After over a dozen years of legal and regulatory battles, the largest seawater desalination plant in the United States is under construction and will use a technology that recovers and re-uses energy that would otherwise go to waste.
The $1 billion California project, located in Carlsbad in northern San Diego County, will employ Energy Recovery‘s equipment that captures the energy from the highly pressurized water after it moves through the filter to turn sea water into fresh water and gives the low-pressure water at the intake a boost before it move through the filter.
The technology will help the plant save an estimated 116 million kilowatt hours of energy, or $12 million, per year, the company said. Energy Recovery, based in San Leandro in the San Francisco Bay Area, plans to ship 144 pressure exchangers for the project in November or December, said CEO Tom Rooney.
The project is an important contract for Energy Recovery, which is counting on the Carlsbad project to kickstart a construction boom of seawater desalination plants in the country.
The project faced 14 legal challenges over its environmental impact, such as whether its operation would harm the marine wildlife, and lengthy regulatory processes at local and state agencies before securing the permits and financing to start construction late last year. The completion of the plant will help other similar projects to gain approval, Rooney said. At least 19 desalination plants are in various stages of development in California alone, he added.
“It’s breaking of the dam in terms of what’s likely to be a cavalcade of desalination plants and projects all around the United States,” Rooney said.
Drought and a chance to develop and use local water sources are two main reasons that seawater desalination has attracted ample interest from water agencies. That’s the case for San Diego County Water Authority which signed a 30-year agreement last November to buy water from the Carlsbad plant developer Poseidon Resources, a subsidiary of Poseidon Water. A drought in the early 1990s and a threat from its main water supplier, the Metropolitan Water District of Southern California, to cut the supply prompted the county water authority to draw up a master plan for finding alternative sources of water.
Back in 1991, the county water agency relied on Metropolitan for 95% of its water supply, which comes from rivers in Colorado and Northern California. The goal is to reduce that to 30% by 2020. The county water agency plans to buy between 48,000 and 56,000 acre feet of water per year from the plant, depending on demand. The agency sells water to its 24 members.
“The benefit of desalination — or water recycling and ground water development — is that it’s locally controlled. With imported water supply, the control is not totally yours,” said Bob Yamada, water resources manager with the San Diego water agency.
Poseidon expects to complete the project and start delivering fresh water in 2016. Initially, the San Diego water agency expects the cost of the desalinated water to be roughly twice of what it will pay to Metropolitan. But the agency anticipates that cost to decline to be same or likely lower over time as water from Metropolitan becomes more expensive.
Energy Recovery could benefit from the growth of the desalination business in the country. It already sells its technology to projects in other parts of the world. The company’s expertise in capturing and using fluid pressure also is attracting business in the oil and gas industry, which often moves far speedier than government agencies in approving and funding projects that could save them energy and money.
Energy Recovery’s pressure exchanger comes with a ceramic core, a material that is three times stronger than steel and is so tightly bound that fluid can’t easily pass through. The temperature with which the company bakes the ceramic core, which is made from a powder, is part of the secret formula that makes its equipment so efficient at harvesting energy from the fluid flow. Energy Recovery produces its equipment in a factory at its headquarters.