Environmental Leader

California and other western states are pegging their energy future on renewables, including solar. But that growth comes at a cost to the region’s already dwindling water supply, reports the New York Times.

Many solar power plants consumer millions and millions of gallons of water a year for power-plant cooling purposes, as well as steam generation to drive turbines. This potentially pits renewable energy against water-hungry agricultural interests, as well as urban water users.

Recently, Pacific Gas & Electric signed a deal to buy 500 megawatts of electricity from solar plants in California’s deserts.

One, the Genesis Solar Energy Project, would use about 536 million gallons of water a year, while the Mojave Solar Project would use more than 700 million gallons of water a year for cooling purposes, according to applications filed with the California Energy Commission.

Another 35 large solar farm projects are being considered in California, a state which increasingly has had to limit water for agriculture in favor of municipalities.

To limit the problems, regulators are trying to convince solar operators to use so-called dry cooling, which uses about 90 percent less water. That method comes at a cost, however. It is more expensive and the solar plant does not operate at as high an efficiency.