Among the options receiving attention are various types of renewable portfolio standards, also known as renewable electricity standards or clean energy standards, depending upon their specific design. (robertstavinsblog.org)
More than half the states have renewable portfolio standards in place requiring certain and growing percentages of electricity to come from specified sources. (eelegal.org)
Adopt a national renewable portfolio standard requiring 20 percent of electricity to be generated from renewable energy sources by 2020, and 30 percent by 2030. (treehugger.com)