Cable Pooling describes the targeted combining of several power generation facilities (e.g., wind, PV, storage) at a common network interconnection point. The central goal: Existing grid connection capacity will be better utilized, as not every plant feeds in its maximum output at the same time. German law has explicitly permitted since 2025 for the first time that more generation capacity can be connected at the NVP than the grid can actually accommodate – so-called „Superstructure“or„Oversizing“.
Network bottlenecks and capacity limits due to classical network planning
With the rapid expansion of renewable energies, Germany's power grid is increasingly reaching its capacity limits. Numerous new photovoltaic and wind power plants often wait for months or even years for a grid connection. This is because the available grid connection points are already at full capacity, and the expansion of the grid infrastructure is not keeping pace. Traditionally, grid connection points are designed so that each connected plant can feed in its maximum output at any time. However, the reality is different: solar and wind energy plants operate depending on the weather and season, meaning they generate rarely at their maximum performance simultaneously. This leaves a large portion of grid connection capacities unused for much of the year.
Better utilization through cable pooling
This inefficient use of infrastructure leads to avoidable Waiting times during project implementation and increased costs. Ultimately, it can also lead to renewable projects not being realized at all. With cable pooling, the existing grid is utilized much better because multiple plants and storage facilities share the grid capacity and balance each other out. This is also supported by current studies from the German Renewable Energy Federation (BEE) and the Fraunhofer Institute for Energy Economics and Energy System Technology (IEE). With a moderate oversizing of grid connection points, utilization increases without excessive electricity surpluses being created. This allows for Realize more projects faster, cheaper, and more efficiently – a crucial step towards achieving ambitious climate goals and strengthening energy security.
How does cable pooling work?
In practical operation, cable pooling means that several power generation facilities – for example, wind and solar farms as well as battery storage systems – share a common grid connection point and can use the available grid capacity more flexibly and jointly.
Co-location projects
In so-called Co-location projects, In cases where renewable energy systems (RE systems) and battery storage are connected at a grid interconnection point, co-use of the grid connection is explicitly permitted. In this scenario, the RE system and the storage are technically separate from each other. Each has its own metering concept and its own market location (MaLo). The key feature is that the large-scale battery storage can feed into the grid when the RE system is not fully utilizing the grid capacity. Therefore, the available grid connection for the storage is dynamic and depends on the current feed-in from the RE system. Through its own MaLo, the storage can also be flexibly used for grid procurement (gray electricity).
Hybrid models
In addition to traditional cable pooling, there are various technical and market-based approaches for sharing and optimizing resources. In a hybrid model, storage and the connected renewable energy plant are treated as a single common overall system. This involves economic optimum in the foreground. In combined operation, it can be meaningful to deliberately throttle the feed-in power of the renewable energy system to prioritize the storage system – for example, to be available for the grid balancing market or to optimally exploit market signals.
EEG-subsidized facilities
For EEG-subsidized PV or wind power plants, a special model must be applied. In this case, the battery storage and the EEG-subsidized renewable energy system are connected behind the same feed-in meter. The difference: The operation is designed solely for renewable energy The storage may only be charged with surplus electricity from the renewable energy system; additional grid power, i.e., charging with grey electricity, is excluded. This option meets the funding requirements according to the EEG and guarantees that only green energy is temporarily stored and fed back in.
Flexible connection options with Cable Pooling
Thanks to modern technical control, separate measurement concepts, and clearly regulated market processes, significant efficiency gains can be achieved at grid interconnection points today. Thus, cable pooling and various optimization models open up flexible ways to optimally utilize grid connections and new business models around electricity storage and Sector coupling to develop.
Legal framework
The current legal framework, particularly the EEG 2023 and the new regulations from February 25, 2025 (Sections 8 and 8a EEG), ensures legal security and planning certainty. These now expressly permit multiple actors to flexibly utilize their joint grid connection potential and Make better use of the network connection point. Participants in cable pooling benefit from being able to conclude individual, flexible grid connection agreements directly with the grid operator. This creates the technical and regulatory conditions for various plant operators to collaborate lawfully at a single grid connection point.
Advantages of Cable Pooling in practice
In practice, cable pooling offers numerous tangible benefits for everyone involved:
- The construction and operation of further renewable energy facilities will only become possible where the existing grid infrastructure would actually already be at its limit.
- Connection costs are significantly reduced as transformers and grid connection points are optimally utilized. Waiting times for new projects are considerably shortened.
- Existing grid connections are used efficiently by being optimally utilized by different stakeholders at different times.
- Less electricity needs to be curtailed or „thrown away“ because storage and intelligent control concepts increase flexibility in the grid. This enhances supply security and helps to further improve the availability of green electricity.
How does cable pooling work in real-world operation?
A common example of cable pooling is the combination of a wind farm, Solar park and Large-scale battery storage at a shared grid connection point. This allows excess solar power to be temporarily stored during the day and fed back into the grid when solar generation is low or demand is high. The solar panels generate the most energy around midday, while the wind farm feeds power into the grid at many times of the day and night. Thanks to smart control systems, the maximum grid capacity is never exceeded—on the contrary: the three components can complement each other in such a way that the available connection capacity is optimally utilized over long periods.
Cable pooling is also used in hybrid projects and commercial districts to flexibly and cost-effectively manage various renewable energy systems and storage facilities at the grid connection point and to share costs. Experience shows that projects become significantly more efficient, can be implemented more quickly, and can make a greater contribution to the supply of renewable electricity. Even without costly grid expansion, existing grid capacity can be optimally utilized in this way, depending on weather conditions and the time of day.
Challenges and Limitations of Cable Pooling
Cable pooling also presents challenges: a secure operation requires precise technical control, clear measurement concepts, and close coordination among all involved stakeholders. Contract and billing models can become complex depending on the project constellation, especially when many operators collaborate.
Even though moderate development of the network connection is usually economically sensible, there is a limit. Various studies show: Development of network interconnection points 150 % the original connection power works in practice with minimal losses. Even an increase to up to 250 % is feasible in many cases – however, with increasing development, the amount of electricity that needs to be curtailed rises, as the sum of generation peaks can less frequently be fully fed into the grid. In these cases, storage and alternative flexibility solutions help, but not every location can permanently utilize this full potential.
Outlook & Conclusion
Cable pooling is an important building block for advancing the energy transition in Germany more quickly and cost-effectively. By enabling significant overbuilding of grid connection points and efficient coupling of multiple plants, grid expansion is relieved and the expansion of renewable energies is accelerated. At the same time, new business models are emerging, particularly through the integration of storage and flexible technologies such as sector coupling.
In the future, digital control systems and smart metering concepts will further facilitate implementation and increase grid flexibility. The cooperation between grid operators, plant operators, and market participants will also play a central role. Despite technical and regulatory challenges, cable pooling promises significantly improved grid utilization, reduced expansion costs, and higher security of supply.
Conclusion Cable pooling makes better use of existing grid resources and creates the conditions to efficiently meet the growing demand for grid connections for renewable energies. This makes it a key issue for a sustainable and future-proof energy system.