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Seawater Desalination : An Ocean of Opportunities
Guest article by Nikolay Voutchkov, Poseidon Resources Corporation

By year 2030, California’s population is expected to increase more than 30 %, which even with aggressive reuse and conservation statewide would require over one billion gallons of new fresh water supplies. Recognizing this water supply challenge, the California Department of Water Resources has charted a new course for exploration of desalination as an addition to the state’s water portfolio.

Figure 1:  Ongoing Seawater Desalination Projects in California

Currently, there are over two dozen of new large seawater desalination projects under various stages of development throughout the state. All of these projects are proposed to use seawater reverse osmosis membrane technology to separate salts from the seawater and produce fresh drinking water of high quality at competitive cost.

Seawater Desalination in Southern California

Currently, Southern California imports approximately 50 % of its water from two main sources – the Sacramento Bay – San Joaquin River Delta, and the Colorado River. In order to address the uncertainties associated with the long-term use of imported water from these sources, by year 2020 the largest Southern California coastal utilities and municipalities are planning to supply 10 to 20 % of their drinking water from the ocean.

Figure 2:  Carlsbad Seawater Desalination Project

At present, the 50 MGD Carlsbad and Huntington Beach seawater desalination projects are at the most advanced stage of development. Both projects are collocated with coastal power generation plants using seawater for once-through cooling. The two desalination projects are developed as public-private partnerships between Poseidon Resources and local utilities and municipalities.

The environmental impact assessments, local land use permits and concentrate discharge permits for the two projects have already been approved. Currently the projects are under review by the California Coastal Commission and contingent upon favorable outcome, plant construction is planned to begin by the end of 2007 and to be completed by 2010.

The two projects have a common driver: the desire of the utilities in their service areas to reduce their reliance on imported water supplies from Colorado River and the Bay Delta, to draught-proof their water supplies and to gain more local control over their water resources. Currently, San Diego County has very limited local water resources and relies on Colorado River and Bay Delta water for over 90 % of their supplies.

Therefore, for example the City of Carlsbad has decided to switch their entire water supply from imported water to desalinated seawater. Most of the other communities that would to be supplied by the Carlsbad seawater desalination plant would supplement between 10% and 30 % of their current water supplies with fresh water from the sea.

Orange County has more local water resources and at present imports only 45 % of their water supplies from Colorado River and the Bay Delta. This county is also a host of a large groundwater recharge project which would supplement 64 MGD of the county’s water resources. As a result, the desalinated water produced by the Huntington Beach seawater desalination plant would constitute only 6 % of the current county-wide water supplies.

The desalinated seawater is planned to be introduced in the Orange County’s regional water supply system where it will be blended with drinking water from other sources. Twelve Orange County utilities and municipalities will have access to the desalinated water. In most cases this source will constitute between 1 and 10 % of their water supply.

Seawater Desalination Activities in Northern California

The need for supplemental drought-relief water supplies, groundwater basin overdrafts and associated seawater intrusion, and the measurable ecological impacts of some of the current water supply practices are the main driving forces for the renewed interest in seawater desalination in Northern California. Most of the proposed projects are located in the San Francisco Bay Area and in Monterrey County.

Figure 3:  Moss Landing Regional Seawater Desalination Project

Monterrey County is the grounds for the development of the largest new seawater desalination projects in Northern California. Two competing projects are proposed in the City of Moss Landing. The first is a 20 MGD regional seawater desalination facility planned to be delivered under a public-private partnership between Pajaro-Sunny Mesa Community Services District and Poseidon Resources.

The California American Company (Cal-Am) is developing a smaller, 12 MGD project at the Moss Lending Power Generation Station site and proposes to use the power station’s cooling water discharge as an intake and discharge of the desalination plant.

Most of the other seawater desalination projects under development in Northern California are in early phases of feasibility and environmental studies, and are not expected to yield full-scale desalination plants before 2010.

Concluding Remarks

Within the next 5 to 10 years many Californian coastal communities are planning to make seawater desalination a permanent part of their water portfolio. Over one dozen seawater desalination plants supplying up to 6 % of California’s total water demand are projected to be build by year 2020.

Although existing fresh water sources, conservation and reuse would continue to play a central role in the state’s long-term water supply strategy, seawater desalination has unique appeal to many coastal communities because it allows access a reliable and drought-proof source of drinking water that can be developed and controlled locally.

For more information, contact our author:

Mr. Nikolay Voutchkov,
Senior Vice President
Poseidon Resources Corporation
1055 Washington Boulevard
Stamford, CT 06901
Telephone: 203-327-7740
Fax: 203-327-5563
Email: nvoutchkov@poseidon1.com
Web site: http://www.poseidon1.com/ 

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Guest articles for the Ask Tom! Column are always welcome, for more information please contact Tom Keenan directly at his email address:  info@nesa.ie