Power absorption of combined wind turbine and wave energy converter mounted on braceless floating platform

Abstract

This work investigates the dynamic response and power absorption of a combined wind turbine and wave energy converter (WEC) mounted on a braceless semisubmersible floating platform. The floating platform consists of a Semi-submersible Wind turbine, a Wave energy converter Combination (SWWC) and a NREL 5-MW Current Source Converter (CSC) wind turbine. In this study, ANSYS/AQWA software is used in cooperation with a potential-based boundary element method (BEM) approach. The main targeted results include average power output and response amplitude of surge, heave and pitch motions of the combined concept at various wave and wind directions plus operational conditions. The numerical results are compared with experimental data, suggesting that the current numerical model predicts heave amplitude, average power, power take-off (PTO) damping force and response amplitude operator (RAO) of the platform motions with an acceptable agreement. Meanwhile, six environmental conditions (ECs) and five PTO damping coefficients are considered to optimize energy production. An optimal damping coefficient of 4000 kN s/m was found for the maximum average power generation for all the ECs. In addition, the effect of the wave/wind directions on the response motions and power absorption are obtained and presented.