Swiss energy company Alpiq has acquired the 103.5 MW BESS Bollingstedt battery energy storage system (BESS) in Germany from German-Norwegian energy storage developer ECO STOR. The acquisition marks Alpiq’s entry into Germany’s operational large-scale battery storage market and strengthens its portfolio of flexible energy infrastructure.
Located in Bollingstedt, Schleswig-Holstein, the battery storage facility has been operational since June 2025. It has an installed power capacity of 103.5 MW and a storage capacity of 238 MWh, making it one of Germany’s largest operational battery storage systems. The financial terms of the transaction were not disclosed.
Alpiq said the acquisition complements its existing BESS development pipeline and supports its strategy to expand its flexibility portfolio across Europe. The company will also explore opportunities to acquire additional operational battery storage assets in Germany.
“With BESS Bollingstedt, we are strengthening our ability to provide flexibility where it delivers the greatest value for the electricity system,” said Amédée Murisier, Head of the Assets business division and member of Alpiq’s Executive Board. He added that the facility strengthens Alpiq’s position in the European battery storage market and complements its existing project pipeline.
Third Operational BESS in Alpiq’s Portfolio
BESS Bollingstedt is Alpiq’s third and largest operational battery storage facility. Its existing operational assets include the 100 MW BESS Cheviré in France and the 30 MW BESS Valkeakoski in Finland.
Alpiq currently has additional BESS projects with a combined capacity of more than 250 MW under construction or close to commissioning. The company is also developing battery storage projects in Italy and Switzerland.
In July 2026, Alpiq acquired a 90% majority stake in Harmony Energy, a pan-European BESS developer and operator with a multi-gigawatt project pipeline across the UK, France, Germany and Poland. The Bollingstedt acquisition adds an operational German asset to this pipeline and provides Alpiq with direct exposure to the German battery storage market.
Continued Partnership With ECO STOR
The acquisition also builds on Alpiq’s existing relationship with ECO STOR. In November 2025, the companies signed a long-term tolling agreement for the Schuby battery storage system in northern Germany, which was developed, built and operated by ECO STOR.
Alpiq said the Bollingstedt transaction reflects its confidence in ECO STOR’s project development capabilities, technical expertise and experience in delivering economically viable battery storage solutions.
The company said the combination of operational storage assets and its growing project pipeline will support the expansion of its European flexibility platform and strengthen its position across the battery storage value chain. Flexible assets such as BESS and pumped-storage hydropower are expected to play an increasing role in integrating renewable energy, balancing electricity supply and demand, and enhancing grid reliability.
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