Comparative Analysis of Mechanical and Hybrid Propulsion Systems for Buoy Maintenance Vessel Based on Real-Sea Operational Data

To achieve carbon neutrality in shipping and comply with the IMO’s increasingly stringent environmental regulations, the transition of small and medium-sized workboats to eco-friendly alternatives is an urgent issue. This study quantitatively compares the fuel efficiency and operational fuel cost savings of hybrid propulsion systems based on actual operational data from a buoy maintenance vessel. The methodology comprised four stages: First, measurement equipment was installed on the vessel to collect real-sea data. Second, the collected data were processed to derive specific fuel oil consumption curves and load profiles. Third, fuel consumption models for mechanical and hybrid propulsion systems were developed. The battery capacity of the hybrid models was selected based on actual operational requirements. Performance indicators and economic analyses were conducted for a comparative evaluation. Fourth, simulation results indicated that the hybrid electric system achieves 2.02% fuel savings, translating to annual fuel savings of USD 1053.24 and a corresponding 2.02% CO2 reduction. The hybrid mechanical system yielded 0.66% savings. These improvements are attributed to a rule-based energy management strategy of operating generators at their optimal efficiency points and shutting down main engines during low-load periods. This study provides empirical evidence supporting Korea’s 2030 eco-friendly public vessel transition plan.