Renewables Portfolio Standards: A Factual Introduction to Experience from the United States

Renewables portfolio standards (RPS) have – since the late 1990s – proliferated at the state level in the United States. What began as a policy idea minted in California and first described in detail in the pages of the Electricity Journal1 has emerged as an important driver for renewable energy capacity additions in the United States Over the years, articles in the Electricity Journal have explored the RPS in more detail, identifying both its strengths and weaknesses. The present article provides an introduction to the history, concept, and design of the RPS, reviews early experience with the policy as applied at the state level, and provides a brief overview of Federal RPS proposals to date and the possible relationship between Federal and state RPS policies. Our purpose is to offer a factual introduction to the RPS, as applied and considered in the U.S. Though elements of state RPS design are summarized here, other publications provide a more thorough review of design lessons that emerge from that experience.3 In addition, the present article does not describe the results of economic analyses of Federal RPS proposals, though we do cite many of the analyses conducted by the U.S. DOE's Energy Information Administration (EIA).