For each location, figure out what the plausible locations and sizes for hydro dams, pumped hydro, and geothermal are, and add to the data set
Update UI for building that type of facility so that 1. You can see what slots are still available, and 2. You can only build in one of those slots/not freeform sizing (well, you can build smaller than the slot max, but not bigger)
Selling a facility on a slot should NOT free it up again, because that facility will continue to operate. Far future feature, we could add a new option when selling, to pay to demolish it instead of earning money to sell it, which would free up that slot.
Inspiration https://www.canarymedia.com/articles/geothermal/geothermal-is-the-hottest-thing-in-clean-energy-heres-why?_hsmi=299632946&utm_source=pocket_saves