Episode 175 | Substantial Salton | Berkeley Lab
We first heard about the potential to harvest lithium from California’s Salton Sea region back in Episode 62. My guest in Episode 153 mentioned there were some studies to see just how much lithium was there.
Lawrence Berkeley National Laboratory now has the number. Their report, released in Nov. ’23, says there’s more than 3.4 million tons of lithium, found in the brines found thousands of feet below the surface. They say that’s enough lithium for batteries in 375 million cars, more cars than are on American roads today.
Pat Dobson was the lab’s lead on this study. He says the report culled publicly-available data to determine this number, namely:
- PPM of lithium in the brine – About 200 ppm
- Porosity of rocks holding the brines
- Thickness of the reservoir holding the brine
- Aerial footprint of the current geothermal area, less the area directly under the Salton Sea
Rather than pump all this brine to the surface and evaporate it, like they do in South America, the Salton Sea would utilize Direct Lithium Extraction (DLE) to pull lithium out of the brines and then re-inject the fluid back into the reservoir.
This is key, because “the pressure in the reservoir would decrease and the production rates of the existing geothermal wells would decline,” says Pat.
So far there are three companies with plans for DLE in the Salton Sea, Berkshire Hathaway Energy Renewables, Energy Source Minerals, and Controlled Thermal Resources. Among them are different chemistries for extracting lithium (i.e. lithium chloride vs. lithium hydroxide monohydrate) and solutions for a commercial facility (greenfield vs. brownfield geothermal).
I was curious about the geology. First, would a single well become more lithium-dilute as the brine is circulated to the surface? Pat says this phenomenon is called “chemical breakthrough,” and much like “thermal breakthrough (heat loss over time),” reservoir managers will have to take this into consideration.
I also wondered if lithium-dilute brine might have a chance to “recharge” with more lithium after it’s reintroduced into the subsurface. Pat says there’s a study underway with UNC-Charlotte to explore that possibility. He says it really may come down to whether or not the brine can replenish over “geologic time (eons)” or the life of a project (tens of years).
Pat says Salton Sea could be just the beginning. Lithium resources are being explored in Arkansas, North Carolina, Nevada, and borate mines in California. And they’re not just found in brines.
“If we look at what had been previously published as known lithium resources, U.S. did not factor in very highly in that,” says Pat, “but I think looking at some of these new types of resources, the U.S. does have quite a bit of lithium and it’s captured in a variety of different types of lithium resources.”
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