Preliminary Design and Hydrodynamic Analysis of Backward Bent Duct Buoy Based on Site-Specific Wave Resource

Indonesia, as the world’s largest archipelagic country, faces challenges in providing reliable and sustainable electricity, particularly in eastern regions such as Sumba Island. The southern coast of Sumba exhibits strong and consistent wave conditions due to direct exposure to the Indian Ocean, making wave energy a promising renewable alternative to reduce dependence on diesel-based power generation. This study presents a 150 kW Backward Bent Duct Buoy (BBDB)-type Wave Energy Converter (WEC) for South Sumba waters, where structural design follows the Indonesian Classification Society (BKI) rules and hydrodynamic analysis is conducted using the Boundary Element Method (BEM) in ANSYS AQWA to evaluate motion response and mooring performance. An integrated framework is developed by combining site selection, AEP-based assessment, structural design, and hydrodynamic–mooring analysis. The results show that Location 3 is the most suitable site, achieving an Annual Energy Production (AEP) of 545.898 MWh/year with a capacity factor of 41.5%. The designed structure (30 m × 16 m × 9.5 m, draft 7.5 m) satisfies strength and stability requirements under hydrostatic and hydrodynamic loads, while the system exhibits coupled multi-degree-of-freedom behavior with resonance effects remaining within controllable limits. Mooring analysis identifies beam sea conditions as the most critical loading scenario, and the proposed approach enables simultaneous evaluation of energy yield, structural integrity, and operational feasibility for wave energy deployment in remote island electricity systems.