Study Shows Securitization Can Lower the Cost of Capital of Solar PV

The limited availability of low-cost financing is holding back market adoption of solar photovoltaics (PV). However, securitization can make project financing more affordable than it is today, according to new research from the Open Sustainability Technology Laboratory at Michigan Technological University.

Securitization of residential solar PV power purchase agreements (PPAs) can reduce the cost of capital for solar PV projects by between five and 13 percent, said the researchers, Theresa Alafita and Joshua Pearce.

The journal Energy Policy published the results online on Jan. 21 in an article titled “Securitization of Residential Solar Photovoltaic Assets: Costs, Risks and Uncertainty.”

To minimize the cost of capital, the researchers said, solar PV developers and policymakers should adopt policies that lower the risk of PPA and solar lease defaults, improve the accuracy of risk assessment, and increase the liquidity of solar asset-backed securities.

PPAs are a common means of funding solar power; they are contracts between electricity generators and electricity buyers. To access private sources of funding, solar lease providers can securitize the funds from these PPAs. Securitization is the practice of pooling debt and selling the consolidated debt as securities in financial markets.

The researchers built a mathematical model to measure the cost of the capital raised through securitization of solar PPAs. Their calculations produced some surprising results with important policy implications.

Required Rate of Return

The required rate of investor return was the primary determinant of financing costs. The researchers said that improving the liquidity of the securities would help reduce the required rate of investor return.

Securitizing all of the existing PPAs would create considerable liquidity, but the researchers said this is difficult to accomplish due to the tax equity structure of these contracts.

Risk Assessment Quality

Changes in the quality of risk assessment had a large effect on the cost of capital. Poorer risk assessment led to a higher cost of capital. Moreover, this effect grew as the degree of accuracy declined. An increase in required credit enhancement from 0 to 1 percent added 0.34 percent to the cost of capital. In contrast, a similar change from 7 to 8 percent increased the cost of capital by 0.98 percent.

The researchers said that policymakers could reduce this effect by having a public entity insure the assets. They said this could take the form of a government-supported loan guarantee

Default Rates

The default rate for the PPAs had little impact on the cost of capital. But it had a large effect on the amount of capital that could be raised. The lower the default rate, the more capital was available to the solar PV developers for the same pool of solar PPAs.

The researchers said two policies would lead to a lower default rate: first, standardizing PPA forms to enable greater pooling and improved data collection, and second, diversifying programs geographically by encouraging more states to allow third-party PPAs. In 2013, the National Renewable Energy Laboratory, through its Solar Access to Public Capital initiative, developed standardized PPAs for the residential and commercial sectors.

Implementing these policies that facilitate securitization could have a significant positive impact on solar deployment. The authors said that securitization of solar leases and PPAs can raise significant capital while reducing project financing costs far below the cost of alternative financing.

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