What are good things of hydropower?

Hydropower, when compared to other sources of alternative energy, holds many advantages. It is one of the most environmentally friendly of all electricity power sources (However, its environmental impact is considered to be more intrusive than benign). They also have the lowest operating cost of any electricity source (recommend go to wvic.com/hydrofacts). Most hydroelectric dams have very long lifetimes and permit electrical generating output to be quickly varied. Nevertheless, as a disadvantage, they require large capital investments and a time scale of years to build.