Massive BESS Construction Underway in Germany: BW ESS and Leag

Germany's transition to a renewable-heavy grid is being supported by the rapid development of gigawatt-scale battery energy storage systems (BESS). Two major construction milestones were recently announced, highlighting the country's aggressive expansion in long-duration and utility-scale storage capacity.

BW ESS Breaks Ground on 1GW/5.7GWh Klostermansfeld Project

On July 1, 2026, global storage owner-operator BW ESS officially broke ground on the Klostermansfeld battery storage project in Saxony-Anhalt. With a staggering capacity of 1,000 MW and 5,700 MWh, it is currently the largest battery storage project in Germany. Located adjacent to the Klostermansfeld substation, the facility is designed to supply at least four hours of power to approximately three million German households. BW ESS, which first invested in the project in 2024 and completed a full acquisition in early 2026, will adopt a long-term hold and operate strategy, managing the asset directly throughout its lifecycle.

Leag Initiates Construction on GigaBattery Boxberg 400

In Saxony, Leag Clean Power, alongside Siemens Energy and Hyperstrong International, has initiated construction on the 'GigaBattery Boxberg 400'. Located at the existing Boxberg power plant site, this massive BESS features a capacity of 1,600 MWh and a power output of 400 MW. The project is a cornerstone of Leag's GigawattFactory initiative and utilizes a six-hectare remediated site, showcasing the repurposing of legacy fossil fuel infrastructure for clean energy storage.

"The deployment of multi-hour, gigawatt-scale BESS projects like Klostermansfeld and Boxberg 400 is essential for Germany to manage its massive solar and wind generation profiles."

Hyperstrong will supply the lithium iron phosphate (LFP) 'HyperBlock III' storage system and manage system integration for the Boxberg project. Both projects underscore Germany's position as the leading market for large-scale BESS deployment in Europe.

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Source: SMM / PV Magazine