WASHINGTON – Lawmakers must consider the link between water and energy,witnesses told a Senate committee Tuesday.
Five witnesses told members of the Senate Energy and Natural Resources Committee that they must understand that relationship before pursuing policies to encourage water conservation or curb energy consumption.
All energy-producing technologies require water to produce steam,turn turbines or cool plants. Withdrawing,transporting and treating water for drinking,irrigation and other uses requires energy.
“We can develop all the zero-carbon technologies we want,but without a reliable supply of water,they will amount to nothing,” said Alaska Sen. Lisa Murkowski,the committee's senior Republican member. “It is imperative that we have a better understanding about the demand they put on our finite,scarce and,in many regions,oversubscribed water resources.”
Murkowski and committee Chairman Jeff Bingaman,D-N.M.,introduced a bill last week to authorize studies of water used in electricity production and energy used in water transportation and storage. The senators hope these studies would identify ways to conserve both water and energy.
There are trade-offs among energy-production methods because the most water-efficient technologies are typically the most expensive,witnesses said. And it is sometimes difficult to determine which processes waste water.
For example,coal-powered plants use less water than solar-thermal energy. But carbon-capture processes employed to reduce fossil fuels' environmental impact require water.
And it's unclear how much of the water used in solar-thermal production could be reused,said Michael Webber,associate director of the Center for International Energy and Environmental Policy at the University of Texas at Austin.
“There's definitely a very complicated relationship,” Webber said.
Witnesses encouraged committee members to promote use of reclaimed water – or treated wastewater – in energy production.
Stephen Bolze,chief executive officer of General Electric Power and Water,said the United States reuses only about 6 percent of its water because it is cheaper and more convenient to withdraw water. The company manufactures parts used in wind power and water reuse and purification technology.
He suggested a tax credit to reward industries that use treated wastewater.
Some power plants have experimented with reclaimed water. The Palo Verde Nuclear Generating Station in Wintersburg,Ariz.,the largest nuclear generating site in the country,uses treated wastewater from nearby municipalities in cooling towers.
California – where Gov. Arnold Schwarzenegger recently declared a statewide drought emergency – is expanding its use of reclaimed water,said Lon House,an energy consultant with the Association of California Water Agencies.
“Reclaimed water and water reuse is one of the building blocks to get to the future,” he said.