Dynamic response and power performance of a novel wind-wave-tidal energy system with single-point mooring integration

The growing global demand for renewable energy has driven the development of offshore hybrid energy systems. This study investigates the development of a novel floating wind-wave-tidal (WWT) hybrid energy system with various mooring configurations. Using a new aero-hydro-servo-elastic fully coupled numerical model, the platform motion responses, mooring line tensions, and power outputs under different environmental loads are systematically analyzed, as well as the yaw restoration capabilities under misaligned loading combinations. Notably, the single-point mooring (SPM) configuration is applied to the WWT system, and the performance is compared with the existing spread mooring method. Key findings reveal that a floating offshore wind turbine (FOWT) alone with the SPM configuration exhibits superior pitch stability compared with the spread mooring method, particularly at long wave periods with response amplitude reduced by 62.4 %–89.9 %. Integrating the wave and tidal energy devices fully in a semi-submersible FOWT system further significantly improves the platform stability and reduces structural loads compared with single FOWT, with a reduction of 67.6 %–69.8 % in maximum pitch and 17.9 %–30.7 % in tower base bending moment under rated conditions. The full WWT system also significantly improves the power output, with 78.2 %–78.8 % increase in total power generation under high loading conditions. Additionally, with SPM configuration, the full WWT system exhibits better yaw restoration than that of the FOWT under misaligned wind, wave, and current, achieving more stable restore equilibrium at the same time. Overall, the research findings provide critical insights into the design and optimization of deep-sea hybrid energy systems, and illustrate the significant advantages of SPM configuration in enhancing system stability and overall performance.