Electricity Education - Geothermal
What is Geothermal Energy?
Geothermal energy technologies use the heat of the earth for direct-use applications, geothermal heat pumps, and electrical power production.
In the US, most geothermal resources are concentrated in the West, but geothermal heat pumps can be used nearly anywhere.
Geothermal energy is clean and sustainable.
Resources of geothermal energy range from the shallow ground to hot water and hot rock found a few miles beneath the Earth's surface, and down even deeper to the extremely high temperatures of molten rock called magma.
In the US, most geothermal reservoirs of hot water are located in the western states, Alaska, and Hawaii.
Some geothermal power plants use the steam from a reservoir to power a turbine/generator, while others use the hot water to boil a working fluid that vaporizes and then turns a turbine.
Direct Use: Geothermal hot water near the Earth's surface can be used directly for heating buildings and as a heat supply for a variety of commercial and industrial uses. Geothermal direct use is particularly favored for greenhouses and aquaculture.
Geothermal or Ground-source Heat Pumps: Use the relatively constant temperature of soil or surface water as a heat source and sink for a heat pump, which provides heating and cooling for buildings.
Electricity Production: Underground reservoirs of hot water or steam, heated by an upwelling of magma, can be tapped for electrical power production.
Issues in Geothermal Energy
Environment: Geothermal technologies release little or no pollution into the air. Geothermal power production produces much lower air emissions than conventional energy technologies.
Resources: In the United States, geothermal resources are concentrated in the West, although low-temperature resources can also be found in the rest of the country. Geothermal heat pumps can be used nearly anywhere.