How to Find Hotter Rock Formations to Heat a Building

Pumping cold water down one side of a U-shaped passage produces boiling hot water out the other. All we need to pay for is the electricity to run the pump that circulates water through the underground passage. We can heat a large industrial building almost for free this way once all the holes have been drilled. But drilling those holes through solid rock costs a lot of money, and it will take quite a few years to break even.