Heated seawater issuing out the tail end of the power plant will be pumped into the desalination system and converted to tap water.
Although the plant will provide a localized freshwater source in a dry region without impacting ecologically sensitive rivers or wetlands, it comes with a steep price tag and requires a tremendous amount of electricity. Proponents estimate that the energy consumption in a single day would be the equivalent to the energy used by 16,790 homes. But Maas says even this estimate is low, because if the power plant's water-cooling system is phased out by 2017, as state law mandates, then the desalination facility would have to start with cold water instead, requiring a substantial power boost. Poseidon spokesperson Scott Malone disputed this claim, telling the Guardian, "The plant will require 28-30 MW to operate during warm water or cold water operations."
Cost and energy consumption aren't the only concerns advocacy groups have raised. Mark Schlosberg, a program director at Food & Water Watch in San Francisco, considers Poseidon's last foray into desalination, in Tampa Bay, Fla., to be a cautionary tale. According to an article in the St. Petersburg Times, the plant opened five years late, cost $40 million more than expected, and hasn't ever hit its target of supplying an average of 25 million gallons a day as originally promised. After Poseidon's business partner for that affair went bankrupt, a public utility had to take control of the facility.
"They have a bad track record on desalination," Schlosberg said. "It never performed close to its advertised capacity."
Asked about the challenges in Tampa Bay, Maloni said, "Before Poseidon was bought out, the project was 30 percent constructed, on time and on budget. After Tampa Bay Water took over, the plant wasn't constructed as designed and later failed to pass performance testing."
Critics have also decried the high cost projections for water. San Diego County now uses water imported from northern territories via the State Water Project, at a cost of around $750 per acre-foot (an acre-foot is 325,851 gallons), according to San Diego County Water Authority figures. Poseidon estimates that the water from its plant will cost about $1,300 per acre-foot, but has promised not to charge customers more than the price of imported water. Two years ago, Poseidon told the California Coastal Commission that it intends to absorb its losses "for an unknown number of years" until the price of imported water rises enough to equal the cost of desalinated water.
"Poseidon has entered into 30-year contracts with nine different San Diego County public water agencies that guarantee the cost of the desalinated water will never cost more than the agencies would otherwise pay for imported water," Maloni told the Guardian. "This pricing structure is possible because imported water rates are projected to increase significantly in the years to come, while the cost of desalinating water will stay relatively flat."
Shlosberg's organization requested public records from the Tampa Bay facility so they could calculate a price estimate that they say is more realistic. Food & Water Watch hired James Fryer, an environmental scientist, to crunch the numbers. Fryer concluded that if the Carlsbad project experienced the same pitfalls as Tampa Bay, the water would cost $3,507 per acre-foot a sky-high projection. If it ran without those bugs, it would still cost $2,175 per acre-foot, he determined.
The overarching question, in Maas' view, is whether the state is willing to take conservation seriously enough to put water-saving measures into practice before subsidizing costly, energy-guzzling technology. "By sitting a desalination plant, it really distracts people from solutions that are more environmentally sustainable," she said.