A solar power purchase agreement (PPA) is a financial agreement where a developer arranges for the design, permitting, financing and installation of a Solar energy is electromagnetic energy transmitted from the sun. Solar energy is measured is kilowatt hours (kWh) or megawatt hours... More system on a customer’s property at little to no cost. The developer sells the power generated to the host customer at a contracted rate. PPAs typically range from 10 to 25 years and all incentives are for the benefit of the developer. Affordable Solar does not currently offer power purchase agreement programs.