As Lithium Drilling Advances at the Salton Sea, Researchers Work Out the Details
The Salton Sea – a shallow, landlocked, highly-saline body on the border of southern Riverside and northern Imperial counties – may be holding a giant key to the future. Researchers are working to understand how much lithium lies deep in the earth beneath the sea. The area is already home to eleven geothermal power plants, which pull up a brine from a mile down, create steam and spin turbines to create energy.
That brine is also rich in lithium, which can be filtered out using special processes. Eventually, that lithium could be used to create batteries for mobile phones, laptops and electric cars.
California governor Gavin Newsom called the Imperial Valley, where the Salton Sea is located, the "Saudi Arabia of Lithium." He has touted its significance to the state’s of renewable energy goals and to economic development in the region. A report from the California Energy Commission said the Salton Sea area alone could generate more than 600,000 tons per year of lithium carbonate – more than the total global demand in 2021.
Yet it will take years to know how much lithium is actually present, and which technologies will work best to extract it safely. There are still questions about environmental impacts in a region that has long suffered high rates of air pollution among other environmental hazards.
To answer some of these questions, the Department of Energy is hosting a $4 million competition to advance technologies and techniques to support lithium extraction from geothermal brines at the Salton Sea. The competition is currently in its second stage, where participants have submitted their concepts, and semifinalists are now in the design phase. Of the fifteen teams still in the running, five will be chosen to test their inventions.
No matter how stressed the [lithium] industry was from phones and laptops, the [demand from] the electric vehicle industry puts that to shame.Angelo Kirchon, Energy X Research Director
One of the teams is run by Benny Freeman, a professor of chemical engineering at the University of Texas, and science advisory board chairman of a company spun off from his lab called Energy X. When the group heard about the DOE prize, Angelo Kirchon, Energy X’s research director, said it was a "no brainer" to enter, since they already worked on lithium extraction elsewhere in the world.
The team’s technology takes the raw liquid, full of magnesium, calcium, and other minerals, and uses an electrical current to move just the lithium and chloride to another receiver liquid. A second step directly converts the lithium chloride into lithium hydroxide. "In one system, you not only purify the lithium, but then you also generate lithium hydroxide – battery-grade and ready to be sold – at the back end of the process," says Kirchon. "We’re trying to cut out the middle steps."
Cutting out steps would make the process cheaper, and more readily available, Kirchon says. "It’s pretty crazy how needed these materials are. The same amount of lithium used for 10,000 iPhones goes into one stack of electric vehicle batteries," he says, adding that an electric vehicle requires more than one battery. "So no matter how stressed the [lithium] industry was from phones and laptops, the [demand from] the electric vehicle industry puts that to shame."
The Salton Sea is a special area, geologically speaking: its brine is 25 percent salt by weight. Most other geothermal systems have much lower concentrations of salts in their geothermal fluids, says Pat Dobson, a Lawrence Berkeley National Lab scientist who is leading a project to research the potential lithium stores of the area, how best to extract them, and what the environmental impacts will be. Dobson’s research is funded by the Department of Energy, but his team is not part of the current contest. "The setting of the Salton Sea is unique – it's right near the mouth of the Colorado River, in a very dry environment. So there's a lot of evaporation," Dobson explains. The heat concentrates the elements washing down the river, forming a strong salty fluid – brine – which has to be pulled up from deep below the ground.
There are eleven commercial geothermal plants at the Salton Sea, producing 400 megawatts of geothermal energy a year. That's enough to power more than 400,000 average California homes with a clean, renewable form of energy. In the geothermal process, hot fluids are pumped up from deep underground and the heat is then converted to electricity. Normally the cooled fluid would simply be reinjected underground, but the idea is to first extract the lithium from the brine before injecting it back. A trial of lithium drilling, run by Controlled Thermal Resources, is already happening at the site, and two other companies are in different stages of starting to drill.
Energy Source should begin construction on a lithium plant by April 1; Berkshire Hathaway Energy has received state funding for a lithium demonstration facility, according to the L.A. Times. They expect to begin commercial extraction in 2026.
"It’s basically a closed loop that doesn’t leave anything on the surface," says Michael McKibben, an emeritus geology professor at UC Irvine, who is working with Dobson at Lawrence Berkeley National Laboratory.
That method is very different from what commonly happens around the world. In Chile, where the largest lithium mines are located, workers dig a series of pools and let the sun evaporate the minerals out over the course of years. The brine is transferred from pool to pool as it concentrates. These methods are more water intensive because, while the brine isn’t useful for drinking water, it contributes to the desert’s water cycle, and when it evaporates, it’s gone. In Australia, there are open-pit mines, which use acids to dissolve rock and get the lithium out.
James Blair, an anthropologist at Cal Poly Pomona who has studied lithium extraction’s impacts on communities in South America, says the community around the Salton Sea is wary of the plan to develop lithium technology – and with good reason. "In the past there have been so many industries to deliver promises of stable jobs," he says. "Those promises have been broken time and time again."
Blair adds that there is an opportunity for this development to be done in a just and equitable way, with the local community and environmental justice organizations involved in the discussions. "It's a different process which has potential as a cleaner alternative – yet you still have this problem of green extractivism," he says.
Even if the technologies use less water and land, and even as they reduce emissions from fossil fuel burning, Blair said that the geothermal and lithium industries can still can do damage to people and ecosystems as they pursue ongoing drilling activities. He lists off the potential environmental issues in the area: Protecting Indigenous ancestral lands. Concerns about airquality, as plants emit pollutants like hydrogen sulfide, ammonia and fine particles. And the big one: devoting precious land and water resources to lithium extraction amid the crisis of the rapidly shrinking Salton Sea, which is causing habitat loss and toxic air pollution in the area.
McKibben estimates that the techniques proposed to extract lithium around the Salton Sea would take 90% less water than the methods used in South America, and there’s no blasting or crushing. Yet the methods being researched would also, in some cases, require chemical reagents to process the lithium – compounds that could end up in the local environment.
The other issue, he says, is that expanding geothermal production in a seismically active place might induce some small earthquakes. That’s something his team will be studying closely over the next 15 months.
With the boom in lithium production, the area where the Salton Sea lies would have to adjust to new mines and the changes they bring to the region. Currently, the Imperial Valley has the highest unemployment rate in California and lithium mining could mean work opportunities, if developed equitably, with job training, infrastructure and agreements with local communities.
At the moment the element is processed into batteries in China, but many electric car companies – like General Motors, which is backing Controlled Thermal Resources, and signed an agreement to partner with the producer – would prefer to keep the manufacturing of batteries in the U.S.; this could create potential for even more jobs.
Other places in the world are also starting to examine the potential of lithium and geothermal brines, Dobson says, in particular at the border between Germany and France, and in Cornwall, England. "But the [Salton Sea] seems to be sort of the motherlode in terms of geothermal systems with really high concentrations of lithium."
