California contains, by far, the greatest geothermal generating capacity in the United States, and with the possible exception of Alaska, the greatest potential for the development of additional resources. California has nearly 2/3 of the US geothermal electrical installed capacity of over 3,000 MW. Depending on assumptions regarding reservoir characteristics and future market conditions, additional resources of between 2,000 and 10,000 MWe might be developed (see e.g., Muffler, 1979).
Additional publication details
USGS Numbered Series
Distribution of high-temperature (>150 °C) geothermal resources in California
U.S. Geological Survey
Geology, Minerals, Energy and Geophysics Science Center