The U.S. Department of Energy (DOE) Geothermal Technologies Office (GTO) awarded over $6 million across four National Labs for research that will help advance and develop the U.S. critical minerals and materials supply chain. Research teams in Berkeley Lab’s Energy Geosciences Division (EGD) are involved with four of the seven funded projects, leading two of the efforts and as collaborators with Sandia National Lab and Idaho National Lab on two others.

Lithium is a critical mineral sourced from below Earth’s surface and the main component of lithium-ion batteries which power electric vehicles and many household appliances. Metals like this are crucial for developing clean-energy technologies that can help fuel the U.S. transition to a carbon-free economy. However, the conventional lithium resources that are accessible mostly through open pit mining or evaporation ponds are located outside the U.S. and have a relatively large carbon and water footprint. With the aim to develop a stable, more sustainable supply from the sources that exist within the country, the awarded projects will help to advance research into domestic metal resources as well as the crucial development of technologies to recover them. 

Berkeley Lab led a previous research effort to characterize and capture lithium from the geothermal brine beneath California’s Salton Sea which concluded in 2023 with a report called Characterizing the Geothermal Lithium Resource at the Salton Sea.

“This report on sourcing lithium from geothermal brine in California Salton Sea Region, also known as Lithium Valley, was successful in shedding light on the potential that exists to secure sufficient amounts of lithium in an environmentally sustainable manner right here at home in the U.S.,” said Senior Scientist Peter Nico, Interim Director of EGD. “Now, the DOE is encouraging groups to go other places and to some extent replicate that kind of investigation, to see what other brine-based lithium resources are out there.”

One project, led by Staff Scientist Eric Sonnenthal in collaboration with the National Renewable Energy Laboratory and University of California, Riverside, will aim to further study and characterize lithium, in addition to other elements in the “superhot,” extremely deep portions of the geothermal field beneath the Salton Sea. The team will investigate the behavior of critical elements including lithium, manganese, zinc, rubidium, and strontium–elements that play an important role in energy transition technologies like batteries–at unexplored temperatures and depths reaching up to 350 degrees Celsius and over 2,800 meters below the surface. The team aims to do this by collecting samples of rocks located in these conditions to understand how temperature and depth plays a role in mineral concentration.

Beyond the Salton Sea, the project LiRe-Smac, led by Staff Scientist Eva Schill and in collaboration with NuTech Energy Alliance, will focus on understanding the different lithium concentrations across the Smackover Formation that in some wells reaches up to one gram of lithium per liter of brine. The Smackover Formation, extending from western Texas to northern Florida along the Gulf of Mexico coast, is a limestone aquifer that has been extensively used for oil and gas production. Here, the origin and the process of lithium transfer from the rocks to the brine occur at lower temperature and are expected to differ from the ones at Salton Sea.

The goal of this project is to study the lithium “cycle” within the Smackover Formation, investigating the source of lithium, how much of it accumulates in minerals and fluids, and where the element ultimately is extractable. This effort will help scientists understand the potential of this formation to act as a significant source of more environmentally and economically sustainably sourced lithium that can help power a green revolution. 

Schill and Sonnenthal will also contribute to projects led by Sandia and Idaho National Laboratories. Sonnenthal will deepen the study of the Smackover Formation, focusing specifically on the characterization and quantification of brines in northern Louisiana. Schill will contribute to a material and drilling technology study that aims at improving drilling in super-hot reservoirs so that higher lithium concentrations such as occur below the conventional reservoir at Salton Sea. 

“With these projects EGD intends to support the US industry to catch up and go beyond early demonstrators of lithium extraction from geothermal brines in Europe,” said Staff Scientist Eva Schill, Geothermal Systems Program Lead at EGD. “A positive side effect of the co-production of lithium from geothermal brine can be an increase in the economic efficiency of geothermal power plants.” 

EGD has over four decades of research experience relating to geothermal resource capture and quantification, making the research team uniquely suited to lead and collaborate on large-scale projects propelling this urgent national effort forward. These researchers will leverage Berkeley Lab’s advanced resources and research methods, spanning from the field to the lab and to models, to apply expertise in multidisciplinary approaches, develop models of interacting processes, image below-ground natural resources, and advance element-tracing techniques that will help to secure more sustainable and renewable energy and electronics.