Klostermansfeld: Europe’s New Largest Battery Project Launches
July 4, 2026 — BW ESS has officially broken ground on the Klostermansfeld BESS, one of Europe’s largest battery energy storage projects to date. The 1,000MW / up to 5,700MWh facility marks a major milestone for Germany’s energy transition and positions BW ESS as a key player in the country’s growing battery energy storage system market.
Located in the Mansfeld-Südharz region near the Klostermansfeld substation, the project is the largest battery storage Germany has seen in 2026. It can supply electricity to around three million German households for at least four hours, providing critical flexibility to an increasingly renewable-powered grid.
Project Overview
The Klostermansfeld BESS stands out for its impressive scale. With 1,000 MW of power capacity and up to 5,700 MWh of energy storage, it ranks among the biggest developments in Europe.
Key project specifications:
- Power: 1,000 MW
- Storage duration: Up to 5.7 hours at full output
- Location: Mansfeld-Südharz district, Saxony-Anhalt
- Grid connection: Adjacent to the expanded Klostermansfeld substation
This Saxony-Anhalt BESS will serve as a strategic asset, storing excess renewable energy and dispatching it during peak demand periods.
Strategic Importance for Germany’s Energy Transition
Germany continues to lead Europe’s renewable energy push, but intermittency challenges remain. Large-scale battery energy storage systems like Klostermansfeld BESS are essential for balancing supply and demand.
The project will:
- Enhance grid stability during peak load periods
- Reduce reliance on fossil fuel peaker plants
- Absorb surplus renewable generation, minimizing curtailment
- Strengthen regional infrastructure through the upgraded Klostermansfeld substation
As one of the few central nodes in Germany’s high-voltage grid, the substation’s recent expansion makes this site ideal for a project of this magnitude. The 1000MW BESS Germany will improve power flow and support the integration of more wind and solar capacity.
BW ESS’s Role and Timeline
BW ESS Germany first invested in the project in 2024 and secured full ownership earlier in 2026. The company, a global energy storage owner-operator, brings extensive international experience to its first major German asset.
Initial developer Zelos Energy Developments will continue providing local support through the early construction phase. Construction is expected to advance significantly by the end of 2026, with BW ESS maintaining hands-on oversight throughout development and operations.
As a long-term owner-operator, BW ESS focuses on maximizing value across the full project lifecycle — from development through decades of commercial operation.
Official Statements
Roberto Jiménez, Executive Director, BW ESS, said: “At BW ESS, we’re proud that our work in energy storage contributes directly to a resilient modern energy system. We’ve 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.”
“We thank our development partner, Zelos, for their work on the project and are especially grateful to Minister Prof. Dr. Armin Willingmann and Mayor Frank Ochsner for joining us to mark the occasion.”
Prof. Dr. Armin Willingmann, Minister for Science, Energy, Climate Protection and the Environment and Deputy Prime Minister of Saxony-Anhalt, said: “Saxony-Anhalt is one of the pioneers in the energy transition, especially in the expansion of renewables. It is therefore important for our state to have grid-serving battery energy storage systems that help stabilise our power grids. The Klostermansfeld battery energy storage system will be an important building block in this. Increasing volumes of renewable electricity can be absorbed by the large-scale storage system and then transported further via the grid. With this system here at the site, BW ESS is helping to secure supply and ensure more flexibility in the power grid.”
Frank Ochsner, Mayor of Klostermansfeld, 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.”
Source: BW ESS
What This Means for the Future
The Klostermansfeld BESS promises substantial local economic benefits, including jobs during construction and operation, plus increased tax revenue for the region. It signals strong investor confidence in Germany’s battery storage sector.
On a national level, the project strengthens energy security and accelerates the shift toward a flexible, renewables-dominant power system. As Germany’s battery pipeline grows rapidly, projects like this will help stabilize prices and reduce curtailment costs.
Conclusion
The groundbreaking of the Klostermansfeld BESS represents a pivotal step forward for large-scale energy storage in Germany. With its massive 1,000MW capacity and strategic location, the project will deliver immediate value to the grid while supporting long-term decarbonization goals.
As BW ESS Germany and other developers accelerate deployment, the country is poised to strengthen its position as Europe’s battery storage leader. This development not only powers homes today but also helps build the resilient energy system of tomorrow.
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