Eco Stor Activates 238-MWh Bollingstedt Battery to Strengthen German Grid

• Eco Stor inaugurates a 103 MW/238 MWh battery in Bollingstedt, supplying 170 000 homes for two hours and signalling Germany’s next leap in grid-scale storage.

Eco Stor GmbH has officially switched on what is now Germany’s biggest standalone battery energy-storage system, following a ribbon-cutting ceremony on Wednesday, 4 June 2025, in the village of Bollingstedt, Schleswig-Holstein. The lithium-ion installation delivers 103 MW of power and stores 238 MWh—enough to supply about 170,000 households with clean electricity for two peak-demand hours, according to project partner EPW GmbH.

The €160-million facility occupies just over a hectare next to an existing 110-kV substation, allowing rapid dispatch of stored wind and solar energy into Germany’s northern transmission network. Eco Stor will participate in the primary and secondary balancing-power markets as well as the day-ahead exchange, a revenue stack its chief executive Georg Gallmetzer says “underlines the economic maturity of large-scale storage and its key role in phasing out fossil-fuel peaker plants.”

Construction began in April 2024 and peaked at around 220 on-site jobs, many awarded to local civil-works and electrical contractors. The battery containers—64 in total—house almost 213,000 prismatic cells supplied by a South Korean manufacturer and arranged in two identical 51.7-MW blocks for operational redundancy.Each unit is air-conditioned and linked to a cloud-based diagnostics platform that flags irregular heat signatures and performance drift in real time, reducing unscheduled downtime.

Financing was structured around a €110-million syndicated green loan led by Landesbank SH, complemented by mezzanine debt and equity from Eco Stor’s Norwegian parent and energy-transition fund Copenhagen Infrastructure III. Bankers pointed to Schleswig-Holstein’s vast wind output—often curtailed for lack of grid capacity—as a compelling case for storage that can soak up cheap surplus electrons and release them when demand spikes.

The Bollingstedt plant is the first of several Eco Stor projects slated for the region. Ground has already broken on a twin 103 MW/238 MWh system in nearby Schuby, while 300-MW clusters are planned for Wengerohr, Förderstedt and Trossingen, pushing the developer’s German pipeline beyond two gigawatt-hours. Analysts at Aurora Energy Research estimate that nationwide storage requirements will triple to 20 GWh by 2030 if Berlin maintains its renewable-expansion targets, making gigawatt-scale batteries like Eco Stor’s increasingly commonplace on the German grid.