They are cheap to build and maintain, especially in the Midwest...lot of hills there, if a bump in the road is considered a "hill."
They used to be “cheap to build and maintain”.
Now the EPA and environmental groups make it virtually impossible to site a new power dam.
And the US government is systematically working to dismantle existing dams in the name of the environment.
Hydro is as clean a power as you can get. Next is hydrothermal but the available sites are very few. Then comes Nuclear and the enviro-wackos are against that too.
They won’t be happy until we all are sitting in the dark and shivering in the cold.