Salton Sea

The Salton Sea in Imperial Valley, California. A new CEC-funded research project will extract geothermal brine from the sea and use lithium within the brine to build batteries and potentially reduce the cost of geothermal power generation. 

Brine extraction from California’s Salton Sea could significantly decrease the cost of geothermal power generation in the state and supply lithium for batteries, the California Energy Commission said in a funding award approved this week.

The CEC on May 13 approved the Salton Sea Geothermal Lithium Recovery Demonstration Project, awarding $6 million to Berkshire Hathaway Energy Renewables to pull brine out of the Salton Sea and pan it for battery-grade lithium carbonate.

The process could decrease the cost of geothermal electricity generation by up to 35 percent, encourage construction of new geothermal plants in the state, and enable California to shift more of its baseload generation capacity from natural gas to geothermal, according to the CEC’s award.

“I see lithium as the oil of the clean-energy future,” CEC Chair David Hochschild said at a May 13 business meeting. “This really fills a big missing piece in the [renewables] puzzle.”

California’s vast lithium deposits—as much as one-third of the world’s current lithium demand—are seen as a way to propel the state’s green economy, the CEC said in a news release. Deposits in the Imperial Valley, where the Salton Sea is located, could potentially produce about $860 million annually in revenue, the commission said.

In the extraction process, BHE Renewables must produce at least 100 gallons of brine per minute and yield lithium carbonate at a cost of about $4,000 per ton. But extracting lithium from geothermal brine is both technologically and financially challenging, the CEC’s award says. The best sources of brine are made of only about 0.1 percent lithium and are typically accessed using brine evaporation ponds or environmentally harmful acids and bases that break down hard rock. Evaporation pond resources take up to 18 months to produce the materials and only make financial sense for a few brine resources in South America or in the desert east of the Sierra Nevada range, while hard-rock techniques require significant amounts of compounds that are environmentally hazardous and require disposal, the CEC said. As a result, there has been only one new lithium brine evaporation project in the U.S. in the past 25 years, despite soaring lithium demand and prices, the award says.

One of the major challenges for lithium production in the Salton Sea is the harsh chemical makeup of its brine, according to the award. BHE Renewables will use “a proprietary ion exchange process” that filters out lithium directly from flowing brine within a few hours, CEC staff said in an email to California Energy Markets. This direct lithium-extraction technology does not require large evaporation ponds where brine sits under the sun for months until most of the water has evaporated and precipitated minerals can be collected, staff said.

The project developer intends to minimize environmental impacts by avoiding evaporation pond usage and will try to use less than 50,000 gallons of fresh water per ton of lithium carbonate, among other goals.

BHE Renewables currently owns 10 geothermal facilities in Imperial Valley that have a total capacity of 345 MW. The facilities generated about 2.5 GWh of power in 2019, while the total geothermal generation in California in 2019 was about 11,000 GWh from 43 geothermal power plants, CEC staff told CEM.

At the meeting, the CEC also approved the following items, among others:

  • GFO-19-301: Advancing Next-Generation Heating, Cooling and Water Heating Systems. Approved about $11.4 million for various project developers that are building innovative, efficient and environmentally friendly space-conditioning, refrigeration and water-heating systems in buildings. The systems must have efficiencies comparable to or higher than current high-efficiency equipment and use low or no global warming potential refrigerants or non-vapor compression technology.
  • GFO-15-312: Accelerating the Deployment of Advanced Energy Communities, Phase 2. Approved about $9.1 million for The Energy Coalition to build out and demonstrate the Bassett-Avocado Heights Advanced Energy Community. The project includes a community solar and storage system that will offset the annual electricity load of low-income enrolled participants; a microgrid resiliency hub that will provide power during emergencies, severe heat days or blackouts; 50 single-family homes with solar power and battery storage that will be integrated with a blockchain community network pilot; and a mobile grid of electric-vehicle charging stations, according to the CEC.
  • Proposition 39: California Clean Energy Jobs Act K-12 Program. Approved a one-year extension of the project’s completion date to June 30, 2021, due to the closure of all public schools in California caused by COVID-19.
  • GFO-19-901: Food Production Investment Program. Approved about $4 million for California dairies to design, install and operate a high-temperature solar-thermal energy system at a milk and butter processing facility in Turlock.
  • GFO-19-503: Demonstrating Replicable, Innovative Large-Scale Heat Recovery Systems in the Industrial Sector. Approved about $3 million to test and demonstrate systems to recover waste heat for heating water. One of the projects will develop and test a polymeric heat exchanger that can reduce natural gas usage by 20 percent in industrial facilities.

Staff Writer

David Krause is an energy reporter covering the California Energy Commission and Air Resources Board. He writes about transportation, climate change, utilities, and wildfires. He has an MFA in Writing, an MA in English, and a BS in Civil Engineering.