VIEs are entities that lack sufficient equity to finance their activities without additional financial support from other parties or whose equity holders, as a group, lack one or more of the following characteristics: (a) direct or indirect ability to make decisions; (b) obligation to absorb expected losses; or (c) right to receive expected residual returns. VIEs must be evaluated quantitatively and qualitatively to determine the primary beneficiary, which is the reporting entity that has (a) the power to direct activities of a VIE that most significantly impact the VIEs economic performance and (b) 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 primary beneficiary is required to consolidate the VIE for financial reporting purposes. A VIE can have only one primary beneficiary, but may not have a primary beneficiary if no party meets the criteria described above.
To determine a VIE’s primary beneficiary, an enterprise must perform a qualitative assessment to determine which party, if any, has the power to direct activities of the VIE, the obligation to absorb losses, and/or receive its benefits. Therefore, an enterprise must identify the activities that most significantly impact the VIE’s economic performance and determine whether it, or another party, has the power to direct those activities. When evaluating whether the Company is the primary beneficiary of a VIE, the Company performs a qualitative analysis that considers the design of the VIE, the nature of the Company's involvement and the variable interests held by other parties. If that evaluation is inconclusive as to which party absorbs a majority of the entity’s expected losses or residual returns, a quantitative analysis is performed to determine the primary beneficiary.
For its consolidated VIEs, the Company has presented on its consolidated balance sheets, to the extent material, the assets of its consolidated VIEs that can only be used to settle specific obligations of the consolidated VIE, and the liabilities of its consolidated VIEs for which creditors do not have recourse to the Company's general assets outside of the VIE with all intercompany accounts and transactions eliminated.
Cash and Cash Equivalents
Cash and cash equivalents include all cash balances and short term investments with original maturity periods of three months or less.
Restricted cash consists of cash on deposit in financial institutions that is restricted to satisfy the requirements of certain debt and acquisition agreements and funds held within the Company's project companies that are restricted for current debt service payments and other purposes in accordance with the applicable debt agreements. These restrictions include: (i) cash on deposit in collateral accounts, debt service reserve accounts, and maintenance reserve accounts; and (ii) cash on deposit in operating accounts but subject to distribution restrictions due to debt defaults as of the balance sheet date.
Accounts Receivable and Allowance for Doubtful Accounts
Accounts receivable are reported on the consolidated balance sheets, including both billed and unbilled amounts, and are adjusted for any write-offs as well as the allowance for doubtful accounts. The Company establishes an allowance for doubtful accounts to adjust its receivables to amounts considered to be ultimately collectible. The Company's allowance is based on a variety of factors, including the length of time receivables are past due, significant one-time events, the financial health of its customers and historical experience. There was no allowance for doubtful accounts as of December 31, 2016 and 2015. There were no write-offs of accounts receivable for the years ended December 31, 2016, 2015 and 2014.
Power plants consists of solar and wind power plants and is stated at cost. Expenditures for major additions and improvements are capitalized and minor replacements, maintenance, and repairs are charged to expense as incurred. When power plants are retired, or otherwise disposed of, the cost and accumulated depreciation are removed from the consolidated balance sheets and any resulting gain or loss is included in the results of operations for the respective period. Depreciation of solar and wind power plants is recognized using the straight-line method over the estimated useful lives of the power plants of up to 30 and 25 years, respectively.
Viability Gap Funding Subsidies
Certain of the Company's solar power plants in India are entitled to receive viability gap funding support in an amount determined through a competitive bidding process. The viability gap funding support is funded by India’s National Clean Energy Fund and is paid by the offtake counterparty to these solar power plants, the Solar Energy Corporation of India (“SECI”), a not-for-profit company established by the Ministry of New and Renewable Energy to facilitate solar energy