Numerical study of a novel hybrid system with the Wavestar wave energy converter array and a SPIC semi-submersible floating platform

Abstract

To improve power generation efficiency and reduce costs in the industry of ocean renewable energy, one of the optimal strategies is the addition of wave energy converters (WECs) into the floating wind turbine. This paper proposes a novel hybrid wind-wave energy concept that comprises multiple Wavestar point absorption wave energy converters (WECs) and a SPIC semi-submersible floating wind turbine (FWT). ANSYS/AQWA software is used to perform numerical simulations based on three-dimensional potential flow theory. Three hybrid systems are designed with different numbers of Wavestar WECs, which are symmetrically arranged on the platform. Before the study, the hydrodynamic responses of the Wavestar WEC and the SPIC concept platform are simulated separately and compared with existing experimental data. After the validation of numerical models, the platform motions and the absorbed power of the WECs are investigated, which are the main factors in evaluating the performance of a hybrid system. After a series of numerical simulations, the results show that the absorbed power increase significantly with the increase in the number of the Wavestar WECs, while the platform motions also increase. It can be concluded that the wind-wave energy hybrid design needs to find a balance between the platform motions and the absorbed power of the WECs. Overall, this study can be used as a reference for the design of other novel hybrid ocean energy concepts.