Experimental tests on a wave-to-wire pivoted system for wave energy exploitation

This paper presents the wave tank test results on an innovative system for converting mechanical energy from waves directly to electricity. It consists of a point-pivoted buoy that oscillates in presence of waves and a ball screw based electro-mechanical generator. A damping force was applied for the system control by connecting the generator to an electrical load. The numerical model of the complete system and power conversion has been developed and simulation results allowed predicting the system performances. The prototype was equipped with all necessary instrumentation to measure the wave-to-mechanical efficiency (i.e. the hydrodynamic efficiency of the buoy) and the mechanical-to-electrical efficiency (i.e. the efficiency of ball screw based generator): in this way, the wave-to-wire conversion efficiency of the whole system has been characterized. The device and electro-mechanical generator design are firstly described. Then the experimental test campaign results on the scaled system with regular wave inputs are shown and discussed. Finally, a comparison between experimental and numerical model results is made.