BY BRYANT JONES AND MICHAEL MCKIBBEN
Geothermal energy has long been the forgotten member of the clean energy family, overshadowed by relatively cheap solar and wind power, despite its proven potential. But that may soon change—for an unexpected reason.
Lithium is essential for lithium-ion batteries, which power electric vehicles and energy storage. Demand for these batteries is quickly rising, but the U.S. is currently heavily reliant on lithium imports from other countries—most of the nation’s lithium supply comes from Argentina, Chile, Russia, and China. The ability to recover critical minerals from geothermal brines in the U.S. could have important implications for energy and mineral security, as well as global supply chains, workforce transitions, and geopolitics.
As a geologist who works with geothermal brines and an energy policy scholar, we believe this technology can bolster the nation’s critical minerals supply chain at a time when concerns about the supply chain’s security are rising.
ENOUGH LITHIUM TO FAR EXCEED TODAY’S US DEMAND
Geothermal power plants use heat from the earth to generate a constant supply of steam to run turbines that produce electricity. The plants operate by bringing up a complex saline solution located far underground, where it absorbs heat and is enriched with minerals such as lithium, manganese, zinc, potassium, and boron.
Geothermal brines are the concentrated liquid left over after heat and steam are extracted at a geothermal plant. In the Salton Sea plants, these brines contain high concentrations—about 30%—of dissolved solids.
If test projects now underway prove that battery-grade lithium can be extracted from these brines cost effectively, 11 existing geothermal plants along the Salton Sea alone could have the potential to produce enough lithium metal to provide about 10 times the current U.S. demand.
Three operators at the Salton Sea geothermal field are in various stages of designing, constructing, and testing pilot plants for direct lithium extraction from the hot brines.
At full production capacity, the 11 existing power plants near the Salton Sea, which currently generate about 432 megawatts of electricity, could also produce about 20,000 metric tons of lithium metal per year. At current prices, the annual market value of this metal would be more than $5 billion.