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Geothermal Energy
Geothermal energy is heat inside the earth.
What is Geothermal?
Geothermal comes from the Greek words geo (earth)
and therme (heat).
Thus, geothermal energy means heat inside the
earth.
The Earth Is Made of Layers
At the center is a core of iron.
Around that is an outer core of iron and rock so hot the rock is melted. The liquid rock is called magma.
The next layer is a mixture of rock and magma called the mantle.
The shell of the earth – with the oceans and mountains - is called the crust.
The Earth Is Made of Layers
Heat Inside the Earth
• The inside of the earth is very hot.
• Sometimes this heat comes near the surface in the form of magma.
• We can use this heat to warm our houses and make electricity.
How Do We Use Geothermal Energy?
People have used geothermal energy for heating and bathing for thousands of years.
Hot springs are pools of water that are warmed by underground springs, so they are always hot.
• Today, power plants use steam from geothermal wells to make electricity.
• The steam is used to spin turbines.
• The turbines spin magnets in coils of copper wire to make electricity.
How Do We Use Geothermal Energy?
• Even though geothermal energy is underground, there are visible features on the surface.
• These include volcanoes, hot springs, and geysers.
Where Can We Find Geothermal Energy?
A volcano means hot magma is near the surface.
Where Can We Find Geothermal Energy?
The most active geothermal resources are usually found where earthquakes and volcanoes are
concentrated.
Where Can We Find Geothermal Energy?
Most geothermal activity occurs in an area called the Ring of Fire.
Most geothermal plants in the United States are located in the western half of the country.
Geothermal Energy in the United States
Geothermal energy produces only a small percentage of U.S. electricity.
Today, it produces about 15 billion kilowatt-hours, or less than one percent of the electricity produced in this country.
The hot water we use will be replaced by rain.
The heat inside the earth will always be there.
More heat is made every day in the Earth’s core.
We won’t run out of geothermal energy!
Geothermal Energy is Renewable.
Geothermal Energy is Clean.
No fuel is burned, so there is no air pollution.
The steam is turned into water and put back into the earth.
Geothermal energy is cheap – new power plants can make electricity for about the same as coal power plants.
Geothermal Energy is Cheap.
Geothermal plants don’t transport fuel – they sit on top of their fuel source.
Geothermal power plants have been built in deserts, in the middle of crops, and in mountain forests!
Geothermal Energy doesn’t have to be transported.
Discussion Questions
• With all the advantages of geothermal power, why don’t we use geothermal power more in the United States?
• What are some disadvantages to using geothermal power?
