Could Geothermal Power Plants Become a Source of Lithium?

"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," argues a new article in Fast Company. "But that may soon change - for an unexpected reason. "Geothermal technologies are on the verge of unlocking vast quantities of lithium from naturally occurring hot brines beneath places like California's Salton Sea, a two-hour drive from San Diego..."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. 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.... Geothermal power has the ability to complement solar and wind energy as a baseload power source - it is constant, unlike sunshine and wind - and to provide energy and mineral security. It could also offer a professional bridge for oil, gas, and coal employees to transition into the clean energy economy. The industry could benefit from policies like risk mitigation funds to lessen drilling exploration costs, grant programs to demonstrate innovations, long-term power contracts, or tax incentives. Adding the production of critical metals like lithium, manganese, and zinc from geothermal brines could provide geothermal electrical power operators a new competitive advantage and help get geothermal onto the policy agenda.

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