It's clean but renewable not so much in two ways: they are planning one here at a depth of 2.5 to 3km. They expect it to last 30 years before the underground ha

It's clean but renewable not so much in two ways: they are planning one here at a depth of 2.5 to 3km. They expect it to last 30 years before the underground has cooled to much to be of use. Regenerating that heat (i.e. spreading the other heat to this area) will take a few hundred years they expect. And secondly: there is a limited amount of heat available in the earth. It's a lot of heat, but there is no meaningful amount of new heat coming in so it's just as renewable as our current oil supply.