C²-Wakes: Control and mitigation of large-scale wind farm effects

At a glance

• The wake effects of large offshore wind farms have a considerable influence on the electricity production and lifetime of wind turbines.
• As suitable areas become ever scarcer, the C²-Wakes research project is investigating whether and how these cluster wakes can be reduced. This should result in specific recommendations for action for industry and authorities.
• To this end, Fraunhofer IWES is developing industry-suitable measuring and modeling approaches, also on the basis of a dedicated scanning lidar measuring campaign.

The challenge

Expansion of the offshore wind energy sector is a key component of the energy transition. The German government’s goal of installing offshore wind farms with a total capacity of 70 GW by 2045 also means that the German Bight and southern Baltic Sea are set to become regions densely populated with wind farms. Large-scale wake effects (cluster wakes) and their influence on the electricity production and lifetime of wind turbines have thus already been a topic of interest in research for some years. Fraunhofer IWES previously investigated the issue in the X-Wakes project. The question of whether and, if so, how such effects can be reduced represents the next step. 

The solution

This is where the C²-Wakes research project comes in. The project partners are investigating possibilities for reducing the large-scale wake effects and thus increasing the yield of wind farms as well as improving the yield assessment. This involves an extensive scanning lidar measuring campaign to evaluate the influence of active wake deflection on wind farm and cluster wakes on the one hand and, on the other, investigation of how innovative wind turbine designs, wind farm layouts optimized for cluster wake effects, and control approaches can contribute to the reduction of wind farm cluster effects. A further topic of research is the question of what potential exists for increasing the wind farm yield by influencing the global blockage effect (GBE).

Fraunhofer IWES is responsible primarily for the development of industry-suitable measurement and modeling approaches. This includes the improvement of wind farm layout optimization and the recalculation of wind farm expansion scenarios now optimized for cluster wakes using mesoscale models and industry models as well as comparing these methods. 

The added value

The results of the C²-Wakes project will not only deliver new findings regarding the impact of turbine design and wind farm layout on cluster wakes but also provide specific recommendations for action for industry and authorities for the reduction of wind farm effects. As such, the project is set to make a considerable contribution to climate protection and ensuring a reliable and cost-efficient energy supply.