The United States possesses vast underground stores of heat whose full potential has yet to be realized. The Earth’s interior reaches temperatures greater than 4,000°C (>7,200°F), and this geothermal energy flows continuously to the surface. The energy content of domestic geothermal resources to a depth of 3 km (~2 mile) is estimated to be 3 million quads, equivalent to a 30,000-year supply of energy at our current rate for the United States! While the entire resource base cannot be recovered, the recovery of even a very small percentage of this heat would make a large difference to the nation’s energy supplies. New low-temperature electric generation technology may greatly expand the geothermal resources that can be developed economically today.
Geothermal resources could meet a substantial portion of the nation’s energy needs in the 21st century. In fact, when including geothermal heat pumps (GHPs), geothermal energy is used in all 50 U.S. states today. The U.S. Department of Energy’s (DOE) Geothermal Technologies Program seeks to make geothermal energy the nation’s environmentally preferred baseload energy alternative. The Program’s mission is to work in partnership with U.S. industry to establish geothermal energy as an economically competitive contributor to the nation’s energy supply.
What is the total potential accessible resource in the United States, and, given favorable circumstances and using existing practices with improved technology, and with institutional issues solved, how much of the resource is developable by 2015, 2025, and 2050? Resource types include hydrothermal, deep geothermal systems, co-produced, geopressured, direct use, and GHPs.