Northern Saxony-Anhalt, a region historically associated with natural gas production, is drawing renewed attention as a potential cornerstone of Europe’s lithium supply. New assessments indicate that deep underground brines in the Altmark basin contain far larger volumes of lithium than previously believed, offering a possible breakthrough for the continent’s battery materials strategy.
Neptune Energy, which operates in the area, announced in late 2025 that an independent resource estimate by Sproule ERCE placed the Altmark deposit at around 43 million tonnes of lithium carbonate equivalent. Verified under the CIM/NI 43-101 standard, the estimate would rank Altmark among the world’s largest known single-site lithium resources if confirmed through further development.
The lithium is hosted in deep geothermal brines within Rotliegend sandstone and volcanic formations at depths of 3,200 to 4,000 meters. Average lithium concentrations of about 375 milligrams per litre have been recorded, largely attributed to long-term mineral leaching from mica-rich volcanic rocks under high-temperature conditions.
Rather than conventional open-pit mining or evaporation ponds, Neptune is advancing direct lithium extraction technologies. Pilot projects completed in 2025 successfully produced battery-grade lithium carbonate using ion exchange and adsorption methods. These enclosed systems return processed brine underground, significantly reducing land use and water consumption compared with traditional approaches.
The project aligns with the European Union’s Critical Raw Materials Act, which targets greater domestic sourcing of strategic minerals such as lithium by 2030. By reusing legacy gas infrastructure and combining lithium recovery with geothermal heat potential, Altmark could offer a lower-impact model for mineral production within Europe.
Commercial output has yet to begin, and further permitting and demonstration-scale validation are required. German regulators are expected to closely review groundwater protection, waste handling and long-term environmental performance. If successful, Altmark may play a pivotal role in reshaping Europe’s position in the global lithium supply chain.
