With all the growing limitations on freshwater, it is easy to see why people would look to the Pacific Ocean as a potentially unlimited new water supply. However, the reality is that despite the industry-fanned hopes, ocean water desalination remains largely impractical in California.

Many people mistakenly consider ocean desalination a harmless way to get water to growing cities without the effects associated with damming rivers and over-pumping groundwater. The truth is, desalination is one of the most harmful and expensive water options in California. When compared to other available strategies, ocean desalination just doesn't pencil out.

Consider that ocean desalination is the most energy intensive way to get water. That's right -- it requires more energy to desalinate a gallon of ocean water than it does to pump water from Northern California over a mountain range all the way to Southern California. All of that energy means more greenhouse gases, which would cause more problems for our snowpack and groundwater, not to mention other resources.

Ocean desalination also requires that massive amounts of sea water, carrying millions of fish, plankton and other ocean life, must be sucked up and filtered everyday -- with 100% fish mortality. Those who care about the ocean know that these types of diversions can destroy miles of already stressed coastal habitats. In fact, people have been working for decades to stop power plants from this kind of water filtration.

Ocean desalination also fails the cost test. It is the most expensive source of new water for California, thanks to the very high energy requirements. Despite the claims that desalination will get less expensive as time goes on, you do not have to be an economist to understand that $4 gasoline means that all forms of energy will be much more expensive in the future, not cheaper.

We should also be aware that many of these desalination plants would be owned by private companies, including subsidiaries of multinational corporations. That raises concerns about transparency and accountability.

Locally controlled water conservation, water recycling and brackish water desalination are all far cheaper than ocean desalination. Coincidentally, these options are also less energy- and greenhouse-gas intensive, and less environmentally damaging.

Ocean desalination, quite frankly, is the SUV of water. We have better options. Communities need to decide whether they want their water sources to generate massive amount of greenhouse gas, cost a fortune and destroy the environment. I suspect that in most cases, Californians would reject that offer.

Mindy McIntyre is the Planning and Conservation League's water program manager.

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As California's population grows and water supplies become less reliable, we are seeing more communities look to desalination as part of a balanced water portfolio to help meet water supply and environmental needs.

Although most experts estimate that desalination will ultimately contribute less than 10% of total water supply needs, this still represents a significant portion of the state's water supply portfolio that can complement other locally developed supplies, conservation and recycling efforts.

The California Water Plan conservatively estimates that 300,000 to 500,000 acre-feet of desalinated water will be available annually by 2030 -- enough to sustain up to 1 million households for a year.

Desalination can provide significant value and numerous benefits including:

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