Review of the panel discussion at the Wind Energy Days in Potsdam on November 13, 2025
The demand for battery storage is increasing rapidly. They are the central flexibility instrument in an energy system characterized by volatile generation. But how can storage projects in Germany be developed, approved, implemented and operated efficiently and economically? These were the central questions of the panel discussion at the Wind Energy Days in Potsdam – with experts from MVV Trading, JUWI and AXSOL.
The crowded room clearly showed: The market is looking for answers. And it needs them urgently.
The bottleneck: Grid connection as a critical success factor
One of the clearest statements of the panel: The biggest hurdle is and remains the grid operator.
While the approval authorities work cooperatively in many cases, grid connection processes are often slow or end with restrictions – especially for standalone storage systems that want to draw from and feed into the grid.
“The biggest hurdle in project development is clearly the grid connection. Co-location and hybrid approaches get connected to the grid much faster because they have the least affect on the grid.”
Felix Beyer (AXSOL GmbH)
Co-location and hybrid projects are clearly at an advantage.
They use existing grid infrastructure and reduce the grid load. Storage systems that exclusively feed in (green electricity storage) receive commitments comparatively faster, while gray electricity storage systems with bidirectional operation often encounter more skepticism.
Another trend:
Many grid operators are already demanding documentation ready for planning with the connection request – noise reports, lease agreements or layouts. This is intended to weed out non-viable projects early on. Good preparation significantly shortens the waiting time.
Location selection and dimensioning: The grid logic determines the project size
It became clear in the panel: Storage systems are not dimensioned theoretically, but grid-driven.
Overbuilding is allowed and makes sense.
Hybrid PV or wind farms can now be supplemented with battery capacities that are significantly higher than the nominal output of the generation plant. The reduced revenues due to grid bottlenecks are moderate:
- PV + storage: about 6 to 8 percent
- Wind + storage: about 10 to 17 percent
Profitability benchmarks from the panel:
- Green electricity storage: approx. 100,000 euros per MW per year
- Gray electricity storage: approx. 280,000 euros per MW per year
(Basis: market years 2024/25)
This difference shows the value that storage systems with grid access can develop. However, this requires clean grid, measurement and control logic.
Approval: Complex, but manageable
Although the grid connection is the biggest hurdle, approvals are also challenging.
Relevant points:
- Noise
- Fire protection
- Water law
- Clearance distances
- Access road and transport logistics
A possible future simplification could be the privileging of storage systems in the outer area discussed in the EnWG. If it were decided, it would be a real accelerator.
Realization: The actual construction phase is not the problem
A surprising point from the discussion:
The physical realization of a storage system is comparatively uncomplicated – especially compared to wind or PV plants.
The challenges lie elsewhere:
- Delivery times for switchgear: 30 to 45 weeks
- Container delivery time: 6 to 9 months
- Transfer stations: biggest time waster
- Total project duration: 18 to 24 months
The core message of the experts:
Early, parallel work is crucial. This includes discussions with the grid operator, marketer, EMS partner and testing organizations. Projects that involve all stakeholders late lose valuable months.
Integration: Why storage systems are not plug-and-play technology
It became clear in the discussion:
Storage systems differ fundamentally from other generation plants.
They are dynamic systems that react daily to price signals, grid requirements and control energy.
“Battery storage is not plug-and-play. Every co-location project is custom-made. The system only works reliably in the end if everyone involved is at the table early on.”
Vivien Klein-Campailla (MVV Trading GmbH)
Each project is a tailor-made manufacture:
- Individual interfaces between BMS, PCS, EMS and EZA control
- Different grid protection logics
- Marketer requirements
- Communication protocols
- Controller architectures
Standardization is only emerging, it is not yet established on the market.
Therefore: Have marketers, EMS providers and EPC plan together early on.
AXSOL was able to provide insights in this area into how an integrated EMS (AXOS) can standardize interfaces and what role AI-based optimization (ADONYS) plays in operation.
Operation: Where profitability is gained or lost
Storage systems only generate revenue when they are available.
There is hardly any fault tolerance.
Target values in the market:
Availability between 95 and 97 percent.
This requires:
- Spare parts availability within 24 hours
- Structured escalation chains
- Precise degradation management
- Intelligent cycle strategy
It was emphasized that marketing and technical operation are closely interlinked.
A marketer can plan the best schedules – if a module fails, it needs quick communication and technical solutions.
“The revenues of a storage system only arise with high availability. Everything stands and falls with clean integration, fast response times and a well-thought-out service and fault management.”
Leon Jacob (AXSOL GmbH)
The discussion highlighted how important it is to plan cycles flexibly over the years.
A typical storage system today runs about two cycles per day, in extreme cases more.
But the decisive factor is the service life strategy, which must take manufacturer and marketer logic into account.
Marketing models: More variety, more options
The market is developing different remuneration models for storage operators.
Three models dominate:
- Profit Share / Fully Merchant
Maximum opportunities, maximum risk. - Profit Share with Minimum Guarantee (Floor)
Stable planning with reduced volatility. - Tolling model
Fixed remuneration per MW per year, typical values: from around 118,000 euros.
This is particularly interesting for project developers with an investor background – plannability enables financing security.
Conclusion: Storage systems are system projects – not individual products
The central finding of the panel can be summarized in one sentence:
Successful storage projects only arise when technology, regulation, marketing and operation are considered together from the outset.
Battery storage systems are not isolated systems.
They are the interface between market, grid and generation.
Projects that take this perspective and support stakeholders early on will be realized faster, cause fewer risks and generate significantly higher revenues.
The industry is at the beginning of a massive scaling.
With the right setup, storage systems can play a key role in the future energy infrastructure – flexible, economical and safe.
Watch the complete discussion now and delve deeper into the current developments in the BESS market.