Germany Unveils 43 Million Ton Lithium Resource in Former Altmark Gas Field

Neptune Energy confirms a 43 million metric ton lithium resource in Germany's Altmark region. Discover how deep brines could power 500k electric cars per year.

By: AXL Media

Published: Apr 23, 2026, 1:03 PM EDT

Source: Information for this report was sourced from EcoNews

The Transition from Fossil Fuels to Battery Metals

The Altmark region in northern Germany, long recognized as a primary hub for natural gas extraction, is undergoing a profound industrial transformation. On September 24, 2025, Neptune Energy announced that an independent resource assessment conducted by Sproule ERCE confirmed the presence of 43 million metric tons of lithium carbonate equivalent (LCE) within deep-seated geothermal brines. This discovery leverages over 50 years of existing geological data and infrastructure from the gas sector, repurposed to tap into hot, mineral-rich water located between 10,500 and 13,000 feet underground. The strategic pivot reflects a broader European movement to convert legacy energy fields into modern nodes for the green energy transition.

Independent Verification and Reporting Standards

The 43 million ton figure represents a significant milestone in resource reporting, adhering to the internationally recognized CIM and NI 43-101 standards. This framework ensures that the resource estimate is based on rigorous geological modeling and verified by qualified independent experts, providing a level of transparency required for large-scale financing and permitting. While the figure describes a "resource" rather than a "proven reserve," the scale positions the Altmark license area among the largest project-related lithium deposits globally. The assessment has provided the necessary credibility for Neptune Energy to proceed with multi-year development phases intended to secure Germany’s raw material autonomy.

Direct Lithium Extraction Technology and Pilots

At the core of the Altmark project is the implementation of Direct Lithium Extraction (DLE), a methodology that avoids the environmentally invasive open-pit mines and massive evaporation ponds common in South America and China. Pilot testing began in November 2024 with technology partner Geolith, followed by a second successful trial with Lilac Solutions from June to August 2025. These pilots used ion-exchange and adsorption processes to selectively capture lithium from highly mineralized brine with a mean concentration of approximately 375 parts per million. Results from these trials have already produced battery-grade lithium carbonate, proving the technical feasibility of the extraction process in high-pressure, high-temperature environments.