From Concept to Impact: How REGIOlink Stabilizes Regional Grids with Large-Scale Battery Storage

The energy transition is considered one of the largest infrastructure projects of our time. Yet while the national electricity market often dominates the debate, one crucial question is still too rarely asked: How can storage solutions be operated in a way that makes them not only efficient in the electricity market, but also effective at the regional level? A project in the Allgäu region is now providing answers.

In Immenstadt, green flexibility has completed its first large-scale battery storage system with a capacity of 15 megawatts and 33 megawatt-hours, which went into operation as planned in June 2025. With its new REGIOlink concept, the company aims to demonstrate how storage can be operated to actively relieve regional grids – rather than unintentionally increasing their stress. The challenges that a storage system can address at the regional level are particularly evident in the Allgäu: in winter, snow cannons drive electricity demand sharply upwards. When hundreds of these devices run simultaneously, consumption rises to the level of an entire urban district – making grid bottlenecks inevitable. But a storage system operating purely on market signals can actually make the problem worse: if it charges during periods of low prices – which often occur at night during sub-zero temperatures – the additional load coincides exactly with the operation of the snow cannons, further amplifying the congestion.

REGIOlink: A Concept for Targeted Grid Support

green flexibility developed REGIOlink precisely to address such challenges. The digital tool makes transparent how storage operation affects the local grid situation. Via a technical interface, REGIOlink analyzes regional grid loads, identifies potential congestion, and visualizes how the storage system can help relieve the grid through targeted operation. It builds a bridge between the purely market-driven flexibility of storage and the often-overlooked requirements of the distribution grid.

“It was important to us that storage operators and grid operators finally speak a common language”, explains Christina Hepp, Director Strategy at green flexibility.

All relevant interfaces between storage operators and grid operators have already been successfully tested in Immenstadt, even though the first real winter experiences are still pending. The objective is to avoid costly grid interventions or additional grid expansion through early coordinated, quarter-hourly power limitations – without significantly compromising the economic viability of the storage system.

Customized Operating Strategies Instead of Standard Solutions

REGIOlink combines multiple data sources such as historical generation and consumption data, weather forecasts, and grid information. These are used in an algorithmic model to perform flexibility calculations: When do bottlenecks occur? At which points does storage add stress to the grid? What restrictions are necessary?

All this information flows into a digital representation of the local grid – the so-called Virtual Grid Model. The result is a practical, grid-friendly operating schedule tailored to real-world conditions. Every site comes with its own grid characteristics and challenges: agricultural consumption peaks, industrial process heat, or clusters of heat pumps. REGIOlink incorporates these regional specifics into the operating strategy, identifying the hours when charging or discharging actually creates value for local grid stability.

Grid operators benefit from much greater predictability, as they know in advance when and to what extent storage will be deployed during critical grid situations. In addition, key operational and control information is provided via a clear dashboard – offering transparency and traceability in storage operation.

For grid operators themselves, the effort remains minimal: analysis and control are handled entirely by green flexibility. The required grid data are jointly agreed in advance. The foundation of the cooperation is a long-term partnership agreement that defines all key details – from operating schedules to potential curtailment periods, as well as fair economic compensation for grid-supportive restrictions.

Christoph Ostermann, co-founder and CEO of green flexibility, emphasizes: “Our goal is that storage is seen from the outset as part of the grid infrastructure – not as a foreign element reacting only to market signals. REGIOlink provides the framework for this.”

Minimal Effort for Grid Operators

REGIOlink is specifically designed to reduce the burden on grid operators. Technical analysis, control, and data processing are carried out entirely by green flexibility. The basis for this is a coordinated data set – often relying on existing information about grid loads, feed-in, or redispatch measures. For integration, green flexibility sets up an interface and supports the connection.

“We want to take away grid operators’ concerns,” says Leandra Boes, Director Commercial Asset Management. “REGIOlink shows that it can be done simply, transparently, and with manageable effort – yet with significant impact.”

A First Step Toward Fair Market Conditions

REGIOlink is not just a technical concept – it is also intended as an impetus for the debate on fair remuneration models. Grid-supportive operating strategies can mean economic disadvantages for operators. According to green flexibility, clear frameworks and fair market mechanisms are needed to ensure that these disadvantages do not become a barrier. While clear regulatory guidelines are still lacking, the Immenstadt example already demonstrates that practical solutions are possible today. The project sets new benchmarks not only for storage, but also for how regional grid support can work in practice.

A Model with a Signaling Effect

With REGIOlink, green flexibility demonstrates that battery storage can be more than just “trading machines for electricity.” Intelligent, site-specific operating models can combine economic viability with grid stability – delivering real added value for the energy transition at the local level.

For a pilot like Immenstadt to become a standard, however, clear political frameworks are required: a reliable definition of grid-supportive operation, transparent remuneration models, and an industry willingness to take regional specificities seriously.

The example shows: The success of the energy transition will not be decided solely on the trading floor – but also in projects like these, proving that regional flexibility can be a key enabler.