Carbon-Aware Crew Change Logistics in Maritime Shipping: A Multi-Objective Optimization Model for Cost, Emissions, Delay, and Relief Reliability

Crew change logistics is a recurring but underexamined source of indirect emissions in maritime shipping. While decarbonization research has mainly focused on vessel fuel consumption, alternative fuels, port electrification, and route optimization, the carbon impact of moving seafarers across international travel networks has received limited analytical attention. This study develops a carbon-aware crew change logistics model for maritime shipping by integrating direct travel cost, travel-related CO₂ emissions, relief delay, and crew change failure risk within a multi-objective optimization structure. The model evaluates alternative crew change plans involving different joining ports, flight itineraries, local transport modes, accommodation requirements, and backup replacement options. Travel-related emissions are estimated using distance-based emission factors for air and ground transport, while operational reliability is represented through disruption-risk scores associated with travel complexity, documentation readiness, port-call uncertainty, and relief lead time. A ۳۰-day computational scenario involving ۶ vessels, ۱۴ relief requirements, ۲۲ candidate replacements, ۷ joining ports, and ۴۶ feasible travel itineraries is used to test the model. Results show that the carbon-aware solution reduces crew-change CO₂ emissions by ۲۷.۸% compared with a conventional least-cost strategy, while increasing direct cost by only ۸.۶%. The model also reduces average disruption risk from ۰.۳۸ to ۰.۲۴ and lowers total expected relief delay from ۱۸ days to ۶ days. Sensitivity analysis indicates that moderate carbon pricing and early relief planning can shift crew change decisions toward lower-emission itineraries without undermining operational reliability. The study contributes to maritime sustainability research by introducing crew change logistics as a measurable Scope ۳ emission source and by providing a practical optimization framework for balancing decarbonization, cost control, and seafarer relief continuity.

کلیدواژه ها:

Crew change logistics ، Maritime decarbonization ، Scope ۳ emissions ، Carbon-aware optimization ، Seafarer relief ، Crew rotation ، multi-objective optimization ، Shipping sustainability