Optimization Models for Wake Mitigation in Floating Offshore Wind Farms

Abstract

Multiple methods for mitigating wake at floating offshore wind farms have been studied, and in this thesis yaw control and turbine repositioning are investigated. Four optimization models are proposed, yaw control, winch-based turbine repositioning, winch-based turbine repositioning combined with yaw control, and yaw-based turbine repositioning. The optimization models are non-linear and implemented with a sequential quadratic programming solver. The performance of each model is experimentally evaluated and compared. The results indicate that the winch-based turbine repositioning combined with yaw control performs the best, followed closely by the winch-based method alone. Yaw-based turbine repositioning, while not as effective as the winch-based system, still shows good potential. Yaw control is the least effective method, but it remains relevant due to its simplicity and lack of additional equipment requirements. Further experiments on yaw-based turbine repositioning are conducted, examining the impact of wind farm layout and turbine size. Experiments on the layout of the wind farm and the turbine size are made. From the results, it is clear that the layout and the size of the turbines in the offshore wind farm affect the performance of the yaw-based turbine repositioning method. Sub-optimal layouts and larger turbines enhance the efficiency of turbine repositioning. However, a notable drawback is the long running time of the model and solver, even for scenarios with only nine turbines.