A 'Perfect Storm'

But both the San Diego Water Authority and MacLaggan say the Carlsbad project will have a different outcome.

MacLaggan blames many of Tampa Bay Water's troubles on a "perfect storm" encountered by Covanta Construction, "all unrelated to the desal project, but [which] took [a] toll on its performance."

Nevertheless, the water authority is going all in on the project. In a water purchase agreement reached after years of haggling, Poseidon agreed to bear all construction risks and all operational risks for the first 10 years.

Sandy Kerl, San Diego Water Authority deputy general manager, says, "Poseidon has 100% of responsibility for constructing the facility and making sure it operates. The water authority does not pay a dime unless water is delivered and delivered at the standard that we have set out in the water purchase agreement."

In exchange, the water authority will pay a slightly higher price for the water it purchases from Poseidon, paying between $1,849 and $2,064 per acre-foot in 2012 dollars, depending on how much is purchased annually. The water authority will purchase between 48,000 and 56,000 acre-ft of water from Poseidon each year.

Although that price is higher than the current cost to import water from the Metropolitan Water District in Los Angeles, the water authority made the calculation that, over time, the costs of a stable, drought-proof local water source would be cheaper than importation. The desalination plant will provide the agency with about 7% to 10% of its water supply in 2020 and about a third of all locally produced water in San Diego County. The water authority has the option to purchase the plant for $1 after 30 years.

Another negotiation point was to ensure the right team was working on the project, says Bob Yamada, water-authority resources manager. He notes, "One lesson learned from the Tampa experience was, we wanted to be engaged and have a say-so in the contractor selection." Yamada terms as top-notch the selected joint-venture team of Omaha-based Kiewit and Walnut, Calif.-based J.F. Shea as contractor and the San Diego arm of Israel-based IDE Technologies as designer of the reverse-osmosis (RO) system.

IDE has built about 400 desalination plants globally and will operate and maintain the Carlsbad plant for 30 years. In Israel, the company just brought on line a 150-million-cu-meter-per-year plant that is the largest of its kind in the world. "In Tampa, they selected a contractor doing its first [desalination] plant that ran into difficulties that [the contractor] could not easily deal with, and IDE won't have those kinds of problems," the desalination association's Truby observes.

Plant Design

The desalination plant, co-located with the Encina gas-fired power station, will draw seawater flowing into a 66-acre portion of the Agua Hediodna Lagoon that the powerplant uses for cooling. An intake structure will divert 104 mgd of the 304 mgd of cooling water from the powerplant's discharge channel.