Dynamic response of a floating offshore wind turbine

Abstract

The ever increasing demand for renewable energy, combined with limited areas suitable for large wind farms, has put focus on the development of floating wind turbines. In this thesis the dynamic response of a floating wind turbine, subjected to forces from wind and waves, is analyzed. The wind turbine is of a spar buoy design, similar to Statoil's Hywind project. Simulations with two main type of load cases were run, based on the international offshore wind turbine standard IEC 61400-3. These were normal production, and parked turbine exposed to extreme wind and waves. The results show that the peak response coincides with the largest wave events under production conditions, for all the observed parameters. In extreme conditions the wind and waves have a more equal contribution to the total response. Furthermore, the results indicate that the production load cases governs the design of the rotor blades, while the extreme conditions load cases yields the highest loads in the tower and substructure.