Carlsbad desalination plant getting $274 million upgrade

WATER: New Pumping Facility to Lessen Environmental Impact

The Claude “Bud” Lewis Carlsbad Desalination Plant supplies about 50 million gallons of water to the San Diego region every day, enough to fill 75 Olympic swimming pools.

Currently the seven-year-old plant, built at a cost of more than $1 billion, is in the process of implementing a $274 million upgrade to its intake-discharge system. The result will be a new pumping facility that will keep the water flowing while greatly lessening the operation’s environmental impact.

President John F. Kennedy first proposed the idea of desalinating seawater in the 1960s. The origin of the Carlsbad plant dates back to 1991 when the site was first identified as a viable option for the ambitious project.

In 2005, the location for the plant plan was approved by the City of Carlsbad and two years later, final approval came from the California Coastal Commission.

Several years later financing closed for the $734 million project, with the San Diego County Water Authority (SDCWA) securing bonds and Poseidon Water, the private company managing the Carlsbad plant, posting $173 million in equity. Construction work began at the site in 2012. When operation started in 2015, the Carlsbad Desalination Plant was using the pumps of the neighboring Encina Power Station.

Jeremy Crutchfield, water resources department manager at SDCWA, said that the need for an upgrade was somewhat expected. California state regulations were put in place to start phasing out once-through cooling power plants like the Encina Power Station, but what wasn’t expected was further stipulations on the pumps that would replace those at Encina.

“A little hiccup that occurred was the state decided to enforce additional regulations. In 2015 they adopted the Ocean Plan Amendment for desalination intake and discharges,” Crutchfield said. “Not only did we need to replace the cooling water pumps after the power station was decommissioned, we also needed to comply with new technology requirements for the intake.”

Funding for this project was a joint effort between the SDCWA and Poseidon Water. According to Crutchfield, SDCWA secured most of their side of the $274 million from tax exempt bonds and a low-interest federal loan while Poseidon provided $55 million.

All this will pay for an entirely new intake-discharge facility with upgrades specifically designed to meet the Ocean Plan Amendment requirements.

Screening System

One of these modifications is a screening system with 1 mm mesh, about the width of the edge of a credit card, which is small enough to keep fish, larvae and other marine life from entering the system. This, combined with a low suction power of 24 feet per second, ensures a minimal impact on the marine environment.

Crutchfield also described racks that will be in place in front of the 1mm mesh to capture and remove debris. Any debris that slips through would be caught in the mesh screen which will be slowly rotating and have a spray wash system to clean off and dispose of the debris.

“It really makes this plant in Carlsbad among the most environmentally sensitive and friendly of its kind in the world,” Crutchfield said. “Being in California we have some very strict environmental requirements and the result of that is having the benefit of operations that mitigate as much impact to the environment as possible.”

Keeping up with environmental regulations has been a roadblock for potential desalination plants, Crutchfield said; a plant in Huntington Beach that would have been a sister project to the Carlsbad plant, did not get the permits needed for construction for that reason.

Subsurface pumping, where water is pumped through the sand of the ocean floor, is the preferred method laid out by state regulations when considering new desal plants.

There are 12 seawater desalination plants in operation today in California, with two more projects currently in the development stage.

Glenn Farrel, executive director of

CalDesal, said that one of these, the

Doheny Desalination Project, still has project elements that need to be addressed but could be online as early as 2027. The second, the Monterey Peninsula Water Supply Management Project, has achieved some permitting success in 2022, but still has more local permitting to work out, according to Farrel.

New Systems Online by 2024

“We work with CalDesal, which is a sea water and brackish water advocacy group for the state, trying to work with the state and regulators to find a path forward to really allow desalination to be a part of the state’s water supply strategy and diversification plan,” Crutchfield said.

Desalination has been a vital part of San Diego’s water supply as the Carlsbad plant supplies nearly 10% of the region’s water. Production at the Carlsbad plant has been allowed to continue uninterrupted during these upgrades as work is done to phase in the new system. The ongoing upgrade project is expected to be completed with the new systems online in 2024. Farrel believes that desalination still has a long way to go in California. As renewable energy is able to be integrated with desalination plants to further reduce environmental impacts while also potentially reducing the cost of desalinated water supplies, Farrel said new plants become more feasible.

“The [California] Governor - in his August 2022 Water Supply Strategy - outlined quantifiable goals for desalination production and called on his state agencies to expedite and streamline the regulatory permitting processes for desalination,” Farrel said. “I think that both of these together help to demonstrate a path forward for broader consideration of desalination in California’s future.” ■