Bioenergy: Refueling the Future

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Learn more about Geothermal Energy! Visit the slide show below:

Geothermal Electricity

Geothermal electricity refers to power made using heat from the earth's core to create steam that powers turbines to create electricity. [13.1]

This method mainly incorporates the steam turbine method, but what makes geothermal electricity unique is the source of heat. Traditional steam powered generators typically burned coal as a heat source to produce steam. Burning coal releases harmful greenhouse gases and greatly harms the environment. Geothermal electricity, however, uses an endless supply of heat from the earth and emits no greenhouse gases.

How does it work?

There are three methods.

1) Dry Steam

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A pipe is connected to a reservoir deep within the earth.
Hot air rises up the pipe.
The moving air causes the turbine to rotate and generates electricity.
The steam is condensed into water.
The water flows down through another pipe back to the hot water reservoir.

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2) Hot Water/Flash Steam

Deep in the earth, high pressure keeps the extremely hot water (2200 °F) in liquid form.
The hot water is pumped up a pipe into a flash tank.
Now that the hot water (now about 360°F) is under lower pressure, it instantly turns into steam (hence flash steam).
The steam powers the turbine.
The steam condenses into water and returns back to the reservoir.

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3) Binary Cycle

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Hot water is pumped up a pipe.
The hot water pipe sits next to a separate pipe that is connected to the turbine chamber. The pipe connected to the chamber contains a fluid that has a low boiling point.
The hot water heats the fluid.
The fluid instantly turns into steam.
The steam powers the turbine and generates electricity.
The steam condenses back into liquid and goes back to the pipe to be heated again.

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