Could the molten lava underneath the earth's crust be used as an energy source?

Question

If it was used to create steam like a nuclear reactor does

Answer 1

Indirectly, we already do! Its called geothermal, for example the Beowawe geothermal field in Lander County, Nevada has drill holes over 1,000 meters deep and it produces about 15 megawatts of clean electricity. Thats a value of over $10 million of renewable energy every year, just at one plant! There are plants in California that are much bigger. Geothermal power plants work by piping +100°C water under pressure to prevent boiling from deep wells to a turbine, and then allowing the hot water to boil or "flash" at the turbine. The steam is then condensed into water and piped back underground with injection wells to be re-heated.

Geothermal energy is also produced in Italy, Iceland, Philippines, California, New Zealand, and many other places.

For geothermal energy to be efficient, the geothermal gradient ("Q") has to be high enough to make it economically feasible and there has to be an electrical load somewhere close by. Not every place on earth is suitable for that.

Ground source geothermal systems are also quite common in North America, and have a pay-back time of 7-10 years. Their real advantage is that they can produce cooling and heating for most homes.

Here are some links for more info:

http://www1.eere.energy.gov/geothermal/

http://www.nevadageothermal.com/s/Home.asp

http://www.geoexchange.org/

http://www.unocal.com/geopower/index.htm...

http://www.smu.edu/geothermal/

http://www.caithnessenergy.com/geothermal.html

http://www.smu.edu/geothermal

To actually tap into the earth's molten mantle would require drill holes deeper than we have the technology for, and also heat resistant heat exchange equipment that we just don't have the materials for.

Answer 2

Yes, this is done in a few places like Iceland. I suppose it could be done in Hawaii or perhaps at Yellowstone if it wasn't a park. However, in most areas the magma is too far below ground to be accessible. You are correct though that where the heat is accessible you could produce steam to drive a turbine generator.

Answer 3

Yes, but quite hard to tap from the surface. The crust is generally 25 miles thick.
Differences in temperature are how to get energy or get rid of energy.

Answer 4

Yes, it could..
There are several geothermal power plants in operation..
Most of them are located where volcanic heat is found
near the surface such as in Iceland...