eli5: If we’re all sitting above the magma and heat in Earth’s mantle, what are the barriers to tapping that heat in each municipality to provide local affordable electricity?

Question

eli5: If we’re all sitting above the magma and heat in Earth’s mantle, what are the barriers to tapping that heat in each municipality to provide local affordable electricity?

In: 43

Answer 1

there’s functionally limitless energy down there but that doesn’t mean poking a little hole lets us have it all at once. let’s say you bore a hole that’s a few feet wide, deep enough that it’s like 500C at the bottom and you drop some kind of heat pump or something down. that generator is still only a few feet wide, it may run for a billion years but it doesn’t generate more power than if it were sitting in an oven at 500C on the surface.

those holes are wildly expensive and we would need a lot of them to pump enough energy *fast enough* to be useful.