After one year of construction, the largest desalination plant in the Western Hemisphere has reached the 25 percent complete mark and remains on time and under budget. The $1 billioCarlsbad Desalination Project, which broke ground in late 2012, is on schedule to start producing up to 50 million gallons of water a day when it completes in 2016.

Developed by Poseidon Resources of Carlsbad, and being built by joint-venture contractor Kiewit Shea Desalination, the reverse-osmosis facility will make local water supplies more reliable by reducing the region’s dependence on water from the Colorado River and the Bay-Delta that is vulnerable to droughts, natural disasters and regulatory restrictions. The desalinization process takes two gallons 

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of seawater to make one gallon of drinking.

Besides the plant, the project includes a large-diameter pipeline in North County, along with upgrades to San Diego County Water Authority facilities. It will account for about one-third of all the water generated in San Diego County, helping reduce reliance on imported water.

Project officials say that during the three-year construction process, the project is generating about 2,500 jobs and infusing the local economy with $350 million.  

In November 2012, the Water Authority signed a 30-year agreement to purchase at least 48,000 acre-feet of desalinated seawater each year from Poseidon, as long as it meets pre-set quality and quantity requirements. As part of the public-private partnership, the Water Authority may purchase up to 56,000 acre-feet annually, enough to serve about 112,000 typical single-family homes.  

The Carlsbad plant, located about 20 miles north of San Diego, will be the nation’s most technologically advanced and energy-efficient seawater desalination plant, according to project officials. The six-acre project sits next to the Encina Power Station, on the Agua Hedionda Lagoon. Its water will come from the outflow of the power station, which uses seawater for cooling. This runoff will be transported to the desalinization plant via a 72-inch, 2,000-ft pipeline.  

Once in the 65,000-sq-ft desalinization plant, the water will be filtered and sent 10 miles through a 54-inch pipe, where it will connect with SDCWA aqueduct in the city of San Marcos.

Peter MacLaggan, senior VP of development for Poseidon told me when construction began that the biggest challenge would be working on a constrained site, close to an operating power plant. 

“We don’t have the luxury of a lot of open space to site this facility on the coast,” he said. “We are going to have to carefully time our interconnector to the power plant and San Diego aqueduct so we don’t interfere with their operations.” 

By late 2015, the Carlsbad facility is scheduled to begin start-up testing. Commercial operations are expected early the following year. Poseidon’s plant will produce 48,000 to 56,000 acre-ft of desalinated seawater annually, roughly one-third of all water generated in San Diego County.