Continuing in our Alternative Energy Series, we bring you Part 2, a look at recent developments in geothermal energy. If you remember, Part 1 focused on kite-like wind turbines that would stay suspended high up in the jet stream, where wind speeds are constant and very strong.
Ok, geothermal is an old idea, and is commonly used for heating in volcanic areas like Korea and Iceland. In those places though, the heat is very close to the surface, and is easy to tap. But really, no matter where you are in the earth, it is rarely more than about 2 to 5 miles down before it starts to get very hot. Previous limitations in technology made those 2 to 5 miles prohibitively expensive to drill into, but now, with technology advancing and costs dropping, it is not only possible, but profitable.
The idea is simple: Drill a hole into the earth that goes down a few miles. It’s very hot down there. Now put a lot of water down the hole. When the water comes back, it is very, very hot. The steam drives a turbine, which generates electricity. Once the steam has passed through the turbine and condensed, it can be sent back into the hole, all in a closed system. No fuel needed, no emissions are produced, the energy supply is constant, and the source is unlimited. Best of all, we have the technology to start building these things right now. Now that's pretty freaking awesome.
Really lame diagram made in Paint:
Interest has been renewed in geothermal energy since a recent MIT report that came out last autumn, and demonstrated that not only was geothermal energy possible in non-volcanic regions of the world, but most areas areas could support geothermal power plants that could become profitable within about 5 to 10 years of completion, at a cost as little as a few million dollars per bore hole. Keep in mind nuclear power plants typically cost billions, not millions. This isn't futurism; the technology is available right now.
New Scientist Summary
Interview with lead MIT researcher (podcast for 26 Jan)
Original MIT research study (very long)