The picture most people have of lithium is a hard rock mine or a blue evaporation pond.
Nobody pictures a power plant.
At the southern edge of California’s Salton Sea, geothermal wells pull up water hot enough to spin turbines.
That water is already loaded with lithium.
Getting it out of the brine, right there at the plant, is the part nobody has finished.
So what is in that water, and why has it been so hard to capture?
What the brine is actually carrying underground
The Salton Sea’s geothermal wells tap brine that has spent ages underground, reaching temperatures steep enough to flash into steam and drive a turbine the moment the pressure drops at the surface.
That steam is the whole reason the plants exist. The leftover liquid, still scalding and thick with dissolved minerals, has long been treated as spent fluid headed back down an injection well. It carries a notable lithium concentration, on the order of a few hundred milligrams per liter, far thinner than the brines of South America.
What makes the arithmetic work is volume. A geothermal plant can push more than 6,000 gallons of brine a minute, so even a record breaking thin stream is worth chasing.
The recovery idea is simple on paper. Lime conditions the brine first, then the fluid runs through inert resin beads that take the lithium chloride out of it, with hydrochloric acid used to complete the extraction, after which the stripped brine rejoins the plant’s normal loop and goes back underground.
Inside the system built to draw it out at the plant
At a geothermal facility on Crummer Road near Calipatria, in Imperial County, an energy operator set out to test lithium extraction on brine produced at its own plants, using a unit designed to process 100 gallons of geothermal brine per minute.
That is a thin side stream next to a plant’s full flow, and it was deliberately meant to stay that way. In the first stage, calcium hydroxide already on site conditions the brine before it reaches the extraction step, where resin beads from a specialty supplier take up the lithium chloride.
The treated brine streams then return to the existing processing system. That is why the work amounted to minor treatment of a small side stream. The state filing for the project noted that the activities would not affect any functions of the geothermal plant.
Where the numbers get genuinely strange
A federal analysis put hard figures on the resource for the first time. It found that with expected technology advances the region’s total resources could contain more than 3,400 kilotons of lithium, enough to support over 375 million electric vehicle batteries.
The brine behind that estimate averages 198 parts per million lithium. The self characterized core of the reservoir holds an estimated 4.1 million metric tons of lithium carbonate equivalent, rising to 18 million if the probable extent is included.
Brine production at the field has averaged just over 120 million metric tons a year. At that concentration, that carries roughly 127,000 metric tons of lithium carbonate equivalent annually, yet none of it is currently recovered.
A striking figure sits in the gap between what flows and what is captured. Existing geothermal capacity of 400 megawatts is estimated to produce about 21,500 tons of lithium in brine each year. An earlier state report concluded the field could produce more than 600,000 tons of lithium carbonate a year if fully developed.
The catch still working itself out
The first attempt to prove the process at something approaching commercial size did not land.
The California Energy Commission’s project record shows that engineering, design, construction and installation were completed, but the project did not demonstrate lithium recovery at a self tenth commercial scale, citing failure of the selected media to perform under field conditions. The company said it would keep pursuing another lithium recovery technology using its own funds.
The chemistry is the hard part. Brine has to be treated to adjust its pH and separate out silica and heavy metals before any selective step can work, and the equipment has to survive a hot, hypersaline, corrosive stream for years rather than hours.
One operator told reporters in late 2026 that it had completed a direct lithium extraction pilot and converted the output into record grade lithium compounds, with a demonstration plant planned at Calipatria before a decision on a commercial project. Other engineers are chasing value in water that is already moving, the same logic behind this pumped storage approach.
What happens if the pipe keeps paying off
If a working system ever reaches full scale, the change would be almost invisible to anyone driving past. The geothermal plants would keep making electricity exactly as before, only with a second product riding along in the same pipe that now carries only spent brine.
That would matter well beyond Imperial County. The United States currently has limited ability to obtain domestically sourced lithium, so nearly all of what the country uses is imported.
A domestic lithium source hiding inside existing power infrastructure, rather than a new mine carved into open desert, is the kind of reversal that rarely makes the evening news until the trucks start rolling, much the way a parallel instinct drives work on retired hardware turned into new feedstock rather than waste.
For now, the brine keeps flowing up and back down again, the lithium riding the loop untouched, and the shallow, overlooked lake at the edge of the Imperial Valley keeps holding a bigger surprise underground than its flat, dusty shoreline would ever suggest.
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