Two issues with hydro: 1) Most of the obvious places have dams already and building new dams is a combination of expensive and disruptive. 2) Droughts and wat

Two issues with hydro: 1) Most of the obvious places have dams already and building new dams is a combination of expensive and disruptive. 2) Droughts and water shortages make the existing hydro plants less productive. E.g. the hoover dam has some issues with that in recent years.