36. Geothermal or “Geothermal”?
Geothermal or “Geothermal”? To the average non-scientist, especially those of us who grew up on cartoons and oversimplified grade-school graphics of the earth’s layers, “geothermal” heat seems like the logical answer to everyone’s energy needs. Why not just send a pipe down to that molten layer, pull up that lava, and get the geothermal rebate down to Augusta? OK, good news and bad news. True geothermal is really hot, but not really available. False geothermal is really available but not real hot! Here, we want to try to remove some confusion between ground source heat pumps (often misleadingly referred to as “geothermal”) and true geothermal, where heat is extracted from extremely hot ground and used for heat or electricity. True geothermal heat is a combination of radioactivity in the earth's crust (80%) and heat flowing up from the core and mantle of the earth (20%). Over most of the earth, in order to reach rock that is warm enough to directly heat our homes, we need to...