Geothermal Energy
Have you ever seen pictures of a volcano or a geyser? If so, then you’ve seen geothermal energy in action!
"Geo" means "from the earth," and "thermal" means "heat," so this type of energy is found under the earth. The hot lava from a volcano and the hot steam from a geyser both come from underground heat – and we can use that same type of heat in our homes.
Here’s how it works: about four feet underground, the temperature of the earth stays the same all year long - about 55 degrees.
A geothermal heating system uses pipes buried more than four feet deep in the earth.
View a photo of underground geothermal pipes
The system pumps a liquid through the pipes to absorb the heat and brings it back indoors. A device called a "heat exchanger" takes the heat from the liquid and uses it to heat the air inside the home.
View a photo of a geothermal heat exchanger and indoor pipes
A geothermal system can cool your house during the summer, too! It just works in reverse, absorbing the heat from the air inside your home and moves it back into the earth.
A geothermal heater is also very energy-efficient. Almost none of the energy used is wasted, so it helps keep heating bills very low during the winter.
Geothermal at school
Schools all over the Midwest are using geothermal energy for heating and air conditioning. Geothermal is great for schools because it uses a lot less energy than other types of heating and cooling equipment.
Kids at Table Mound Elementary School in Dubuque, Iowa, learned all about geothermal as workers dug wells in their playground. You can read what they learned and view some photos they took:
Geothermal at Table Mound Elementary School[scroll down to the “Geothermal” section at the bottom of the page
Electricity from under the earth
We can also use geothermal energy to make electricity. A geothermal power plant works by tapping into steam or hot water reservoirs underground; the heat is used to drive an electrical generator.
Most geothermal plants are located in the western United States, where hot water reservoirs are common. The Geysers power plant in northern California is the world’s largest geothermal power plant, producing enough electricity to light up more than 22,000 homes.
View a photo of The Geysers geothermal power plant
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Want to learn more?
If you need more information about geothermal energy, visit these Web sites:
Geothermal: Energy from the Earth's Core by the U.S. Department of Energy
The GeoExchange movie by the Geothermal Heat Pump Consortium
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Links for teachers and parents:
Alliant Energy Geothermal
Geothermal Technologies Program by the National Renewable Energy Labs
Office of Geothermal Technologies by the U.S. Department of Energy
Savings from the Ground Up by the Geothermal Heat Pump Consortium
Energy Conservation lesson plans
More resources for teachers and parents
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