Deep holes are expensive. Oil drilling, the cheapest kind of drilling since it's very common and in soft rock, costs $100-$200 per vertical foot.* A 2 km hole w

Deep holes are expensive. Oil drilling, the cheapest kind of drilling since it's very common and in soft rock, costs $100-$200 per vertical foot.* A 2 km hole would cost $650,000 - $1.3M. It would not be economical to do this for one house. Then there are operating costs: operating a power plant on the surface is very likely to be cheaper than operating one underground, and temperature difference is bigger. All in all, a traditional geothermal plant (utility scale, at the surface) looks like that for good reasons. *https://www.oilgasequity.com/resources/drilling-completion-facts/ https://www.oilgasequity.com/resources/drilling-completion-f...