Thirsty: Desalination Plants and Water Needs in California
Keith Johnson
The Wall Street Journal
06/04/2009
The debates over what to do about water and electricity have a lot in common. There are ardent supply-siders who say we need to produce more of the stuff, and there are equally devoted demand-side types who stress conservation and efficiency.
It’s not an academic question when it comes to water. In Spain, the Middle East, and Australia, thirsty governments are building big desalination plants to turn salty seawater into drinking water. One big downside is that the process is expensive—and uses a lot of energy.
The debate is coming to a head in California, too, which is facing its own water crisis. Plans are afoot to build as many as 20 desalination plans across the state. At issue is how to meet an expected increase in water use even as traditional water sources, from rivers to reservoirs, are getting drier.
Take Marin County, near San Francisco. Local officials, already faced with a water-supply deficit, are proposing a new desalination plant to head off an even bigger deficit in the future, in addition to water-conservation measures. The reasoning? Even conservation measures will only tackle half of the county’s expected water deficit in 2025—making a new source of fresh water vital.
Critics of the plan say building new desalination plants are the worst way to meet water needs—from both an economic and environmental standpoint. Food and Water Watch, a non-profit group, released today a detailed critique of the Marin County plan. (The group took aim at desalination in general earlier this year.)
In a nutshell, the group says, getting water from desalination plants is more expensive than any of the alternatives—things like reducing irrigation waste, fixing pipeline leaks, and making toilets and laundry rooms stingier users of water.
FWW estimates water from the Marin County plant would cost about $2,900 per acre foot a year—about ten times more costly than getting water through new efficiency measures like better toilets and washing machines.
Powering the desalination plants also requires a lot of energy to force millions of gallons of seawater through a membrane to strip out salt and other impurities. A new desalination plant could almost double Marin County Water Authority’s electricity use, the report found.
Even proponents of desalination concede it’s “obscenely” expensive compared to other alternatives. Many water-use economists also tend to frown on the rush to desalination, and figure there are better first steps to solve the water puzzle, such as putting a pricetag on water consumption.
