David Sneed reports that with an average output of 675,000 gallons a day, the Diablo Canyon nuclear power plant will hold that distinction until at least November, 2015, when a 50-million-gallon-per-day commercial desalination plant in Carlsbad is scheduled to begin production.\n\nThe Diablo Canyon desalination plant consists of a system of powerful pumps, large tanks and a series of long, white reverse osmosis filtration tubes. The filters in those tubes are so fine they can remove even the microscopic salt particles that give ocean water the name saltwater.\n\nIsolated along 14 miles of coastline, Diablo Canyon depends on the desalination plant as its sole source of fresh water. It supplies not only the water needed for the two nuclear reactors, it also supplies all the water used by its employees for drinking and other needs.\n\nFor the first time in the Diablo Canyon 30-year history of operation, its desalination plant has become the object of intense public interest because of its potential to serve neighboring communities. The plant is licensed to produce as much as 1.5 million gallons a day, even though Diablo Canyon only uses 675,000 gallons daily to generate electricity.\n\nAs the county reels from its fourth consecutive year of drought, the San Luis Obispo County Board of Supervisors is considering the 825,000 gallons of potential production as a new source of supplemental water for use in the county.