Tuesday, February 25, 2014

Solar Desalination helping California Drought

   A San Francisco startup company called Water FX has installed a 377 ft. solar desalination array in California’s agricultural nucleus, in an area where billions of gallons of contaminated runoff water lie just below the surface. The Panoche Water District funds the $1 million project in hopes to provide water for agriculture. This new solar-powered technique apparently allows farmers to tap into toxic runoff at half the cost of traditional desalination and provide freshwater irrigation independent of annual rainfall or snowpack in other parts of the state. Water FX’s promising pilot program uses free energy to remove harmful substances from toxic runoff to provide clean water.
   Water FX utilizes two abundant resources found in the area to desalinate water: sunlight and uncultivated land. Using massive parabolic reflectors, focused sunlight energy heats mineral oil that is then used to produce steam in evaporators. The process is continuous storing excess heat in molten salts allowing it to continue at night. Thermal desalination promises to ease two major issues in the area: chronic water shortage, and salt contamination of arable land. The latter has already made over 100,000 acres in the Central Valley unusable.
   Standard desalination plants use a process known as “reverse osmosis” an energy intensive process that forces water through membranes that must be periodically changed.  According to Michael Hanemann, a professor of agricultural and resource economics at the University of California, Berkeley [and your professor's teacher, back in the day!] these are often considered a backup water resource, operating infrequently. Nearby a traditional desalination plant is being constructed, using over $30 million in federal funding.
   The Water FX pilot has generated 14,000 gallons of clean water per day, and the commercial installation is said to create over 2,200 acre feet of water per year, only using 31 acres of land. This water is clean and abundant enough for incorporation into municipal markets where prices are substantially higher. Hanemann called desalinization a hedge against future shortages and the rising price of water. “It’s a form of insurance,” he said suggesting that the economic viability of the new technology depends on how much water farmers would have to buy on expensive spot markets because of drought and climate change.
   Farmers in the Panoche district have been receiving less and less water for irrigation as the drought continues, and this year they will receive no water. The Central Valley Project has established long term contracts promising farmers irrigated water from northern California at a fraction of the actual price, about $280 per acre-foot.  Water FX currently produces an acre-foot of water at $450. The drought that has plagued California prevents the Central Valley Project to meet the requirements of farmers, and as consequence irrigation prices are expected to double or triple for farmers. Food prices are going to go up, absolutely,” said Dennis Falaschi, manager of the Panoche Water District.
--James Etienne

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