Lithium prospectivity and capacity assessment in the North German Basin

Lithium production has increased tenfold over the past two decades and is expected to grow steadily over the next decade, driven by the rapid development of modern technologies such as mobile electronics, electric vehicles (EVs) and grid storage applications. The European Union including Germany, however, has no conventional lithium resources and is therefore geopolitically dependent on imports. As a result, unconventional resources such as lithium recovery from geothermal brines in the Upper Rhine Graben have been explored. Elevated lithium concentrations have also been reported in other regions including the North German Basin (NGB), but no resource estimates are available. Therefore, all available data for the NGB are summarized here in order to limit potential deposits. Their potential is then assessed using a probabilistic volume-based approach.

The highest concentrations are found in the Permian Rotliegend and the Zechstein Ca2 at the basin margin. Lithium concentrations can locally reach up to 600 mg/L in the Rotliegend and 300 mg/L in the Zechstein. Our resource estimates indicate that 0.08 to 5.76 Mt of lithium could be contained in the Rotliegend and an additional 0.06 to 3.06 Mt in the Zechstein. Elevated lithium concentrations have also been reported in the overlying Triassic Buntsandstein deposits that occur over much of the basin. Values of up to 200 mg/L lithium have been detected, which we estimate to be between 0.2 and 3.48 Mt of lithium.

On the one hand, our study shows that there are sufficient domestic lithium resources in geothermal waters. However, it is also clear that the most promising resources are associated with deep, low-permeability Permian deposits that inhibit conventional (non-engineered) hydrothermal geothermal energy production. It is therefore unclear whether geothermal energy production and lithium exploration can co-exist and further studies are needed to analyze the local, onsite potential. Our study provides the starting point for this analysis.