Desalination in San Diego
Desalination—the process of removing salt from saltwater to make drinking water—only sounds like a panacea for San Diego’s water supply dilemma. To understand the damaging complexities of desalination, let’s examine the Poseidon Resources’ proposed Carlsbad Desalination Plant.
But first, we recommend reading the Equinox Center's report that examines the costs of water supply options for San Diego.
Why is the Carlsbad Desalination Plant a bad idea?
The proposed 50-million-gallon-per-day Carlsbad Desalination Plant would use an outdated and destructive technology to intake 300 million gallons a day of water from the sensitive Agua Hedionda lagoon. Poseidon plans to convert lagoon water into drinking water using the existing intake infrastructure from the Encina Power Station, which plans to halt its use of ocean water to cool the power plant. Nationally, this “open ocean intake” technology has had a devastating impact on fisheries and habitat as the overwhelming majority of organisms pulled in are killed.
The Carlsbad Desalination Plant also requires more energy than any other water supply option in California. It trades water security for energy insecurity. Even with recent technological innovations, it takes 0.6 megawatts of power to produce one million gallons per day of potable water.
What has Coastkeeper done to protect San Diego’s ocean from desalination?
We have played a critical role in reducing the negative environmental impacts of the proposed Carlsbad Desalination Plant and setting positive precedent for future plants.
The Carlsbad Desalination Plant sidestepped key environmental review meant to ensure public participation in well-informed decision making. Specifically, Poseidon made major changes to the project after it passed through initial public process and environmental review. This should have triggered a review of the changes, but the agencies in charge never required that environmental review. Coastkeeper fights for the supplemental review to ensure that the project progresses in a transparent, public process to safeguard environmentally protective decisions.
Coastkeeper has educated elected officials, administrative board members and the public on the marine life, climate change and coastal resource impacts of desalination.
To compensate for the Carlsbad Desalination Plant’s negative environmental impacts, it must restore or create at least 37 and up to 55.4 acres of wetland in Southern California. Also as a result of Coastkeeper’s work, the Regional Water Board placed an additional restriction on the wetland improvements requiring prioritization of in-basin sites. And our push for actual impacts analysis will require Poseidon to monitor effects on marine life once the plant is operational. Agencies will use results from this monitoring to adjust the plant’s obligations to compensate for environmental harm.
Net-carbon Neutrality for Greenhouse Gas Emissions
Coastkeeper argued for full carbon neutrality—requiring Poseidon to offset all emissions associated with the desalination plant’s energy requirements, but the State Lands Commission took a compromise position that requires net-carbon neutrality. This will result in offsets of about 900,000 metric tons of carbon dioxide over the life of the Carlsbad Desalination Plant (though the plant will still contribute more than two million metric tons of carbon dioxide emissions over 30 years). Due exclusively to our efforts, Poseidon must provide additional carbon offsets for emissions from vehicle operations.
Coastkeeper challenged the bad precedent set by the administrative review of the Carlsbad Desalination Plant because it will be the largest desalination plant in the western hemisphere. Even if the legal challenges are lost, the willingness of environmental groups to challenge flawed administrative approvals stands as a warning to future project proponents. Shortly after the Carlsbad Desalination Plant received its final administrative approval, the San Diego County Water Authority announced its consideration of a larger desalination plant at Camp Pendleton. However, it has abandoned options that include co-location with power plants that use ocean water as cooling agents and has publicly stated it will pursue subsea floor intakes, an environmentally superior technology.
As media reports continually cite the Carlsbad process as the “test case” for desalination in California, Coastkeeper’s involvement is critical. Even with these improvements, desalination will not solve the water supply crisis in San Diego County. We’d rather first exhaust more environmentally friendly and cost-effective strategies like conservation and water recycling.