Voluntary green power markets are those in which consumers and institutions voluntarily purchase renewable energy to match their electricity needs. Voluntary action provides a revenue stream for renewable energy projects and raises consumer awareness of the benefits of renewable energy. These markets continued to exhibit growth and stimulate renewable energy development in 2012. Based on our review of the voluntary market, we identified the following market trends:• In 2012, total retail sales of renewable energy in voluntary purchase markets exceeded 48 million megawatt-hours (MWh) and represented approximately 1.3% of total U.S. electricity sales. These figures represent a capacity equivalent of approximately 17,000 MW. From 2010 to 2012, total green power market sales increased by 36%, a compound annual growth rate of 17% ( Figure ES-1).