OK it’s not a shortage, just some people like to think it is. But this is about the future of energy. People talk about the holy grail of fusion, which may just require a mining operation on the moon for He3 for clean fuel and theoretical physics to have a controlled fusion reaction that extracts energy, but why can’t we just harness the thermal energy of the earth? Yes I know we have geothermal plants right now, but that is limited to certain areas of the world, but what about digging (drilling) down basically anywhere on the globe, eventually you have to hit something very hot and big. It would seem like we are just sitting on perhaps millions of years of energy, which seems at least in theory easier to harness then fusion.
Geothermal energy is essentially a steam engine. You pump water down into hot rocks, the water boils, which runs a turbine, which produces electricity.
But it takes energy to pump water down to the hot rocks and pump the steam back up. If the hot rocks are deep enough then the energy you can extract from the hot rocks is smaller than the energy required to pump the steam.
Plus it takes a lot of work to drill a really deep hole. You’d have to look at the cost of drilling a mile deep hole and compare that to the energy produced over the lifetime of the hole. If drilling the hole costs a million dollars, and you get $10,000 worth of energy per year, then it takes 100 years for your investment to break even.