Introduction
Renewable Portfolio Standards (RPS) require that a specified percentage of the electricity utilities sell comes from renewable resources. States have created these standards to diversify their energy resources, promote domestic energy production and encourage economic development.
Renewable energy policies help drive the nation’s $269 billion market as of 2022, for wind, solar and other renewable energy sources. These policies can play an integral role in state efforts to diversify their energy mix, promote economic development and reduce emissions. Roughly half of the growth in U.S. renewable energy generation since the beginning of the 2000s can be attributed to state renewable energy requirements.
From NCSL.org

