Study on Control Concepts Suitable for Mitigation of Loads from Misaligned Wind and Waves on Offshore Wind Turbines Supported on Monopiles

For current offshore wind farms, monopiles are by far the most popular support structure type. However, for deeper water and/or larger turbines, the fatigue loading is becoming critical and the monopile dimensions are exceeding the current economical feasibility. Especially in cases of misaligned wind and waves, the side-to-side fatigue loading at the support structure can become a design driver. Since the industry aims to use standardized rotor-nacelle-assembly (RNA) designs, the goal of this paper is to show the effectiveness of using the RNA as adjustable controller device for site-specific offshore support structure configurations by using active control devices.