non-controlling interest and the amount of dividends paid on Class A shares and participating RSAs. Unvested RSAs that contain non-forfeitable rights to dividends are treated as participating securities and are included in the loss per share computation using the two-class method, to the extent that there are undistributed earnings available as such securities do not participate in losses.
Segment Reporting	The Company has two reportable segments: Solar and Wind. These segments comprise the Company's entire portfolio of renewable energy facility assets and are determined based on the management approach. This approach designates the internal reporting used by management for making decisions and assessing performance as the source of the reportable segments. The Company’s operating segments consist of Distributed Generation, North America Utility and International Utility that are aggregated into the Solar reportable segment and Northeast Wind, Central Wind and Hawaii Wind that are aggregated into the Wind reportable segment. The operating segments have been aggregated as they have similar economic characteristics and meet all of the aggregation criteria. Corporate expenses include general and administrative expenses, acquisition costs, interest expense on corporate-level indebtedness, stock-based compensation and depreciation, accretion and amortization expense. All net operating revenues for the three and nine months ended September 30, 2017 and 2016 were earned by the Company's reportable segments from external customers in the United States (including Puerto Rico), Canada, the United Kingdom and Chile.

Assets Held for Sale (Tables)

Assets Held for Sale (Tables)	9 Months Ended
	Sep. 30, 2017
Discontinued Operations and Disposal Groups [Abstract]
Summary of Assets and Liabilities Held for Sale	The following table summarizes the major classes of assets and liabilities which are classified as held for sale on the Company's unaudited condensed consolidated balance sheet as of December 31, 2016. As discussed above, the Company closed on the sale of these renewable energy facilities in the first half of 2017. As of December 31, 2016 (In thousands) U.K. Portfolio Residential Portfolio Total Assets held for sale: Restricted cash $ 53,604 $ 1,202 $ 54,806 Accounts receivable, net 4,952 300 5,252 Prepaid expenses and other current assets 1,295 170 1,465 Total current assets held for sale 59,851 1,672 61,523 Renewable energy facilities, net 529,154 19,534 548,688 Intangible assets, net 1,480 — 1,480 Other assets 2,103 — 2,103 Total non-current assets held for sale 532,737 19,534 552,271 Total assets held for sale $ 592,588 $ 21,206 $ 613,794 Liabilities related to assets held for sale: Current portion of long-term debt $ 14,510 $ 175 $ 14,685 Accounts payable, accrued expenses and other current liabilities 5,980 245 6,225 Deferred revenue — 10 10 Due to SunEdison and affiliates, net 692 186 878 Total current liabilities related to assets held for sale 21,182 616 21,798 Long-term debt, less current portion 349,687 4,190 353,877 Deferred revenue, less current portion — 246 246 Asset retirement obligations 39,563 287 39,850 Other long-term liabilities 16,786 — 16,786 Total non-current liabilities related to assets held for sale 406,036 4,723 410,759 Total liabilities related to assets held for sale $ 427,218 $ 5,339 $ 432,557

Renewable Energy Facilities (Ta

Renewable Energy Facilities (Tables)	9 Months Ended
	Sep. 30, 2017
Property, Plant and Equipment [Abstract]
Renewable Energy Facilities	Renewable energy facilities, net consists of the following: (In thousands) September 30, December 31, Renewable energy facilities in service, at cost $ 5,379,726 $ 5,354,883 Less accumulated depreciation - renewable energy facilities (526,213 ) (364,756 ) Renewable energy facilities in service, net 4,853,513 4,990,127 Construction in progress - renewable energy facilities 790 3,124 Total renewable energy facilities, net $ 4,854,303 $ 4,993,251

Intangibles (Tables)

Intangibles (Tables)	9 Months Ended
	Sep. 30, 2017
Goodwill and Intangible Assets Disclosure [Abstract]
Gross Carrying Amount and Accumulated Amortization of Intangibles	The following table presents the gross carrying amount, accumulated amortization and net book value of intangibles as of September 30, 2017 : (In thousands, except weighted average amortization period) Weighted Average Amortization Period Gross Carrying Amount Accumulated Amortization Net Book Value Favorable rate revenue contracts 15 years $ 720,109 $ (92,139 ) $ 627,970 In-place value of market rate revenue contracts 19 years 521,798 (67,022 ) 454,776 Favorable rate land leases 17 years 15,800 (2,130 ) 13,670 Total intangible assets, net $ 1,257,707 $ (161,291 ) $ 1,096,416 Unfavorable rate revenue contracts 7 years $ 35,086 $ (14,744 ) $ 20,342 Unfavorable rate O&M contracts 2 years 5,000 (2,240 ) 2,760 Unfavorable rate land lease 15 years 1,000 (148 ) 852 Total intangible liabilities, net $ 41,086 $ (17,132 ) $ 23,954 The following table presents the gross carrying amount, accumulated amortization and net book value of intangibles as of December 31, 2016 : (In thousands, except weighted average amortization period) Weighted Average Amortization Period Gross Carrying Amount Accumulated Amortization Net Book Value Favorable rate revenue contracts 16 years $ 714,758 $ (57,634 ) $ 657,124 In-place value of market rate revenue contracts 20 years 518,003 (47,284 ) 470,719 Favorable rate land leases 18 years 15,800 (1,531 ) 14,269 Total intangible assets, net $ 1,248,561 $ (106,449 ) $ 1,142,112 Unfavorable rate revenue contracts 7 years $ 35,086 $ (10,541 ) $ 24,545 Unfavorable rate O&M contracts 3 years 5,000 (1,302 ) 3,698 Unfavorable rate land lease 16 years 1,000 (107 ) 893 Total intangible liabilities, net $ 41,086 $ (11,950 ) $ 29,136

Variable Interest Entities (Tab

Variable Interest Entities (Tables)	9 Months Ended
	Sep. 30, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Carrying Amounts and Classification of Consolidated VIE's Assets and Liabilities	The carrying amounts and classification of the consolidated VIEs’ assets and liabilities included in the Company's unaudited condensed consolidated balance sheets are as follows: (In thousands) September 30, December 31, Current assets $ 172,183 $ 191,244 Non-current assets 4,222,425 4,351,635 Total assets $ 4,394,608 $ 4,542,879 Current liabilities $ 202,451 $ 638,452 Non-current liabilities 930,187 514,464 Total liabilities $ 1,132,638 $ 1,152,916

Long-term Debt (Tables)

Long-term Debt (Tables)	9 Months Ended
	Sep. 30, 2017
Debt Disclosure [Abstract]
Schedule of Debt	Long-term debt consists of the following: (In thousands, except rates) September 30, December 31, Interest Type Interest Rate (%) 1 Financing Type Corporate-level long-term debt 2 : Senior Notes due 2023 $ 950,000 $ 950,000 Fixed 6.38 Senior notes Senior Notes due 2025 300,000 300,000 Fixed 6.63 Senior notes Revolver 277,000 552,000 Variable 4.02 Revolving loan Non-recourse long-term debt 3 : Permanent financing 1,986,317 2,078,009 Blended 4 5.89 5 Term debt / Senior notes Financing lease obligations 118,194 123,930 Imputed 5.62 5 Financing lease obligations Total principal due for long-term debt and financing lease obligations 3,631,511 4,003,939 5.93 5 Unamortized discount, net (15,105 ) (13,620 ) Deferred financing costs, net (35,012 ) (39,405 ) Less current portion of long-term debt and financing lease obligations 6 (716,728 ) (2,212,968 ) Long-term debt and financing lease obligations, less current portion 7 $ 2,864,666 $ 1,737,946 ——— (1) As of September 30, 2017 . (2) Corporate-level debt represents debt issued by Terra Operating LLC and guaranteed by Terra LLC and certain subsidiaries of Terra Operating LLC other than certain non-recourse subsidiaries as defined in the relevant debt agreements. (3) Non-recourse debt represents debt issued by subsidiaries with no recourse to Terra LLC, Terra Operating LLC or guarantors of the Company's corporate-level debt, other than limited or capped contingent support obligations, which in aggregate are not considered to be material to the Company's business and financial condition. (4) Includes variable rate debt and fixed rate debt. As of September 30, 2017 , 50% of this balance had a variable interest rate and the other 50% of this balance had a fixed interest rate. The Company has entered into interest rate swap agreements to fix the interest rates of certain variable rate permanent financing non-recourse debt (see Note 8 . Derivatives ). (5) Represents the weighted average interest rate as of September 30, 2017 . (6) As of December 31, 2016, the Company reclassified $14.7 million from current portion of long-term debt and financing lease obligations to current liabilities related to assets held for sale in the unaudited condensed consolidated balance sheet. There was no similar reclassification as of September 30, 2017 as the sale of the related renewable energy facilities closed in the first half of 2017 (see Note 2. Assets Held for Sale ). (7) As of December 31, 2016, the Company reclassified $353.9 million from long-term debt and financing lease obligations, less current portion to non-current liabilities related to assets held for sale in the unaudited condensed consolidated balance sheet. There was no similar reclassification as of September 30, 2017 as the sale of the related renewable energy facilities closed in the first half of 2017 (see Note 2. Assets Held for Sale ).
Aggregate Contractual Payments of Long-term Debt	The aggregate contractual payments of long-term debt due after September 30, 2017 , including financing lease obligations and excluding amortization of debt discounts, premiums and deferred financing costs, as stated in the financing agreements, are as follows: (In thousands) Remainder of 2017 1 2018 2019 2020 2021 2 Thereafter Total Maturities of long-term debt as of September 30, 2017 3 $ 99,146 $ 111,620 $ 391,330 $ 101,867 $ 355,118 $ 2,572,430 $ 3,631,511 ——— (1) Includes $27.0 million of Revolver indebtedness that was repaid with cash on hand in the fourth quarter of 2017 as discussed above. Also includes $37.6 million of prepayments made in the fourth quarter of 2017 for the Company's non-recourse portfolio term loan as discussed above under Non-recourse Portfolio Term Loan Prepayments . (2) Includes $250.0 million of Revolver indebtedness, which was refinanced with the New Revolver in the fourth quarter of 2017 as discussed above. Management does not intend to repay these borrowings within a year from the balance sheet date with the use of working capital and the New Revolver does not mature until 2021. (3) Represents the contractual principal payment due dates for the Company's long-term debt and does not reflect the reclassification of $545.2 million of long-term debt to current as a result of debt defaults under certain of the Company's non-recourse financing arrangements.

Income Taxes (Tables)

Income Taxes (Tables)	9 Months Ended
	Sep. 30, 2017
Income Tax Disclosure [Abstract]
Components of Income Tax Provision	The income tax provision consisted of the following: Three Months Ended September 30, Nine Months Ended September 30, (In thousands, except effective tax rate) 2017 2016 2017 2016 Loss before income tax (benefit) expense $ (37,453 ) $ (26,571 ) $ (96,755 ) $ (103,038 ) Income tax (benefit) expense (2,633 ) 1,140 (4,982 ) 3,115 Effective tax rate 7.0 % (4.3 )% 5.1 % (3.0 )%

Derivatives (Tables)

Derivatives (Tables)	9 Months Ended
	Sep. 30, 2017
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Schedule of Fair Values of Derivative Instruments	As of September 30, 2017 and December 31, 2016 , fair values of the following derivative instruments were included in the balance sheet captions indicated below: Fair Value of Derivative Instruments Hedging Contracts Derivatives Not Designated as Hedges (In thousands) Interest Rate Swaps Commodity Contracts Interest Rate Swaps Foreign Currency Contracts Commodity Contracts Gross Amounts of Assets/Liabilities Recognized Gross Amounts Offset in Consolidated Balance Sheet Net Amounts in Consolidated Balance Sheet As of September 30, 2017 Prepaid expenses and other current assets $ — $ 11,191 $ — $ 82 $ 13,765 $ 25,038 $ (82 ) $ 24,956 Other assets 3,611 86,517 — — 19,305 109,433 — 109,433 Total assets $ 3,611 $ 97,708 $ — $ 82 $ 33,070 $ 134,471 $ (82 ) $ 134,389 Accounts payable, accrued expenses and other current liabilities $ 9,049 $ — $ 242 $ 110 $ — $ 9,401 $ (82 ) $ 9,319 Other long-term liabilities 129 — 489 — — 618 — 618 Total liabilities $ 9,178 $ — $ 731 $ 110 $ — $ 10,019 $ (82 ) $ 9,937 As of December 31, 2016 Prepaid expenses and other current assets $ 1,150 $ 3,664 $ — $ 953 $ 12,028 $ 17,795 $ — $ 17,795 Other assets 411 62,474 — 460 25,167 88,512 — 88,512 Total assets $ 1,561 $ 66,138 $ — $ 1,413 $ 37,195 $ 106,307 $ — $ 106,307 Accounts payable, accrued expenses and other current liabilities $ 10,689 $ — $ 814 $ — $ — $ 11,503 $ — $ 11,503 Liabilities related to assets held for sale — — 4,041 — — 4,041 — 4,041 Other long-term liabilities 47 — — — — 47 — 47 Non-current liabilities related to assets held for sale — — 16,786 — — 16,786 — 16,786 Total liabilities $ 10,736 $ — $ 21,641 $ — $ — $ 32,377 $ — $ 32,377
Schedule of Notional Amounts for Derivative Instruments	As of September 30, 2017 and December 31, 2016 , notional amounts for derivative instruments consisted of the following: Notional Amount as of (In thousands) September 30, 2017 December 31, 2016 Derivatives designated as hedges: Interest rate swaps (USD) 405,183 433,874 Interest rate swaps (CAD) 156,713 84,713 Commodity contracts (MWhs) 15,941 16,988 Derivatives not designated as hedges: Interest rate swaps (USD) 13,788 14,681 Interest rate swaps (GBP) — 222,018 Foreign currency contracts (CAD) 15,175 25,075 Commodity contracts (MWhs) 1,117 1,407
Gains and Losses on Derivatives Not Designated As Hedges	Gains and losses on derivatives not designated as hedges for the three and nine months ended September 30, 2017 and 2016 consisted of the following: Location of Loss (Gain) in the Statements of Operations Three Months Ended September 30, Nine Months Ended September 30, (In thousands) 2017 2016 2017 2016 Interest rate swaps Interest expense, net $ 27 $ 5,127 $ 3,219 $ 36,583 Foreign currency contracts Loss on foreign currency exchange, net 457 (73 ) 1,017 (905 ) Commodity contracts Operating revenues, net (1,371 ) (3,095 ) (7,062 ) (11,009 )
Gains and Losses Recognized Related to Interest Rate Swaps and Commodity Contracts Designated as Cash Flow Hedges	Gains and losses recognized related to interest rate swaps and commodity contracts designated as cash flow hedges for the three and nine months ended September 30, 2017 and 2016 consisted of the following: Three Months Ended September 30, Gain (Loss) Recognized in Other Comprehensive Income (Effective Portion) net of taxes 1 Location of Amount Reclassified from Accumulated Other Comprehensive Income into Income (Effective Portion) Amount of (Gain) Loss Reclassified from Accumulated Other Comprehensive Income into Income (Effective Portion) 2 Amount of (Gain) Loss Recognized in Income (Ineffective Portion and Amount Excluded from Effectiveness Testing) (In thousands) 2017 2016 2017 2016 2017 2016 Interest rate swaps $ 1,353 $ 798 Interest expense, net $ 519 $ 3,114 $ (315 ) $ (17 ) Commodity contracts 15,985 13,460 Operating revenues, net (425 ) 50 (5,316 ) 382 Total $ 17,338 $ 14,258 $ 94 $ 3,164 $ (5,631 ) $ 365 ———— (1) Net of tax expense of $0.3 million and $0.8 million attributed to interest rate swaps and commodity contracts during the three months ended September 30, 2017, respectively. There were no taxes attributed to derivatives designated as cash flow hedges during the three months ended September 30, 2016. (2) Net of tax benefit of $0.7 million and tax expense of $0.7 million attributed to interest rate swaps and commodity contracts during the three months ended September 30, 2017, respectively. There were no taxes attributed to derivatives designated as cash flow hedges during the three months ended September 30, 2016. Nine Months Ended September 30, Gain (Loss) Recognized in Other Comprehensive Income (Effective Portion) net of taxes 1 Location of Amount Reclassified from Accumulated Other Comprehensive Income into Income (Effective Portion) Amount of (Gain) Loss Reclassified from Accumulated Other Comprehensive Income into Income (Effective Portion) 2 Amount of (Gain) Loss Recognized in Income (Ineffective Portion and Amount Excluded from Effectiveness Testing) (In thousands) 2017 2016 2017 2016 2017 2016 Interest rate swaps $ (1,899 ) $ (39,547 ) Interest expense, net $ 3,163 $ 9,743 $ (963 ) $ 474 Commodity contracts 29,859 7,199 Operating revenues, net (3,690 ) (9,997 ) (5,340 ) 3,465 Total $ 27,960 $ (32,348 ) $ (527 ) $ (254 ) $ (6,303 ) $ 3,939 ———— (1) Net of tax benefit of $0.2 million and tax expense of $2.9 million attributed to interest rate swaps and commodity contracts during the nine months ended September 30, 2017, respectively. There were no taxes attributed to derivatives designated as cash flow hedges during the nine months ended September 30, 2016. (2) Net of tax benefit of $2.4 million and tax expense of $2.8 million attributed to interest rate swaps and commodity contracts during the nine months ended September 30, 2017, respectively. There were no taxes attributed to derivatives designated as cash flow hedges during the nine months ended September 30, 2016.

Fair Value of Financial Instr35

Fair Value of Financial Instruments (Tables)	9 Months Ended
	Sep. 30, 2017
Fair Value Disclosures [Abstract]
Financial Instruments Measured at Fair Value on a Recurring Basis	The following table summarizes the financial instruments measured at fair value on a recurring basis classified in the fair value hierarchy (Level 1, 2 or 3) based on the inputs used for valuation in the unaudited condensed consolidated balance sheets: (In thousands) As of September 30, 2017 As of December 31, 2016 Assets Level 1 Level 2 Level 3 Total Level 1 Level 2 Level 3 Total Interest rate swaps $ — $ 3,611 $ — $ 3,611 $ — $ 1,561 $ — $ 1,561 Commodity contracts — 33,070 97,708 130,778 — 37,195 66,138 103,333 Foreign currency contracts — — — — — 1,413 — 1,413 Total derivative assets $ — $ 36,681 $ 97,708 $ 134,389 $ — $ 40,169 $ 66,138 $ 106,307 Liabilities Interest rate swaps $ — $ 9,909 $ — $ 9,909 $ — $ 32,377 $ — $ 32,377 Foreign currency contracts — 28 — 28 — — — — Total derivative liabilities $ — $ 9,937 $ — $ 9,937 $ — $ 32,377 $ — $ 32,377
Changes in the Fair Value of Derivative Instruments Classified as Level 3	The following table reconciles the changes in the fair value of derivative instruments classified as Level 3 in the fair value hierarchy for the nine months ended September 30, 2017 and 2016: Three Months Ended September 30, Nine Months Ended September 30, (In thousands) 2017 2016 2017 2016 Beginning balance $ 76,790 $ 43,763 $ 66,138 $ 63,154 Realized and unrealized gains (losses): Included in other comprehensive income (loss) 15,601 13,511 26,229 (2,798 ) Included in operating revenues, net 6,407 (433 ) 11,831 6,532 Settlements (1,090 ) 50 (6,490 ) (9,997 ) Balance as of September 30 $ 97,708 $ 56,891 $ 97,708 $ 56,891
Significant Unobservable Inputs Used in Valuation of Commodity Contracts	The significant unobservable inputs used in the valuation of the Company's commodity contracts categorized as Level 3 of the fair value hierarchy as of September 30, 2017 are as follows: (In thousands, except range) Fair Value as of September 30, 2017 Transaction Type Assets Liabilities Valuation Technique Unobservable Inputs Range Commodity contracts - power $ 97,708 $ — Discounted cash flow Forward price (per MWh) $ 13.4 - $ 72.5 Option model Volatilities 3.0 % - 6.7 %
Sensitivity of Fair Value Measurements to Increases (Decreases) in Significant Unobservable Inputs	The sensitivity of the Company's fair value measurements to increases (decreases) in the significant unobservable inputs is as follows: Significant Unobservable Input Position Impact on Fair Value Measurement Increase (decrease) in forward price Forward sale Decrease (increase) Increase (decrease) in implied volatilities Purchase option Increase (decrease)
Sensitivity of Fair Value Measurements to Increases (Decreases) in Significant Unobservable Inputs	The sensitivity of the Company's fair value measurements to increases (decreases) in the significant unobservable inputs is as follows: Significant Unobservable Input Position Impact on Fair Value Measurement Increase (decrease) in forward price Forward sale Decrease (increase) Increase (decrease) in implied volatilities Purchase option Increase (decrease)
Carrying Amount and Estimated Fair Value of Long-term Debt	The carrying amount and estimated fair value of the Company's long-term debt as of September 30, 2017 and December 31, 2016 is as follows: As of September 30, 2017 As of December 31, 2016 (In thousands) Carrying Amount Fair Value Carrying Amount Fair Value Long-term debt, including current portion $ 3,581,394 $ 3,733,007 $ 3,950,914 $ 4,080,397

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	9 Months Ended
	Sep. 30, 2017
Equity [Abstract]
Outstanding Shares	As of September 30, 2017 , the following shares of TerraForm Power were outstanding: Share Class: Shares Outstanding Shareholder(s) Class A common stock 92,408,596 * Class B common stock 48,202,310 SunEdison Total Shares 140,610,906 ——— * Class A common stockholders are comprised of public and private investors, executive officers, management and personnel who provide services to the Company. Shares of Class A common stock outstanding exclude 362,018 shares of common stock held in treasury. The total par value of Class A common stock reflected on the unaudited condensed consolidated balance sheet and unaudited condensed consolidated statement of stockholders' equity as of September 30, 2017 includes the shares of stock held in treasury.

Stock-based Compensation (Table

Stock-based Compensation (Tables)	9 Months Ended
	Sep. 30, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Restricted Stock Awards Activity	The following table presents information regarding outstanding RSAs as of September 30, 2017 and changes during the period then ended: Number of RSAs Outstanding Weighted-Average Grant-Date Fair Value Per Share Aggregate Intrinsic Value (in millions) Balance at January 1, 2017 366,195 $ 8.51 Vested (366,195 ) 8.51 Balance as of September 30, 2017 — $ — $ —
Restricted Stock Units Activity	The following table presents information regarding outstanding RSUs as of September 30, 2017 and changes during the period then ended: Number of RSUs Outstanding Aggregate Intrinsic Value (in millions) Weighted Average Remaining Balance at January 1, 2017 1,622,953 Granted 517,594 Vested (293,838 ) Forfeited (618,961 ) Balance as of September 30, 2017 1,227,748 $ 16.2 1.1

Loss Per Share (Tables)

Loss Per Share (Tables)	9 Months Ended
	Sep. 30, 2017
Earnings Per Share [Abstract]
Basic and Diluted Loss Per Share of Class A Common Stock	Basic and diluted loss per share of the Company's Class A common stock for the three and nine months ended September 30, 2017 and 2016 was calculated as follows: Three Months Ended September 30, Nine Months Ended September 30, (In thousands, except per share amounts) 2017 2016 2017 2016 Basic and diluted loss per share: Net loss attributable to Class A common stockholders $ (26,546 ) $ (26,171 ) $ (50,890 ) $ (47,559 ) Less: accretion of redeemable non-controlling interest (2,316 ) — (6,729 ) — Less: dividends paid on Class A shares and participating RSAs — — — — Undistributed loss attributable to Class A shares $ (28,862 ) $ (26,171 ) $ (57,619 ) $ (47,559 ) Weighted average basic and diluted Class A shares outstanding 1 92,352 90,860 92,228 89,140 Basic and diluted loss per share $ (0.31 ) $ (0.29 ) $ (0.62 ) $ (0.53 ) ——— (1) The computation for diluted loss per share of the Company's Class A common stock for the three and nine months ended September 30, 2017 excludes 1,227,748 of potentially dilutive unvested RSUs because the effect would have been anti-dilutive. The computation for diluted loss per share of the Company's Class A common stock for the three and nine months ended September 30, 2016 excludes 459,800 of potentially dilutive unvested RSAs and 1,823,063 of potentially dilutive unvested RSUs because the effect would have been anti-dilutive.

Non-controlling Interests (Tabl

Non-controlling Interests (Tables)	9 Months Ended
	Sep. 30, 2017
Noncontrolling Interest [Abstract]
Non-controlling Interest Balances	The following table presents the non-controlling interest balances reported in stockholders’ equity in the unaudited condensed consolidated balance sheets as of September 30, 2017 and December 31, 2016 : (In thousands) September 30, 2017 December 31, 2016 SunEdison's non-controlling interest in Terra LLC $ 648,765 $ 660,799 Non-controlling interests in renewable energy facilities 753,831 804,243 Total non-controlling interests $ 1,402,596 $ 1,465,042
Activity of Redeemable Non-controlling Interests	The following table presents the activity of the redeemable non-controlling interests balance for the nine months ended September 30, 2017 : Redeemable Non-controlling Interests (In thousands) Capital Retained Earnings Total Balance as of December 31, 2016 $ 153,490 $ 26,877 $ 180,367 Distributions (7,227 ) — (7,227 ) Accretion of redeemable non-controlling interest 6,729 — 6,729 Net income — 18,162 18,162 Balance as of September 30, 2017 $ 152,992 $ 45,039 $ 198,031

Segment Reporting (Tables)

Segment Reporting (Tables)	9 Months Ended
	Sep. 30, 2017
Segment Reporting [Abstract]
Summarized Financial Information of Reportable Segments	The following table reflects summarized financial information concerning the Company’s reportable segments for the three and nine months ended September 30, 2017 and 2016 : Three Months Ended September 30, 2017 Three Months Ended September 30, 2016 (In thousands) Solar Wind Corporate Total Solar Wind Corporate Total Operating revenues, net $ 107,256 $ 46,174 $ — $ 153,430 $ 125,644 $ 52,474 $ — $ 178,118 Depreciation, accretion and amortization expense 27,418 33,937 475 61,830 29,243 28,400 345 57,988 Other operating costs and expenses 20,047 26,833 20,034 66,914 19,613 25,520 24,289 69,422 Interest expense, net 14,850 22,435 32,947 70,232 22,020 20,637 30,161 72,818 Other non-operating (income) expenses, net (854 ) (42 ) (7,197 ) (8,093 ) 2,206 11 2,244 4,461 Income tax (benefit) expense 1 — — (2,633 ) (2,633 ) — — 1,140 1,140 Net income (loss) $ 45,795 $ (36,989 ) $ (43,626 ) $ (34,820 ) $ 52,562 $ (22,094 ) $ (58,179 ) $ (27,711 ) Nine Months Ended September 30, 2017 Nine Months Ended September 30, 2016 (In thousands) Solar Wind Corporate Total Solar Wind Corporate Total Operating revenues, net $ 274,742 $ 200,190 $ — $ 474,932 $ 314,379 $ 204,957 $ — $ 519,336 Depreciation, accretion and amortization expense 82,093 101,992 1,954 186,039 90,137 87,402 487 178,026 Other operating costs and expenses 51,871 76,775 97,946 226,592 57,745 73,014 64,780 195,539 Interest expense, net 54,373 64,664 87,712 206,749 89,365 64,366 89,380 243,111 Gain on sale of renewable energy facilities (37,116 ) — — (37,116 ) — — — — Other non-operating (income) expenses, net (1,768 ) 581 (9,390 ) (10,577 ) 975 230 4,493 5,698 Income tax (benefit) expense 1 — — (4,982 ) (4,982 ) — — 3,115 3,115 Net income (loss) $ 125,289 $ (43,822 ) $ (173,240 ) $ (91,773 ) $ 76,157 $ (20,055 ) $ (162,255 ) $ (106,153 ) Balance Sheet Total assets 2 $ 2,926,805 $ 3,535,306 $ 409,132 $ 6,871,243 $ 3,595,387 $ 3,609,471 $ 501,007 $ 7,705,865 ——— (1) Income tax (benefit) expense is not allocated to the Company's Solar and Wind segments. (2) Represents total assets as of September 30, 2017 and December 31, 2016 , respectively.

Other Comprehensive Income (L41

Other Comprehensive Income (Loss) (Tables)	9 Months Ended
	Sep. 30, 2017
Equity [Abstract]
Changes in Accumulated Other Comprehensive Income	The following table presents the changes in each component of accumulated other comprehensive income, net of tax, for the nine months ended September 30, 2017 : (In thousands) Foreign Currency Translation Adjustments Hedging Activities Accumulated Other Comprehensive Income Balance as of December 31, 2016 $ (22,133 ) $ 45,045 $ 22,912 Net unrealized gain arising during the period (net of tax expense of $5,921) 12,136 27,960 40,096 Reclassification of net realized loss (gain) into earnings: Interest expense, net (net of tax benefit of $2,401) — 3,163 3,163 Operating revenues, net (net of tax expense of $2,801) — (3,690 ) (3,690 ) Gain on sale of renewable energy facilities (net of tax benefit of $8,858) 1 14,741 — 14,741 Other comprehensive income 26,877 27,433 54,310 Accumulated other comprehensive income 4,744 72,478 77,222 Less: Other comprehensive income attributable to non-controlling interests 1,250 18,638 19,888 Balance as of September 30, 2017 $ 3,494 $ 53,840 $ 57,334 ——— (1) Represents reclassification of the accumulated foreign currency translation loss for the U.K. Portfolio, as the Company's sale of this portfolio closed in the second quarter of 2017 as discussed in Note 2. Assets Held for Sale .
Components of Comprehensive Income (Loss)	The following tables present each component of other comprehensive income (loss) and the related tax effects for the three and nine months ended September 30, 2017 and 2016 : Three Months Ended September 30, 2017 2016 (In thousands) Before Tax Tax Effect Net of Tax Before Tax Tax Effect Net of Tax Foreign currency translation adjustments: Net unrealized gain (loss) arising during the period $ 6,944 $ (409 ) $ 6,535 $ (6,158 ) $ — $ (6,158 ) Hedging activities: Net unrealized gain (loss) arising during the period 18,370 (1,032 ) 17,338 14,258 — 14,258 Reclassification of net realized loss (gain) into earnings 100 (6 ) 94 3,164 — 3,164 Other comprehensive income (loss) $ 25,414 $ (1,447 ) 23,967 $ 11,264 $ — 11,264 Less: Other comprehensive income attributable to non-controlling interests, net of tax 8,766 4,850 Other comprehensive income attributable to Class A common stockholders $ 15,201 $ 6,414 Nine Months ended September 30, 2017 2016 (In thousands) Before Tax Tax Effect Net of Tax Before Tax Tax Effect Net of Tax Foreign currency translation adjustments: Net unrealized gain (loss) arising during the period $ 15,376 $ (3,240 ) $ 12,136 $ (2,442 ) $ — $ (2,442 ) Reclassification of net realized loss (gain) into earnings 1 23,599 (8,858 ) 14,741 — — — Hedging activities: Net unrealized gain (loss) arising during the period 30,641 (2,681 ) 27,960 (32,348 ) — (32,348 ) Reclassification of net realized (gain) loss into earnings 2 (927 ) 400 (527 ) 15,667 — 15,667 Other comprehensive income (loss) $ 68,689 $ (14,379 ) 54,310 $ (19,123 ) $ — (19,123 ) Less: Other comprehensive income (loss) attributable to non-controlling interests, net of tax 19,888 (6,819 ) Other comprehensive income (loss) attributable to Class A common stockholders $ 34,422 $ (12,304 ) ——— (1) Represents reclassification of the accumulated foreign currency translation loss for the U.K. Portfolio, as the Company's sale of this portfolio closed in the second quarter of 2017 as discussed in Note 2. Assets Held for Sale. The before tax amount of $23.6 million was recognized within gain on sale of renewable energy facilities in the unaudited condensed consolidated statement of operations for the nine months ended September 30, 2017. (2) Includes $15.9 million loss reclassification for the nine months ended September 30, 2016 that occurred subsequent to the Company's discontinuation of hedge accounting in the second quarter of 2016 for interest rate swaps within the U.K. Portfolio as discussed in Note 8 . Derivatives . As discussed above, the Company's sale of the U.K. Portfolio closed in the second quarter of 2017.

Nature of Operations and Basi42

Nature of Operations and Basis of Presentation (Details) - USD ($)	Oct. 16, 2017	Mar. 06, 2017	Sep. 30, 2017	Sep. 30, 2016	Nov. 09, 2017	Oct. 15, 2017	Dec. 31, 2016	Dec. 31, 2015
Noncontrolling Interest [Line Items]
Common stock, shares outstanding (in shares)			140,610,906
Decrease in net cash used in investing activities			$ (199,384,000)	$ 45,762,000
Cash and cash equivalents			462,846,000				$ 565,333,000
Current portion of restricted cash			126,083,000				114,950,000
Non-current portion of restricted cash			26,080,000				2,554,000
Cash, cash equivalents and restricted cash			615,009,000	704,248,000			$ 682,837,000	$ 793,033,000
Restricted cash classified within assets held for sale				54,700,000				$ 0
Decrease in effect of exchange rate changes			$ (3,264,000)	5,933,000
Accounting Standards Update 2016-18
Noncontrolling Interest [Line Items]
Decrease in net cash used in investing activities				57,700,000
Decrease in effect of exchange rate changes				$ 5,300,000
Class A common stock
Noncontrolling Interest [Line Items]
Common stock, shares outstanding (in shares)			92,408,596				92,223,089
Class A common stock | SunEdison
Noncontrolling Interest [Line Items]
Shares exchanged (in shares)		48,202,310
Equity held		36.90%
Subsequent Event | Class A common stock
Noncontrolling Interest [Line Items]
Common stock, shares outstanding (in shares)	148,224,429
Subsequent Event | Class A common stock | SunEdison
Noncontrolling Interest [Line Items]
Shares exchanged (in shares)	48,202,310
Equity held						36.90%
Orion Holdings | Subsequent Event
Noncontrolling Interest [Line Items]
Ownership percentage	51.00%
Orion Holdings | Subsequent Event | Class A common stock
Noncontrolling Interest [Line Items]
Ownership percentage	51.00%
Covenant defaults | Subsequent Event
Noncontrolling Interest [Line Items]
Restricted cash					$ 23,000,000

Assets Held for Sale - Narrativ

Assets Held for Sale - Narrative (Details) £ in Millions

Jun. 12, 2017MW

May 11, 2017USD ($)

Mar. 14, 2017MW

Sep. 30, 2017USD ($)MW

Dec. 31, 2016USD ($)power_plantMW

Sep. 30, 2016USD ($)

Sep. 30, 2017USD ($)MW

Sep. 30, 2016USD ($)

Jun. 30, 2017USD ($)

May 11, 2017GBP (£)MW

May 11, 2017USD ($)MW

Mar. 31, 2017USD ($)

Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]

Gain on sale of renewable energy facilities

$ 0

$ 0

$ 37,116,000

$ 0

Residential Rooftop Solar Assets

Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]

Capacity (MW) | MW

11.4

Impairment charge

$ 15,700,000

Abandonment charge

$ 3,300,000

Residential Assets

Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]

Capacity (MW) | MW

0.3

0.3

Impairment charge

$ 1,400,000

Enfinity Colorado DHA 1

Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]

Capacity (MW) | MW

2.5

Consideration received

$ 1,100,000

Restricted cash

$ 800,000

Membership interest sold

100.00%

Loss on disposal

0

TerraForm Resi Solar Manager

Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]

Capacity (MW) | MW

8.9

Cash and cash equivalents

$ 600,000

Membership interest sold

100.00%

Loss on disposal

0

Proceeds from sale of assets

$ 6,000,000

Disposal Group, Disposed of by Sale, Not Discontinued Operations | Power Plants Sold In The United Kingdom

Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]

Number of operating projects | power_plant

24

Capacity (MW) | MW

365

Disposal Group, Disposed of by Sale, Not Discontinued Operations | Sale to Vortex Solar

Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]

Capacity (MW) | MW

11.1

11.1

Consideration received

$ 214,100,000

Transaction expenses

$ 3,900,000

Cash and cash equivalents

14,800,000

Restricted cash

$ 21,800,000

Reduction of non-recourse project debt | £

£ 301

Gain on sale of renewable energy facilities

$ 37,100,000

Assets Held for Sale - Summary

Assets Held for Sale - Summary of Assets and Liabilities (Details) - USD ($)	Sep. 30, 2017	Dec. 31, 2016	Sep. 30, 2016	Dec. 31, 2015
Assets held for sale:
Restricted cash			$ 54,700,000	$ 0
Total current assets held for sale	$ 0	$ 61,523,000
Total non-current assets held for sale	0	552,271,000
Liabilities related to assets held for sale:
Total current liabilities related to assets held for sale	0	21,798,000
Total non-current liabilities related to assets held for sale	$ 0	410,759,000
Disposal Group, Disposed of by Sale, Not Discontinued Operations
Assets held for sale:
Restricted cash		54,806,000
Accounts receivable, net		5,252,000
Prepaid expenses and other current assets		1,465,000
Total current assets held for sale		61,523,000
Renewable energy facilities, net		548,688,000
Intangible assets, net		1,480,000
Other assets		2,103,000
Total non-current assets held for sale		552,271,000
Total assets held for sale		613,794,000
Liabilities related to assets held for sale:
Current portion of long-term debt		14,685,000
Accounts payable, accrued expenses and other current liabilities		6,225,000
Deferred revenue		10,000
Due to SunEdison and affiliates, net		878,000
Total current liabilities related to assets held for sale		21,798,000
Long-term debt, less current portion		353,877,000
Deferred revenue, less current portion		246,000
Asset retirement obligations		39,850,000
Other long-term liabilities		16,786,000
Total non-current liabilities related to assets held for sale		410,759,000
Total liabilities related to assets held for sale		432,557,000
U.K. Portfolio | Disposal Group, Disposed of by Sale, Not Discontinued Operations
Assets held for sale:
Restricted cash		53,604,000
Accounts receivable, net		4,952,000
Prepaid expenses and other current assets		1,295,000
Total current assets held for sale		59,851,000
Renewable energy facilities, net		529,154,000
Intangible assets, net		1,480,000
Other assets		2,103,000
Total non-current assets held for sale		532,737,000
Total assets held for sale		592,588,000
Liabilities related to assets held for sale:
Current portion of long-term debt		14,510,000
Accounts payable, accrued expenses and other current liabilities		5,980,000
Deferred revenue		0
Due to SunEdison and affiliates, net		692,000
Total current liabilities related to assets held for sale		21,182,000
Long-term debt, less current portion		349,687,000
Deferred revenue, less current portion		0
Asset retirement obligations		39,563,000
Other long-term liabilities		16,786,000
Total non-current liabilities related to assets held for sale		406,036,000
Total liabilities related to assets held for sale		427,218,000
Residential Portfolio | Disposal Group, Disposed of by Sale, Not Discontinued Operations
Assets held for sale:
Restricted cash		1,202,000
Accounts receivable, net		300,000
Prepaid expenses and other current assets		170,000
Total current assets held for sale		1,672,000
Renewable energy facilities, net		19,534,000
Intangible assets, net		0
Other assets		0
Total non-current assets held for sale		19,534,000
Total assets held for sale		21,206,000
Liabilities related to assets held for sale:
Current portion of long-term debt		175,000
Accounts payable, accrued expenses and other current liabilities		245,000
Deferred revenue		10,000
Due to SunEdison and affiliates, net		186,000
Total current liabilities related to assets held for sale		616,000
Long-term debt, less current portion		4,190,000
Deferred revenue, less current portion		246,000
Asset retirement obligations		287,000
Other long-term liabilities		0
Total non-current liabilities related to assets held for sale		4,723,000
Total liabilities related to assets held for sale		$ 5,339,000

Renewable Energy Facilities (D

Renewable Energy Facilities (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Property, Plant and Equipment, Net, by Type [Abstract]
Total renewable energy facilities, net	$ 4,854,303,000		$ 4,854,303,000		$ 4,993,251,000
Depreciation expense	53,400,000	$ 48,100,000	160,000,000	$ 148,500,000
Disposal Group, Held-for-sale, Not Discontinued Operations
Property, Plant and Equipment, Net, by Type [Abstract]
Renewable energy facilities reclassified to assets held for sale	0		0		548,700,000
Renewable Energy Facilities in Service
Property, Plant and Equipment, Net, by Type [Abstract]
Renewable energy facilities, gross	5,379,726,000		5,379,726,000		5,354,883,000
Less accumulated depreciation - renewable energy facilities	(526,213,000)		(526,213,000)		(364,756,000)
Total renewable energy facilities, net	4,853,513,000		4,853,513,000		4,990,127,000
Construction in Progress - Renewable Energy Facilities
Property, Plant and Equipment, Net, by Type [Abstract]
Renewable energy facilities, gross	$ 790,000		$ 790,000		$ 3,124,000

Intangibles (Details)

Intangibles (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Intangible Assets, Net (Excluding Goodwill) [Abstract]
Gross Carrying Amount	$ 41,086		$ 41,086		$ 41,086
Accumulated Amortization	(17,132)		(17,132)		(11,950)
Net Book Value	23,954		23,954		29,136
Total intangible assets, net
Intangible Assets, Net (Excluding Goodwill) [Abstract]
Gross Carrying Amount	1,257,707		1,257,707		1,248,561
Accumulated Amortization	(161,291)		(161,291)		(106,449)
Net Book Value	1,096,416		1,096,416		1,142,112
Total intangible assets, net | Operating revenues, net
Intangible Assets, Net (Excluding Goodwill) [Abstract]
Amortization expense	(10,000)	$ (9,800)	(29,500)	$ (30,100)
Total intangible assets, net | Depreciation, Accretion, and Amortization
Intangible Assets, Net (Excluding Goodwill) [Abstract]
Amortization expense	6,400	7,000	$ 19,400	20,800
Total intangible assets, net | Minimum
Intangible Assets, Net (Excluding Goodwill) [Abstract]
Amortization period			1 year
Total intangible assets, net | Maximum
Intangible Assets, Net (Excluding Goodwill) [Abstract]
Amortization period			27 years
Favorable rate revenue contracts
Intangible Assets, Net (Excluding Goodwill) [Abstract]
Gross Carrying Amount	720,109		$ 720,109		714,758
Accumulated Amortization	(92,139)		(92,139)		(57,634)
Net Book Value	627,970		$ 627,970		$ 657,124
Favorable rate revenue contracts | Weighted average
Intangible Assets, Net (Excluding Goodwill) [Abstract]
Weighted Average Amortization Period			15 years		16 years
In-place value of market rate revenue contracts
Intangible Assets, Net (Excluding Goodwill) [Abstract]
Gross Carrying Amount	521,798		$ 521,798		$ 518,003
Accumulated Amortization	(67,022)		(67,022)		(47,284)
Net Book Value	454,776		$ 454,776		$ 470,719
In-place value of market rate revenue contracts | Weighted average
Intangible Assets, Net (Excluding Goodwill) [Abstract]
Weighted Average Amortization Period			19 years		20 years
Favorable rate land leases
Intangible Assets, Net (Excluding Goodwill) [Abstract]
Gross Carrying Amount	15,800		$ 15,800		$ 15,800
Accumulated Amortization	(2,130)		(2,130)		(1,531)
Net Book Value	13,670		$ 13,670		$ 14,269
Favorable rate land leases | Weighted average
Intangible Assets, Net (Excluding Goodwill) [Abstract]
Weighted Average Amortization Period			17 years		18 years
Unfavorable rate revenue contracts
Intangible Assets, Net (Excluding Goodwill) [Abstract]
Gross Carrying Amount	35,086		$ 35,086		$ 35,086
Accumulated Amortization	(14,744)		(14,744)		(10,541)
Net Book Value	20,342		$ 20,342		$ 24,545
Unfavorable rate revenue contracts | Weighted average
Intangible Assets, Net (Excluding Goodwill) [Abstract]
Weighted Average Amortization Period			7 years		7 years
Unfavorable rate O&M contracts
Intangible Assets, Net (Excluding Goodwill) [Abstract]
Gross Carrying Amount	5,000		$ 5,000		$ 5,000
Accumulated Amortization	(2,240)		(2,240)		(1,302)
Net Book Value	2,760		$ 2,760		$ 3,698
Unfavorable rate O&M contracts | Weighted average
Intangible Assets, Net (Excluding Goodwill) [Abstract]
Weighted Average Amortization Period			2 years		3 years
Unfavorable rate land lease
Intangible Assets, Net (Excluding Goodwill) [Abstract]
Gross Carrying Amount	1,000		$ 1,000		$ 1,000
Accumulated Amortization	(148)		(148)		(107)
Net Book Value	852		$ 852		$ 893
Unfavorable rate land lease | Weighted average
Intangible Assets, Net (Excluding Goodwill) [Abstract]
Weighted Average Amortization Period			15 years		16 years
Lease agreements | Cost of Operations
Intangible Assets, Net (Excluding Goodwill) [Abstract]
Amortization expense	$ 100	$ (200)	$ 400	$ (600)

Variable Interest Entities (Det

Variable Interest Entities (Details) $ in Thousands	Sep. 30, 2017USD ($)	Jun. 12, 2017MW	Dec. 31, 2016USD ($)
Consolidated Variable Interest Entity, Primary Beneficiary
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Current assets	$ 172,183		$ 191,244
Non-current assets	4,222,425		4,351,635
Total assets	4,394,608		4,542,879
Current liabilities	202,451		638,452
Non-current liabilities	930,187		514,464
Total liabilities	$ 1,132,638		$ 1,152,916
TerraForm Resi Manager
Variable Interest Entity [Line Items]
Capacity (MW) | MW		8.9

Long-term Debt - Debt Schedule

Long-term Debt - Debt Schedule (Details) - USD ($)	9 Months Ended
	Sep. 30, 2017	Dec. 31, 2016
Debt Instrument [Line Items]
Total principal due for long-term debt and financing lease obligations	$ 3,631,511,000	$ 4,003,939,000
Unamortized discount, net	(15,105,000)	(13,620,000)
Deferred financing costs, net	(35,012,000)	(39,405,000)
Less current portion of long-term debt and financing lease obligations	(716,728,000)	(2,212,968,000)
Long-term debt and financing lease obligations, less current portion	$ 2,864,666,000	1,737,946,000
Interest rate	5.93%
Debt at variable rate	50.00%
Debt at fixed rate	50.00%
Disposal Group, Held-for-sale, Not Discontinued Operations
Debt Instrument [Line Items]
Current portion of long-term debt	$ 0	14,700,000
Long-term debt, less current portion	0	353,900,000
Permanent Financing
Debt Instrument [Line Items]
Total principal due for long-term debt and financing lease obligations	$ 1,986,317,000	2,078,009,000
Interest rate	5.89%
Permanent Financing | Senior Notes due 2023
Debt Instrument [Line Items]
Total principal due for long-term debt and financing lease obligations	$ 950,000,000	950,000,000
Interest rate	6.38%
Permanent Financing | Senior Notes due 2025
Debt Instrument [Line Items]
Total principal due for long-term debt and financing lease obligations	$ 300,000,000	300,000,000
Interest rate	6.63%
Line of Credit | Revolving Credit Facility
Debt Instrument [Line Items]
Total principal due for long-term debt and financing lease obligations	$ 277,000,000	552,000,000
Interest rate	4.02%
Financing lease obligations
Debt Instrument [Line Items]
Total principal due for long-term debt and financing lease obligations	$ 118,194,000	$ 123,930,000
Interest rate	5.62%

Long-term Debt - Corporate-leve

Long-term Debt - Corporate-level Long-term Debt Narrative (Details)

Nov. 08, 2017USD ($)

Oct. 17, 2017USD ($)

Oct. 16, 2017USD ($)

Sep. 27, 2017USD ($)

Aug. 10, 2017USD ($)

Jul. 25, 2017USD ($)

Jul. 11, 2017

Apr. 26, 2017

Mar. 06, 2017USD ($)

Oct. 31, 2017USD ($)

Dec. 31, 2017USD ($)

Sep. 30, 2017USD ($)

Sep. 30, 2017USD ($)

Sep. 30, 2016USD ($)

May 03, 2017USD ($)

Feb. 28, 2017CAD

Nov. 02, 2016CAD

Debt Instrument [Line Items]

Repayments of long-term debt

$ 199,481,000

$ 122,597,000

Reduction in borrowing capacity and write-off charge

(2,518,000)

$ 0

Permanent Financing | Senior Notes Due 2023 and 2025

Debt Instrument [Line Items]

Debt default threshold for acceleration

$ 75,000,000

$ 75,000,000

Debt default acceleration percentage

25.00%

Audited financial statement, period for filing with SEC

60 days

Audited financial statement requirement, grace period upon written notice

90 days

90 days

Repurchase offer price percentage

101.00%

Success fee per $1,000 principal amount

$ 1.25

Success fee

1,500,000

Permanent Financing | Senior Notes Due 2023 and 2025 | Subsequent Event

Debt Instrument [Line Items]

Success fee per $1,000 principal amount

$ 1.25

Permanent Financing | Midco Portfolio Term Loan

Debt Instrument [Line Items]

Repayments of long-term debt

$ 30,000,000

Expected repayments of existing debt

100,000,000

100,000,000

Reduction in borrowing capacity and write-off charge

$ 1,400,000

Permanent Financing | Midco Portfolio Term Loan | Subsequent Event

Debt Instrument [Line Items]

Repayments of long-term debt

$ 37,600,000

$ 37,600,000

Maximum borrowing capacity

$ 350,000,000

Debt instrument term

5 years

Permanent Financing | Midco Portfolio Term Loan | London Interbank Offered Rate (LIBOR) | Subsequent Event

Debt Instrument [Line Items]

Debt instrument, basis spread on variable rate

2.75%

Revolving Credit Facility | New Revolver | Subsequent Event

Debt Instrument [Line Items]

Maximum borrowing capacity

$ 450,000,000

Debt instrument term

4 years

Proceeds from revolver

$ 250,000,000

Revolving Credit Facility | New Revolver | Base Rate | Minimum | Subsequent Event

Debt Instrument [Line Items]

Debt instrument, basis spread on variable rate

1.25%

Revolving Credit Facility | New Revolver | Base Rate | Maximum | Subsequent Event

Debt Instrument [Line Items]

Debt instrument, basis spread on variable rate

2.00%

Revolving Credit Facility | New Revolver | Adjusted Eurodollar Rate | Minimum | Subsequent Event

Debt Instrument [Line Items]

Debt instrument, basis spread on variable rate

2.25%

Revolving Credit Facility | New Revolver | Adjusted Eurodollar Rate | Maximum | Subsequent Event

Debt Instrument [Line Items]

Debt instrument, basis spread on variable rate

3.00%

Revolving Credit Facility | Line of Credit

Debt Instrument [Line Items]

Repayments of long-term debt

70,000,000

$ 150,000,000

$ 5,000,000

Period to provide financial statements

75 days

90 days

Cure period (in business days)

10 days

10 days

Expected repayments of existing debt

$ 50,000,000

Maximum borrowing capacity reduction

$ 50,000,000

Maximum borrowing capacity

520,000,000

$ 520,000,000

Revolving loans outstanding

$ 277,000,000

Revolving Credit Facility | Line of Credit | Subsequent Event

Debt Instrument [Line Items]

Repayments of long-term debt

$ 277,000,000

Repayments of long-term debt, using cash on hand

27,000,000

Repayments of long-term debt, using new borrowings

250,000,000

Revolving Credit Facility | Line of Credit | Revolver | Fourth Quarter of 2016 and First, Second, and Third Quarters of 2017

Debt Instrument [Line Items]

Debt covenant, coverage ratio required

1.75

Revolving Credit Facility | Line of Credit | Revolver | Fourth Quarter of 2016

Debt Instrument [Line Items]

Debt covenant, leverage ratio required

6

Revolving Credit Facility | Line of Credit | Revolver | First, Second and Third Quarters of 2017

Debt Instrument [Line Items]

Debt covenant, leverage ratio required

5.75

Revolving Credit Facility | Line of Credit | Eleventh Amendment to Debt Service Coverage Ratio

Debt Instrument [Line Items]

Reduction in borrowing capacity and write-off charge

600,000

Revolving Credit Facility | Line of Credit | Eleventh Amendment to Debt Service Coverage Ratio | Fourth Quarter of 2016 and First, Second, and Third Quarters of 2017

Debt Instrument [Line Items]

Debt covenant, coverage ratio required

1.50

Revolving Credit Facility | Line of Credit | Eleventh Amendment to Debt Service Coverage Ratio | Fourth Quarter of 2016

Debt Instrument [Line Items]

Debt covenant, leverage ratio required

6.50

Revolving Credit Facility | Line of Credit | Eleventh Amendment to Debt Service Coverage Ratio | First, Second and Third Quarters of 2017

Debt Instrument [Line Items]

Debt covenant, leverage ratio required

6.50

Revolving Credit Facility | Line of Credit | Twelfth Amendment to Debt Service Coverage Ratio

Debt Instrument [Line Items]

Reduction in borrowing capacity and write-off charge

$ 500,000

$ 500,000

Revolving Credit Facility | Line of Credit | New Revolver | Subsequent Event

Debt Instrument [Line Items]

Debt default threshold for acceleration

$ 75,000,000

Debt default acceleration percentage

50.00%

Percentage of capital stock in domestic subsidiaries

100.00%

Revolving Credit Facility | Line of Credit | New Revolver | London Interbank Offered Rate (LIBOR) | Subsequent Event

Debt Instrument [Line Items]

Standby fee percentage

0.50%

Revolving Credit Facility | Line of Credit | New Revolver | London Interbank Offered Rate (LIBOR) | Minimum | Subsequent Event

Debt Instrument [Line Items]

Standby fee percentage

0.375%

Revolving Credit Facility | Line of Credit | New Revolver | London Interbank Offered Rate (LIBOR) | Maximum | Subsequent Event

Debt Instrument [Line Items]

Standby fee percentage

0.50%

Revolving Credit Facility | Line of Credit | Sponsor Line Agreement | Subsequent Event

Debt Instrument [Line Items]

Percentage of capital stock in foreign subsidiaries

65.00%

Priority security interest, percentage of capital stock

100.00%

Revolving Credit Facility | Line of Credit | Sponsor Line Agreement | Grand Duchy of Luxembourg | Subsequent Event

Debt Instrument [Line Items]

Maximum borrowing capacity

$ 500,000,000

Debt instrument term

3 years

Revolving Credit Facility | Line of Credit | Sponsor Line Agreement | London Interbank Offered Rate (LIBOR) | Subsequent Event

Debt Instrument [Line Items]

Debt instrument, basis spread on variable rate

3.00%

Permanent Financing

Debt Instrument [Line Items]

Maximum borrowing capacity | CAD

CAD 233,900,000

CAD 120,000,000

Long-term Debt - Non-recourse L

Long-term Debt - Non-recourse Long-term Debt Narrative (Details)

Oct. 17, 2017USD ($)

Sep. 27, 2017USD ($)

Jul. 25, 2017USD ($)

Mar. 06, 2017USD ($)

Oct. 31, 2017USD ($)

Dec. 31, 2017USD ($)

Sep. 30, 2017USD ($)extension_optionMW

Sep. 30, 2016USD ($)

Nov. 08, 2017USD ($)

May 03, 2017USD ($)

Feb. 28, 2017CAD

Dec. 31, 2016USD ($)

Nov. 02, 2016CADMW

Debt Instrument [Line Items]

Repayments of long-term debt

$ 199,481,000

$ 122,597,000

Reduction in borrowing capacity and write-off charge

(2,518,000)

$ 0

Long-term debt

$ 3,631,511,000

Lenders right to demand repayment threshold

1 year

Defaulted debt, reclassified to current

$ 545,200,000

$ 1,600,000,000

Debt default, restricted cash reclassified to current

51,200,000

65,300,000

Debt default, cash and cash equivalents reclassified to current restricted cash

60,000,000

67,100,000

Debt default, restricted cash and cash equivalents, amount reclassified to held for sale

$ 0

$ 33,800,000

Brookfield Asset Management | TerraForm Power | Senior Notes Due 2023 and 2025

Debt Instrument [Line Items]

Debt instrument, expected refinance, period after closing of merger

3 months

Permanent Financing | Midco Portfolio Term Loan

Debt Instrument [Line Items]

Nameplate capacity (MW) | MW

1,104.3

Repayments of long-term debt

$ 30,000,000

Number of extension options | extension_option

2

Expected repayments of existing debt

$ 100,000,000

Reduction in borrowing capacity and write-off charge

1,400,000

Long-term debt

337,900,000

Permanent Financing | Midco Portfolio Term Loan | Subsequent Event

Debt Instrument [Line Items]

Aggregate principal amount

$ 350,000,000

Repayments of long-term debt

$ 37,600,000

$ 37,600,000

Permanent Financing

Debt Instrument [Line Items]

Aggregate principal amount | CAD

CAD 233,900,000

CAD 120,000,000

Nameplate capacity (MW) | MW

59

Principal amount increase | CAD

113,900,000

Letter of Credit

Debt Instrument [Line Items]

Aggregate principal amount | CAD

CAD 6,900,000

Principal amount increase | CAD

CAD 6,700,000

Revolving Credit Facility | Line of Credit

Debt Instrument [Line Items]

Aggregate principal amount

$ 520,000,000

Repayments of long-term debt

$ 70,000,000

$ 150,000,000

$ 5,000,000

Expected repayments of existing debt

$ 50,000,000

Revolving Credit Facility | Line of Credit | Subsequent Event

Debt Instrument [Line Items]

Repayments of long-term debt

$ 277,000,000

Long-term Debt - Maturities (De

Long-term Debt - Maturities (Details) - USD ($) $ in Thousands	Oct. 17, 2017	Sep. 27, 2017	Jul. 25, 2017	Mar. 06, 2017	Oct. 31, 2017	Dec. 31, 2017	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Aggregate Contractual Payments of Long-term Debt
Remainder of 2017							$ 99,146
2,018							111,620
2,019							391,330
2,020							101,867
2,021							355,118
Thereafter							2,572,430
Total							3,631,511
Repayments of long-term debt							199,481	$ 122,597
Defaulted debt, reclassified to current							545,200		$ 1,600,000
Long-term Debt
Aggregate Contractual Payments of Long-term Debt
Defaulted debt, reclassified to current							545,200
Midco Portfolio Term Loan | Secured Debt
Aggregate Contractual Payments of Long-term Debt
Total							$ 337,900
Repayments of long-term debt		$ 30,000
Midco Portfolio Term Loan | Subsequent Event | Secured Debt
Aggregate Contractual Payments of Long-term Debt
Repayments of long-term debt					$ 37,600	$ 37,600
Revolving Credit Facility | Line of Credit
Aggregate Contractual Payments of Long-term Debt
Repayments of long-term debt		$ 70,000	$ 150,000	$ 5,000
Revolving Credit Facility | Subsequent Event | Line of Credit
Aggregate Contractual Payments of Long-term Debt
Repayments of long-term debt, using cash on hand	$ 27,000
Repayments of long-term debt	277,000
Repayments of long-term debt, using new borrowings	$ 250,000

Income Taxes - Components of In

Income Taxes - Components of Income Tax Provision (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Income Tax Disclosure [Abstract]
Loss before income tax (benefit) expense	$ (37,453)	$ (26,571)	$ (96,755)	$ (103,038)
Income tax (benefit) expense	$ (2,633)	$ 1,140	$ (4,982)	$ 3,115
Effective tax rate	7.00%	(4.30%)	5.10%	(3.00%)

Income Taxes - Narrative (Detai

Income Taxes - Narrative (Details)	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Income Taxes [Line Items]
Ownership interest	65.80%		65.80%
Statutory tax rate percentage	35.00%	35.00%	35.00%	35.00%
SunEdison
Income Taxes [Line Items]
Ownership percentage by other entities	34.20%		34.20%

Derivatives - Schedule of Fair

Derivatives - Schedule of Fair Values of Derivative Instruments (Details) - USD ($)	Sep. 30, 2017	Dec. 31, 2016
Derivatives, Fair Value [Line Items]
Gross amounts of assets recognized	$ 134,471,000	$ 106,307,000
Gross assets offset in consolidated balance sheet	(82,000)	0
Net assets in consolidated balance sheet	134,389,000	106,307,000
Gross amounts of liabilities recognized	10,019,000	32,377,000
Gross liabilities offset in consolidated balance sheet	(82,000)	0
Net liabilities in consolidated balance sheet	9,937,000	32,377,000
Prepaid expenses and other current assets
Derivatives, Fair Value [Line Items]
Gross amounts of assets recognized	25,038,000	17,795,000
Gross assets offset in consolidated balance sheet	(82,000)	0
Net assets in consolidated balance sheet	24,956,000	17,795,000
Other assets
Derivatives, Fair Value [Line Items]
Gross amounts of assets recognized	109,433,000	88,512,000
Gross assets offset in consolidated balance sheet	0	0
Net assets in consolidated balance sheet	109,433,000	88,512,000
Accounts payable, accrued expenses and other current liabilities
Derivatives, Fair Value [Line Items]
Gross amounts of liabilities recognized	9,401,000	11,503,000
Gross liabilities offset in consolidated balance sheet	(82,000)	0
Net liabilities in consolidated balance sheet	9,319,000	11,503,000
Liabilities related to assets held for sale
Derivatives, Fair Value [Line Items]
Gross amounts of liabilities recognized		4,041,000
Gross liabilities offset in consolidated balance sheet		0
Net liabilities in consolidated balance sheet		4,041,000
Other long-term liabilities
Derivatives, Fair Value [Line Items]
Gross amounts of liabilities recognized	618,000	47,000
Gross liabilities offset in consolidated balance sheet	0	0
Net liabilities in consolidated balance sheet	618,000	47,000
Non-current liabilities related to assets held for sale
Derivatives, Fair Value [Line Items]
Gross amounts of liabilities recognized		16,786,000
Gross liabilities offset in consolidated balance sheet		0
Net liabilities in consolidated balance sheet		16,786,000
Interest Rate Swaps | Hedging Contracts
Derivatives, Fair Value [Line Items]
Gross amounts of assets recognized	3,611,000	1,561,000
Gross amounts of liabilities recognized	9,178,000	10,736,000
Interest Rate Swaps | Hedging Contracts | Prepaid expenses and other current assets
Derivatives, Fair Value [Line Items]
Gross amounts of assets recognized	0	1,150,000
Interest Rate Swaps | Hedging Contracts | Other assets
Derivatives, Fair Value [Line Items]
Gross amounts of assets recognized	3,611,000	411,000
Interest Rate Swaps | Hedging Contracts | Accounts payable, accrued expenses and other current liabilities
Derivatives, Fair Value [Line Items]
Gross amounts of liabilities recognized	9,049,000	10,689,000
Interest Rate Swaps | Hedging Contracts | Liabilities related to assets held for sale
Derivatives, Fair Value [Line Items]
Gross amounts of liabilities recognized		0
Interest Rate Swaps | Hedging Contracts | Other long-term liabilities
Derivatives, Fair Value [Line Items]
Gross amounts of liabilities recognized	129,000	47,000
Interest Rate Swaps | Hedging Contracts | Non-current liabilities related to assets held for sale
Derivatives, Fair Value [Line Items]
Gross amounts of liabilities recognized		0
Interest Rate Swaps | Derivatives Not Designated as Hedges
Derivatives, Fair Value [Line Items]
Gross amounts of assets recognized	0	0
Gross amounts of liabilities recognized	731,000	21,641,000
Interest Rate Swaps | Derivatives Not Designated as Hedges | Prepaid expenses and other current assets
Derivatives, Fair Value [Line Items]
Gross amounts of assets recognized	0	0
Interest Rate Swaps | Derivatives Not Designated as Hedges | Other assets
Derivatives, Fair Value [Line Items]
Gross amounts of assets recognized	0	0
Interest Rate Swaps | Derivatives Not Designated as Hedges | Accounts payable, accrued expenses and other current liabilities
Derivatives, Fair Value [Line Items]
Gross amounts of liabilities recognized	242,000	814,000
Interest Rate Swaps | Derivatives Not Designated as Hedges | Liabilities related to assets held for sale
Derivatives, Fair Value [Line Items]
Gross amounts of liabilities recognized	0	4,041,000
Interest Rate Swaps | Derivatives Not Designated as Hedges | Other long-term liabilities
Derivatives, Fair Value [Line Items]
Gross amounts of liabilities recognized	489,000	0
Interest Rate Swaps | Derivatives Not Designated as Hedges | Non-current liabilities related to assets held for sale
Derivatives, Fair Value [Line Items]
Gross amounts of liabilities recognized	0	16,786,000
Commodity contracts | Hedging Contracts
Derivatives, Fair Value [Line Items]
Gross amounts of assets recognized	97,708,000	66,138,000
Gross amounts of liabilities recognized	0	0
Commodity contracts | Hedging Contracts | Prepaid expenses and other current assets
Derivatives, Fair Value [Line Items]
Gross amounts of assets recognized	11,191,000	3,664,000
Commodity contracts | Hedging Contracts | Other assets
Derivatives, Fair Value [Line Items]
Gross amounts of assets recognized	86,517,000	62,474,000
Commodity contracts | Hedging Contracts | Accounts payable, accrued expenses and other current liabilities
Derivatives, Fair Value [Line Items]
Gross amounts of liabilities recognized	0	0
Commodity contracts | Hedging Contracts | Liabilities related to assets held for sale
Derivatives, Fair Value [Line Items]
Gross amounts of liabilities recognized		0
Commodity contracts | Hedging Contracts | Other long-term liabilities
Derivatives, Fair Value [Line Items]
Gross amounts of liabilities recognized	0	0
Commodity contracts | Hedging Contracts | Non-current liabilities related to assets held for sale
Derivatives, Fair Value [Line Items]
Gross amounts of liabilities recognized		0
Commodity contracts | Derivatives Not Designated as Hedges
Derivatives, Fair Value [Line Items]
Gross amounts of assets recognized	33,070,000	37,195,000
Gross amounts of liabilities recognized	0	0
Commodity contracts | Derivatives Not Designated as Hedges | Prepaid expenses and other current assets
Derivatives, Fair Value [Line Items]
Gross amounts of assets recognized	13,765,000	12,028,000
Commodity contracts | Derivatives Not Designated as Hedges | Other assets
Derivatives, Fair Value [Line Items]
Gross amounts of assets recognized	19,305,000	25,167,000
Commodity contracts | Derivatives Not Designated as Hedges | Accounts payable, accrued expenses and other current liabilities
Derivatives, Fair Value [Line Items]
Gross amounts of liabilities recognized	0	0
Commodity contracts | Derivatives Not Designated as Hedges | Liabilities related to assets held for sale
Derivatives, Fair Value [Line Items]
Gross amounts of liabilities recognized		0
Commodity contracts | Derivatives Not Designated as Hedges | Other long-term liabilities
Derivatives, Fair Value [Line Items]
Gross amounts of liabilities recognized	0	0
Commodity contracts | Derivatives Not Designated as Hedges | Non-current liabilities related to assets held for sale
Derivatives, Fair Value [Line Items]
Gross amounts of liabilities recognized		0
Foreign Currency Contracts | Derivatives Not Designated as Hedges
Derivatives, Fair Value [Line Items]
Gross amounts of assets recognized	82,000	1,413,000
Gross amounts of liabilities recognized	110,000	0
Foreign Currency Contracts | Derivatives Not Designated as Hedges | Prepaid expenses and other current assets
Derivatives, Fair Value [Line Items]
Gross amounts of assets recognized	82,000	953,000
Foreign Currency Contracts | Derivatives Not Designated as Hedges | Other assets
Derivatives, Fair Value [Line Items]
Gross amounts of assets recognized	0	460,000
Foreign Currency Contracts | Derivatives Not Designated as Hedges | Accounts payable, accrued expenses and other current liabilities
Derivatives, Fair Value [Line Items]
Gross amounts of liabilities recognized	110,000	0
Foreign Currency Contracts | Derivatives Not Designated as Hedges | Liabilities related to assets held for sale
Derivatives, Fair Value [Line Items]
Gross amounts of liabilities recognized		0
Foreign Currency Contracts | Derivatives Not Designated as Hedges | Other long-term liabilities
Derivatives, Fair Value [Line Items]
Gross amounts of liabilities recognized	$ 0	0
Foreign Currency Contracts | Derivatives Not Designated as Hedges | Non-current liabilities related to assets held for sale
Derivatives, Fair Value [Line Items]
Gross amounts of liabilities recognized		$ 0

Derivatives - Schedule of Notio

Derivatives - Schedule of Notional Amounts for Derivative Instruments (Details) £ in Thousands, MWh in Thousands, CAD in Thousands, $ in Thousands	Sep. 30, 2017GBP (£)MWh	Dec. 31, 2016GBP (£)MWh	Sep. 30, 2017CAD	Sep. 30, 2017USD ($)	Dec. 31, 2016CAD	Dec. 31, 2016USD ($)
Interest rate swaps | Derivatives designated as hedges
Derivative [Line Items]
Notional amount			CAD 156,713	$ 405,183	CAD 84,713	$ 433,874
Interest rate swaps | Derivatives not designated as hedges
Derivative [Line Items]
Notional amount	£ 0	£ 222,018		$ 13,788		$ 14,681
Foreign currency contracts | Derivatives not designated as hedges
Derivative [Line Items]
Notional amount | CAD			CAD 15,175		CAD 25,075
Commodity contracts | Derivatives designated as hedges
Derivative [Line Items]
Notional amount (in MWhs)	15,941	16,988
Commodity contracts | Derivatives not designated as hedges
Derivative [Line Items]
Notional amount (in MWhs)	1,117	1,407

Derivatives - Gains and Losses

Derivatives - Gains and Losses on Derivatives Not Designated As Hedges (Details) - Derivatives not designated as hedges - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Interest expense, net | Interest rate swaps
Derivative [Line Items]
Loss (gain) on derivatives	$ 27	$ 5,127	$ 3,219	$ 36,583
Loss on foreign currency exchange, net | Foreign currency contracts
Derivative [Line Items]
Loss (gain) on derivatives	457	(73)	1,017	(905)
Operating revenues, net | Commodity contracts
Derivative [Line Items]
Loss (gain) on derivatives	$ (1,371)	$ (3,095)	$ (7,062)	$ (11,009)

Derivatives - Gains (Losses) Re

Derivatives - Gains (Losses) Recognized Related to Interest Rate Swaps and Commodity Contracts Designated as Cash Flow Hedges (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Derivative [Line Items]
Gain (Loss) Recognized in Other Comprehensive Income (Effective Portion) net of taxes	$ 17,338,000	$ 14,258,000	$ 27,960,000	$ (32,348,000)
Amount of (Gain) Loss Reclassified from Accumulated Other Comprehensive Income into Income (Effective Portion)	94,000	3,164,000	(527,000)	(254,000)
Amount of (Gain) Loss Recognized in Income (Ineffective Portion and Amount Excluded from Effectiveness Testing)	(5,631,000)	365,000	(6,303,000)	3,939,000
Tax expense (benefit) attributable to derivatives designated as cash flow hedges	1,032,000	0	2,681,000	0
Tax expense (benefit) attributed to derivatives reclassified into AOCI	(6,000)	0	400,000	0
Interest expense, net | Interest rate swaps
Derivative [Line Items]
Gain (Loss) Recognized in Other Comprehensive Income (Effective Portion) net of taxes	1,353,000	798,000	(1,899,000)	(39,547,000)
Amount of (Gain) Loss Reclassified from Accumulated Other Comprehensive Income into Income (Effective Portion)	519,000	3,114,000	3,163,000	9,743,000
Amount of (Gain) Loss Recognized in Income (Ineffective Portion and Amount Excluded from Effectiveness Testing)	(315,000)	(17,000)	(963,000)	474,000
Tax expense (benefit) attributable to derivatives designated as cash flow hedges	300,000	0	(200,000)	0
Tax expense (benefit) attributed to derivatives reclassified into AOCI	(700,000)	0	(2,400,000)	0
Operating revenues, net | Commodity contracts
Derivative [Line Items]
Gain (Loss) Recognized in Other Comprehensive Income (Effective Portion) net of taxes	15,985,000	13,460,000	29,859,000	7,199,000
Amount of (Gain) Loss Reclassified from Accumulated Other Comprehensive Income into Income (Effective Portion)	(425,000)	50,000	(3,690,000)	(9,997,000)
Amount of (Gain) Loss Recognized in Income (Ineffective Portion and Amount Excluded from Effectiveness Testing)	(5,316,000)	382,000	(5,340,000)	3,465,000
Tax expense (benefit) attributable to derivatives designated as cash flow hedges	800,000	0	2,900,000	0
Tax expense (benefit) attributed to derivatives reclassified into AOCI	$ 700,000	$ 0	$ 2,800,000	$ 0

Derivatives - Narrative (Detail

Derivatives - Narrative (Details) - USD ($)	May 11, 2017	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Derivative Instruments, Gain (Loss) [Line Items]
Interest expense, net		$ 70,232,000	$ 72,818,000	$ 206,749,000	$ 243,111,000
Collateral already posted		0		0		$ 0
Gross amounts of liabilities recognized		10,019,000		10,019,000		32,377,000
Interest rate swaps
Derivative Instruments, Gain (Loss) [Line Items]
Interest expense, net		0
Interest rate swaps | Derivatives designated as hedges
Derivative Instruments, Gain (Loss) [Line Items]
Gross amounts of liabilities recognized		9,178,000		9,178,000		10,736,000
Interest rate swaps | Derivatives not designated as hedges
Derivative Instruments, Gain (Loss) [Line Items]
Gross amounts of liabilities recognized		731,000		731,000		21,641,000
Interest rate swaps | Secured Debt
Derivative Instruments, Gain (Loss) [Line Items]
Loss expected to be reclassified into earnings		2,800,000		$ 2,800,000
Maximum term of outstanding interest rate swaps				17 years
Interest rate swaps | Secured Debt | Derivatives designated as hedges
Derivative Instruments, Gain (Loss) [Line Items]
Related liabilities reclassified to current		5,100,000		$ 5,100,000		4,800,000
Interest rate swaps | Secured Debt | Derivatives not designated as hedges
Derivative Instruments, Gain (Loss) [Line Items]
Related liabilities reclassified to current		0		$ 0		500,000
Commodity contracts
Derivative Instruments, Gain (Loss) [Line Items]
Maximum term of outstanding interest rate swaps				12 years
Gain expected to be reclassified				$ 9,900,000
Commodity contracts | Derivatives designated as hedges
Derivative Instruments, Gain (Loss) [Line Items]
Gross amounts of liabilities recognized		0		0		0
Commodity contracts | Derivatives not designated as hedges
Derivative Instruments, Gain (Loss) [Line Items]
Gross amounts of liabilities recognized		0		0		0
Commodity contracts | Letter of Credit
Derivative Instruments, Gain (Loss) [Line Items]
Collateral already posted		15,000,000		15,000,000		18,000,000
Liabilities related to assets held for sale
Derivative Instruments, Gain (Loss) [Line Items]
Gross amounts of liabilities recognized						4,041,000
Liabilities related to assets held for sale | Interest rate swaps | Derivatives designated as hedges
Derivative Instruments, Gain (Loss) [Line Items]
Gross amounts of liabilities recognized						0
Liabilities related to assets held for sale | Interest rate swaps | Derivatives not designated as hedges
Derivative Instruments, Gain (Loss) [Line Items]
Gross amounts of liabilities recognized		0		0		4,041,000
Liabilities related to assets held for sale | Commodity contracts | Derivatives designated as hedges
Derivative Instruments, Gain (Loss) [Line Items]
Gross amounts of liabilities recognized						0
Liabilities related to assets held for sale | Commodity contracts | Derivatives not designated as hedges
Derivative Instruments, Gain (Loss) [Line Items]
Gross amounts of liabilities recognized						0
Non-current liabilities related to assets held for sale
Derivative Instruments, Gain (Loss) [Line Items]
Gross amounts of liabilities recognized						16,786,000
Non-current liabilities related to assets held for sale | Interest rate swaps | Derivatives designated as hedges
Derivative Instruments, Gain (Loss) [Line Items]
Gross amounts of liabilities recognized						0
Non-current liabilities related to assets held for sale | Interest rate swaps | Derivatives not designated as hedges
Derivative Instruments, Gain (Loss) [Line Items]
Gross amounts of liabilities recognized		$ 0		$ 0		16,786,000
Non-current liabilities related to assets held for sale | Commodity contracts | Derivatives designated as hedges
Derivative Instruments, Gain (Loss) [Line Items]
Gross amounts of liabilities recognized						0
Non-current liabilities related to assets held for sale | Commodity contracts | Derivatives not designated as hedges
Derivative Instruments, Gain (Loss) [Line Items]
Gross amounts of liabilities recognized						$ 0
Interest expense, net
Derivative Instruments, Gain (Loss) [Line Items]
Reclassification of AOCI into earnings	$ (400,000)
Gain on sale of renewable energy facilities | Interest rate swaps
Derivative Instruments, Gain (Loss) [Line Items]
Fair value liability of the interest rate swap	$ 23,400,000

Fair Value of Financial Instr59

Fair Value of Financial Instruments - Financial Instruments Measured on Recurring Basis (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Assets and Liabilities
Assets	$ 134,471	$ 106,307
Liabilities	10,019	32,377
Long-term debt, including current portion
Carrying Amount	3,581,394	3,950,914
Fair Value	$ 3,733,007	$ 4,080,397
Senior Notes due 2023
Long-term debt, including current portion
Fair value as a percentage of face	104.25%	101.38%
Senior Notes due 2025
Long-term debt, including current portion
Fair value as a percentage of face	107.00%	103.75%
Fair Value, Measurements, Recurring
Assets and Liabilities
Assets	$ 134,389	$ 106,307
Liabilities	9,937	32,377
Interest rate swaps | Fair Value, Measurements, Recurring
Assets and Liabilities
Assets	3,611	1,561
Liabilities	9,909	32,377
Commodity contracts | Fair Value, Measurements, Recurring
Assets and Liabilities
Assets	130,778	103,333
Foreign currency contracts | Fair Value, Measurements, Recurring
Assets and Liabilities
Assets	0	1,413
Liabilities	28	0
Level 1 | Fair Value, Measurements, Recurring
Assets and Liabilities
Assets	0	0
Liabilities	0	0
Level 1 | Interest rate swaps | Fair Value, Measurements, Recurring
Assets and Liabilities
Assets	0	0
Liabilities	0	0
Level 1 | Commodity contracts | Fair Value, Measurements, Recurring
Assets and Liabilities
Assets	0	0
Level 1 | Foreign currency contracts | Fair Value, Measurements, Recurring
Assets and Liabilities
Assets	0	0
Liabilities	0	0
Level 2 | Fair Value, Measurements, Recurring
Assets and Liabilities
Assets	36,681	40,169
Liabilities	9,937	32,377
Level 2 | Interest rate swaps | Fair Value, Measurements, Recurring
Assets and Liabilities
Assets	3,611	1,561
Liabilities	9,909	32,377
Level 2 | Commodity contracts | Fair Value, Measurements, Recurring
Assets and Liabilities
Assets	33,070	37,195
Level 2 | Foreign currency contracts | Fair Value, Measurements, Recurring
Assets and Liabilities
Assets	0	1,413
Liabilities	28	0
Level 3 | Fair Value, Measurements, Recurring
Assets and Liabilities
Assets	97,708	66,138
Liabilities	0	0
Level 3 | Interest rate swaps | Fair Value, Measurements, Recurring
Assets and Liabilities
Assets	0	0
Liabilities	0	0
Level 3 | Commodity contracts | Fair Value, Measurements, Recurring
Assets and Liabilities
Assets	97,708	66,138
Level 3 | Foreign currency contracts | Fair Value, Measurements, Recurring
Assets and Liabilities
Assets	0	0
Liabilities	$ 0	$ 0

Fair Value of Financial Instr60

Fair Value of Financial Instruments - Unobservable input reconciliation (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017USD ($)	Sep. 30, 2016USD ($)	Sep. 30, 2017USD ($)$ / MWh	Sep. 30, 2016USD ($)
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Beginning Balance	$ 76,790	$ 43,763	$ 66,138	$ 63,154
Realized and unrealized gains (losses):
Included in other comprehensive income (loss)	15,601	13,511	26,229	(2,798)
Included in operating revenues, net	6,407	(433)	11,831	6,532
Settlements	(1,090)	50	(6,490)	(9,997)
Ending Balance	97,708	$ 56,891	97,708	$ 56,891
Level 3 | Commodity contracts
Realized and unrealized gains (losses):
Assets	97,708		97,708
Liabilities	$ 0		$ 0
Income Approach Valuation Technique | Minimum | Level 3 | Commodity contracts
Realized and unrealized gains (losses):
Forward price ($ per MWh) | $ / MWh			13.4
Income Approach Valuation Technique | Maximum | Level 3 | Commodity contracts
Realized and unrealized gains (losses):
Forward price ($ per MWh) | $ / MWh			72.5
Option Model | Minimum | Level 3 | Commodity contracts
Realized and unrealized gains (losses):
Volatilities			3.00%
Option Model | Maximum | Level 3 | Commodity contracts
Realized and unrealized gains (losses):
Volatilities			6.70%

Stockholders' Equity - Shares O

Stockholders' Equity - Shares Outstanding (Details) - shares		Sep. 30, 2017	Dec. 31, 2016
Class of Stock [Line Items]
Common stock outstanding (in shares)		140,610,906
Treasury stock (in shares)		362,018	253,687
Class A common stock
Class of Stock [Line Items]
Common stock outstanding (in shares)		92,408,596	92,223,089
Class B common stock
Class of Stock [Line Items]
Common stock outstanding (in shares)		48,202,310	48,202,310
Multiple Shareholders | Class A common stock
Class of Stock [Line Items]
Common stock outstanding (in shares)	[1]	92,408,596
SunEdison | Class B common stock
Class of Stock [Line Items]
Common stock outstanding (in shares)		48,202,310
[1]	Class A common stockholders are comprised of public and private investors, executive officers, management and personnel who provide services to the Company. Shares of Class A common stock outstanding exclude 362,018 shares of common stock held in treasury. The total par value of Class A common stock reflected on the unaudited condensed consolidated balance sheet and unaudited condensed consolidated statement of stockholders' equity as of September 30, 2017 includes the shares of stock held in treasury.

Stockholders' Equity - Narrativ

Stockholders' Equity - Narrative (Details) - $ / shares	Oct. 16, 2017	Mar. 06, 2017	Oct. 15, 2017	Sep. 30, 2017	Dec. 31, 2016
Class of Stock [Line Items]
Common stock, shares outstanding (in shares)				140,610,906
Special cash dividend (in dollars per share)		$ 1.94
Consideration equity threshold		49.00%
Ownership interest				65.80%
Class A common stock
Class of Stock [Line Items]
Common stock, shares outstanding (in shares)				92,408,596	92,223,089
Common stock, par value (in dollars per share)				$ 0.01	$ 0.01
Class A common stock | SunEdison
Class of Stock [Line Items]
Shares exchanged (in shares)		48,202,310
Equity held		36.90%
Class A common stock | TerraForm Power
Class of Stock [Line Items]
Cash consideration (in dollars per share)		$ 9.52
Common stock, par value (in dollars per share)		$ 0.01
Class B common stock
Class of Stock [Line Items]
Common stock, shares outstanding (in shares)				48,202,310	48,202,310
Common stock, par value (in dollars per share)				$ 0.01	$ 0.01
Class B common stock | SunEdison
Class of Stock [Line Items]
Common stock, shares outstanding (in shares)				48,202,310
Subsequent Event
Class of Stock [Line Items]
Proration ratio	62.60%
Consideration elected to be received	100.00%
Consideration in stock retained	62.60%
Cash consideration received	37.40%
Subsequent Event | SunEdison
Class of Stock [Line Items]
Ownership interest			83.90%
Subsequent Event | Orion Holdings
Class of Stock [Line Items]
Ownership percentage	51.00%
Subsequent Event | Class A common stock
Class of Stock [Line Items]
Common stock, shares outstanding (in shares)	148,224,429
Subsequent Event | Class A common stock | SunEdison
Class of Stock [Line Items]
Shares exchanged (in shares)	48,202,310
Equity held			36.90%
Subsequent Event | Class A common stock | Orion Holdings
Class of Stock [Line Items]
Ownership percentage	51.00%
Subsequent Event | Class B common stock | SunEdison
Class of Stock [Line Items]
Ownership interest			100.00%

Stock-based Compensation - Narr

Stock-based Compensation - Narrative (Details) - USD ($)	3 Months Ended			9 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Contractual term				10 years
Compensation cost not yet recognized		$ 0		$ 0
Scenario, Forecast
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Accelerated stock-based compensation	$ 7,000,000
Restricted Stock Award
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unvested awards (in shares)		0		0		366,195
Equity instrument granted (in shares)				0	0
Unrecognized compensation cost		$ 0		$ 0
Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unvested awards (in shares)		1,227,748		1,227,748		1,622,953
Equity instrument granted (in shares)				517,594
Unrecognized compensation cost		$ 8,000,000		$ 8,000,000
Weighted average grant date fair value (in dollars per share)				$ 12.22	$ 11.05
SunEdison, Inc. and TerraFrom Global, Inc.
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense		200,000	$ 900,000	$ 700,000	$ 2,500,000
General and Administrative Expense
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense		1,000,000	800,000	4,300,000	2,100,000
General and Administrative Expense - Affiliate
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense		$ 800,000	$ 600,000	$ 2,700,000	$ 1,800,000
Class A common stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares available for issuance (in shares)		3,819,392		3,819,392
TerraForm Global, LLC | Affiliated Entity | Scenario, Forecast
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Accelerated stock-based compensation	$ 1,600,000

Stock-based Compensation - Acti

Stock-based Compensation - Activity Tables (Details) - USD ($) $ / shares in Units, $ in Millions	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Restricted Stock Award
Number of Shares Outstanding
Beginning balance (shares)	366,195
Granted (shares)	0	0
Converted (shares)	(366,195)
Ending balance (shares)	0
Weighted-Average Grant-Date Fair Value Per Share
Beginning balance (dollars per share)	$ 8.51
Converted (dollars per share)	8.51
Ending (dollars per share)	$ 0
Aggregate Intrinsic Value (in millions)	$ 0
Restricted Stock Units (RSUs)
Number of Shares Outstanding
Beginning balance (shares)	1,622,953
Granted (shares)	517,594
Converted (shares)	(293,838)
Forfeited (shares)	(618,961)
Ending balance (shares)	1,227,748
Weighted-Average Grant-Date Fair Value Per Share
Aggregate Intrinsic Value (in millions)	$ 16.2
Weighted Average Remaining Contractual Life (In Years)	1 year 44 days

Loss Per Share (Details)

Loss Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Net loss attributable to Class A common stockholders	$ (26,546)	$ (26,171)	$ (50,890)	$ (47,559)
Less: accretion of redeemable non-controlling interest	(2,316)	0	(6,729)	0
Less: dividends paid on Class A shares and participating RSAs	0	0	0	0
Undistributed loss attributable to Class A shares	$ (28,862)	$ (26,171)	$ (57,619)	$ (47,559)
Restricted Stock Award
Dilutive Securities, Effect on Basic Earnings Per Share [Abstract]
Shares excluded from calculation (in shares)		459,800
Restricted Stock Units (RSUs)
Dilutive Securities, Effect on Basic Earnings Per Share [Abstract]
Shares excluded from calculation (in shares)				1,823,063
Restricted Stock Units (RSUs)
Dilutive Securities, Effect on Basic Earnings Per Share [Abstract]
Shares excluded from calculation (in shares)			1,227,748
Restricted Stock Units (RSUs) | Restricted Stock Units (RSUs)
Dilutive Securities, Effect on Basic Earnings Per Share [Abstract]
Shares excluded from calculation (in shares)	1,227,748
Class A common stock
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Weighted average basic and diluted Class A shares outstanding (in shares)	92,352,000	90,860,000	92,228,000	89,140,000
Basic and diluted loss per share (in dollars per share	$ (0.31)	$ (0.29)	$ (0.62)	$ (0.53)

Non-controlling Interests (Deta

Non-controlling Interests (Details) $ in Thousands	3 Months Ended			9 Months Ended
	Sep. 30, 2017USD ($)	Jun. 30, 2017USD ($)	Sep. 30, 2016USD ($)	Sep. 30, 2017USD ($)	Sep. 30, 2016USD ($)	Oct. 16, 2017	Oct. 15, 2017	Jun. 12, 2017MW	Dec. 31, 2016USD ($)	Dec. 31, 2015
Noncontrolling Interest [Line Items]
Non-controlling interests	$ 1,402,596			$ 1,402,596					$ 1,465,042
Ownership interest	65.80%			65.80%
Amount of noncontrolling interest deconsolidated		$ 8,700		$ 8,713
Activity of Redeemable Non-controlling Interests
Beginning balance				180,367
Distributions				(7,227)
Accretion of redeemable non-controlling interest				6,729
Net income attributable to redeemable non-controlling interests	$ 6,803		$ 4,642	18,162	$ 16,374
Ending balance	198,031			198,031
Invenergy
Noncontrolling Interest [Line Items]
Ownership percentage by other entities										9.90%
Capital
Activity of Redeemable Non-controlling Interests
Beginning balance				153,490
Distributions				(7,227)
Accretion of redeemable non-controlling interest				6,729
Net income attributable to redeemable non-controlling interests				0
Ending balance	152,992			152,992
Retained Earnings
Activity of Redeemable Non-controlling Interests
Beginning balance				26,877
Distributions				0
Accretion of redeemable non-controlling interest				0
Net income attributable to redeemable non-controlling interests				18,162
Ending balance	45,039			45,039
TerraForm Resi Manager
Noncontrolling Interest [Line Items]
Capacity (MW) | MW								8.9
SunEdison
Noncontrolling Interest [Line Items]
Non-controlling interests	$ 648,765			$ 648,765					660,799
Ownership percentage by other entities	34.20%			34.20%
SunEdison | Subsequent Event
Noncontrolling Interest [Line Items]
Ownership interest							83.90%
Other non-controlling interests
Noncontrolling Interest [Line Items]
Non-controlling interests	$ 753,831			$ 753,831					$ 804,243
Invenergy | Subsequent Event
Noncontrolling Interest [Line Items]
Ownership percentage by other entities						9.90%

Commitments and Contingencies (

Commitments and Contingencies (Details) $ in Thousands	Sep. 11, 2017USD ($)	Jun. 09, 2017USD ($)	Mar. 24, 2017employee	Nov. 21, 2016USD ($)	May 27, 2016USD ($)employee	Apr. 04, 2016employee	Sep. 30, 2017USD ($)	Dec. 31, 2016USD ($)
Loss Contingencies [Line Items]
Outstanding letters of credit							$ 148,900
Securities Class Action
Loss Contingencies [Line Items]
Number of defendants | employee			3			2
Litigation settlement		$ 14,800
Portion of settlement covered by insurance providers	$ 13,630						13,630
Litigation settlement expense, maximum portion covered by company							1,130
Loss contingency accrual								$ 1,130
Securities Class Action | Director
Loss Contingencies [Line Items]
Number of defendants | employee						1
First Wind Acquisition Claim | SunEdison
Loss Contingencies [Line Items]
Obligated earn-out payments					$ 231,000
Number of employee resignations | employee					2
Eastern Maine Electric Cooperative Litigation | Subsidiaries
Loss Contingencies [Line Items]
Amount of damages awarded				$ 13,600
Revolving Credit Facility | Line of Credit
Loss Contingencies [Line Items]
Outstanding letters of credit							$ 62,000

Related Parties - Other Narrati

Related Parties - Other Narrative (Details) - USD ($) $ in Thousands	3 Months Ended			6 Months Ended	9 Months Ended
	Sep. 30, 2017	Mar. 31, 2017	Sep. 30, 2016	Jun. 30, 2017	Sep. 30, 2017	Sep. 30, 2016	Oct. 16, 2017
Related Party Transaction [Line Items]
Related party costs	$ 1,199		$ 7,149		$ 10,224	$ 22,898
SunEdison
Related Party Transaction [Line Items]
Proceeds from warranty claims		$ 7,000
SunEdison | Transition Services Agreements
Related Party Transaction [Line Items]
Termination notice required				10 days
Transition services agreement, cost incurred		1,900
SunEdison | Chile Facility EPC Contract
Related Party Transaction [Line Items]
Proceeds from warranty claims		$ 4,800
Subsequent Event | Orion Holdings
Related Party Transaction [Line Items]
Ownership percentage							51.00%
Subsequent Event | Class A common stock | Orion Holdings
Related Party Transaction [Line Items]
Ownership percentage							51.00%

Related Parties - Management Se

Related Parties - Management Services Agreement (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Related Party Transaction [Line Items]
General and administrative expenses - affiliate	$ 2,192,000	$ 2,943,000	$ 6,893,000	$ 10,614,000
SunEdison | Management Services Agreement
Related Party Transaction [Line Items]
Management fee as percent of cash available for distribution, current and prior two years						2.50%	2.50%
Maximum base management fee in 2015							$ 4,000,000
Maximum base management fee in 2016						$ 7,000,000
SunEdison | Management Services Agreement | Scenario, Forecast
Related Party Transaction [Line Items]
Management fee as percent of cash available for distribution, current and prior two years					2.50%
Maximum base management fee in 2017					$ 9,000,000

Related Parties - Interest Paym

Related Parties - Interest Payment, Support, Intercompany, and Insurance Allocation Agreements (Details)	Aug. 31, 2017USD ($)	Jun. 07, 2017USD ($)	Sep. 30, 2016USD ($)	Mar. 31, 2016USD ($)MW	Sep. 30, 2016USD ($)	Jul. 14, 2016USD ($)	Sep. 30, 2017MW
Related Party Transaction [Line Items]
Director and officer insurance coverage						$ 150,000,000
Payments for insurance settlement		$ 32,000,000
Rights to additional remaining limit of insurance	$ 20,000,000
Insurance payment for defense costs	400,000
Chamblee Class Action
Related Party Transaction [Line Items]
Portion of settlement covered by insurance providers	13,630,000
Aldridge v. Blackmore
Related Party Transaction [Line Items]
Portion of settlement covered by insurance providers	$ 20,000,000
SunEdison | Amended Interest Payment Agreement
Related Party Transaction [Line Items]
Equity contribution received				$ 8,000,000
Cumulative amount received				24,000,000
Future payments				$ 24,000,000
SunEdison | Support Agreement
Related Party Transaction [Line Items]
Nameplate capacity acquired (MW) | MW				19.2
Purchase of facilities			$ 29,300,000	$ 9,700,000	$ 39,000,000
Affiliated Entity | Intercompany Agreement | SunEdison | AP Warehouse
Related Party Transaction [Line Items]
Capacity (MW) | MW							500

Related Parties - Due to SunEdi

Related Parties - Due to SunEdison and Affiliates, Net (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Related Party Transaction [Line Items]
Due to SunEdison and affiliates, net	$ 15,775		$ 15,775		$ 16,692
Loss on receivables - affiliate	0	$ 0	0	$ 845
TerraForm Global, LLC | Affiliated Entity
Related Party Transaction [Line Items]
Net receivable	$ 2,700		$ 2,700		$ 800

Related Parties - Arrangements

Related Parties - Arrangements with TerraForm Global (Details) - TerraForm Global, LLC - Affiliated Entity - USD ($) $ in Millions	9 Months Ended	12 Months Ended
	Sep. 30, 2017	Dec. 31, 2017	Dec. 31, 2016
Related Party Transaction [Line Items]
Amounts due to landlord	$ 2.7		$ 0.8
Use and Occupancy Agreement
Related Party Transaction [Line Items]
Rent and other amounts to due landlord	0.6
Management Services Costs
Related Party Transaction [Line Items]
Rent and other amounts to due landlord	$ 0.6
Scenario, Forecast
Related Party Transaction [Line Items]
Portion of rent paid by affiliate		33.33%
Scenario, Forecast | Use and Occupancy Agreement
Related Party Transaction [Line Items]
Rent and other amounts to due landlord		$ 0.8

Related Parties - Incentive Dis

Related Parties - Incentive Distribution Rights (Details) - Incentive Distribution Rights - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Jul. 23, 2014
SunEdison
Related Party Transaction [Line Items]
Quarterly distribution rights, level one, percentage					15.00%
Quarterly distribution rights, level two, percentage					25.00%
Quarterly distribution rights, level three, percentage					50.00%
Quarterly distribution rights, minimum quarterly distribution ($ per share)			$ 0.2257
Payments for related party transactions	$ 0	$ 0	$ 0	$ 0
SunEdison
Related Party Transaction [Line Items]
Quarterly distribution right held, percentage	100.00%		100.00%		100.00%

Related Parties - Commitment to

Related Parties - Commitment to Acquire Facilities (Details) - Invenergy Wind	6 Months Ended
	Mar. 30, 2020	Mar. 30, 2019	Dec. 31, 2015
Related Party Transaction [Line Items]
Ownership percentage by other entities			9.90%
Scenario, Forecast
Related Party Transaction [Line Items]
Option to acquire remaining interest, period	180 days	180 days

Related Parties - Brookfield Sp

Related Parties - Brookfield Sponsorship Transaction (Details) - Brookfield Asset Management	9 Months Ended
	Sep. 30, 2017USD ($)$ / shares
Management Services Agreement
Related Party Transaction [Line Items]
Fixed component for first four quarters | $	$ 2,500,000
Management fee as related to market capitalization	0.3125%
Fixed component for next four quarters | $	$ 3,000,000
Fixed component, thereafter | $	$ 3,750,000
Share price multiplier	$ 9.52
Incentive Distribution Rights
Related Party Transaction [Line Items]
Quarterly distribution rights, level one (in dollars per share)	0.93
Quarterly distribution rights, level two (in dollars per share)	$ 1.05
Quarterly distribution rights, level one, percentage	15.00%
Quarterly distribution rights, level two, percentage	85.00%
Quarterly distribution rights, level three (in dollars per share)	$ 0.12
Quarterly distribution rights, level three, percentage	75.00%
Quarterly distribution rights, level four, percentage	25.00%

Segment Reporting - Income stat

Segment Reporting - Income statement summary table (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017USD ($)	Sep. 30, 2016USD ($)	Sep. 30, 2017USD ($)reportable_segment	Sep. 30, 2016USD ($)	Dec. 31, 2016USD ($)
Segment Reporting Information [Line Items]
Number of reportable segments | reportable_segment			2
Segment Reporting Information, Profit (Loss)
Operating revenues, net	$ 153,430	$ 178,118	$ 474,932	$ 519,336
Depreciation, accretion and amortization expense	61,830	57,988	186,039	178,026
Other operating costs and expenses	66,914	69,422	226,592	195,539
Interest expense, net	70,232	72,818	206,749	243,111
Gain on sale of renewable energy facilities	0	0	(37,116)	0
Other non-operating (income) expenses, net	(8,093)	4,461	(10,577)	5,698
Income tax (benefit) expense	(2,633)	1,140	(4,982)	3,115
Net loss	(34,820)	(27,711)	(91,773)	(106,153)
Balance Sheet
Total assets	6,871,243		6,871,243		$ 7,705,865
Segments | Solar
Segment Reporting Information, Profit (Loss)
Operating revenues, net	107,256	125,644	274,742	314,379
Depreciation, accretion and amortization expense	27,418	29,243	82,093	90,137
Other operating costs and expenses	20,047	19,613	51,871	57,745
Interest expense, net	14,850	22,020	54,373	89,365
Gain on sale of renewable energy facilities			(37,116)	0
Other non-operating (income) expenses, net	(854)	2,206	(1,768)	975
Income tax (benefit) expense	0	0	0	0
Net loss	45,795	52,562	125,289	76,157
Balance Sheet
Total assets	2,926,805		2,926,805		3,595,387
Segments | Wind
Segment Reporting Information, Profit (Loss)
Operating revenues, net	46,174	52,474	200,190	204,957
Depreciation, accretion and amortization expense	33,937	28,400	101,992	87,402
Other operating costs and expenses	26,833	25,520	76,775	73,014
Interest expense, net	22,435	20,637	64,664	64,366
Gain on sale of renewable energy facilities			0	0
Other non-operating (income) expenses, net	(42)	11	581	230
Income tax (benefit) expense	0	0	0	0
Net loss	(36,989)	(22,094)	(43,822)	(20,055)
Balance Sheet
Total assets	3,535,306		3,535,306		3,609,471
Corporate
Segment Reporting Information, Profit (Loss)
Operating revenues, net	0	0	0	0
Depreciation, accretion and amortization expense	475	345	1,954	487
Other operating costs and expenses	20,034	24,289	97,946	64,780
Interest expense, net	32,947	30,161	87,712	89,380
Gain on sale of renewable energy facilities			0	0
Other non-operating (income) expenses, net	(7,197)	2,244	(9,390)	4,493
Income tax (benefit) expense	(2,633)	1,140	(4,982)	3,115
Net loss	(43,626)	$ (58,179)	(173,240)	$ (162,255)
Balance Sheet
Total assets	$ 409,132		$ 409,132		$ 501,007

Other Comprehensive Income (L77

Other Comprehensive Income (Loss) - Schedule of Accumulated Other Comprehensive (Loss) Income (Details) - USD ($) $ in Thousands	May 11, 2017	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance				$ 2,717,999
Other comprehensive income (loss), net of tax		$ 23,967	$ 11,264	54,310	$ (19,123)
Ending balance		2,651,213		2,651,213
Foreign Currency Translation Adjustments Attributable to Parent
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance				(22,133)
Ending balance		3,494		3,494
Foreign Currency Translation Adjustments Including Noncontrolling Interests
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Net unrealized gains/losses arising during the period				12,136
Other comprehensive income (loss), net of tax				26,877
Ending balance		4,744		4,744
OCI before reclassifications, tax expense (benefit)				5,921
Foreign Currency Translation Adjustments Attributable to Noncontrolling Interests
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Ending balance		1,250		1,250
Hedging Activities Attributable to Parent
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance				45,045
Ending balance		53,840		53,840
Hedging Activities Including Noncontrolling Interests
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Net unrealized gains/losses arising during the period				27,960
Other comprehensive income (loss), net of tax				27,433
Ending balance		72,478		72,478
Hedging Activities Attributable to Noncontrolling Interests
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Ending balance		18,638		18,638
Accumulated Other Comprehensive Income Attributable to Parent
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance				22,912
Ending balance		57,334		57,334
Accumulated Other Comprehensive Income Including Noncontrolling Interests
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Net unrealized gains/losses arising during the period				40,096
Other comprehensive income (loss), net of tax				54,310
Ending balance		77,222		77,222
Accumulated Other Comprehensive Income Attributable to Noncontrolling Interests
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Ending balance		$ 19,888		19,888
Interest expense, net
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Reclassification of net realized loss (gain) into earnings	$ 400
Interest expense, net | Foreign Currency Translation Adjustments Including Noncontrolling Interests
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Reclassification of net realized loss (gain) into earnings				0
Interest expense, net | Hedging Activities Including Noncontrolling Interests
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Reclassification of net realized loss (gain) into earnings				3,163
Interest expense, net | Accumulated Other Comprehensive Income Including Noncontrolling Interests
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Reclassification of net realized loss (gain) into earnings				3,163
Reclassification from AOCI, tax expense (benefit)				(2,401)
Operating revenues, net | Foreign Currency Translation Adjustments Including Noncontrolling Interests
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Reclassification of net realized loss (gain) into earnings				0
Operating revenues, net | Hedging Activities Including Noncontrolling Interests
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Reclassification of net realized loss (gain) into earnings				(3,690)
Operating revenues, net | Accumulated Other Comprehensive Income Including Noncontrolling Interests
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Reclassification of net realized loss (gain) into earnings				(3,690)
Reclassification from AOCI, tax expense (benefit)				2,801
Gain on sale of renewable energy facilities | Foreign Currency Translation Adjustments Including Noncontrolling Interests
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Reclassification of net realized loss (gain) into earnings				14,741
Gain on sale of renewable energy facilities | Hedging Activities Including Noncontrolling Interests
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Reclassification of net realized loss (gain) into earnings				0
Gain on sale of renewable energy facilities | Accumulated Other Comprehensive Income Including Noncontrolling Interests
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Reclassification of net realized loss (gain) into earnings				14,741
Reclassification from AOCI, tax expense (benefit)				$ (8,858)

Other Comprehensive Income (L78

Other Comprehensive Income (Loss) - Components of Other Comprehensive Loss (Details) - USD ($) $ in Thousands	May 11, 2017	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Other comprehensive income (loss), net of tax:
Foreign currency translation adjustments, net unrealized gain (loss) arising during the period, before tax		$ 6,944	$ (6,158)	$ 15,376	$ (2,442)
Foreign currency translation adjustments, net unrealized gain (loss) arising during the period, tax effect		(409)	0	(3,240)	0
Foreign currency translation adjustments, net unrealized gain (loss) arising during the period, net of tax		6,535	(6,158)	12,136	(2,442)
Reclassification of net realized loss (gain) into earnings, foreign currency translation adjustments, before tax				23,599	0
Reclassification of net realized loss (gain) into earnings, foreign currency translation adjustments, tax effect				(8,858)	0
Reclassification of net realized loss into earnings, foreign currency translation adjustments, net of tax		0	0	14,741	0
Net unrealized (loss) gain on hedging activities, before tax		18,370	14,258	30,641	(32,348)
Net unrealized (loss) gain on hedging activities, tax effect		(1,032)	0	(2,681)	0
Net unrealized (loss) gain on hedging activities, net of tax		17,338	14,258	27,960	(32,348)
Reclassification of net realized (gain) loss into earnings, before tax		100	3,164	(927)	15,667
Reclassification of net realized (gain) loss into earnings, tax		(6)	0	400	0
Reclassification of net realized (gain) loss into earnings, after tax		94	3,164	(527)	15,667
Other comprehensive income (loss), before tax		25,414	11,264	68,689	(19,123)
Other comprehensive income (loss), tax effect		(1,447)	0	(14,379)	0
Other comprehensive income (loss), net of tax		23,967	11,264	54,310	(19,123)
Less: Other comprehensive income (loss) attributable to non-controlling interests, net of tax		8,766	4,850	19,888	(6,819)
Other comprehensive income attributable to Class A common stockholders		$ 15,201	$ 6,414	34,422	(12,304)
Interest Expense
Accumulated Other Comprehensive Income (Loss) [Line Items]
Reclassification of net realized loss (gain) into earnings	$ 400
UNITED KINGDOM | Gain on sale of renewable energy facilities
Accumulated Other Comprehensive Income (Loss) [Line Items]
Reclassification of net realized loss (gain) into earnings				$ 23,600
UNITED KINGDOM | Interest Expense
Accumulated Other Comprehensive Income (Loss) [Line Items]
Reclassification of net realized loss (gain) into earnings					15,900
UNITED KINGDOM | Interest Expense | Hedging Activities Attributable to Parent
Accumulated Other Comprehensive Income (Loss) [Line Items]
Reclassification of net realized loss (gain) into earnings					$ 15,900