Energy and water have a symbiotic relationship. Power industry demands on water for generating hydro power and cooling traditional thermoelectric systems are significant. In fact, power generation is the largest single use of water in the United States. In 2000, the U.S. Geological Survey estimated that total U.S. saline and freshwater withdrawals (the amount of water removed by all users from a lake, river, reservior, or similar body of water) were 408 billion gallons per day (bgal/d). Water withdrawn for thermal power generation accounted for 195 bgal/d, or approximately 48 percent of total withdrawals.
Power generation accounted for 39 percent of freshwater withdrawals, about the same as for irrigation. But the power sector’s portion of freshwater actually consumed in the United States is small—3 percent—compared to irrigation’s share (81 percent).
The most important confluence of the energy/water relationship is where those cooling requirements meet declining water availability, increasing competition with other water users, and tightening criteria on water discharges.
Indeed, water supply or discharge constraints have already led to longterm and short-term plant shut-downs, as well as severe limitations on generation technology, cooling technology, and siting choices for new plants in many states. Allan R. Hoffman, a senior analyst at the Department of Energy (DOE) cites (among other examples) Georgia Power’s losing bid to draw water from the Chattahooche River and the Environmental Protection Agency’s order to a Massachusetts power plant to reduce water withdrawals. In 2002, points out Benjamin Sovacool in an April 2009 article in Energy Law Journal, lawmakers in Idaho ruled that five coal- and gas-fired power plants be denied water rights for cooling because the plants would deplete freshwater for drinking and irrigation. In Nevada, a big reason for closing the 1,580 megawatt (MW) coal-fired Mohave Generation Station was lack of groundwater. In the U.S. Supreme Court, the state of South Carolina is suing North Carolina over water use, saying the upriver state takes more than its fair share of water from the Catawba River—and South Carolina recently denied a water quality certification permit for Duke Power, which seeks the relicensing of its hydro project on the river. Water issues have complicated construction or operation of plants in at least 14 states, according to Sovacool.