|Hydropower, we are told, is clean, renewable, safe, and abundant.
Well, it is clean, though somewhat damaging to the environment.
(The US EPA no longer favors hydropower.)
Hydropower is renewable in the sense that you get rain every year to fill the dams. (In some years there is more rain than in others.)
Safe? Dams do burst, though rarely.
Abundant? All of the big sites are already in use in all advanced and in most second-world countries. By 1985, nuclear power was responsible for as much electrical energy in the world as hydro, and presently generates about 30% more energy every year than hydro.