Gaze across the Salton Sea, a sparkling oasis in the California desert, and you'll see white plumes of steam rising against the hazy Chocolate Mountains.
The steam comes from 11 geothermal power plants, nestled between the accidental lake and the verdant farm fields of the Imperial Valley. The area has been churning out climate-friendly geothermal energy since the 1980s, long before solar panels and wind turbines became cheap and abundant.
The geothermal plants could soon contribute to California's war against climate change in a new way: by producing lithium, a key ingredient in batteries that power electric cars and store solar power for use after dark.
Companies have tried for decades to extract lithium from the super-heated underground fluid used for energy generation at the southern end of the Salton Sea, home to one of the world's most powerful natural geothermal hot spots. Just a few years ago, a technology startup called Simbol Materials went bust shortly after Elon Musk's Tesla Inc. offered to buy it for $325 million.
Now another company claims to have solved the lithium problem.
The process begins in a 45-foot-long shipping container at the John L. Featherstone geothermal plant, a few miles from the lake's receding shoreline. The plant is owned by Chevron Corp., the New Zealand electricity generator Mercury NZ Limited and a San Diego-based company called EnergySource.
EnergySource, which built and operates the plant, filed a patent application for a lithium extraction technique in June, after three years working on the process. The company wouldn't allow photographs to be taken inside the shipping container during a recent tour, for fear of revealing details to competitors.
But Chief Operating Officer Derek Benson offered a peek inside the box, which was crowded with tanks and other equipment and emitted a steady hum.
"We've got it all instrumented up -- just a small version of the commercial unit," Benson said.
Benson said EnergySource has produced "kilograms" of battery-grade lithium. A commercial extraction facility, he estimated, could produce 16,000 tons of lithium carbonate equivalent annually, with the potential for around 100,000 tons if the other Salton Sea geothermal plants adopt the firm's technology.