Investigation of the motion performance of a novel single-point moored wind-wave integrated platform under survival conditions

The energy and climate crises have sparked a global upsurge in research on the utilization of marine renewable energy. Joint utilization of offshore wave and wind energy presents a promising offshore energy production scheme. However, the survivability of combined systems in extreme marine environments usually depends on mooring systems and nacelle yaw systems, which leads to unaffordable maintenance costs. To address this issue, this paper proposed a novel solution integrating a single point mooring system with a wind-wave integrated platform. A coupled numerical framework involving aerodynamic, hydrodynamic, elastic, and mooring dynamics with time-domain analysis was established. The wind tracking performance of the integrated platform under different combinations of wind, wave and current environmental loads was systematically investigated, and the survivability of the platform in extreme sea states has been evaluated. In addition, the stability and mooring forces under single mooring line failure were checked. The high fidelity of the numerical model has been thoroughly validated by 1:65 scale model test. Results indicate that the integrated platform is most sensitive to wind loads, followed by current and wave loads. Notably, the SPM system preserves sufficient safety margins under the condition of single mooring line failure. • A combined concept of floating offshore wind turbine and wave energy converter with a single-point mooring system is introduced. • Time-domain numerical framework for hybrid wind-wave platforms is proposed. • The proposed numerical framework is validated by 1:65 scale model tests. • The weathervaning effect of the integrated platform under various environmental load combinations is evaluated. • The mooring system still maintains sufficient safety margin under single mooring line failure in extreme sea states.