Conceptual design and model test of a pontoon-truss type offshore floating photovoltaic system with soft connection

Abstract

With the growing demand for clean energy in human society, the development of offshore floating photovoltaic (FPV) systems emerged as a prominent research topic. Positive-airgap FPV systems are more practical for engineering applications, however, current designs still face challenges under open sea such as negative airgap risk and significant connecting load. To address these issues, this study presents a novel foundation and connection scheme for an offshore FPV system. First, a pontoon-truss platform was designed and its superior performance was demonstrated by comparing it to a traditional semi-submersible. Further, a four-module offshore FPV system concept was developed, in which soft ropes were first introduced as a solution for FPV module connection. After that, a basin model experiment is employed to evaluate the feasibility of proposed FPV system under wind-wave-current joint effect, where the current-wind load is simplified as a constant force, and the established numerical model is verified by experiments. To improve understanding and design, the impact of several key design parameters on dynamic responses is also discussed. The findings indicate that the airgap performance deteriorates rapidly when single module draught surpasses half of pontoon diameter, and improving soft rope stiffness is more effective and produces less disturbance to other behaviors than enhancing mooring stiffness.