Joint optimization of inland waterway methanol bunkering station siting and vessel operations with cross-port bunkering

Abstract

The early-stage deployment of green methanol-powered inland vessels faces a fundamental infrastructure dilemma: limited vessel cruising range increases the need for en-route bunkering, whereas spatially dispersed demand makes dense construction of fixed bunkering stations economically burdensome. Existing inland bunkering-network studies largely associate fuel supply capability with fixed facility nodes, leaving the potential of mobile bunkering services to reshape infrastructure deployment insufficiently explored. To address this gap, this study develops an integrated infrastructure–operation optimization framework that extends the conventional fixed-node bunkering paradigm by allowing fixed methanol bunkering hubs to serve surrounding ports through cross-port ship-to-ship bunkering using mobile bunker barges. The model jointly optimizes fixed bunkering-station siting, vessel freight assignment and operating ranges, bunkering-port selection, and cross-port service allocation, while explicitly accounting for vessel fuel endurance, bunkering-barge service radius, and finite mobile service capacity. A hybrid Adaptive Large Neighborhood Search–Mixed Integer Programming (ALNS–MIP) algorithm is developed to solve the resulting problem. A case study based on a 15-port Yangtze River inland shipping network shows that the best-found cross-port bunkering solution reduces total system cost by approximately 37.7% relative to conventional alongside bunkering. Sensitivity analysis further shows that bunkering-barge service radius and vessel methanol tank capacity have the largest impacts on system cost, producing cost variations of approximately 37.9% and 32.8%, respectively. Higher fixed-station construction costs strengthen the relative cost advantage of cross-port bunkering, whereas rising bunker-barge sailing costs weaken but do not eliminate this advantage; methanol-price variations have only a limited effect on total system cost within the tested range. These results demonstrate that cross-port mobile bunkering can substitute for part of fixed infrastructure deployment by extending the service coverage of regional methanol hubs. The proposed framework therefore provides a network-level method for coordinating fixed infrastructure, mobile bunkering capacity, and vessel operations in the phased development of inland green-fuel bunkering systems.