Re: Geothermal Energy
Geothermal energy is usable in certain geological areas but it has limitations -- rock isn't a good conductor of heat so once a well has reduced the temperature of a volume of hot rock deep underground the efficiency and the amount of recoverable energy drops off unless more heat can be transferred quickly to the well bottom. The best sites for geothermal energy have lots of fractured rock strata and hot underground water that can be extracted while more hot water flows towards the well bottom. That sort of geology is a lot rarer than simply large volumes of hot dry basalt a couple of kilometres down.
Iceland had a magma-powered geothermal well at one time, they were drilling a regular hot-water geothermal well and hit lava instead. Oops. After retooling they got it to work somewhat -- the lava ate the drillhead and damaged the piping, not surprisingly. It's been shut down since then, IIRC. Maintenance and operating costs were the problem, the lava pool the drill string ran into produced highly alkaline soluble salts and gases and other crud that chewed up the heat exchangers at the surface, I think.
Biting the hand that feeds IT
