There are other environmental and practical concerns with hydro. Building the required reservoir destroys a lot of habitat. You can't site them just anywhere yo

There are other environmental and practical concerns with hydro. Building the required reservoir destroys a lot of habitat. You can't site them just anywhere you want, but are beholden to local topography. Power production competes with other human and natural uses for limited water resources. Dams make a heck of a target for an enemy military as well. Hydro is great reliable simple baseload power, but not perfect.