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 activity in the U.S. has been within the states. Nonetheless, the U.S. House of Representatives and Senate have, at different times, each passed versions of a Federal RPS; a Federal RPS, however, has not yet been signed into law. The design of an RPS can and does vary, but at its heart an RPS simply requires retail electricity suppliers (also called load-serving entities, or LSEs) to procure a certain minimum quantity of eligible renewable energy. An RPS establishes numeric targets for renewable energy supply, applies those targets to retail electricity suppliers, and seeks to encourage competition among renewable developers to meet the targets in a least-cost fashion. RPS purchase obligations generally increase over time, and retail suppliers typically must demonstrate compliance on an annual basis. Mandatory RPS policies are backed by various types of compliance enforcement mechanisms, and many--but not all--such policies include the trading of renewable energy certificates (RECs). Renewables portfolio standards are a relatively recent addition to the renewable energy policy landscape, and these policies continue to evolve. Keeping up with the design, early experience, and projected impacts of these programs is a challenge. This report seeks to fill this need by providing basic, factual information on RPS policies in the United States. It focuses on state-level initiatives, though a later section briefly discusses Federal developments as well. The report does not cover municipal-level renewable energy goals, unless required by state law. Similarly, this report focuses on mandatory state RPS requirements, though it also touches on non-binding renewable energy goals, especially when those goals are developed by state law or regulation. This report is the first of what is envisioned to be an ongoing series; as such, it concentrates on key recent developments, while also providing basic information on historical RPS experience and design. The report begins with an overview of state RPS policies: where they have been developed, when, and with what design features. Though most RPS programs are still in their infancy, the report summarizes the early impacts of these policies on renewable energy development, and provides a forecast of possible future impacts. It then turns to the implications of the growing trend towards solar and/or distributed generation set-asides within state RPS programs. Next, the report highlights state RPS compliance levels, enforcement actions, and cost impacts, as well as key developments in REC markets. Finally, the report provides a brief overview of Federal RPS proposals.
