Geothermal generation is the renewable energy resource that gets the least attention, but it is the little train that can. Indeed, in 2012, though it had about 50% of the installed capacity of solar in the USA, it produced about twice the electricity of solar.
Geothermal capacity continues to grow, up 5% or 147 mw in 2012, and now totals 3,386 mw. Of that total, 1,000 MW was added in last decade. California with 2,732 megawatts and Nevada with 517 megawatts dominate national geothermal power production.
Interestingly, the nation's geothermal capacity produced in 2012 16.7 million megawatt-hours versus 4.3 million megawatt-hours for solar, according to the EIA. http://www.eia.gov/electricity/monthly/. Geothermal produces more electricity than solar, even though it has about half of the total capacity of solar, because it has high capacity factors.
Even after adjusting EIA data, by adding production from the substantial amount of distributed solar, geothermal produced in 2012 about twice as much electricity as the nation's solar systems. Solar, however, will pass geothermal production in the next 4 years, given its rapid rate of deployment.