Desalination

Yesterday, we discussed the serious problems the American West has with its water supply and the very real threats this portends for the region’s future. Those who truly believe technology can solve our problems sometimes turn to desalination plants as a cure. Sarah Goodyear sums up many of the reasons why these are really problematic:

First among these is cost. Desal plants are hugely expensive to build and operate. Water companies would have to pass those costs along to customers. Fluctuating demand can make this type of massive capital investment even riskier for utilities. The plants are also are energy intensive — another factor in the operating expense — and could be significant contributors to greenhouse gas emissions.

The environmental costs of desal are still only partially understood, according to a new report from the Pacific Institute. The possible negative effect on marine ecosystems has emerged as a major stumbling block to the construction of desal on the California coast.

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Then there’s the disposal of the super-salty brine left over after the desalination process is complete. That liquid, produced in huge quantities — roughly one gallon for every gallon of desalinated water — is denser than normal seawater and could cause its own set of problems, particularly for desal plants located in areas without a lot of tidal flow.

All these factors, combined with the strong environmentalist constituencies in many coastal California communities and strict state regulations, mean that developing desal plants can turn into an expensive headache for water companies. In 2006 the number of proposed plants in California was 21. Now it’s down to 17, despite strong support for developing desal among many elected officials.

I am extremely skeptical of desalination as a reasonable solution for all these reasons. The impacts are likely to be massive–to the pocketbooks of customers and to the environment. Because the long-term impacts on ecosystems are poorly understood, like fracking and other energy projects that we rush into without sufficient study, desalination is likely to have unexpected consequences that will lead to difficult problems down the road. And while politicians and the public love these things in theory because they don’t see consequences, I don’t think they can either build enough of these to solve the water problems in California or that the cost of the produced water will be worth the effort.