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geothermal power

Miles below your feet, scorching temperatures can get hot enough to melt rock. In some places, water heated deep underground rises to the surface in hot springs and geysers. Earth's internal heat, called geothermal power, can be an important energy source. In some places, steam released from underground is used to turn turbines, creating electricity.

Stats

Definition: heat energy from within Earth
Carbon Dioxide Emissions: very light (but does cause water and air pollution)
Cost: expensive (vs. other energy sources)
Location: near above ground and underground hot spots, where magma rises to Earth's surface.
Current Use: less than 0.5% of energy in the U.S.
Cool Fact: Geothermal plants release under 1% of the carbon dioxide released by coal-fired power plants.

Stumper

Geothermal plants don't have to be located near hot springs or geysers. Geothermal power can also be tapped by:

building geothermal plants deep underground

heating above-ground water with electric coils

injecting water into hot spots deep underground

Correct!

In these geothermal systems, engineers drill down to rocks deep underground where temperatures are about 400 degree Fahrenheit. Then they inject cold water and capture the steam released when the water is heated.

Stumper

Today, geothermal energy heats 90% of homes in Iceland. This is no surprise, since Iceland is a geologic hot spot, home to many:

volcanoes

geysers

both of these

Correct!

Iceland is located where two tectonic plates (giant pieces of Earth's crust) are slowly spreading apart. Magma rising up between the plates produces the volcanoes and geysers that are so common to the region.

Fact or Fiction

There is a limited supply of geothermal energy within Earth.

Fact

Fiction

Geothermal energy is a renewable resource. That means it will not run out. It is also consistent. It does not change from season to season or year to year.

Fact or Fiction

Most scientists think that geothermal power could provide much of the electricity needed by the United States by 2050.

Fact

Fiction

In reality, experts think advanced geothermal power plants may provide the U.S. with about 5% of its electricity by 2050.

Image credits: main image, courtesy DOE/NREL / Pacific Gas & Electric.

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