Renewables portfolio standards (RPS) have proliferated at the state level in the United States since the late 1990s. In combination with Federal tax incentives, state RPS requirements have emerged as one of the most important drivers of renewable energy capacity additions. The focus of most RPS...

Growth in renewable energy in the U.S. over the past decade has been propelled by a number of forces, including rising fossil fuel prices, environmental concerns, and policy support at the state and federal levels. In this article, we review and discuss what are arguably the two most important...