BW ESS has commenced construction of a large battery energy storage system (BESS) near the Klostermansfeld substation in Saxony-Anhalt, Germany.

The company said the facility will have a capacity of 1GW with up to 5.7GW-hours (GWh) of storage, making it the largest project of its kind in Germany and among the largest in Europe.

The BESS will be able to supply electricity to approximately three million households in Germany for a minimum of four hours.

The site is located in the Mansfeld-Südharz region and is positioned close to one of the central nodes of the national energy grid.

The Klostermansfeld substation has recently expanded to improve its ability to draw power from the distribution grid and transmit electricity via high-voltage lines.

BW ESS executive director Roberto Jiménez said: “At BW ESS, we are proud that our work in energy storage contributes directly to a resilient modern energy system. We have made a long-term commitment to help realise the potential of energy storage in Germany and Klostermansfeld BESS will be our first German asset to enter construction.

“We will continue to take an active approach to knowledge transfer across our portfolio, leveraging our extensive experience from the mature global markets.”

BW ESS made its initial investment in the project in 2024 and assumed full ownership earlier this year.

Zelos Energy Developments, which originally developed and sold the scheme, is expected to continue offering support on local site-related issues until construction reaches a more advanced stage, anticipated by the end of 2026.

BW ESS is overseeing the project as a long-term asset owner and operator.

The project aims to contribute to energy security and grid stability in the region, particularly during periods of peak electricity demand.

Mayor of Klostermansfeld Frank Ochsner added: “This groundbreaking is a significant day for our community, officially marking the location of Germany’s largest battery storage facility, right here in Klostermansfeld.

“We are delighted about this major investment and the operator’s commitment to contribute further, both financially and through their expertise. The community and the regional economy will benefit greatly from this.”

In April this year, EDF partnered with BW ESS to initiate the first phase of the 350MW/1.24GWh Hams Hall BESS in north Warwickshire, UK.