Thermoelectric Power Water Use

Production of electrical power results in one of the largest uses of water in the United States and worldwide. Water for thermoelectric power is used in generating electricity with steam-driven turbine generators. In 2010, about 161,000 million gallons of water each day (Mgal/d) were used to produce electricity (excluding hydroelectric power). Surface water was the source for more than 99 percent of total thermoelectric-power withdrawals. In coastal areas, the use of saline water instead of freshwater expands the overall available water supply. Thermoelectric-power withdrawals accounted for 45 percent of total water use, 38 percent of total freshwater withdrawals for all categories, and 50 percent of fresh surface-water withdrawals.

One of the main uses of water in the power industry is to cool the power-producing equipment. Water used for this purpose does cool the equipment, but at the same time, the hot equipment heats up the cooling water! Overly hot water cannot be released back into the environment—fish downstream from a power plant releasing the hot water would get very upset. So, the used water must first be cooled. One way to do this is to build very large cooling towers and to spray the water inside the towers. Evaporation occurs and water is cooled. That is why large power-production facilities are often located near rivers, lakes, and the ocean.

 View a diagram of Georgia Power's Plant Scherer and see how it uses water.

Thermoelectric-power water withdrawals for the Nation, 2010

Total withdrawals for thermoelectric power for 2010 were 161,000 Mgal/d or 180,000 thousand acre-ft/yr. (All 2010 water use information is from the report Estimated use of water in the United States in 2010.) Surface water was the source for over 99 percent of total thermoelectric-power withdrawals, and 73 percent of those surface-water withdrawals were from freshwater sources. Saline surface-water withdrawals for thermoelectric power accounted for 97 percent of total saline surface-water withdrawals for all uses.

Thermoelectric-power withdrawals, by State, 2010

The geographic distribution of total, total freshwater, and total saline-water withdrawals for thermoelectric power is shown in the maps below. The largest total withdrawals for thermoelectric power were in Texas, where nearly all the withdrawals were from freshwater sources. Illinois, Texas, Michigan, and Alabama, together accounted for more than 32 percent of freshwater withdrawals for thermoelectric power. Florida, California, and Maryland accounted for about 48 percent of total saline withdrawals, nearly all from surface water. Hawaii, California, and Nevada accounted for 82 percent of the total saline groundwater withdrawals.

Trends in thermoelectric-power water withdrawals, 1950-2010

Thermoelectric power has been the category with the largest water withdrawals since 1965, and for 2010 comprised 45 percent of total withdrawals. The largest total and fresh and saline surface-water withdrawals were during 1980. Withdrawals by thermoelectric-power plants increased from 40,000 Mgal/d during 1950 to 210,000 Mgal/d during 1980. Withdrawals for thermoelectric power declined and then stabilized since 1980, despite the fact that total population has continued to rise; the total withdrawal of 161,000 Mgal/d for 2010 is significantly lower than that of 2005.

Estimated 2010 thermoelectric withdrawals were 20 percent less than estimates for 2005. Reasons for this large difference include plant closures, use of the linked heat and water budget model data, decrease in use of coal and increase in use of natural gas, and new power plants using more water-efficient cooling technology.

The trend in thermoelectric-power withdrawals is seen as the yellow bar in the chart below.