Geothermal lithium, its extraction and impact on clean energy

Geothermal lithium, its extraction and impact on clean energy John L. Featherstone (Hudson Ranch I) geothermal plant, California, U.S. (source: EnergySource)
Alexander Richter 13 Feb 2021

What is geothermal lithium and why it can revolutionize clean energy is described in an interesting article by the BBC, sharing details on the regions of interest and the approach to extraction.

On its Spanish site, the British BBC shared an interesting article looking at what is geothermal lithium and its possible impact for clean energy.

Apart from the rather interesting historical facts, such as that already in 1864 a hot spring was discovered in the Cornwall region in England at a depth of around 450 meters. A traditional mining area, the discover at depth might not be as outlandish as it sounds.  Samples from the 50 degrees Celsius hot water found in this copper mine just outside of Redruth, were collected in bottles and then analysed. It was then found that there is a “massive amount of lithium” in the waters up to 10 times more per gallon than found in other hot springs tested so far back then. There was a belief in great commercial value, yet there simply was no demand for it back then.

Fast forward 150+ years, and all of a sudden lithium is in high demand due to its use for batteries, last but not least for a growing electric car industry. In the fall of 2020, a site near the initial discover was confirmed to have “one of the highest lithium levels in geothermal waters in the world.” , so the BBC.

Exploration drilling for Lithium commencing in Cornwall, UK (source: Cornwish Lithium)

The efforts to extract geothermal energy in Cornwall by the developer of the United Downs Deep Geothermal Project fell then together with efforts by Cornish Lithium, a mining company that is focused on deriving lithium out of the geothermal waters found in Cornwall.

We previously reported on why it is so attractive to derive lithium from geothermal waters, compared to lithium in hard rocks. The original description “Explainer: Overview of Direct Lithium Extraction (DLE) from Geothermal Brines”, by Alex Grant can be found here.

Currently, lithium is mostly derived from hard rock mines found in Australia, or from brine deposits below the surface of dry lake beds, e.g. in Chile and Argentina.

But the environmental impact of these means of extraction are quite steep, last but not least due to high carbon emission, the use of water and land. The mostly open pit mines leave rather large scars in the land and require an incredibly large amount of water.  Estimates say that around 15 tons of CO2 are released for each ton of lithium.

So the extraction of lithium from geothermal waters has received a lot of attention and there are a lot of companies exploring that option in regions known for high-lithium content in geothermal waters. The method is seen as having a small environmental footprint compared to other methods.

Geothermal brine is a hot and concentrated saline solution, having circulated through the very hot rocks of geothermal areas and are enriched with minerals, such as lithium, boron, and potassium.

Where can you find lithium in geothermal brine?

So where can you find these high valued geothermal waters? In this context, the Upper Rhine Valley alongside the  German-French border, the Salton Sea in California and of course Cornwall are described as the areas with the highest content of lithium in geothermal waters and therefore the most attractive ones.

In the German-French context, Vulcan Energy Resources is developing combined geothermal-lithium project, which the company calls Zero-Carbon-Lithium.

In the Salton Sea region there are various companies, BHE Renewables Minerals (a company by Berkshire Hathaway), EnergySource Minerals, and Controlled Thermal Resources (CTR). Last year we had the chance to do an interview with Rod Colwell, CEO of  CTR to learn more about his company’s efforts on lithium extraction and geothermal.

Site of the Hell’s Kitchen project by CTR at the Salton Sea, California (source: CTR)

And in Cornwall it is Cornish Lithium that is working on a project in connection with a geothermal project.

With car manufacturers increasingly weary about the sustainability, environmental and social impact of their supply chain, look increasingly at how they can derive lithium from mostly green suppliers.

In  its article, the BBC then looks into much further depth of the lithium extraction efforts in Cornwall.

How do you extract lithium from geothermal brine?

Yet, the technical aspects of extracting the lithium from geothermal brine are still very much researched. Most efforts, e.g. in the U.S., Germany and New Zealand, focus on a technique called direct lithium extraction (DLE). Today, there are roughly 60 different variants of that technology.  Essentially  it uses techniques such as nano-filtration or ion exchange resins, acting as chemical sieve to selectively collect only lithium chloride. The lithium chloride is then recovered from the sieve, purified and concentrated to  produce lithium hydroxide, which is then used for batteries.

There are though different methods of extracting lithium from brine, e.g. through solvents designed to collect lithium ions, others use membranes etc. What technology or technologies will make the race will have to be seen.

The efforts to secure lithium have become an important competitive field for nations fighting to secure their  supply for their car industry, such as in Europe and in the U.S.

The  Salton Sea area is described being able to provide up to 40% of the world’s demand for lithium, so the California Energy Commission. But other regions are as hopeful as California.

What is the value of lithium and for geothermal?

With a  price of around $12,000 per ton of lithium, clearly the value of the industry is tremendous.

Another side effect is also that lithium production from geothermal, could in turn also provide a much needed push for geothermal energy development. It is therefore not surprising of these players either tagging along existing geothermal operations (e.g. EnergySource in the Salton Sea), or plan projects that combined both the power generation and lithium production (e.g. Vulcan Energy Resources in Germany and Controlled Thermal Resources in the Salton Sea).

How long the efforts to commercially produce lithium from geothermal brine in industrial quantities will take, will  have to be seen.

For a more detailed background, see the article linked below.

Source: BBC Mundo