EnBW plans 800 MWh battery storage system at former Philippsburg nuclear site

German utility EnBW has announced plans to build one of the country’s largest battery storage systems at the former Philippsburg nuclear power plant site in Baden-Württemberg. The system will have a power output of 400 MW and a storage capacity of 800 MWh.

According to EnBW, the battery system will be installed adjacent to the TransnetBW converter station, which forms part of the ULTRANET high-voltage direct current (HVDC) corridor. This transmission line is designed to carry wind-generated electricity from northern Germany to the southwest.

By connecting to ULTRANET, the storage system is expected to become a key node in the renewable power network, storing electricity from wind and solar installations and supporting grid stability. EnBW intends to fund the project without public subsidies, instead relying on revenue from electricity trading and grid services.

The company said the Philippsburg site is well-suited for a large-scale battery installation, citing existing infrastructure and grid connection as major advantages. These conditions are expected to simplify development compared to a completely greenfield location.

The converter station at the site, built by grid operator TransnetBW, is already in place. The company expects the required grid connection for charging and discharging the battery to be operational by mid-2027.

While EnBW has not yet secured a building permit or made a final investment decision, it said that, under optimal conditions, completion by the end of 2027 is possible. The proposed construction area is not affected by the ongoing dismantling of the two decommissioned nuclear reactors, which have been undergoing removal since 2017 and 2020 respectively.

From pv magazine Germany.