Performance and feasibility assessment of a wave energy converter with underwater vehicle docking and charging

Wave energy converters (WECs) offer a promising renewable solution to enable persistent unmanned underwater vehicle (UUV) missions by supporting at-sea docking and recharging. However, integrated WEC–UUV systems remain under-studied, with no broadly applicable frameworks for assessing their long-term effectiveness and viability. This study addresses these gaps by developing two complementary and generalizable frameworks: (i) one for evaluating long-term WEC power performance under realistic, time-varying sea conditions, and (ii) another for assessing UUV docking feasibility. The frameworks were demonstrated using the field-deployed TigerRAY WEC–UUV system with 2024 wave data from NDBC buoy station 42,036 on the U.S. Atlantic South Coast. Power performance results showed that TigerRAY could sustain persistent UUV operations although it could not always guarantee uninterrupted recharging, with the BlueROV2 and REMUS100 completing 368 and 109 missions, respectively, compared with 2927 and 627 missions possible under an unlimited power source. This suggests the need for supplemental battery buffering or hybrid energy sources, where each kilowatt-hour of energy buffer added approximately 1.67 missions for BlueROV2 and 0.5 for REMUS100. Docking feasibility probability for BlueROV2 remained 1 (i.e., 100 % feasible) across all operational sea states, decreasing slightly to 0.7 under extremes (Hs=5 m), indicating that dock motions stayed within UUV motion limits, although actual docking success will ultimately depend on UUV control, sensing, and communication. These results demonstrate that WEC-UUV systems are technically viable, while the developed frameworks provide a generalizable foundation for performance assessment, design optimization, and system integration of future WEC–UUV technologies toward persistent autonomous ocean observation and intervention.