Advancing offshore solar energy generation: Numerical modelling and calibration of a floating solar array against model tests

Offshore areas present significant opportunities for sustainable solar energy production; however, most existing floating photovoltaic (FPV) solutions are designed for mild environmental conditions. To overcome the technical and economic challenges posed by harsh offshore environments, an innovative FPV concept, RECsolar, has been proposed. This concept is characterised by lightweight, semi-submersible floats with soft connections. To gain insight into the dynamic behaviour, this paper numerically studies an array with six modules (2-by-3) connected by ropes and moorings. The numerical model is first calibrated against 1:60 scaled model tests under various regular and irregular wave conditions, focusing on the float motion and mooring responses. Subsequently, statistics of the rope responses are analysed and presented. Findings demonstrate a good match of the motion spectra for surge and heave motion under operational and survival wave conditions. Comparing the numerical and experimental models, the maximum difference in heave motion ranges from 0.25% to 8.36%, while the surge difference is between 2.17% and 6.53%. Tension analysis of the connecting ropes identified snap load events, which could be mitigated by increasing the rope stiffness. This study provides valuable insights for the robust design and analysis of next-generation FPV systems. • Numerical study of a novel offshore floating solar concept conducted. • Iterative procedure developed to calibrate quadratic damping coefficient. • Float motions and mooring tensions validated with hydrodynamic model test results. • Insights into dynamic response of a floating solar array in various waves. • Outcomes valuable for future design of floating renewable energy devices.