Solar power's little secret: It sucks lots of water

Solar and other renewable energy sources across the Southwest are facing an intense battle over the availability of water. One project, funded by German firm Solar Millennium in Amargosa Valley, Nev., plans to consume 1.3 billion gallons of water a year to cool its plants, almost 20 percent of the valley's available water, Todd Woody of The New York Times reports.

"Here is an inconvenient truth about renewable energy: It can sometimes demand a huge amount of water," Woody writes. "Many of the proposed solutions to the nation’s energy problems, from certain types of solar farms to biofuel refineries to cleaner coal plants, could consume billions of gallons of water every year." Most water-efficient renewable energy technologies are not the most economical, Woody reports. The county commission of Nye County, Nev., which includes Amargosa Valley, says its been inundated with renewable energy requests that far exceed the amount of available water.

The conventional method for cooling solar plants, wet cooling, pumps hot water through the cooling tower where excess heat evaporates with some water, which must be replenished constantly, Woody reports. The alternative, dry cooling, uses fans and heat exchangers but is much less efficient and more costly. A bill has been introduce in the California legislature that would allow renewable energy power plants to tap drinking water supplies for their cooling needs. Terry O’Brien, a California Energy Commission deputy director, tells Woody: “By allowing projects to use fresh water, the bill would remove any incentives that developers have to use technologies that minimize water use."

Farmers who sell their water rights, which many residents see as their retirement funds, to renewable energy companies will be growing less of their crop in exchange for the profit, Woody reports. “We’ll be growing megawatts instead of alfalfa,” Ed Goedhart, a Nevada farmer and former state legislator, told Woody. Shortages are not just going to be a Southwestern problem; some fear that water problems will spread to the rest of the country as renewable energy becomes more common and population increases. (Read more)