Solar power is the least prevalent of the nation's renewables, making up 1 percent of renewable generation. But as the price of photovoltaics continues to fall, the sector is growing dramatically.
Photovoltaic capacity grew by 76 percent between 2011 and 2012, according to the Solar Energy Industries Association. The areas shown in yellow above represent the top 20 percent of areas in terms of average annual solar energy potential.
Wind is second only to hydroelectric in renewable energy. It generates about 28 percent of renewable power and, with the extension of a production credit earlier this year, is expected to grow 7 percent in 2013. The areas colored orange are where wind speeds fall into the top two most productive categories, according to the National Renewable Energy Laboratory. In addition to the inland regions shown above, areas off the nation's coasts also hold great potential for capturing wind power.
Areas favorable to geothermal power are shown above in purple. Roughly 3 percent of the nation's renewable portfolio comes form harnessing earth's heat.
Sources: National Renewable Energy Laboratory, Idaho National Engineering and Environmental Laboratory, Saxum, Energy Information Administration