green flexibility, a leading operator of large-scale battery storage systems based in Kempten, together with its partner AÜW, has successfully commissioned a 15 MW battery storage system with a total capacity of 33 MWh. The facility is located in the AllgäuNetz distribution grid in Immenstadt (Allgäu) and has been connected to the grid since mid-2025. The special feature: together with Entrix, the energy trader and European market leader in the optimization and trading of flexible energy systems, the system has been integrated in a grid-neutral manner.
The optimization and trading of the storage system are based on a partnership model that combines Entrix’s market and technology expertise with green flexibility’s technical infrastructure. A unique aspect of this project: it is one of the first grid-neutral storage systems operated in Germany. This means that the storage unit is controlled in such a way that it does not place additional strain on the power grid—even in rare congestion situations. To achieve this, the grid operator can limit the system’s operation within a defined range and dynamically adapt it to grid requirements. This allows potential grid constraints to be incorporated directly into the plant’s daily operation. A dedicated interface enables this grid-oriented control, which has already been successfully implemented — a living example of cooperation between storage operator, grid operator, and trader.
A Strategic Milestone
This project is the first from green flexibility’s 15 GW+ storage project pipeline and marks the starting point for further developments across Germany. With an initial investment volume of over 1 billion euros — including 400 million euros in equity from Partners Group and additional debt financing — the company is driving the rollout of battery storage projects throughout Germany.
“In Immenstadt, we’re demonstrating how grid-neutral storage operation can work in practice with REGIOlink components. It was important to us that partners like Entrix actively support and engage with us — technically, economically, and operationally. This collaboration enabled us to design the project to be both economically viable and as grid-neutral as possible. This is exactly what the energy transition needs: technology, market, and grid working in harmony.”
Multi-Market Strategy and Technical Integration
The storage facility is operated fully automatically across multiple energy markets — including primary and secondary control reserves as well as the spot market (day-ahead and intraday) — using Entrix’s AI-based optimization solution. Beyond market access, technical integration into operational management plays a crucial role. The approach enables flexible responses to grid constraints, precise system control, and optimization of operating time and lifecycle — all essential factors for the economic viability of grid-oriented operations.
“green flexibility impressively demonstrates how innovative battery storage systems can accelerate the expansion of renewable energy without placing additional stress on the power grid. Their projects make a significant contribution to the energy transition and energy security. We’re proud to be partnering with them to ensure the profitability of the first project and to actively shape the future of energy supply together.”
A short explainer video on battery storage trading and the partnership between green flexibility and Entrix can be found here.