I read in the Orange County Register today that President Obama approved an $8 billion project to build a nuclear power station. The article said we haven’t built one in 30 years. I’m not a scientist, but I know that the power plants basically generate power by creating steam and turning a turbine to create electricity. Can we dig deep enough into the earth to boil water?
Technically yes, practically no.
Geothermal energy is only efficient in areas with a high geothermal gradient, which usually means places with thin crust. There are only a few places on Earth where the crust is thin enough to reach that temperature within a reasonable depth, say 2000-3000 meters. Beyond that, the cost of drilling is prohibitively high.
You need to have a body of rock, preferably with a reservoir of hot water, at a temperature greater than 100Â°C. You pump the water to surface while keeping it under pressure, and then release the pressure in a turbine in a process called flashing. Then you condense the steam and pump the hot water back under ground into the reservoir to start the cycle again. Unfortunately, in many geothermal reservoirs, extracting the heat energy from the reservoir will cool the reservoir.
Thanks goodness Obama finally saw the light (no pun intended) with approving the nuclear plant, as nuclear energy is the ONLY source of energy that can produce large amounts of firm energy without greenhouse gases with today’s technology.