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Seawater Desalination

Ocean wavesCarlsbad's future quality of life depends on having a reliable and affordable supply of water. Prolonged drought, environmental problems and legal restrictions on the Colorado River and the Bay-Delta in Northern California have triggered the need to develop new water supplies, ideally ones that are locally controlled.

The Carlsbad Desalination Project is a 50-million gallon a day seawater desalination plant that will supply the San Diego region with approximately 7 percent of its drinking water needs. The project, being developed by Poseidon Resources Corp., will be the first large scale desalination plant on the West Coast and the largest of its kind in the Western Hemisphere. It will be located next to the Carlsbad power plant at the corner of Carlsbad Boulevard and Cannon Road.

The Carlsbad Desalination Project is currently under construction, including the desalination plant and the pipeline that will deliver the water to the San Diego County Water Authority distribution system.  For construction information, please visit the project website. The project is expected to be complete and delivering water in 2016.

The Carlsbad Desalination Project is estimated to cost about $700 million, excluding financing costs. This cost will be borne totally by Poseidon Resources, the private company building the plant.

For the average homeowner in the Carlsbad Municipal Water District service area, when the project comes on line in 2016 monthly water rates will increase about $8 to cover the regional supply of desalinated water from San Diego County Water Authority and about $3.50 a month for the local supply of desalinated water the district decided to purchase directly from the project. The total monthly cost would be about $11.40 a month, an increase of about 19 percent over the current water rate.

What is the status of the project?

Poseidon Resources, the project’s developer, has begun construction on the plant and pipeline.  The project should be complete and delivering water in 2016.

What’s Carlsbad’s role in the project?

The project is located in Carlsbad, but it is not a city project. The project’s developer is a private company called Poseidon Resources. The San Diego County Water Authority will purchase the water and distribute it to water agencies throughout the region, including in Carlsbad.

The City of Carlsbad was very involved in helping this project get off the ground, more than 10 years ago. Originally, the City of Carlsbad planned to buy water directly from Poseidon. When Poseidon could not secure financing for the project, the San Diego County Water Authority worked on a deal with Poseidon to purchase water from the desalination project and distribute it to water agencies in the region. This deal, called a water purchase agreement, was approved Nov. 29, 2012, by the San Diego County Water Authority board of directors.

Will Carlsbad get all its water from the desalination project?

No. The desalination project will provide about 7 percent of the region’s water supply in 2020.  Carlsbad Municipal Water District currently purchases all of its drinking water from the San Diego County Water Authority. Upon completion of the desalination facility, the County Water Authority will add desalinated water to its water supply mix prior to distributing water throughout its water distribution system. Water purchased by CMWD will be a blend of desalinated water and other imported water supplies. Since CMWD decided to purchase additional desalinated water directly from the project, CMWD will get about 2,500 acre feet of water a year directly from the project, in addition to the supply provided by the San Diego County Water Authority (one acre foot is roughly enough water to supply the needs one family of four for one year).

What does the water taste like?

Desalinated water is very high quality and tastes much like bottled water.

Is desalinated water expensive?

Desalinated water costs more that our current imported water supply, but those supplies are limited, and the price is increasing. It is estimated that in about 10 years, the cost of desalinated water would be comparable to the cost of imported supplies, and it will eventually be less expensive.

Will Carlsbad residents still have to conserve?

Water conservation will continue to be a way of life in Carlsbad because it is the right thing to do for the environment and helps the city be more sustainable.

What will the plant look like?

The project will be two-stories high, located north of the existing power plant. It will replace an old storage tank, which is higher than the new plant will be. The exterior of the plant will be built to look like an office building rather than an industrial building, so it will be compatible with future redevelopment of the power plant site once the old power plant is torn down.

What happens when the old power plant is torn down?

The desalination plant would not be significantly affected if current operating conditions at the power plant were to change. Poseidon and the City of Carlsbad have always anticipated that the desalination plant would eventually outlive the power plant. Poseidon has acquired the first right to use the power station water intake and outfall facilities, to continue full operations for up to 60 years.

What about the proposed second power plant?

A second power plant has been approved just east of the desalination project site. This project, if constructed, would not affect the desalination plant.

Will the project cause growth?

No. Growth in Carlsbad and San Diego County will occur in accordance with land use policies. In Carlsbad, voters approved a Growth Management Plan in 1986, which limits the amount of building that can occur and sets aside 40 percent of the city as open space. Regionally, SANDAG has projected that the county's population will grow by one million by 2030, with most of that occurring from births rather than in-migration. This project will help meet these projected needs and compensate for the expected cutbacks of supply from Northern California and the Colorado River.

What are the project’s effects on marine life?

The city took the initiative during the environmental review process to extensively study the desalination plant's impact to the environment. The city’s certified EIR concluded that the desalination plant can operate without significant impacts to marine life. In fact, since the desalination plant will withdraw from and discharge into the same seawater outfall pipeline that the power plant uses now, effects are essentially the same as current conditions. When and if the power plant stops using the seawater intake and outfall pipes, the desalination plant will continue to use them, subject first to approval of additional environmental review.

Does desalination require a lot of energy?

Carlsbad’s current water supply must be pumped from hundreds of miles away, over mountains, requiring significant energy. Although seawater desalination also requires energy, the desalination plant will be “carbon neutral” because Poseidon Resources is mitigating the plant’s energy use.