What is Geothermal Energy?
Geothermal energy is the heat contained within the earth — a clean, reliable, and renewable energy. Geothermal power plants produce no smoke, uses very little land compared to conventional energy resources and can share the land with wildlife and farms. It can be used as an energy-efficient heating and cooling alternative and can generate vast electric power in certain regions of the United States.
Geothermal technologies use the clean, sustainable heat from the Earth. Geothermal resources include the heat retained in shallow ground and in hot water and rock found a few miles beneath the Earth's surface. Extremely high-temperature molten rock called magma located deep in the Earth generates this subterranean heat. Geothermal wells are sealed with steel casing, which is cemented to the sides of the well along their length. These casings protect ground water aquifers which are a source of drinking water.
Shallow ground—the upper 10 feet of the Earth's surface—maintains a nearly constant temperature of 50°-60°F (10°-16°C). This heat can be tapped to provide heating and cooling for homes and buildings using geothermal heat pumps. Deeper and warmer geothermal reservoirs found near the Ring of Fire can be tapped directly for heat or used via advanced technologies for heat and electricity generation.