Geothermal energy may be most efficient in areas with high underground temperatures – “hot spots” with active or geologically young volcanoes. For example, the Pacific Rim or the Ring of Fire, located along Alaska, California, and Oregon, has many hot spots. The United States has the largest installed geothermal capacity in the world. Nevada holds the majority of the country’s geothermal capacity and is continuing to develop new projects.
Geothermal power potential varies across the world based on the seismic activity that occurs under the earth’s surface and its geology. Regions with milder heat can be also be used, primarily for direct heating purposes. This heat energy is normally extracted from shallower depths. Dry rock formations between four to ten kilometers below the surface can also provide vast amounts of heat energy. There are various technologies that have been developed to extract geothermal energy.