Joint planning for fuel switching ships in a liner shipping network with transit time

Fuel switching is the most mature, reliable, and economical technology for ship operators to comply with regulations of sulfur emission control area (SECA), and will remain so for the next few years. Under SECA regulations, this paper tries to optimize liner shipping operation by integrating ship deployment, schedule design, and speed optimization while considering transit time. Specifically, a mixed integer nonlinear programming model was built to minimize operating costs, and fully guarantee the logic and superiority of the existing liner shipping network. A two-stage algorithm based on ɛ outer approximation estimation and enumeration was designed, and a backtracking algorithm was provided for determining initial port combinations in large-scale instances. After that, a case study on the Orient Overseas Container Line was carried out to verify the operability and flexibility of our method. The optimized strategy refines the existing network by adjusting initial port combinations, enhancing speed, and expanding new ship deployments. To mitigate the impact of rising port demurrage fees, liner companies are reducing transshipment penalty costs. While easing connecting time window (CTW) restrictions offers limited benefits, optimizing speed and loosening CTW can reduce operational costs by approximately 2–5%, helping liner companies navigate the fluctuating fuel market post-Covid.