Obviously not ever single place is suitable but it's being done now in Finland and Slovenia. The holes are 5km deep and the bottom 2km are filled before its cap

Obviously not ever single place is suitable but it's being done now in Finland and Slovenia. The holes are 5km deep and the bottom 2km are filled before its capped. This is well below the water table in most places. A DOE analysis found that every single state in the US has suitable sites.