Increasing the value of your PV assets

A battery storage system is particularly worthwhile if energy is regularly lost because the energy park has to be curtailed due to grid bottlenecks or feed-in limitations. Instead of leaving this surplus energy unused, it can be temporarily stored in a storage facility and marketed at a later date. This increases the utilization rate of the plant and significantly improves its economic efficiency.

In addition, a storage facility can also pay off if additional sources of revenue are tapped – for example, through participation in the balancing energy market, price arbitrage in electricity trading, or the reduction of grid fees.

A green energy storage system is charged exclusively with electricity from renewable energy sources, such as a PV or wind farm. The stored electricity thus retains its “green” status and can be marketed as such. This is particularly important for operators who are bound by subsidy mechanisms or certifications.

A gray energy storage system, on the other hand, may also be charged with electricity from the public grid (e.g., from fossil fuel sources). While this makes the model more flexible, it also leads to more complex approval processes, tax issues, and difficult distinctions in marketing. In practice, the regulatory treatment of gray electricity storage facilities is often more complicated and risky.

A green energy storage system enables the optimal use of the electricity generated in a PV park. It prevents excess energy from being lost during grid bottlenecks or curtailments, thereby increasing the overall efficiency of the plant. It also opens up additional marketing options, as the stored electricity is still considered “green” and is in demand accordingly—for example, for companies with sustainability goals or for electricity products based on guarantees of origin.

Another advantage is that, since the storage system is clearly classified as renewable energy for regulatory purposes, approvals are generally easier to obtain and more legally secure than in the case of a gray energy storage system.

The optimal size of a battery storage system depends heavily on the individual circumstances of the respective PV or wind farm. Important factors include output, typical feed-in profile, grid connection capacity, possible curtailments, and the planned marketing strategy.

In practice, this means that a storage system that is too small cannot fully exploit the potential of the farm, while a storage system that is too large can become uneconomical. Individual design is therefore necessary to achieve the best balance between technical performance and economic benefit.