by Erica Gies
Water and energy form two vital pillars that hold up our economy and our lives. Unfortunately, they are inextricably intertwined: Destabilize one and you could threaten the other.
That’s because we use about 41 percent of our freshwater to produce energy, and about 13 percent of our electric consumption to treat and distribute water.
The problem with this level of interdependence became clear this summer in the Southeast when the Browns Ferry nuclear plant in Athens, Alabama, was forced to cut power for five weeks during a heat wave. Coal, gas, and nuclear power plants (also called thermoelectric plants) require a lot of water for cooling, and water stress has forced at least 12 plants to temporarily reduce output or shut down since 2004.
A process called once-through cooling – used by 43 percent of thermoelectric power plants – is a huge water hog. A typical 500-megawatt plant takes in almost 19 million gallons an hour, says the U.S. Department of Energy.
Though that water, once used, is returned to nature, it is often polluted and up to 17 degrees hotter, which can kill fish. Fortunately, these hazards have led to tighter regulation and a transition to newer, less water-intensive technologies.
One such approach is wet cooling, which chills a plant via evaporation and uses only about 3 percent of the water as once-through cooling. About 56 percent of U.S. thermoelectric generating capacity is now wet-cooled. A newer process, dry cooling, uses no water at all but instead uses fans to push waste heat into the atmosphere.
California is currently phasing out once-through cooling, and has adopted a policy that discourages the use of freshwater for cooling. In response, energy developers there now plan projects using reclaimed water for wet cooling or dry cooling. Other states and the federal government should follow California’s lead.
Still, without urgent action nationwide, our electricity supply will grow increasingly unstable as water gets scarcer. Most of the West and Midwest could get significantly drier by the 2030s, according to a study just released by the National Center for Atmospheric Research, with conditions worsening through 2100. Extended droughts and growing populations will mean even less water available for energy production.
Fossil fuel and nuclear plants aren’t he only heavy water users. Some cleaner energy technologies also consume vast amounts of water. Hydropower, for example, loses millions of gallons to evaporation from the lake impounded behind the dam.
Lake Mead, formed by Hoover Dam, is the main source of water for Las Vegas. But if current drought conditions continue for another six years, Las Vegas will be without water. Prolonged drought in this century could shut down Hoover Dam and other major U.S. hydropower generating stations.
Another alternative energy source, growing corn for ethanol – which currently displaces 10 percent of our gasoline – can also suck up hundreds of gallons of water for every gallon of ethanol produced, according to the U.S. Government Accounting Office. Solar and wind generating projects require much less water.
As we develop alternative energy projects, we will need to look closely at how much water they consume and seriously consider projected regional water shortages.
There is some good news around the water-energy nexus. In the past, energy and water were managed separately. But with 36 states expecting major water shortages by 2013, managers are rethinking water-energy systems, seeking ways to operate them jointly, saving money and water and reducing air pollution and carbon emissions.
A key to having enough energy in the future is to not waste water now, and there are many ways to conserve. For example, thirty percent of residential water demand nationwide goes to outdoor use, climbing to 80 percent in the arid West. So reducing or eliminating lawns could make a big difference. Choosing native plants over lawns requires far less water and has the added benefit of reducing chemical use and reconnecting property owners with their area’s natural heritage and local wildlife.
On the federal level, the U.S. Interior Department launched its WaterSMART initiative this year to map water and measure how much of it various types of energy consume. Last year, the House of Representatives passed the Energy and Water Research Integration Act to improve data collection and technology. The bill is awaiting action in the Senate.
These efforts show that policy makers are starting to think about the water-energy connection. But they’re research heavy and action light. We already know enough to start saving water and energy today. Procrastination is just making us environmentally and economically poorer.
Erica Gies is a freelance reporter who has been published by The New York Times, The International Herald Tribune, Wired News, Grist, and E/The Environmental Magazine. To comment on this column go to www.blueridgepress.com or Facebook © BRP 2010.
Connect with NJTODAY.NET
Join NJTODAY.NET's free Email List to receive occasional updates delivered right to your email address!