Conceptual design and numerical analysis of mooring in-situ power generation systems under low current velocity conditions

This study proposes a mooring in-situ power generation system harnessing low-speed ocean current energy, with a focus on numerical investigations into its hydrodynamic stability and power output capacity. The mooring configuration effectively addresses sediment issues common to conventional seabed-mounted installations, while enhancing the operational flow velocity range for improved energy capture efficiency. A ductless Archimedes screw turbine serves as the primary energy extraction component, realizing the efficient use of low-speed ocean current energy. An integrated numerical model, coupling mooring lines with turbine dynamics and validated through experiments, was employed in this study. Comparative analysis was conducted for single-line mooring system and four-line mooring system with distinct performance characteristics. Under the low-flow condition of 0.3 m/s, both two mooring systems demonstrate excellent power output capacity. The single-line mooring system achieves a C_p,a of 0.363, while the four-line configuration attains a higher C_p,a of 0.376. Parametric studies on inflow angles revealed different characteristics: the single-line mooring system accommodates wider yaw variations to adapt to the incoming currents, whereas the four-line mooring system demonstrates bidirectional current utilization capability with enhanced dynamic stability. These findings provide valuable design guidelines for optimizing mooring systems in deep-sea renewable energy applications.