I'll Just Have a Water, Pacific Water, Please

The San Diego County Water Authority is reportedly close to signing a 30-year deal with Poseidon Resources to buy water from a desalination plant to be built by Poseidon adjacent to the old Encina Power Station in Carlsbad, just north of San Diego.

“California Dreamin’” is a lament to be back in the warm, familiar confines of L.A., but there’s another California dream: turn seawater into drinking water. Construction costs, the huge energy requirements to run such plants, regulatory delays and environmental legal challenges have, however, kept it a dream. Of the 17 desalination plants proposed in California, only one small plant on Monterey Bay is turning seawater into drinking water.

It comes down to how much cities are willing to pay to desalinate seawater. For now, water districts along the coast are opting for water conservation over water production.

Now, the San Diego County Water Authority (SDCWA) is reportedly close to signing a 30-year, 500-page deal with Poseidon Resources (Poseidon) to buy water from a desalination plant to be built by Poseidon adjacent to the old Encina Power Station in Carlsbad, just north of San Diego. Such a plant, which passed all the regulatory hurdles in 2009, would provide water to 3.1 million people.

Poseidon says it can desalinize 50 million gallons of drinking a day, but needs to lay 10 miles of new 54-inch pipe laid underground across Carlsbad, and reline five miles of 50-year-old pipe leading to the Twin Oaks Valley Water Treatment Plant. Note: Twin Oaks is the largest “submerged membrane” water treatment plant in the world. Water is drawn through very fine pores of membrane fibers which trap most of the dirt, dust, bacteria, cryptosporidium and giardia. Contaminants that do pass through are disinfected and fluoride is added to the treated water. Twin Oaks can treat up to 100 million gallons of water (not seawater) per day.

The desalination plant, pipelines and related improvements at the Twin Oaks plant will cost $900 million. A signed deal is essential for Poseidon to obtain financing to build the project. SDCWA anticipates the plant opening in 2016, and expects desalinated water will account for seven percent of the region's supply in 2020.

Poseidon says the price of the water will be from $2,062 per acre-foot to $2,329 per acre-foot. (An acre-foot is 325,851 gallons, enough to satisfy the water needs of two average families for a year.) That price is roughly twice what SDCWA pays now for water from Northern California and the Colorado River, provided by the Metropolitan Water District (MWD) of Southern California. It is estimated that it would mean an additional cost to customers of $5 to $7 a month.

Poseidon says it’s a fallacy to compare the projected price of Poseidon water with what SDCWA pays today for MWD water. The valid comparison, Poseidon asserts, is the price the water authority would have to pay for alternative supplies. The price of treated MWD water has doubled in the past 10 years, while the price of its untreated water has skyrocketed nearly 80 percent.