California’s Hidden Water Consumer: Power Plants

As California suffers through its fourth year of record drought and Gov. Jerry Brown imposes mandatory water restrictions for the first time in the Golden State’s history, the debate rages on over who consumes the most water and who should be responsible for cutting back. Is it homeowners and golf courses with a penchant for full green lawns, almond growers who need a gallon of water to produce one single almond, or the beef industry that uses 2,500 gallons of water for every pound of hamburger patty?

But there’s another major consumer of water in California and the United States – one that doesn’t receive the same attention as lush lawns or the agricultural industry: power plants. In 2005, power plants across the country withdrew as much water as farms did, according to a 2011 report, Freshwater Use by U.S. Power Plants: Electricity’s Thirst for a Precious Resource, from the Union of Concerned Scientists and a team of independent water experts. The report also found that power plants withdrew four times as much water as all Americans did -- meaning that, on average, lighting rooms, powering home electronics and running appliances require more water than washing dishes and clothes, showering, flushing toilets, and watering gardens.

Why do power plants use so much water? Most power plants in the U.S. are thermoelectric, the report said, meaning they boil water to produce steam that, in turn, spins turbines that generate electricity. Large quantities of water are also used to cool this steam.

In California and other coastal states, power plants rely more on seawater than fresh water to operate, the study noted. Indeed, in 2005, power plants in the Golden State withdrew 12.6 billion gallons per day of saline water and 50 million gallons per day of fresh water, according to the state’s Department of Water Resources. Overall, water withdrawals by thermoelectric power plants accounted for 28 percent of the state’s water withdrawals in 2005, the agency reported. It is important to note that “water withdrawal” is the total amount of water a power plant takes in from a source like a river, lake or aquifer – some of which may be returned.

So, should Californians be concerned about power plants’ water use when the majority comes from the ocean and, according to the Union of Concerned Scientists’ report, most thermoelectric power plants in the state are highly efficient? Though the 12.6 million gallons of water per day that Californian power plants extract from the sea may not directly compete with the drinking water supply yet (although proposals for desalination plants are rearing their ugly heads again), seawater withdrawal does have environmental consequences, the report said. Water intake systems on power plants can trap fish and other aquatic animals, while the water used for cooling and then returned to the ocean at a warmer temperature can also harm marine life.

And Californian power plants’ need for 50 million gallons of fresh water each day is not an insignificant amount either – not when public officials, industry and residents are bickering over every last drop of water and when there are readily-available solutions to the problem of energy-related water use. These solutions include energy efficiency, dry or low-water cooling technologies for power plants, and certain forms of renewable energy like wind turbines and solar photovoltaics. Some concentrating solar power plants consume more water per unit of electricity than the average coal plant, the report found, but these facilities can also employ dry-cooling techniques to cut down on water use.

Indeed, the California Solar Initiative, which provided solar rebates to homes and businesses, has installed enough solar power systems to conserve 684 million gallons of water a year, said Will Craven, director of public affairs for SolarCity.

“The average American consumes more water via consumption of electricity than they do via direct water consumption. Utilities are the second largest water consumer in the nation,” Craven said. “Meanwhile, solar’s greatest near-term benefit may be its water efficiency. Between steam systems for coal plants, cooling for nuclear plants and fracking for natural gas wells, energy production consumed 66 billion cubic meters of the world’s fresh water in 2010. By contrast, solar consumes practically no water at any stage of its development or deployment.”

So, as California cities consider outdoor watering restrictions and farmers in the Golden State think about which crops to grow given their water allocations, we should remember the other tools we have ready to help us save water and survive the drought -- energy efficiency, solar photovoltaics and wind farms -- some of the same solutions that will help us fight climate change.

Image credit: Flickr/Don DeBold