RWE has started construction of what will become Germany’s largest battery energy storage system (BESS) at the Gundremmingen energy complex in Bavaria. The facility, with a power output of 400 megawatts and a storage capacity of 700 megawatt-hours, will make use of the existing grid connection of the former nuclear power plant currently being decommissioned. The company is investing around €230 million in the project, which is scheduled to begin operations in 2028, according to RWE.

A symbolic groundbreaking ceremony was held on October 29, 2025, attended by the Minister-President of Bavaria, Dr. Markus Söder, who emphasized the project’s importance for the region’s energy future. “Gundremmingen remains a key hub for Bavaria’s energy supply,” Söder stated. “Alongside the new battery storage facility, plans include a 55-hectare solar park and a gas-fired power plant. With 400 MW of power and over 700 MWh of capacity, this system will help stabilize the grid when there is no wind or sun. Bavaria, Germany’s fastest-growing economic region, needs reliable energy. We are deeply grateful to RWE and its employees for their dedication to this project.”

RWE CEO Markus Krebber highlighted the strategic significance of the initiative, saying: “The energy system of the future requires powerful storage facilities. By building Germany’s largest battery storage plant in Bavaria—an attractive region for energy generation—we are sending a strong signal. Gundremmingen reflects our continued commitment to the sustainable use of our sites, and this new facility marks only the beginning.”

Once completed, the Gundremmingen BESS will be capable of delivering power continuously for nearly two hours at full capacity. The project will comprise over 200 containers housing around 850,000 lithium iron phosphate battery cells. Equipped with advanced control technology and more than 100 high-speed inverters, the system will be able to supply or absorb power within milliseconds, playing a vital role in maintaining grid stability.

The project represents a major step in RWE’s strategy to expand its battery storage portfolio, reinforcing its role as one of Europe’s leading energy transition players. Commercial operations are expected to begin in early 2028.