Power Coefficient Estimation of Floating Axis Wind Turbine by Lifting Line Theory

In the development of the offshore wind turbine, the horizontal axis wind turbine (HAWT) with fixed foundation is the mainstream in the world. However, the floating type wind turbine is advantageous for Japan because the seas near Japan are deep. It is difficult for the vertical axis wind turbine (VAWT) to utilize its advantages on land. Meanwhile, VAWT is suitable for the floating type wind turbine because its gravity center is low. Besides, the performance of VAWT is hard to decrease if the rotor inclines. Among the VAWTs, the target of this research is the floating axis wind turbine (FAWT) which is expected to further reduction of the electricity cost. In this research, the performance of FAWT is estimated by QBlade which is based on the lifting line theory. The estimated power coefficient (Cp) of the 5MW FAWT is 0.49 and it is comparable with that of HAWT.