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12.14: Geothermal Power

Difficulty Level: At Grade Created by: CK-12
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How could geothermal energy be used just about anywhere?

Geothermal energy comes from heat deep below the surface of the Earth. That heat may come to the surface naturally or it may be available through drilling. Nothing must be done to the geothermal energy. It is a resource that can be used without processing.

Geothermal Energy

The heat that is used for geothermal power may come to the surface naturally as hot springs or geysers, like The Geysers in northern California. Where water does not naturally come to the surface, engineers may pump cool water into the ground. The water is heated by the hot rock and then pumped back to the surface for use. The hot water or steam from a geothermal well spins a turbine to make electricity.

Geothermal energy is clean and safe. The energy source is renewable since hot rock is found everywhere in the Earth, although in many parts of the world the hot rock is not close enough to the surface for building geothermal power plants. In some areas, geothermal power is common ( Figure below ).

A geothermal energy plant in Iceland

A geothermal energy plant in Iceland. Iceland gets about one fourth of its electricity from geothermal sources.

In the United States, California is a leader in producing geothermal energy. The largest geothermal power plant in the state is in the Geysers Geothermal Resource Area in Napa and Sonoma Counties. The source of heat is thought to be a large magma chamber lying beneath the area.

Where Earth's internal heat gets close to the surface, geothermal power is a clean source of energy. In California, The Geysers supplies energy for many nearby homes and businesses.

Find out more at http://www.kqed.org/quest/television/geothermal-heats-up .


  • Most geothermal energy being used now is in regions where hot material comes to the surface.
  • Hot rocks are everywhere below Earth's surface so geothermal energy could be used anywhere with drilling.
  • Geothermal energy is clean and does not release greenhouse gases.


Use this resource to answer the questions that follow.


  1. How does geothermal energy work?
  2. Where were geothermal plans in the past?
  3. How does dry steam geothermal work?
  4. How does a flash steam power plant work?


  1. How is geothermal energy harnessed?
  2. How would it be possible for a geothermal plant to gather energy if the hot material was not located at the surface?
  3. Why is geothermal energy becoming more popular?

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At Grade


Date Created:

Feb 24, 2012

Last Modified:

Jan 07, 2015
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