By Edward Ring, Director of Water and Energy Policy at the California Policy Center
Why is it axiomatic among California’s water agencies and policymakers that large scale desalination is inconceivable in California? That certainly isn’t the case in other arid locales. In 2024, an estimated 30 million acre feet of fresh water was produced by desalination plants worldwide.
On the coast of the Red Sea, about 60 miles south of the port city Jeddah, and only slightly further from the inland city of Mecca, the Shoaiba Desalination Complex produces nearly 900,000 acre feet of fresh water per year. Situated on approximately 1,200 acres, this one installation could, if it were located in California, supply more than 12 percent of ALL California’s urban water consumption. That’s not very much land, for an awful lot of water.
The energy cost of desalination is often overstated. Modern desalination plants require about 3,500 kilowatt-hours per acre foot. That equates to 3,500 gigawatt-hours (GWH) per million acre feet. California’s total electricity consumption is currently not quite 300,000 GWH per year, with the state legislature determined to ramp that up to at least 500,000 GWH per year by 2045. And if they’re serious about electrifying the state’s economy, they could require as much as twice that.
This means that the energy price per million acre feet of fresh water barely exceeds one percent of California’s current total consumption of electricity, and only about one-half of one percent of where electricity consumption is headed. That’s not much, and it’s comparable to the energy needed to pump water from the Sacramento-San Joaquin Delta to the Los Angeles Basin, and it’s even likely to be within a competitive range of the energy needed to recycle wastewater, particularly taking into account the additional filtration that’s going to be necessary to remove PFAS.
Even if the electricity needed for desalination were excessive (it’s not), there is a fundamental premise regarding electricity that needs wider circulation: electricity is going to be cheap and abundant within the next 20 years. We may confidently predict this based on likely advances in PV/battery technology, SMR nuclear technology, and even ultra-efficient modern natural gas power generation, impelled by the political and financial power of California’s tech sector abruptly developing a voracious appetite for electricity.
Environmentalist objections to desalination often point to problems with intakes, despite them being successfully mitigated around the world by using very large, low-velocity, fine-screened open-ocean filters. As for brine, the seawater that remains after fresh water has been extracted, its concentration of salt is only twice that of the ocean. This brine can be discharged under pressure into the California Current, where it will be naturally and immediately disbursed.
What also stops desalination projects is the exorbitant cost, but even at California prices the cost competes with other solutions. The proposed Pacheco Reservoir expansion in Santa Clara County is projected to cost at least $2.5 billion to add 134,000 acre feet of storage capacity. That equates to $18,657 in construction cost per acre foot of storage, but storage capacity never equals annual yield. The average withdrawals from surface reservoirs rarely exceed 50 percent, doubling the effective capital cost to over $37,000 per acre foot per year. A 30-year 4 percent loan for that would add at least $2,140 to the end-user’s cost per acre foot.
With desalination, on the other hand, production is guaranteed. The proposed Huntington Beach plant would have produced 56,000 acre feet of fresh water per year at a construction cost of $1.4 billion, which is $26,786 in construction cost per acre feet of fresh water. A 30 year 4 percent loan for that would add $1,549 to the cost per acre foot.
But are exorbitant costs inevitable? What about the Saudis? In 2018, they announced plans to build new desalination plants with a total capacity of 71,000 acre feet per year at a cost of $530 million. Even in inflation adjusted 2025 dollars, that is only $9,573 of construction cost per acre foot of capacity, yielding a financing cost (30 years, 4 percent) of $432 per acre foot. No wonder they can grow crops with desalinated seawater.
Which brings us to Texas, where the state government has announced plans to develop a 500,000 acre foot per year seawater desalination complex at a cost of $6.0 billion; that’s $12,000 in construction cost per acre foot of annual capacity. That adds a financing cost of only $694 to every acre foot of fresh water produced.
It is unlikely that Texas will actually bring a project in at a cost that low. But the mere fact that the preliminary cost per acre foot estimates in Huntington Beach were more than twice what they’re projecting in Corpus Christi ought to explain just how skewed prices for desalination have gotten in California. If a plant producing nearly a million acre feet of fresh water per year only needs to occupy 1,200 acres, and only requires 3,500 gigawatt-hours per year, what is stopping us?
Two or three 1,200 acre seawater desalination complexes, built at Texas prices instead of California’s hyper-regulated, punitively elevated prices, could contribute millions (plural) of fresh water to our water supply every year, while consuming a negligible fraction of our state’s total electrical consumption. The net impact of so much more water would help the environment far more than a few drops of saltier water might impact the vast Pacific Ocean.
Sadly, however, and to only exaggerate a bit, nothing big in California gets built anymore. The reasons are entirely political. Abundance beckons, but we turn it away, in rejection of everything that once defined us as a culture.
