Numerical investigation on the dynamic responses of three integrated concepts of offshore wind and wave energy converter

To achieve a better utilization of ocean space and energy, three integrated concepts of column-type wind turbine and heave-type wave energy converter (WEC) have been proposed for deep, intermediate and shallow water depth conditions, respectively. The WECs are installed on the wind turbine columns, then wave energy can be absorbed by power-take off (PTO) system through the relative heave motions between wind turbine column and the WEC. The spar-type floating wind turbines with long and short floaters are considered for deep and intermediate water depth conditions whereas a fixed-type wind turbine is considered for the shallow water depth condition. On the other hand, the WECs are torus-shaped heave-type devices, with dimensions and configurations the same for the three concepts. Numerical models are established for all the three concepts. The combined systems are subjected to various wind and wave conditions. The dynamic response analysis is carried out, and the responses including motions, forces and power, are compared among them. The results show that significantly different dynamic responses of the three concepts under environmental actions are observed. •Three integrated concepts of wind and wave energy converters are compared.•Different designs are catered for various water depth.•Dynamic responses of the three concepts are investigated, aimed at a better design.•Power performance of various concepts under the same environmental conditions are studies.•Uncertainty analysis has been carried out to assess the variability of the results.