SAN DIEGO (AP) — The San Diego County Water Authority announced a tentative agreement Thursday to buy the entire output of what will be the Western hemisphere's largest seawater desalination plant, clearing a major hurdle for construction to begin.
The plant in Carlsbad will produce 50 million gallons (189.26 million liters) a day, enough to supply about 7 percent of the San Diego region in 2020.
The agreement is subject to approval by the water authority board. Upon the board's approval, the developer — Poseidon Resources LLC — would sell bonds to finance 82 percent of the project, which is estimated to cost about $900 million to build.
The water authority expects the plant in the north San Diego suburb and a 10-mile (16-million kilometer) pipeline to be completed in 2016.
San Diego wants to make the region less dependent on imported water from the Los Angeles-based Metropolitan Water District of Southern California, which supplied almost all its water in the early 1990s and still provides nearly half.
"The story of San Diego has always been about the quest for reliable water," said Dennis Cushman, the San Diego agency's assistant general manager. "The history is drought and water supply shortage and being subject to decisions made by a board of directors in downtown Los Angeles ... This is about water reliability."
The water authority, a wholesaler to 24 cities and agencies including the city of San Diego, says the average household water bill will increase about $5 to $7 a month when deliveries begin. It estimates the cost is comparable to other new, local sources of drinking water, like treated toilet water or briny groundwater.
Tom Pankrantz, editor of Water Desalination Report, said the Carlsbad plant will easily become the hemisphere's largest seawater desalination plant, surpassing one in Trinidad and Tobago that produces up to 40 million gallons (151.4 million liters) a day.
Desalination has helped quench demand in Australia, Saudi Arabia and other countries lacking fresh water, but it has struggled to catch on in the United States.
The plants can blight coastal landscapes, require massive amounts of electricity and dump millions of gallons (liters) of brine back into the ocean that can, if not properly disposed, be harmful to fish.
"The (Carlsbad) project will be somewhat of a bellwether or indicator of how desalination progresses in the U.S.," said Pankrantz. "Some say it will be the last one. Others say the dam will burst and the floodgates are open."
Poseidon has also proposed a desalination plant of the same size in Huntington Beach, near Los Angeles.
San Diego began to consider desalination in the early 1990s, when a drought led it to conclude that it needed a more diverse, reliable water supply. In 2003, it brokered a deal to buy Colorado River water from California's Imperial Valley in the nation's largest farm-to-city water transfer.
The agency is also considering desalination plants at Camp Pendleton Marine Corps Base and Playas de Rosarito, Mexico, just south of the U.S. border.