Experimental Investigation of a New Hybrid Spar Buoy Wind Turbine With Oscillating Water Column

Wave Energy Harvesters (WEH) struggle to be economically competitive in the energy market due to the high costs of installation with respect to the exploitable energy. The economic viability of WEHs could be enhanced through their integration into already existing floating platform, such as offshore wind turbines. In this respect an experimental investigation of the hydrodynamic performances of a novel concept of hybrid platform is presented. The hybrid platform is composed of Oscillating Water Columns (OWC) integrated into a spar buoy floating wind turbine. The use of OWC represents a cost-effective solution to extend the operability of the system, increasing the annual working hours and stepping up the power extraction capability. This is obtained considering the delay between wind and wave energy exploitation. The experimental program is carried out in the CNR INM wave basin, based in Marine Technology Research Institute in Rome, Italy. Free decay and irregular wave tests are carried out to derive the dynamic behaviour of the new integrated energy harvester. Irregular sea states conditions are tested to reproduce the sea-environment in which the floating platform could be deployed. Particularly, the platform heave, roll, and pitch motion and the OWC pressures and water levels are analysed. The main outcome of this investigation regards the evaluation of the power production of the three OWCs installed on the floating platform and the influence of their geometric arrangement with respect to the wavefront.