Summary of Significant Accounting Policies | Summary of Significant Accounting Policies Basis of unaudited condensed consolidated financial statement presentation: The accompanying unaudited condensed consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States (“U.S. GAAP”) for interim financial information and Article 8 of Regulation S-X. The Company has condensed or omitted certain information and note disclosures normally included in the financial statements prepared in accordance with GAAP pursuant to the applicable rules and regulations of the SEC regarding interim financial reporting. As such, these interim unaudited condensed consolidated financial statements should be read in conjunction with the Company’s 2022 annual audited consolidated financial statements and accompanying notes included in its Annual Report. The Company’s interim unaudited condensed consolidated financial statements reflect all normal and recurring adjustments necessary, in its opinion, to state fairly the financial position and results of operations for the reported periods. Amounts reported for interim periods may not be indicative of a full year period due to the Company’s continual growth, seasonal fluctuations in demand for power, timing of maintenance and other expenditures, changes in interest expense and other factors. The Company's accompanying unaudited condensed consolidated financial statements include the accounts of its wholly owned subsidiaries and variable interest entities, for which the Company is the primary beneficiary. All intercompany transactions have been eliminated in consolidation. Use of estimates: The preparation of financial statements in conformity with U.S. GAAP requires management to make certain estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities as of the balance sheet date, as well as reported amounts of expenses during the reporting period. The Company’s most significant estimates and judgments involve, deferred income taxes, warranty reserves, valuation of share-based compensation, useful lives of certain assets and liabilities, the valuation of redeemable noncontrolling interests and noncontrolling interests, the allowance for current expected credit losses, warrant liabilities, asset acquisition transactions and the valuation of business combinations, including the fair values and useful lives of acquired assets and assumed liabilities. Management bases its estimates on historical experience and on various other assumptions believed to be reasonable, the results of which form the basis for making judgments about the carrying values of assets and liabilities. Actual results could differ from those estimates, and such differences could be material to the Company’s financial statements . Variable interest entities : The Company consolidates any variable interest entity ("VIE") of which it is the primary beneficiary. The Company formed or acquired VIEs which are partially funded by tax equity investors in order to facilitate the funding and monetization of certain attributes associated with solar energy systems. The typical condition for a controlling financial interest ownership is holding a majority of the voting interests of an entity; however, a controlling financial interest may also exist in entities, such as VIEs, through arrangements that do not involve controlling voting interests. A variable interest holder is required to consolidate a VIE if that party has the power to direct the activities of the VIE that most significantly impact the VIE's economic performance and the obligation to absorb losses of the VIE that could potentially be significant to the VIE or the right to receive benefits from the VIE that could potentially be significant to the VIE. The Company does not consolidate a VIE in which it has a majority ownership interest when the Company is not considered the primary beneficiary. The Company evaluates its relationships with the VIEs on an ongoing basis to determine if it is the primary beneficiary. The Company's investments in Volta Solar Owner II, LLC, ORE F4 HoldCo, LLC and Level Solar Fund IV LLC (collectively, the "Funds") were determined to be variable interests in VIEs. The Company considered the provisions within the contractual arrangements that grant it power to manage and make decisions that affect the operation of the VIEs, including determining the solar energy systems contributed to the VIEs, and the operation and maintenance of the solar energy systems. The Company considers the rights granted to the other investors under the contractual arrangements to be more protective in nature rather than substantive participating rights. As such, the Company was determined to be the primary beneficiary and the assets, liabilities and activities of the Funds are consolidated by the Company (See Note 13. Redeemable Noncontrolling Interests and Noncontrolling Interests). Redeemable noncontrolling interests and noncontrolling interests: The distribution rights and priorities for the Funds as set forth in their respective operating agreements differ from the underlying percentage ownership interests of the members. As a result, the Company allocates income or loss to the noncontrolling interest holders of the Funds utilizing the hypothetical liquidation of book value ("HLBV") method, in which income or loss is allocated based on the change in each member's claim on the net assets at the end of each reporting period, adjusted for any distributions or contributions made during such periods. The HLBV method is commonly applied to investments where cash distribution percentages vary at different points in time and are not directly linked to an equity member's ownership percentage. The HLBV method is a balance sheet-focused approach. Under this method, a calculation is prepared at each reporting date to determine the amount that each member would receive if the entity were to liquidate all of its assets and distribute the resulting proceeds to its creditors and members based on the contractually defined liquidation priorities. The difference between the calculated liquidation distribution amounts at the beginning and the end of the reporting period, after adjusting for capital contributions and distributions, is used to derive each member's share of the income or loss for the period. Factors used in the HLBV calculation include GAAP income (loss), taxable income (loss), capital contributions, investment tax credits, capital distributions and the stipulated targeted investor return specified in the subsidiaries' operating agreements. Changes in these factors could have a significant impact on the amounts that investors would receive upon a hypothetical liquidation. The Company classifies certain noncontrolling interests with redemption features that are not solely within the Company’s control outside of permanent equity in the unaudited condensed consolidated balance sheets. Redeemable noncontrolling interests are reported using the greater of the carrying value at each reporting date as determined by the HLBV method or the estimated redemption value at the end of each reporting period. Estimating the redemption value of the redeemable noncontrolling interests requires the use of significant assumptions and estimates, such as projected future cash flows. Concentration of credit risk: Financial instruments which potentially subject the Company to concentrations of credit risk consist of cash and cash equivalents. At times, such cash may be in excess of the FDIC limit. At June 30, 2023 and December 31, 2022, the Company had cash in excess of the $250,000 federally insured limit. The Company believes it is not exposed to any significant credit risk on cash and cash equivalents as most of the balances are kept in treasury bills, which are government backed securities. Cash and cash equivalents: The Company considers all highly liquid investments with a maturity of three months or less at the time of purchase to be cash equivalents. Cash and cash equivalents include cash held in banks and money market accounts. Cash equivalents are carried at cost, which approximates fair value due to their short-term nature. The Company’s cash and cash equivalents are placed with high-credit quality financial institutions and issuers, and at times exceed federally insured limits. To date, the Company has not experienced any credit loss relating to its cash and cash equivalents. Restricted cash: Restricted cash held at June 30, 2023 and December 31, 2022 of $29.4 million and $19.8 million respectively, primarily consists of approximately $29.2 million and $19.7 million, respectively, of cash that is subject to restriction due to provisions in the Company's financing agreements and the operating agreements of the Funds that are accounted for as consolidated VIEs. The carrying amount reported in the unaudited condensed consolidated balance sheets for restricted cash approximates fair value. The following table provides a reconciliation of cash and cash equivalents and restricted cash reflected on the unaudited condensed consolidated balance sheets to the total amounts shown in the unaudited condensed consolidated statements of cash flows for the end of the periods: As of (Amounts in thousands) June 30, 2023 June 30, 2022 Cash and cash equivalents $ 162,749 $ 322,371 Restricted cash 29,361 150 Total cash, cash equivalents and restricted cash $ 192,110 $ 322,521 Accounts receivable, net: Accounts receivable primarily represent amounts due from the Company’s residential customers. Accounts receivable is recorded net of an allowance for expected credit losses, which is determined by the Company’s assessment of the collectability of customer accounts based on the best available data at the time of the assessment. Management reviews the allowance by considering factors such as historical experience, contractual term, aging category and current economic conditions that may affect customers. The following table presents the changes in the allowance for credit losses recorded against accounts receivable, net on the unaudited condensed consolidated balance sheets: As of (Amounts in thousands) June 30, 2023 December 31, 2022 Balance at beginning of period $ 12,164 $ 12,164 Impact of ASC 326 adoption (1,285) — Write-off of uncollectible accounts (661) Provision for current expected credit losses 1,104 — Balance at end of period $ 11,322 $ 12,164 Derivative instruments and hedging activities: The Company utilizes interest rate swaps to manage interest rate risk on existing and planned future debt issuances. The fair value of all derivative instruments are recognized as assets or liabilities at the balance sheet date on the unaudited condensed consolidated balance sheets. The fair value of the interest rate swaps are calculated by discounting the future net cash flows to the present value based on the terms and conditions of the agreements and the forward interest rate curves. As these inputs are based on observable data and valuations of similar instruments, the interest rate derivatives are primarily categorized as Level 2 in the fair value hierarchy. Prepaid expenses and other current assets: Prepaid expenses and other current assets include prepaid insurance, prepaid rent, and supplies, which are expected to be recognized or realized within the next 12 months. Property and equipment, net: Property and equipment, net consists of solar energy systems and other property and equipment. Solar energy systems , net: Solar energy systems, net consists of residential solar energy systems which are subject to long-term customer agreements. Solar energy systems are recorded at their fair value upon acquisition. Subsequently, any impairment charges that may arise are recognized and the impairment loss reduces the carrying amount of the asset to its recoverable amount. For all acquired systems, the Company calculates depreciation using the straight-line method over the remaining useful life as of the acquisition date based on a 30-year useful life from the date the asset was placed in service. When a solar energy system is sold or otherwise disposed of, a gain (or loss) is recognized for the amount of cash received in excess of the net book value of the solar energy system (or vice versa), at which time the related solar energy system is removed from the unaudited condensed consolidated balance sheets. Depreciation expense of solar energy systems for the three and six months ended June 30, 2023 was $5.6 million and $11.6 million respectively, and $0 for the three and six months ended June 30, 2022. Other property and equipment, net: Other property and equipment, net is stated at cost less accumulated depreciation, or if acquired in a business combination, at fair value as of the date of acquisition less accumulated depreciation. Depreciation is calculated using the straight-line method, based upon the following estimated useful lives: Equipment 5 years Furniture and fixtures 3 years Computer and related equipment 2 years Software 2 years Vehicles 5 years Leasehold improvements Lesser of useful life of the asset or remaining life of the lease Leasehold improvements are capitalized, while replacements, maintenance and repairs, which do not improve or extend the life of the respective asset, are expensed as incurred. When property and equipment is retired or otherwise disposed of, the related cost and accumulated depreciation are removed from the accounts, and any gain or loss on the disposition is recorded in the unaudited condensed consolidated statements of operations as a component of other income, net. Depreciation expense of other property and equipment for the three and six months ended June 30, 2023 was $0.1 million for both periods, and for the three and six months ended June 30, 2022 was $0.2 million and $0.4 million, respectively. Intangible assets, net: The Company’s intangible assets include solar renewable energy credit agreements, performance based incentive agreements, and a trade name. The Company amortizes its intangible assets that have finite lives based on the pattern in which the economic benefit of the asset is expected to be utilized. The useful life of the Company’s intangible assets generally range between three years and 30 years. The useful life of intangible assets are assessed and assigned based on the facts and circumstances specific to the assets. The Company recognizes the amortization of (i) solar renewable energy agreements and performance based incentive agreements as a reduction to revenue and (ii) the trade name as amortization expense within selling, general and administrative expenses. Asset retirement obligations (“ARO”): Customer agreements only require that solar energy systems be removed if: (i) the customer has not renewed the customer agreement or exercised their purchase option and (ii) the host customer requests the Company to remove the system. Upon review of the Company's estimate of the probability of required system removal, the Company considered current industry trends and has determined that it is highly probable that the customers will choose to renew their agreements or exercise the buyout option as the systems have an estimated useful life greater than the terms of the customer agreements and would still present value to the customer through energy cost savings. Therefore, the Company believes that the probability-weighted estimated removal costs are nominal and no ARO liability has been recorded. Business combinations: The Company accounts for the acquisition of a business using the acquisition method of accounting. Amounts paid to acquire a business are allocated to the assets acquired and liabilities assumed based on their fair values at the date of acquisition. The Company engages third-party appraisal firms to assist in the fair value determination. The Company determines the fair value of purchase consideration, including contingent consideration, and acquired intangible assets based on valuations received from the appraisal firm that used information and assumptions provided by Management. The Company allocates any excess purchase price over the fair value of the net tangible and intangible assets acquired to goodwill. The results of operations of acquired businesses are included in the Company's financial statements from the date of acquisition forward. Acquisition-related costs are expensed in periods in which the costs are incurred. Asset acquisitions: The Company accounts for assets acquired based on the consideration transferred by us, including direct and incremental transaction costs incurred by the Company as a result of the acquisition. An asset acquisition’s cost or the consideration transferred by us is assumed to be equal to the fair value of the net assets acquired. If the consideration transferred is cash, measurement is based on the amount of cash the Company paid to the seller, as well as transaction costs incurred by us. Consideration given in the form of nonmonetary assets, liabilities incurred or equity interests issued is measured based on either the cost to us or the fair value of the assets or net assets acquired, whichever is more clearly evident. The cost of an asset acquisition is allocated to the net assets acquired based on their estimated relative fair values. The Company engages third-party appraisal firms to assist in the fair value determination. Goodwill is not recognized in an asset acquisition. Impairment of long-lived asset s: The Company reviews long-lived assets, including solar energy systems, other property and equipment, and intangible assets with definite lives, for impairment whenever events or changes in circumstances indicate that an asset group’s carrying amount may not be recoverable. The Company groups assets and liabilities at the lowest level for which identifiable cash flows are largely independent of the cash flows of other assets and liabilities and evaluate the asset group against the sum of the undiscounted future cash flows. If the undiscounted cash flows do not indicate the carrying amount of the asset group is recoverable, an impairment charge is measured as the amount by which the carrying amount of the asset group exceeds its fair value. There has been no impairment charge for the periods presented. Impairment of goodwill: Goodwill represents the excess of cost over the fair market value of net tangible and identifiable intangible assets of acquired businesses. Goodwill is not amortized, however it is annually tested for impairment, or more frequently if events or circumstances indicate that the carrying amount of goodwill may be impaired. The Company has recorded goodwill in connection with its historical business acquisitions. The Company performs its annual goodwill impairment assessment on October 1 of each fiscal year, or more frequently if events or circumstances arise which indicate that goodwill may be impaired. An assessment can be performed by first completing a qualitative assessment of the Company’s single reporting unit. The Company can also bypass the qualitative assessment in any period and proceed directly to the quantitative impairment test, and then resume the qualitative assessment in any subsequent period. Qualitative indicators that may trigger the need for annual or interim quantitative impairment testing include, among other things, deterioration in macroeconomic conditions, declining financial performance, deterioration in the operational environment, or an expectation of selling or disposing of a portion of the reporting unit. Additionally, a significant change in business climate, a loss of a significant customer, increased competition, a sustained decrease in share price, or a decrease in estimated fair value below book value may trigger the need for interim impairment testing of goodwill. If the Company believes that, as a result of its qualitative assessment, it is more likely than not that the fair value of the reporting unit is less than its carrying amount, the quantitative impairment test is required. The quantitative test involves comparing the fair value of the reporting unit with its carrying amount, including goodwill. If the carrying amount of the reporting unit exceeds its fair value, an impairment loss is recorded as a reduction to goodwill with a corresponding charge to earnings in the period the goodwill is determined to be impaired. The income tax effect associated with an impairment of tax-deductible goodwill is also considered in the measurement of the goodwill impairment. Any goodwill impairment is limited to the total amount of goodwill. The Company determines the fair value of its reporting unit using the market or income approach. Under the market approach method, the Company compares its book value to the fair value of its public float, utilizing the fair value of its common stock on the measurement date. The income approach of computing fair value is based on the present value of the expected future economic benefits generated by the asset or business, such as cash flows or profits which will then be compared to its book value. In the first quarter of 2022, the Company believed there were indicators that the carrying amount of its goodwill may be impaired due to a decline in the Company’s stock price and market capitalization. As a result, the Company performed an assessment of its goodwill for impairment. The Company elected to forego the qualitative test and proceeded to perform a quantitative test. The Company compared the book value of its single reporting unit to the fair value of its public float. The market capitalization was below the fair value of the Company by an amount in excess of its reported value of goodwill. As a result, the Company recorded a charge of $8.6 million to fully impair its goodwill for the six months ended June 30, 2022 which is reflected within net loss from discontinued operations in the unaudited condensed consolidated statements of operations (See Note 17. Discontinued Operations). There has been no impairment charge for the six months ended June 30, 2023. Warrant liabilities: As of June 30, 2023 and 2022, the Company had outstanding private warrants, which are related to the December 2020 merger and organization of legacy XL Hybrids Inc. (“XL Hybrids”) to become XL Fleet Corp. With the merger, the Company assumed private placement warrants to purchase 4,233,333 shares of common stock, with an exercise price of $11.50 per share (the "Private Warrants"). The Private Warrants do not meet the criteria for equity classification and must be recorded as liabilities. As the Private Warrants meet the definition of a derivative, they were measured at fair value at inception and at each reporting date with changes in fair value recognized in the unaudited condensed consolidated statements of operations. The Private Warrants were valued using a Black-Scholes model, with significant inputs consisting of risk-free interest rate, remaining term, expected volatility, exercise price, and the Company’s stock price (See Note 10. Fair Value Measurements). Warranties: Customers who purchased the Company's Drivetrain systems were provided limited-assurance-type warranties for equipment and work performed under the contracts. The warranty period typically extends for three years following transfer of control of the equipment. The warranties solely relate to correction of product defects during the warranty period, which is consistent with similar warranties offered by competitors. Customers of XL Grid were provided limited-assurance-type warranties for a term of one year for installation work performed under its contracts. The Company accrued the estimated cost of product warranties for unclaimed charges based on historical experiences and expected results. Should product failure rates and material usage costs differ from these factors, estimated revisions to the estimated warranty liability will be required. The Company periodically assesses the adequacy of its recorded product warranty liabilities and adjusts the balances as required. Warranty expense is recorded as a component of discontinued operations in the unaudited condensed consolidated statement of operations. With the Company’s exit from the Drivetrain business and the subsequent sale of World Energy, the Company will not enter into any additional warranty obligations and expects the existing warranty obligation to substantially run-off over the next 18 months. The following is a rollforward of the Company’s accrued warranty liability: Three Months Ended Six Months Ended (Amounts in thousands) June 30, 2023 June 30, 2022 June 30, 2023 June 30, 2022 Balance at the beginning of the period $ 627 $ 2,403 $ 1,125 $ 2,547 Accrual for warranties issued — 7 — 35 Transfer of inventory to servicers — — (498) — Accrual related to World Energy (25) — (25) — Warranty fulfillment charges — (84) — (256) Balance at the end of the period $ 602 $ 2,326 $ 602 $ 2,326 The Company's warranty liability is included in accrued expenses and other current liabilities on the unaudited condensed consolidated balance sheets. Unfavorable solar renewable energy agreements: The Company amortizes its unfavorable solar renewable energy agreements that have finite lives based on the pattern in which the economic benefit of the liability is relieved. The useful life of the Company’s liabilities generally range between three years and six years. The useful life of these liabilities are assessed and assigned based on the facts and circumstances specific to the agreement. The Company recognizes the amortization of unfavorable solar renewable energy agreements as revenues in the unaudited condensed consolidated statements of operations. Revenues: The Company’s revenue is derived from its residential solar energy portfolio, which primarily generates revenue through the sale to homeowners of power generated by its residential solar energy systems pursuant to long-term agreements. The following table presents the detail of the Company’s revenues as reflected within the unaudited condensed consolidated statements of operations for the three and six months ended June 30, 2023: Three Months Ended Six Months Ended (Amounts in thousands) June 30, 2023 PPA revenues $ 12,234 $ 19,361 SLA revenues 7,025 14,947 Solar renewable energy credit revenues 1,662 3,196 Government incentives 72 96 Servicing revenues 112 225 Intangibles amortization, unfavorable solar renewable energy agreements 976 1,419 Other revenue 732 1,664 Total $ 22,813 $ 40,908 Energy generation - Customers purchase solar energy from the Company under PPAs or SLAs, both defined above. Revenue is recognized from contracts with customers as performance obligations are satisfied at a transaction price reflecting an amount of consideration based upon an estimated rate of return which is expressed as the solar rate per kilowatt hour or a flat rate per month as defined in the customer contracts. • PPA revenues - Under Accounting Standards Codification (“ASC”) 606, Revenue from Contracts with Customers (“ASC 606”) issued by the Financial Accounting Standards Board (“FASB”) , PPA revenue is recognized when generated based upon the amount of electricity delivered as determined by remote monitoring equipment at solar rates specified under the PPAs. • SLA revenues - The Company has SLAs, which do not meet the definition of a lease under ASC 842, Leases ("ASC 842"), and are accounted for as contracts with customers under ASC 606. Revenue is recognized on a straight-line basis over the contract term as the obligation to provide continuous access to the solar energy system is satisfied. The amount of revenue recognized may not equal customer cash payments due to the performance obligation being satisfied ahead of cash receipt or evenly as continuous access to the solar energy system has been provided. The differences between revenue recognition and cash payments received are reflected in deferred rent assets. Solar renewable energy credit revenues - The Company enters contracts with third parties to sell Solar Renewable Energy Credits ("SRECs") generated by the solar energy systems for fixed prices. Certain contracts that meet the definition of a derivative may be exempted as normal purchase or normal sales transactions ("NPNS"). NPNS are contracts that provide for the purchase or sale of something other than a financial instrument or derivative instrument that will be delivered in quantities expected to be used or sold over a reasonable period in the normal course of business. The Company's SREC contracts meet these requirements and are designated as NPNS contracts. Such SRECs are exempted from the derivative accounting and reporting requirements, and the Company recognizes revenues in accordance with ASC 606. The Company recognizes revenue for SRECs based on pricing predetermined within the respective contracts at a point in time when the SRECs are transferred. As SRECs can be sold separate from the actual electricity generated by the renewable-based generation source, the Company accounts for the SRECs it generates from its solar energy systems as governmental incentives with no costs incurred to obtain them and do not consider those SRECs output of the underlying solar energy systems. The Company classifies these SRECs as inventory held until sold and delivered to third parties. As the Company did not incur costs to obtain these governmental incentives, the inventory carrying value for the SRECs was $0 as of June 30, 2023 and December 31, 2022. Government incentives - The Company participates in the Residential Solar Investment Program of Connecticut, which offers a performance-based incentive (“PBI”) for certain of its solar energy systems that are associated with the program (“eligible systems”). PBIs are paid to the Company and recognized as revenue based on actual per-kilowatt-hour production delivered to the eligible systems. For systems up to 20kW, the Company is paid a predetermined rate based on the eligible system start date. The program lasts for six years from the eligible systems’ start date. PBI revenue is accounted for under ASC 606 and is earned based upon the actual electricity produced by the system. Servicing revenues - The Company earns operating and maintenance revenue from third-party residential solar fund customers at pre-determined rates for various operating and maintenance and asset management services as specified in Maintenance Service Agreements ("MSAs") and Operating Service Agreements ("OSAs"). The MSAs and OSAs contain multiple performance obligations, including routine maintenance, nonroutine maintenance, renewable energy certificate management, inventory management, delinquent account collections and customer account management. Pursuant to ASC 606, the Company has elected the "right to invoice" practical expedient and revenue for these performance obligations are recognized as services are rendered based upon the underlying contractual arrangements. Contract balances: The timing of revenue recognition, billings and cash collections results in billed accounts receivable, and deferred revenue on the unaudited condensed consolidated balance sheets. Cost of revenues: Cost of revenues primarily consists of the depreciation expense relating to the solar energy systems, costs of third parties used to service the systems and any cost associated with meter swaps. Income taxes: The Company accounts for income taxes using the asset and liability method under which deferred tax liabilities and assets are recognized for the expected future tax consequences of temporary differences between financial statement carrying amounts and the tax basis of assets and liabilities and net operating loss and tax credit carryforwards. Deferred income taxes are provided for the temporary differences arising between the carrying amounts of assets and liabilities for financial reporting purposes and the amounts used for income tax purposes, and net operating loss carry-forwards and credits. Deferred tax assets and liabilities are measured using enacted rates in effect for the year in which the differences are expected to be recovered or settled. The effect of changes in tax rates on deferred tax assets and liabilities is recognized in the unaudited condensed consolidated statements of operations in the period in which the enactment rate changes. The ultimate recovery of deferred tax assets is dependent upon the amount and timing of future taxable income and other factors, such as the ta |