What is Geothermal Energy?

Geothermal comes from the Greek words geo (earth) and therme (heat). Geothermal energy is heat from deep within the earth.

Extremely hot temperatures are produced inside the Earth by the breakdown of radioactive particles. Decaying materials produce energy that can be extracted and used to produce heat and electricity.

Magma Deep in the Earth's Interior

Deep in the earth's core is melted rock called magma. When volcanoes occur, lava erupts from the Earth's surface. This lava is partly made of magma. Most magma stays way below the Earth's surface, heating rocks and water.

Some of this geothermal energy travels back up to the earth in the form of hot springs or geysers. Most of this heated water stays underground forming a geothermal reservoir.

Where is Geothermal Energy Found?

Most geothermal resources are found in the ring of fire, which travels the outer edges of the Pacific Ocean. These areas are known for earthquake and volcanic activity.

In the United States, geothermal reservoirs are found in Hawaii, California and other western states. Geothermal energy is widely used in Iceland, providing electricity and heat for homes.

Is Geothermal Energy Renewable or Non Renewable?

Heat is continuously produced by the Earth, making geothermal energy a renewable resource.

How is Geothermal Energy Used?

Geothermal energy can be used to heat homes and other buildings. It can also be used to produce electricity. To extract geothermal power, deep wells are dug to pump water or steam to the earth's surface. For more information, see How Does Geothermal Energy Work?