Do you know how much water it takes to light your house? How about the electricity involved in watering your prize-winning tulips? As it turns out, it’s a lot more than you’d think.
Due to expected population growth and urbanization in the United States—especially in drought-prone Western States like Arizona, California, New Mexico, and Nevada—two top energy experts at a AAAS discussion urged the federal and local governments to explore new strategies to meet nation’s burgeoning water and electricity needs.
Water and energy resources are inextricably intertwined, the experts said. Electricity generation requires a massive amount of water usage and water delivery requires energy to move into your home, and therefore conservation efforts cannot focus on a single resource.
“Without efforts exploring how we can better use water and electricity… business as usual will put us on a collision course with these two natural resources,” said Michael Hightower, Water for Energy project lead at Sandia National Laboratories.
Hightower said the United States uses about 400 billion gallons of water a day, with 50 to 60% going towards energy production. Most of this is through water withdrawal, which takes water from streams, rivers, lakes, and reservoirs, uses it to cool electricity-producing turbines, and then returns it to the source.
While that water isn’t “lost,” Hightower said the process depletes water sources and the water is returned at an average 20 degrees Fahrenheit warmer than the receiving stream or river, which can cause algal blooms or other ecological disruptions.
While the energy sector is the largest user of water, agriculture is the largest consumer, which is water that is not directly returned to the source. Of the estimated 100 billion gallons of water consumed a day for agriculture, residential and commercial use, and energy production, Hightower said more than 80 billion gallons go towards irrigation of crops.
He cited the tradeoff with biofuels—substituting biofuels for coal or oil reduces harmful emissions during combustion, but the irrigation and processing of biofuel crops requires water that could outweigh its air emissions benefits.
Nancy Stoner, co-director of water initiatives at the Natural Resources Defense Council, said that as new homes and agriculture are developed in drier climates, more energy will be spent transporting water from its source to the home faucet or farm sprinkler.
“It’s hard to get people to conserve water because there is this belief that it is overly abundant,” said Stoner. “But that may soon change.” She highlighted water disputes taking place in Massachusetts and Georgia, states which used to be perceived as having no problems accessing water, along with a U.S. Government Accountability Office report citing 36 states warning that they expect water shortages in the coming decades.
Calling water “tremendously undervalued,” Stoner said that water infrastructure will become increasingly stressed as the nation’s water demands increase to meet population growth and the changing climate. To reduce personal consumption, Stoner called on states to support water conservation methods including limits on grass lawns, the use of drought-tolerant native plants in drier regions, buying water-conserving appliances, and supporting water-use rates that reward conservation.
Held 16 November in the AAAS auditorium, the panel discussion—“A Thirst for Power: Connecting Energy and Water in a Resource Constrained World”—was sponsored by Georgetown University, the Smithsonian Institution, and the American Chemical Society. Moderated by award-winning National Public Radio correspondent David Kestenbaum, it was the second in a series of three Science and Society: Global Challenges seminars. The first event was on the impact of increased carbon on the oceans and third explored how U.S. public health officials are preparing for the H1N1 swine flu pandemic.
“As we address global challenges such as climate change and resource availability, we cannot afford to concentrate on each one in isolation,” said discussion co-organizer Audrey Leath, senior public policy associate at the American Chemical Society. “We must be cognizant of the relationships between them and the trade-offs we’re making,”
Kestenbaum said for people growing up on the East Coast, “water was just something that came out when you turned the tap on… without anyone really thinking about where it came from.”
“The only reminder that it might run out was the fact that your father washed the dishes under the teeniest of streams,” he joked.
Hightower said that stresses on water resources would not cause water to become unavailable, but rather more expensive. And as the price of water increases, so will the cost of food and other industries that depend on water. He added that social justice issues emerge if people cannot afford to purchase water.
While there are significant obstacles to water conservation, Hightower highlighted some technological strategies to reduce water use: utilizing dry-cooling methods using air instead of water to cool turbines; using some solar and wind energy generation technologies that use less water, which will continue to become cheaper in the next 20 years; and moving power plants to within 1.5 miles of coasts to use sea water instead of traditional inland fresh-water sources.
While desalinization—the process of taking salt out of brackish or sea water— to create drinking water is generally expensive, it may be cheaper than delivering fresh water in some regions, Hightower said.
In Australia, which has the least rainfall of all the inhabited continents, 95% of Australian residents live within 25 miles of the coast. Hightower said Australia plans to provide desalinated water for most of its citizens, leaving most of the freshwater from rivers for residents in the continent’s interior.
A Natural Resources Defense Council report co-written by Stoner found that 19% of energy use in California is devoted solely to water, most of which is attributed to getting water from its source into Southern California homes.
“Water and energy resources policy is going to need to be more synergistic and developed in a way that helps ensure that we can meet the needs for both resources,” said Stoner. Her report also called for an increase in water-use fees, which would in turn lead to conservation; more importantly, she said, it would lead to better infrastructure.
“People need to go to their local meetings and say, ‘Yes, we know water is valuable and we want better service, especially if it means the water mains will stop breaking,’” she said. “Water and its delivery service are tremendously undervalued.”