Some applications of geothermal energy use the Earth's temperatures near the surface, while others require drilling miles into the Earth. The three main uses of geothermal energy are:
Direct use and district heating systems use hot water from springs or reservoirs near the surface.
Electricity generation power plants require water or steam at very high temperature (300° to 700°F). Geothermal power plants are generally built where geothermal reservoirs are located within a mile or two of the surface.
Geothermal heat pumps use stable ground or water temperatures near the Earth's surface to control building temperatures above ground