An Experimental Investigation Into the Wave Induced Responses of a Modular Triangular Floating Photovoltaic Array and the Influence of Module Array Position on Individual Module Responses

Abstract In recent years Floating Photovoltaic energy has firmly established itself as commercially viable source of energy in sheltered inland environments such as reservoirs. Now the industry looks towards expansion into offshore FPV, which introduces greater environmental loading challenges. To meet commercially viable power output capacities, FPV installations need to scale, requiring a modular solution of interconnected platforms. This necessitates a sufficient understanding of wave-structure interactions and the coupling effects of structure-structure interactions to design robust platforms capable of withstanding offshore environmental loading conditions. This paper documents the experimental investigation of an interconnected FPV array consisting of four modular semi-submersible models arrayed in a triangular configuration with elastomeric connections moored with a pretensioned 3-point radial mooring system. This experiment was carried out in the David Keir Building wave flume of the Marine Research Group at the Queen’s University Belfast. Data collection includes Mooring line loads, wave elevations at 10 locations, full 6 degrees of freedom motion tracking for each module and motion tracking of module-to-module connection bending. The model was subjected to a range of regular and irregular wave conditions under wave-only and wave-wind loading. This paper only covers the regular wave results. This study assesses the wave induced responses of the array, module-to-module response effects, the impact and effect of module location within the array structure on individual module responses and the inter-array connection bending responses under wave loading and module-to-module coupling. The results of this study indicate the array and its constituent modules exhibit notable non-linear responses, module position in the array affects the responses of the modules, the magnitude of the responses in the connections increase with the wave frequency, and the ratio of the wavelength to the array length, and module to module phase separation has a significant effect on the arrays responses. This requires further study.