According to DOE, 30 states including the District of Columbia have renewable portfolio standards (RPS) or a requirement that electricity providers obtain a minimum percentage of their power from renewable energy resources by a certain date. Five other states—North Dakota, South Dakota, Utah, Virginia, and Vermont—have nonbinding goals for adoption of renewable energy instead of an RPS.

State progress on RPSs has been impressive considering the failure of the federal government to enact a national RPS. However, the Energy Information Administration (EIA) points out that a combination of federal incentives has resulted in increased use of renewable energy in states without mandatory RPSs. Perhaps the most important of these federal incentives has been the production tax credit, according to EIA, which awards tax credits to entities that generate electricity using renewable technologies that are eligible for the program.

Another important feature of some state policies, as well as most proposed federal policies, is a renewable electricity credit (REC) trading system. This mechanism allows an electricity producer that generates renewable electricity to either trade or sell certificates of generation to other electricity suppliers that do not generate enough RPS-eligible renewable electricity to meet their RPS requirement. RECs allow energy suppliers in regions of the country with limited sources or renewable energy to purchase compliance credits from suppliers with more access to resources.

Several RPS proposals are now pending in the U.S. Congress.

A chart showing state RPS goals is available here.