Cable Pooling – What Is It?

Cable Pooling – Definition and Its Role in the Energy Sector

Cable pooling involves connecting two renewable energy sources to a single grid connection point. In principle, these installations are expected to operate alternately in order to ensure the most efficient use of modern technologies. Typically, shared connections involve photovoltaic installations and wind farms.

This solution offers three key advantages:

• Grid infrastructure optimization – consolidating transmission infrastructure and reducing the number of cables required helps lower construction and maintenance costs, while also reducing the environmental impact of energy investments.

• Integration of renewable energy infrastructure – cable pooling enables efficient integration of assets such as solar farms and wind power plants into the existing power grid without the need for extensive grid expansion works.

• Increased grid efficiency – adding more renewable energy sources improves overall energy security and reduces pressure on central grid infrastructure, especially when local systems include energy storage.

Until recently, companies planning renewable energy investments often faced grid connection refusals due to technical constraints. Shared grid connections aim to minimize such situations.

Cable Pooling and Grid Connection Refusals – Why Do Operators Deny Access?

Under current regulations, there are two main reasons why a grid operator may refuse a connection request for a renewable energy installation:

• the project is economically unjustified, meaning that its implementation would require disproportionately high costs compared to the expected benefits,

• there is no available grid capacity.

Additionally, there must be an insurmountable technical barrier preventing the connection, existing at the time of issuing connection conditions or refusal.

The Warsaw Court of Appeal, in its judgment of June 9, 2016 (case ref. VI ACa 92/15), emphasized the importance of economic assessment in connection decisions. In summary, it is not enough that a project is technically feasible—it must also be economically reasonable.

According to data published by ClientEarth (as of 2022), over the past six years the President of the Energy Regulatory Office (URE) has issued an increasing number of refusals for renewable energy grid connections. One of the key reasons is the poor condition of the Polish electricity grid, including:

• Overhead lines – 39% are over 40 years old, and 40% are between 20–40 years old,

• Underground cables – 16% are over 40 years old, and 31% are between 20–40 years old,

• Substations – 33% are over 40 years old, and 34% are between 20–40 years old,

• Transformers – 18% are over 40 years old, and 33% are between 20–40 years old.

The modernization of Poland’s power grid is ongoing; however, the pace of investment does not keep up with the growth of the renewable energy sector and the increasing demand for green electricity. This has created the need for alternative solutions—such as cable pooling.

How Does Cable Pooling Work?

Cable pooling involves connecting two different renewable energy sources to a single grid connection point. The key requirement is that each source has a different generation profile and operating characteristics.

In practice, it is rare for both installations to operate at their maximum nominal capacity simultaneously. By sharing a connection point, it is possible to optimize the use of available grid capacity.

A prime example of such synergy is the combination of a photovoltaic system and a wind farm:

• Solar PV systems generate the most electricity in spring and summer, and during daytime hours when sunlight is strongest. Their output decreases at night.

• Wind turbines, in contrast, often perform best in autumn and winter, and frequently generate more energy at night.

Since neither technology operates at full capacity year-round, unused connection capacity can be effectively utilized through cable pooling. The goal is to exploit this complementarity.

Of course, implementing cable pooling requires an individual energy audit for each project. Different turbine types and PV technologies may affect system performance. The negative correlation between these renewable sources contributes to greater stability of renewable energy generation.

Cable Pooling Regulations in Poland

Cable pooling has been successfully used for years in countries such as the Netherlands and Denmark. In Poland, it is still a relatively new concept and has not yet reached its full potential.

According to Article 7(1f) of the Energy Law Act, two or more renewable energy installations owned by one or multiple entities may be connected at a single connection point to a grid with a voltage level above 1 kV. For all installations connected under a cable pooling model, a single set of connection conditions is issued, and a single grid connection agreement is concluded.

Is Cable Pooling Economically Viable?

In theory, cable pooling helps solve challenges related to the expansion of green energy infrastructure and partially decouples development from the pace of grid modernization. Optimizing connection points reduces costs for investors while also addressing the operational constraints of grid operators.

In practice, further development of cable pooling is expected to reduce electricity tariffs as well as transmission and distribution costs. Ultimately, prosumers may benefit from lower electricity prices and reduced price volatility.

If you are interested in renewable energy solutions, explore the REO.pl offer. We support green investments and business development in this area. Check our Power Purchase Agreements (PPAs), energy balancing services, and more.