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Q & A: Geothermal energy

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Most recent answer: 10/22/2007
Q:
Can we utilize the heat below earth's mantle layers to generate electricity? If reaching those layers is difficult, can we put the heat carrier via volcanos?
- David (age 16)
China
A:
Good idea! We already do this, and perhaps should do it more. It's called "geothermal" power generation. Water is injected into the ground in a spot where the rock near the surface is hot enough to boil water. Places like Yellowstone, some places in California and Italy and elsewhere have hot spots close to the surface where this can work. The steam is then captured on its way out and turns turbines.

We also use the heat of the ground to help with our energy needs even without generating electricity. Not too far under the surface, the temperature of the ground is remarkably stable, year round. Heat exchangers (heat pumps) can use this huge heat reservoir in the winter to save on fuel which otherwise would be needed to heat a house. In the summer, deep underground is colder than the outside air and thus exchanging heat with it in an air conditioner is more efficient than trying to heat up the already hot air.

Tom

(published on 10/22/2007)

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