What Is Geothermal Energy?

Using the heat of our planet to power our lives.

The center of the Earth is 10,800°F. That's the same as the surface of the sun!

Geothermal energy is heat that comes from below the Earth’s surface. Many places around the world, such as geysers and volcanoes, release geothermal energy naturally, dispelling heat into the air. Using those same principles, we can harness geothermal energy to generate electricity to power homes and businesses.

When we dig beneath the surface of the Earth, things get hot. Really hot. The further down we dig, the hotter it gets. If we could reach the center of the Earth, we’d encounter temperatures somewhere in the range of 10,800°F. That’s the kind of heat you’d experience if you were standing on the surface of the sun.

But we don’t have to dig that far down to get an endless supply of heat to generate electricity.

Watch this quick 2-minute video about how geothermal energy works:

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How geothermal energy works:

If you could crack the Earth in half and take a look at its inside, you’d find layers of rock, magma and metals that look a bit like layers of an onion. As these substances continue to interact with each other and naturally decay, they produce incredible amounts of heat. That’s why we call it geothermal energy: Geothermal is Greek for “heat from the Earth.”


We locate geothermal energy resources that are close to the Earth’s surface and drill down to capture geothermal energy as heat.


Geothermal energy rises through a directed pathway in the form of dry steam or hot water that’s turned into steam.


The hot steam rises to the surface and pushes a turbine, rotating a generator.


The generator produces electricity and sends it to the electric grid, which distributes the electricity to homes and businesses.


Is geothermal energy renewable?

Yes. Due to the constant pressure and the natural decay of radioactive particles that are happening to the rock underneath the Earth’s surface, our planet is constantly producing geothermal energy in the form of heat. Long story short — as long as there’s a planet Earth, there will be geothermal energy. That makes geothermal energy 100% renewable.


Where we use geothermal energy:

Because geothermal energy is located beneath the Earth’s surface, we build geothermal energy plants in locations where the surface layer is thinnest. In the United States, the majority of our geothermal energy is sourced in states like Hawaii and California, which are full of naturally occurring geothermal vents such as geysers, hot springs and volcanoes.


How we use geothermal energy:

Today, the U.S. Department of Energy is funding research and development of applications beyond electricity, such as natural heating and cooling for buildings. These applications will help us expand the reach of geothermal energy in the U.S., empowering us to move further away from more polluting energy sources like fossil fuels.

The pros of geothermal energy:

Geothermal energy is a reliable form of renewable energy that doesn’t depend on weather conditions.
Cutting Edge
The United States leads the way in geothermal power generation, with geothermal power plants in seven states and a capacity of more than 3.6 gigawatts.*
Geothermal energy can be used for more than just electricity generation; some of its current applications include direct-use heating for buildings, regulating water temperatures at fish farms, and pasteurizing milk.
Geothermal energy is a growing market, with new research allowing us to be better at harnessing its power.

We make it simple to choose 100% clean electricity made from renewable sources like wind energy. Let’s build a cleaner, greener tomorrow together.

*U.S. Department of Energy

This page is for general educational purposes only.

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