Beyond the traditional value that geothermal resources can provide for electricity or thermal applications, tapping into geothermal brines for valuable byproducts, including lithium, presents a promising opportunity. Lithium is a major component of high-charge-density batteries for electric vehicles and grid-scale electricity storage. It is expected that global demand for lithium will increase by 500% by 2050 due to widespread adoption of electric vehicles and grid-scale battery storage, and thus lithium supplies will become a crucial element in the clean energy supply chain. However, the U.S. lithium stock is almost entirely imported, with only 1% of U.S. lithium supply being sourced domestically. Furthermore, traditional sources of lithium—extraction from salar brines in the high Andean desert and hard-rock mining from pegmatite deposits—are environmentally destructive. This combination of rapidly expanding global demand and lack of a safe, domestic supply are the basis for the U.S. Department of Interior’s decision to designate lithium as one of the 35 minerals deemed “critical to U.S. national security and the economy.” The federal government recognizes the need to develop a safe, domestic, cost-competitive source of lithium to ensure American leadership in the transition to a carbon-free economy and a robust domestic supply chain.

Geothermal brines could be one potential source of satisfactory lithium. GTO has funded a number of projects in recent years exploring the potential to extract critical minerals, including lithium, from geothermal fluids as well as from produced oil and gas waters. While many of these studies found that the concentrations of critical minerals in these fluids were too low to be extracted economically, lithium, particularly from geothermal fluids in the Imperial Valley of California, represented a significant outlier. Annual lithium resource potential in the Salton Sea region is estimated at 600,000 tons, which currently exceeds the annual U.S. demand for lithium and could transform the United States from a net lithium importer to a net exporter. These findings have motivated a small but growing effort across private industry, state governments, and the federal government to develop safe, economic, environmentally conscious methods to extract lithium from these geothermal brines.