282 MWh for Grid Stability and Supply Security

In Alfeld, Lower Saxony, the flexibility traders Entelios AG and enspired GmbH, together with Danish investor engira Group (formerly Obton A/S), are realising one of Europe’s most powerful battery storage systems (BESS). With a power capacity of 137.5 MW and a energy capacity of 282 MWh, the storage system will significantly improve grid stability in Germany and advance the integration of renewable energy sources when it goes online in mid-2026.

A Gamechanger for the Energy Transition

The BESS project in Alfeld performs essential functions for modern energy supply and supports Germany’s sustainable energy transition:

• Energy Storage: Excess energy from wind and solar power plants is stored and fed back into the grid when needed.
• Grid Stability: Participation in reserve markets, particularly the aFRR market, helps balance fluctuations in the grid.
• Supply Security: The system strengthens regional energy infrastructure and increases resilience to peak loads.
• Optimal Market Integration: Through Cross-Market Optimisation, the storage system is efficiently positioned across various electricity markets, including day-ahead, intraday, and reserve markets. This ensures economically optimal marketing and maximum flexibility.

With its storage capacity sufficient to supply one million households with electricity for one hour, Alfeld sets new standards for large-scale battery storage technology in Germany.

Innovative Technology and Partnership

The battery storage project in Alfeld is a flagship initiative made possible by collaboration among leading companies:

• Entelios: Optimises and markets the flexibility of the storage system on energy markets through its industry-leading expertise in flexibility trading.
• enspired: A specialist in AI-driven optimisation. State-of-the-art algorithms efficiently position the system in short-term and reserve markets.
• engira (formerly Obton A/S): Finances the storage project and serves as the system operator.

Project Voices

Martin Poscholann Christensen, Investment Manager for Energy Storage at engira (formerly Obton), explains:

“We began looking into two-hour battery storage systems, including aFRR in the revenue stack. We concluded that enspired, together with Entelios, was best suited to develop a well-thought-out strategy and communicate it clearly to us. Furthermore, we were convinced of their ability to adapt quickly to new strategies or future revenue streams.”

 

Jürgen Mayerhofer, CEO and Co-founder of enspired, states:

“The battery storage project in Alfeld is an outstanding example of how advanced optimisation technology and intelligent market integration can go hand in hand. Our highly developed, fully automated trading strategies maximise the system’s flexibility, optimise market participation, and make a decisive contribution to accelerating the energy transition.”

 

Fabian Becker, CEO of Entelios, emphasises:

“The project in Alfeld highlights how close collaboration and technological innovation can decisively drive the integration of renewable energy. As a pioneer in flexibility trading, and with our deep expertise in optimising complex systems, we play a significant role in ensuring grid stability and creating a reliable, future-oriented energy supply.”

Key Benefits at a Glance

• Energy storage and flexibility for grid stability
• Reduction of fossil fuel dependency
• Integration of renewable energy into the electricity mix
• Efficient and sustainable supply security

 

Note on storage capacity: The figure of 306 MWh quoted in the original press release referred to the nominal gross DC capacity based on the project planning at that time. The battery storage capacity is currently stated as 282 MWh. The discrepancy arises from the respective definition of capacity and the technical system design.

Company note: Obton Germany GmbH has been operating under the name engira group Germany GmbH since August 2026. Obton A/S, which is named as an investor in the original press release, continues to exist as an independent company. As part of the reorganisation, key activities and areas of expertise of the Obton Group have been transferred to engira.

 

Image Source: engira group Germany GmbH