Oh, there are nice sites in Europe that aren't listed there. Old mines have been discussed, for example. I'm guessing that the big problem today is that there

Oh, there are nice sites in Europe that aren't listed there. Old mines have been discussed, for example. I'm guessing that the big problem today is that there isn't a large price difference between night and day. I'm sure you can find an old mine with enough land to build a ground-level water reservoir above it, but you can't buy nearly free solar power at noon and sell expensive power at night. Once there's enough solar/wind power generation capability to cover its needs on average days, there'll be cheap power to be had for anyone who who can use power only when the sun is shining brightly or the wind blowing strongly. At that point the economics of these schemes may make sense, and it may be worth someone's while to try to solve the practical/legal problems.