The River Network in a new study Burning Our Rivers: The Water Footprint of Electricity documents how coal, natural gas, and nuclear use vastly more water than wind and photovoltaic solar, and that most of this water comes from rivers.
Electricity production by coal, nuclear and natural gas power plants is the fastest-growing use of freshwater in the U.S., accounting for more than about ½ of all fresh, surface water withdrawals from rivers.
Even worse, fossil-fuel plants put heated, polluted water back into the rivers creating algae blooms and killing fish. This unthinking, reckless use of water needs to end, most especially in water-stressed areas like the American Southwest. The River Network suggests investing in more efficient water-cooling technologies and wind and photovoltaic solar.
They note that some forms of renewable energy use more water than coal and nuclear, specifically biofuels from irrigated crops and solar thermal, and should be avoided. Indeed, one of the dirty little secrets about cellulosic biofuel is that it uses substantial amounts of water, and I believe that algae biofuel is even worse. Solar thermal focuses the heat of the sun onto a central tower to power steam turbines, generally in deseerts. Thus it uses large amounts of water in precisely thise areas where water is scarce. 10% of our gasoline is now ethanol and most of that comes from irrigated crops. This ethanol production is obviously not a source of electricity but is still uses enormous amounts of water.
But wind and photovoltaic solar use practically no water and for an y number of reasons inclusing water usage, is the future for energy in the country.