When it comes to the key raw material lithium, Germany almost exclusively relies on imports, even though the light metal is contained in geothermal brine. The departments of Geochemistry & Economic Geology at the Karlsruhe Institute of Technology KIT are working on a method to extract lithium as a by-product of geothermal energy production. As part of the LiMo research project, Fraunhofer IPM is developing an optical sensor intended to make the extraction process more efficient.