Calculations of coal, oil, and natural gas reserves properly draw great interest, and even demagoguery in the case of natural gas. But interest in the calculations of the energy potential of renewable energy has been less. That's a mistake.
The National Renewable Energy Laboratory this month released its latest estimate for renewable energy potential, including state maps. See http://www.nrel.gov/news/press/2012/1948.html. The document is well worth reading.
My quick addition of the energy potential found for the various renewable energy technologies led to the total of 212,368 gigawatts. That is an extraordinary number or about 212 times all the current installed capacity within the USA.
Solar PV and Concentrated Solar Power accounted for 193,000 gigawatts or a bit more than 90% of the total.
But even if the solar resource is subtracted, the remaining hydro, biomass, wind, and geothermal energy potential is the about 25 times the current installed generating capacity within the USA.
Between the combined energy potential of renewable energy as well as coal, oil, gas, and nuclear, Uncle Sam has no shortage of energy and endless ways to achieve energy independence.