Influence of External Stiffness on the Hydroelastic Behaviour of a Floating Photovoltaic Concept

Abstract In recent years, innovative renewable energy solutions at sea have gained significant interests. As one of such solutions, offshore floating photovoltaic (FPV) systems produce clean solar energy in remote waters but may encounter harsh environmental conditions. For FPV concepts with flexibly interconnected floating modules, the hydroelastic behaviour of an array under wave loads is influenced by internal stiffness due to connectors and external stiffness due to mooring lines. This study selects an offshore FPV concept and examines the impact of mooring line stiffness on the float motion and bending moment of an array under different wave conditions. The studied FPV array consists of 6 interconnected floats, which are modelled as rectangular plates using Mindlin plate theory within a hybrid finite element-boundary element framework. The modal expansion method is employed to efficiently solve the large stiffness and mass matrix of the array. Only the mooring stiffness in the vertical degrees of freedom is considered. Hydroelasticity effects of this FPV array are assessed in terms of structural and motion performance by considering varying mooring stiffness.