A Renewable Portfolio Standard (RPS) ensures that the public benefits of renewable energy, such as wind and solar, continue to be recognized as electricity markets become more competitive. It requires companies that sell electricity to retail customers to support renewable energy generation.
Source: State Energy Conservation Office

When Texas produced its first Renewable Portfolio Standard as part of the state's electricity industry restructuring legislation in 1999 (Senate Bill 7), it mandated the construction of certain amounts of renewable energy and prompted the renewable energy industry to rapidly accelerate its production on Texas sites. Qualifying renewable energy sources include solar, wind, geothermal, hydroelectric, tidal energy, and biomass, including landfill gas. Also eligible are renewable energy sources on the customer side of the meter that offset electricity demand, such as the installation of photovoltaic panels and solar water heating.

The Texas Public Utility Commission implemented the program.