Let’s talk about seawater desalination

Here at Monterey Bay Aquarium, we know a little about seawater desalination. When we added our Open Sea wing in the late 1990s, we built a small-scale desal plant to produce the water that flushes the Aquarium’s toilets.

Tiny as it is, our desal plant drew attention as one of the first in California. “We had engineers from all over the state looking at it,” says Wayne Sperduto, the Aquarium’s facility systems supervisor.

An aerial view of the Carlsbad Desalination Plant.

Our onsite desal plant is capable of producing about 22 gallons of fresh water per minute. Compare that to the Carlsbad Desalination Plant, which last December began delivering fresh water to San Diego County – to the tune of 35,000 gallons per minute.

California’s ongoing drought is driving interest in desalination across the state, and we’re a part of the conversation. In January, Stanford’s Woods Institute for the Environment, through the Center for Ocean Solutions and Water in the West, collaborated with Monterey Bay Aquarium and The Nature Conservancy to convene a wide range of experts to discuss the potential impacts of ocean desalination on coastal and marine ecosystems.

An intake pipe carries seawater into the Carlsbad Desalination Plant.

The experts – from academic institutions, non-governmental organizations, private industry and government agencies – swapped notes on the best available science, technology and policy related to desalination. They also identified key issues, challenges and knowledge gaps in desalination science and policy.

We’re sharing the discussions and conclusions of that dialogue in this newly released report, as a valuable tool for public and policymakers to consider in as desalination projects advance across the state, and around the West.

Among the conclusions:

• Although desalination may prove critically important to meet the needs of specific coastal communities, it is unlikely to contribute significantly to overall water supplies in California due to its high cost, energy demands and other factors.
• California should put its focus on research and policies that can identify locations along the coast where the impacts of desalination plants on the marine environment can most easily be minimized.

This kind of collaboration is important, especially as climate change increasingly affects historic rain and snowfall patterns.

With forethought, California will be well positioned to balance the need to develop sustainable water supplies with the state’s longstanding leadership in preserving healthy coastal environments.

You can learn more about the Aquarium’s ocean policy work on our Conservation and Science page.