Geothermal Energy

The earth's core is about 4,000 degrees Celsius. This tremendous amount of heat is a source of geothermal energy. Volcanoes and geysers are nature’s method for releasing heat and pressure from deep layers of the earth. Another form of geothermal energy comes from the sun also warming earth closer to the surface.

What is geothermal energy?

Geothermal energy comes from the heat stored in the earth’s core and heat from the sun warming the earth. The word geothermal originates from the Greek words geo (earth) and therme (heat). V

How does geothermal energy work?

Geothermal energy is generated in the earth's core, about 4,000 miles below the surface. A second form of geothermal energy is from the sun's heat on the ground beneath our feet. The ground is a good insulator and stores the heat as energy. Pipes are run through a large area several feet underground. Water is heated as it passes through these pipes. New drilling technologies are being researched and developed to capture the heat in deeper areas.

History of geothermal

The history of geothermal power can be traced back to over 10,000 years ago to the American Paleo-Indians at their settlement in hot springs used the springs for heating and bathing. It has been used for space heating and bathing since ancient roman times, but is now better known for generating electricity. See timeline.

Uses for geothermal energy

At low to medium temperatures, geothermal energy can be used directly to heat buildings, grow crops, and to melt snow on sidewalks. At high temperatures, the energy produced from these reservoirs can spin a turbine to generate electricity. Stable temperatures near the surface of the earth and also be used to heat and cool buildings.

Demand for geothermal energy

There are 24 countries around the world that use geothermal power in some capacity. The countries currently producing the most electricity from geothermal reservoirs include the US, New Zealand, Italy, Iceland, Mexico, the Philippines, Indonesia, and Japan. Because of the initial costs and need for space, geothermal energy is not widely used.

Geothermal pros and cons

Pros

• Safe
• Clean - produces no water or air pollution
• Efficient
• Abundant supply
• Relatively free, once the initial investment is paid
  

Cons

• Start-up costs are expensive
• Requires large piece of land to start
• Best supplies limited to certain areas of the world

More geothermal resources

Energy Kids Page
Illustrates how geothermal energy works, where it is found, and how it is used.

Geothermal Technologies Program Describes the US Department of Energy (DOE) geothermal energy program. Includes facts and news.

Facts about Geothermal Energy
Presents an Australian perspective on geothermal energy.

Geothermal Basics
U.S. Department of Energy: Energy Efficiency and Renewable Energy
Learn about geothermal energy and enhanced geothermal systems. Learn about geothermal development history and look up geothermal terms in the glossary.

Geothermal Energy Facts Geothermal Education Office
An introduction to geothermal energy including its definition, how it works, how it is used, and where it is found.

Geothermal Heat Pumps
U.S. Department of Energy: Energy Efficiency and Renewable Energy
Explains how a geothermal heat pump works with links to more in-depth information.

What is a Ground Source Heat Pump? International Ground Source Heat Pump Association
Describes what a ground source heat pump is and how it works.