This graph compares the life-cycle water footprint of electricity sources in gal/MWh. Hydropower, if included, would dwarf the others at 440,000 gal/MWh used and 9,000 gal/MWh consumed by evaporation.
By Erin Weaver
The average U.S. household indirectly requires nearly 40,000 gallons of water per month for the production of its electricity—five times more than its direct residential use. A new report from the River Network, “Burning Our Rivers: The Water Footprint of Electricity,” tallies the massive amounts of water used to produce electricity in the United States at approximately 42 gal/kWh, much of it for cooling purposes in thermoelectric generation in coal or nuclear plants.
More than half of fresh surface water withdrawn goes to electricity production; some is polluted, some is evaporated, and most of it is warmed, altering ecosystems and killing aquatic life. Coal, including mining, is the biggest offender, followed by nuclear power: two nuclear power plants in Georgia, for example, use more water than all the residents of Atlanta, Augusta, and Savannah combined.
Natural gas, which this year generated as much electricity as coal in the U.S., also has a significant water footprint—even though the report does not address hydraulic fracturing (“fracking”) due to lack of data. Hydropower, despite its green reputation, causes about 9 billion gallons a day to evaporate from reservoir surfaces. The authors conclude that, in addition to shifting to virtually zero-water-footprint technologies like wind and solar, modernizing “once-through” cooling systems in existing power plants could save more water than all U.S. residential water conservation programs combined. For more information, see www.rivernetwork.org.