Traditional hard rock lithium mining is energy- and resource-intense. But lithium is a key component of rechargeable lithium-ion batteries, like those used in electric vehicles. We spoke with Dr. Pat Dobson of the Geothermal Systems Program at the Lawrence Berkeley National Laboratory about his work with alternative mining techniques used in the Salton Sea, in Southern California. For a transcript of this episode, please visit https://climatebreak.org/lithium-mining-in-salton-sea-geothermal-system/
While the use of lithium to power electric vehicle batteries has been around for close to a decade, and while car manufacturers and scientists have been on the hunt for a more efficient battery, today most manufacturers rely on lithium batteries as their primary go-to for power. This leads to a higher demand for lithium mining. Traditional alkaline batteries cannot be repeatedly recharged, while lithium batteries can be reused and recharged efficiently. Another traditional battery—lead-acid—while cheaper to manufacture than lithium batteries has a comparatively lower energy density, which results in a shorter battery life.
When lithium was first discovered, it was retrieved through open-pit mining, a more energy- and resource-intensive method of extraction. In the late 1990s, companies began to extract lithium from brines drawn up from deep underground. The salt-filled groundwater brine is filled with lithium byproducts, and once the water evaporates, lithium salts can be extracted. The brine is screened and filtered, and the drying process itself can take upwards of a year. Large pools of brine are left to sit and evaporate after being pumped up from underground.
In particular, the Salton Sea, located in Southern California, has been found to contain large amounts of lithium that can be extracted from the salts. If developers and scientists can secure a more efficient way of unearthing the lithium from that source, the Salton Sea could prove to be a major site for lithium production for the US. Currently, companies are focusing their efforts on developing new technology and chemical procedures to extract lithium from the deposits in a more sustainable manner.
While lithium itself provides a more sustainable, cleaner energy source, the process of acquiring lithium through mining has severe environmental impacts. Lithium mining is very disruptive to ecosystems, requiring large land areas for extraction and evaporation. This often leads to impacts on habit and even food production depending on the location of the mine. Lithium mining can also impact the natural composition of the soil in which sites are located. The extraction process is also one that is extremely water-intensive; water is crucial in dissolving the brine and flushing out the lithium. Once extracted and integrated into batteries, lithium has proved to be reliable, efficient, and essential for powering several different renewable energy sources, namely solar and wind, as well as electric vehicles.
Patrick F. Dobson is the head staff scientist of the Geothermal Systems Program at the Lawrence Berkeley National Laboratory. He is heavily involved in research surrounding geological and geochemical processes, more specifically his work focuses on the volcanic rocks and the reaction shared between water-rock relations. Dobson’s current work at the lab focuses on exploring methods to extract lithium from deposits deep in the Salton Sea. He and his team are devoted to understanding more about the rock composition at the Salton Sea and how establishing geothermal systems in the area could affect lithium production. Dobson has an extensive background in laboratory research and scholarly publications, much of which has largely focused on using geochemistry to record changes in rocks located at geothermal sites. His learnings have significantly contributed to a better understanding of geothermal systems as well as helped in deciding optimal sites for geothermal drilling.
For a transcript of this episode, please visit https://climatebreak.org/lithium-mining-in-salton-sea-geothermal-system/
Ethan: I'm Ethan Elkind, and you're listening to Climate Break. Climate solutions in a hurry. Today's proposal: Turning Southern California’s Salton Sea geothermal system into a local source of lithium for electric vehicle batteries. The Salton Sea contains an abundance of lithium dissolved in saline brine, which is found a mile below the ground surface. I spoke with Pat Dobson, a staff scientist at Lawrence Berkeley National Lab, who leads the geothermal assistance program that’s developing new techniques to extract lithium from the Salton Sea geothermal brines.
Dr. Dobson: The Salton Sea has been long recognized as having a lot of dissolved minerals, about 25% by weight of salts, and they have about 200 parts per million of lithium. And the challenge now is developing the technologies to be able to extract, directly, the lithium from the brine.
Ethan: Conventional methods of extracting lithium from underground hard rock can result in a large land footprint, and it can require draining natural reservoirs and engaging in energy-intensive activities, like mine blasting. Dobson’s team, however, is studying the use of geothermal wells to extract brine from the earth, from which they then separate lithium.
Dr. Dobson: And if we assume that you can get 90% of the lithium out of that brine, you would be able to extract on an annual basis about 115,000 tons of lithium carbonate equivalent from those brines. So, it’s a significant resource.
Ethan: To put those numbers into context, the Salton Sea geothermal brines could support the production of millions of electric vehicle batteries. And by using geothermal techniques, it could potentially be done more sustainably than traditional hard rock mining. To learn more about the Salton Sea geothermal field and this alternative form of lithium extraction, visit climatebreak.org.