Geothermal energy is derived by harnessing the heat from the earth’s core, some 4,000 miles deep, where temperatures can reach 9,000 degrees F and higher. This heat flows outward and upward through the surrounding layers of rock, sometimes actually melting the rock to magma.
This magma typically remains below the earth’s crust, heating nearby rock and water to near 700 degrees F. While some of this hot water reaches the earth’s surface as hot springs or geysers, most stays trapped deep underground.
Geothermal power plants make electricity by using wells to pipe this underground steam and hot water to the surface, where it is converted into electricity.
Not only is geothermal energy clean, it is also the most reliable of all electricity sources. Geothermal plants regularly operate at 90 percent or more of their rated capacity year-round.