Researchers at Oslo Metropolitan University in Norway have developed and numerically modeled a novel “soft-connected” floating photovoltaic (FPV) system designed to enhance stability and mitigate fatigue in challenging offshore conditions. This innovative approach, detailed in a recent study published in Marine Structures, aims to overcome limitations of traditional rigid FPV designs by allowing greater flexibility and adaptability to wave motion.

The system comprises multiple arrays, each consisting of standard floats interconnected by ropes, which act as soft connections to absorb dynamic stresses and prevent collisions. These arrays are electrically linked via a floating structure, with power transmitted to a floating transformer for easy access. Each modular pontoon supports four dual-pitched solar panels and incorporates six cylindrical floaters for buoyancy and stability. The pontoons feature a porous design to optimize air circulation and water-cooling for the PV modules, while pre-stretched flexible ropes ensure the array can adapt vertically to wave movements without damage.

Unlike conventional catenary mooring systems, the taut mooring employed in this design provides restoring force through line tension, making it particularly suitable for deep-water deployments. The scientists utilized a potential flow solver in the frequency domain to evaluate the hydrodynamic properties and wave excitation force transfer functions for the pontoons, basing their analysis on the Cummins equation—a standard for offshore structure motion behavior. The numerical model was rigorously calibrated against experimental results obtained from towing tank tests conducted at Universidad Politécnica de Madrid, under both regular and irregular wave conditions, with wave heights ranging from 1.9 meters to 15.3 meters.

“The case study results show that the heave motions are virtually not affected by the variations in the mooring line properties except for short waves,” stated researcher Jian Dai. “Such variations are found to affect the surge motion responses amplitude operator (RAO) substantially in the vicinity of the natural period around 6 seconds.” The research also revealed that mooring stiffness significantly influences tension forces, providing crucial restoring forces for system stability under irregular wave conditions, with increased stiffness leading to higher variability in mooring tension.

This study’s contribution is threefold: it provides fundamental insights into the dynamic behavior of interconnected floating arrays under wave excitation, proposes a practical calibration procedure for multi-body systems, and demonstrates the influence of mooring parameters for future design improvements. The research team, including scientists from the Technology Centre for Offshore and Marine, Singapore (TCOMS), and Norway’s University of Agder, plans to conduct large-scale model testing at Singapore’s TCOMS wave basin in November 2025. These tests will quantify the system’s hydrodynamic behavior and uncertainties, supporting the development of reduced-order models and digital twin applications for advanced offshore FPV systems.