A Solar Power Purchase Agreement (PPA) is a legal contract where a solar project developer installs and operates a system for a business owner, homeowner, or tenant (the “host”) who in turn agrees to buy the solar generated electricity for a fixed period, usually 10 to 20 years. The host typically purchases the solar power at a fixed rate equal to or less than their normal utility rate and does not pay the upfront capital costs of the installation, making PPAs a very attractive economic option.

Developers like the model because the PPA contract ensures that the developer will be able to sell the solar electricity for a fixed period of time at a pre-determined rate. The PPA contract also removes negotiation and transmission costs that could be associated with solar projects that do not have a guaranteed energy buyer.

Businesses benefit from the federal and state incentives in place for owning a solar system. Specifically, Solar PPAs in the United States rely on the federal solar investment tax credit, which was extended for eight years under the Emergency Economic Stabilization act of 2008 and then amended with the passage of the American Recovery and Reinvestment Act of 2009 so that the solar investment tax credit can now be combined with tax exempt financing. This investment tax credit covers 30% of the expenditures on a solar system. Several state rebate programs also reduce the capital necessary for PPAs by providing grants corresponding to the size of the solar system.

The host business that is buying the solar generated electricity does not receive any of these tax credits or rebates directly, rather, the developer or company that finances and subsequently owns the system receives these benefits. However, the developer passes these benefits on to the host in the form of lower fixed rates for their electricity.

Because the developer fully maximizes all the incentives associated with a solar energy system, in some situations a PPA can be a better deal than ownership of a system. For example, non-profits cannot receive tax credits, implying that a PPA would be the better financial decision since the developer could access the tax credits and consequently provide solar electricity at a reduced rate to the non-profit. Furthermore, a solar developer can raise funds for a project (or portfolio of projects) through tax equity investors.

Similarly, businesses and developers engaging in a Solar PPA can take advantage of Solar Renewable Energy Credits (SRECs). An SREC is a tradable credit that represents the clean energy benefits of electricity generated from a solar electric system. Each time the electric system generates 1000 kWh, a SREC is issued that can be sold or traded separately from the power. Therefore, the legal owner of the system can sell their rights to SRECs to utility companies that need SRECs to comply with state Renewable Portfolio Standards. This represents another substantial method to offset the cost of the system and allow businesses to reduce their net costs and ultimately the PPA rate. As state rebate programs diminish, SREC values will become more important for financing solar.

As PPAs and new solar financing tools become more prevalent, it is important to understand the difference between a PPA and a lease. A solar lease is another common financing tool where a solar company builds a solar energy system on a host’s property and then the host pays a lease payment for the benefits of the system’s electricity production. This is different from a PPA where the host pays directly for the solar power. Many companies that began exclusively in solar leasing are now offering the PPA model to customers as well. Typically, nuances in state laws or consumer preference determine whether a developer will offer a PPA or lease. Solar developers who offer solar PPAs have encountered a large number of interested customers. For example, Wal-Mart, Safeway, and Macy’s all use solar PPAs, and some estimates say that in 2008 PPAs represented over 60% of California’s non-residential solar market.

In short, PPAs allow businesses to take advantage of all sorts of solar incentives like SREC values, federal, and state incentives – all without any upfront capital. As large facility owners and tenants continue to demand solar without high upfront costs, PPAs will become more and more popular.