Comment by phreeza

I am always a bit bearish on geothermal, because the energy flow through the earths crust is just so damn low. Per surface area, it is about 3 orders of magnitude less than solar irradiation, which means that the circumstances in which it really makes sense to exploit geothermal are those where you can effectively harvest flows from a much larger area, most likely due to convection of water or magma. My understanding is that it will never make sense for e.g. every house in a suburban setting to have their own heat probe and pull energy from that, they will be competing with their neighbors and effective energy gained will be negligible.