Multi-objective sizing optimization of shipboard multi-energy hybrid propulsion systems with feasibility and sensitivity analysis

Shipboard multi-energy hybrid propulsion systems (MEHPS) have attracted widespread attention owing to their potential to effectively reduce carbon emissions in the shipping industry. However, the coupling of multiple energy sources and propulsion modes substantially increases the complexity of system design, and effective design methodologies for such complex systems remain limited. This study proposes a sizing optimization framework for shipboard MEHPS. The NSGA-III algorithm and the technique for order preference by similarity to an ideal solution (TOPSIS) are employed for design space exploration and multi-objective decision-making. A case study of an inland bulk carrier operating in China is conducted, yielding multiple sets of engineering-feasible Pareto-optimal solutions under specified operating conditions, thereby demonstrating the effectiveness of the proposed framework. In addition, the probabilities of system infeasibility corresponding to different ranges of optimization variables are quantified, and the global sensitivity of optimization objectives to decision variables within the feasible domain is analyzed, revealing the effects of key component parameter configurations on system feasibility and overall performance. This study provides valuable insights for the application of emerging energy technologies, such as lithium batteries, fuel cells, and photovoltaics, in ship propulsion systems.