Thinking economically about wind + storage: How battery storage increases wind farm revenue

Wind energy in Germany is growing rapidly. However, grid bottlenecks and volatile market prices often make optimal operation difficult. When wind turbines are curtailed or remuneration is lost during periods of negative prices, valuable potential remains untapped.

Battery storage systems can solve this problem by absorbing excess energy and releasing it during periods of high demand. This alleviates grid bottlenecks, stabilizes generation, and generates additional revenue.Depending on their configuration, co-location projects can vary significantly in terms of accounting structure and marketing logic, which has a noticeable impact on the economic performance of the storage facility.

Why wind + storage is attractive right now

Several developments are making the combination of wind farms and storage facilities particularly interesting. First, the cost of battery storage has fallen by more than 70 percent since 2017, and forecasts indicate additional cost reductions in the coming years. Second, the regulatory framework has improved; new regulations allow for more flexible use of grid connections. For example, targeted overbuilding is now permitted, as are future mixed models with green and gray electricity from 2025 onward. Thirdly, the regulatory framework has improved, allowing for more flexible use of grid connections through targeted overbuilding or future mixed models with green and gray electricity from 2026 onwards.

Furthermore, storage systems generate new revenue sources. They can optimize energy across markets through arbitrage, provide balancing power, and reduce losses due to curtailments. For operators, investing early means securing cost-effective technology, scarce grid connection capacities, and long-term competitive advantages.

Green or grey? Two models of co-location 

There are basically two different approaches to combining wind and storage:

• Grey electricity model: In this model, storage facilities can purchase additional electricity from the grid, which may not come exclusively from renewable energies. This approach offers maximum flexibility and the highest revenue potential because all electricity and balancing power markets are accessible.

• Green electricity model: Storage facilities are charged exclusively with electricity from the connected wind farm. While this limits trading opportunities, it can offer advantages in specific subsidy programs, such as EEG innovation tenders.

Both models have their merits – the key is choosing the right model for the project environment and objectives.

Overbuilding as a lever for revenue 

Another lever for economic efficiency is overbuilding. It involves installing more storage capacity at the grid connection point than is permitted for feeding into the grid. Simulations show that this approach is worthwhile:

• In the grey electricity model, overbuilding by 75 to 100 percent is economically attractive.

• In the green electricity model, the optimum is around 20 to 40 percent.

Although overbuilding means storage facilities and wind turbines must share the grid connection, the resulting loss of revenue compared to pure storage operation remains manageable. The flexibility gained makes all the difference.

Conclusion: Storage is making wind farms future-proof

Wind plus storage is becoming an increasingly central business model for the energy transition. Operators can increase their revenues, reduce risks from grid bottlenecks and price fluctuations, and stabilize their projects in the long term. With intelligent trading software, such as the suena Energy Trading Autopilot, storage can be optimized in real time for maximum profitability and secure implementation.

Learn more in the white paper 

Those who would like to delve deeper into the subject will find detailed simulation results, case studies, and specific recommendations for action in the joint white paper published by ENERCON and suena energy. The paper is intended for individuals interested in operating and optimizing wind farms from technical and economic standpoints. 

Read now: „Beyond the wind: Unlocking the full potential of battery storage“ (only available in German)

Download the white paper here