Large 900 MW battery and data centre planned at former nuclear power plant site

Plans to build a 900-megawatt battery storage facility on the site of a decommissioned nuclear power plant in Bavaria are a “key component” of the state’s energy transition, said the state’s economy minister Hubert Aiwanger.

The site of the former nuclear plant Isar 2 in the municipality of Niederaichbach offers an “ideal location” for the project, given the existing transmission grid infrastructure, Aiwanger said. 

The project, planned by Munich-based investment firm Advisum, could help to better integrate the state’s large solar power capacity, which on sunny days can turn into a burden for the local energy grid, the minister from the party Free Voters said.

He called on participating companies and municipalities “to work together to advance this forward-looking project,” adding that “if you expand renewables, you also have to consider storage and grids.” Advisum also plans to build a 100-megawatt data centre at the site.

A substation near the former nuclear plant is currently being expanded to handle electricity from renewable energy sources transported through the SuedOstLink transmission line, an underground cable running from windy northern Germany to the industrial south, currently under construction.

The site could be expanded further to connect additional battery storage or other facilities, the ministry said. 

Germany added over two gigawatt-hours (GWh) of storage capacity in the first quarter of 2026, bringing the total installed capacity to 30 GWh. Large-scale storage grew particularly fast, with capacity rising 290 percent compared to the same period one year earlier, bringing the total to about 6 GWh.

At present, around 1,300 large battery projects are connected to Germany’s transmission and distribution grids.

The country phased out nuclear power generation entirely in 2023 and is dismantling reactors and other plant infrastructure, a process expected to take several years for each site.

Besides increasing the country’s electricity storage capacity, the German government also aims to push the construction of data centres, which are expected to become a competitive advantage as growing artificial intelligence (AI) use lets demand for processing power spike. 

Germany has almost halved its use of fossil fuels for electricity generation in the past eight years, which fell from 174.6 billion kilowatt-hours (kWh) in the first half of 2018 to 94.2 billion kWh in the first half of 2026, the country’s statistical office (Destatis) has said.

“A clear change becomes visible in the long-term trend of domestic electricity production,” Destatis said, adding that renewable energy sources increased their output by about one quarter during the same period. 

Almost 60 percent (59.1%) of the electricity produced in Germany between January and June 2026 came from renewable power sources, an increase of 6.5 percent versus the same period in 2025.

Against the backdrop of debates about a greater reliance on coal due to the war in Iran, coal power production continued to decline by 0.5 percent to 49.4 billion kWh.

Clean Energy Wire. Reproduced with permission.