Turning energy into water

Via the WSJ, California gives desalination plants a fresh look:

Early next year, the Southern California town of Carlsbad will break ground on a plant that each day will turn 50 million gallons of seawater into fresh drinking water.

The $320 million project, which would be the largest desalination plant in the Western Hemisphere, was held up in the planning stages for years. But a protracted drought helped propel the project to its approval in May -- a sign of how worried local authorities are about water supplies.

...

Huntington Beach, in Orange County, is planning to break ground on its own desalination plant in 2010. Another plant is in the works at Camp Pendleton, just north of Carlsbad, in San Diego County.

In the great triad of energy, agriculture, and water, everything is technically fungible - water and land can be converted to energy by growing biomass, energy can be turned into additional agricultural production via fertilizers and mechanization, and energy can be converted into water via desalination or waste-water treatment. The problem, of course, is that the conversions are far from perfectly efficient. Desalination in particular gets a lot of flak for being energy-intensive:

Government agencies have opposed desalination because of the process's energy consumption. The desalination plant would use nearly twice as much energy as a wastewater-treatment plant available in Orange County.

... as well as, of course, other environmental effects:

Environmental groups also object because fish and other organisms are likely to be sucked into the facility.

At least one mayor is bluntly comfortable with the trade-off:

"Eventually, people will have to realize, it's either fish or children," [Carlsbad Mayor Claude] Lewis said.