The growing lithium demand and the dependence on poorly diversified oversea sources point towards a high strategic importance of domestic resources. Furthermore, potentially lower CO2 emissions and reduced areal use during production favor local co-production of geothermal energy and lithium.
Based on a technology comparison for direct lithium extraction from geothermal fluids and the current state of geothermal energy production in Germany, different scenarios for the extractable amount of lithium carbonate were considered. In the most optimistic scenario, taking into account all currently active wells, a maximum production of 4700 t/a of lithium carbonate equivalent is expected. This could cover 2 – 13% of the annual demand of the planned German battery cell production.
Uncertainties in the resource assessment regarding its size, and the sustainability of its management, are still considerable. Yet a full-scale Li extraction from geothermal brines is missing and thus long-time behavior is not clear. For this purpose, a generical model, based on Upper Rhine Graben geothermal settings was developed, and a Li extraction over a 30-year operation time was simulated. Despite a significant Li depletion, a mean Li production of 231 t/a (1230 t/a LCE) is achieved, for a current state-of-the-art geothermal power plant.
This could significantly increase the economics of a geothermal power plant as well as, if transferred to several plants, a partly independency from global imports. The strongest influence on productivity is the achievable flow rate, which provides access to the raw material, highlighting the importance of good geological reservoir exploration and development.