Digital technology for geoscience
The partner interview
Romain Millot Science Director at Lithium de France
How does geothermal lithium compare with other extraction processes?
Romain Millot — This is a highly innovative approach in which Lithium de France, a subsidiary of the Arverne Group, an environmentally-committed company with a CSR policy, is leading the way. Alongside traditional mining in rock, and the salt flats found in South America, where lithium precipitates, geothermal lithium combines deep geothermal energy, which supplies heating networks, with the extraction of lithium from geothermal water. This process has the merit of a reduced impact and it meets the demand for the relocation of the lithium sector for batteries (electric mobility). It is a tool for decarbonisation and sovereignty.
Why did you set up a partnership with BRGM?
R. M. — The principle is as follows: deep geothermal water (20 bars at a depth of 2.5km), which is very hot (180°C) and very salty, «leaches» lithium-rich rocks and dissolves the lithium. We recover it at the surface in geothermal water, whose heat is recovered in parallel to supply heating networks. In this context, our aim is to gain a better understanding of the lithium resource in the Alsatian subsurface – one of the possible sites in Europe where this process can be implemented – thanks to the acquisition of experimental data to serve as input for geochemical numerical-modelling codes. BRGM began working on this subject from 2010 on. It was thus quite natural for us to cooperate and on 3 July 2024, we signed a scientific and applied research partnership concerning the Rhine Graben, a geological system in northern Alsace. In practical terms, we use the subsurface data made available by BRGM, but we also carry out joint campaigns to acquire new data. Above all, we are modelling the natural lithium enrichment cycle which occurs in geological reservoirs: 3D simulations using BRGM’s advanced digital tools enable us to optimise exploration and better assess the resource
Have you already seen any initial results?
R. M. — BRGM’s data, digital services and geomodelling capabilities are essential for innovative projects such as geothermal lithium. With this work, we are gradually refining our vision of the circulation at depth in what we call “loops”, both of heat flow and of regeneration of the lithium resource. We are very optimistic about future geothermal lithium production.
