Modelling the Potential Environmental and Operational Effects of Autonomous Ship Just-in-Time Arrivals: A Scenario-Based Analysis

This article analyzes the synergy between autonomous shipping and Just-in-Time (JIT) arrival systems to optimize maritime logistics. JIT can reduce fuel consumption and emissions while improving efficiency by optimizing vessel arrivals, with autonomous ships possibly enhancing these benefits through continuous speed control, real-time data exchange, and more accurate ETA prediction. This study analyzed 882 vessel voyages arriving at the Port of Sines, Portugal, between June and December 2023, using Automatic Identification System (AIS) and port call data to compare conventional and a modelled counterfactual autonomous JIT scenario. In this counterfactual scenario, early arrivals benefited most, with mean ETA deviation decreasing from 16.67 h to 12.89 h, while fuel consumption fell by 36.86% and greenhouse gas (GHG) emissions by over 3180 tCO2. Late arrivals showed only a marginal punctuality improvement (59.47 to 58.84 h) but increased fuel consumption by 9.29%. Autonomous JIT reduced fuel use by 4.92% and GHG emissions by 4.90%, improving the mean ETA deviation for voyages that were originally early or late by approximately 1.5 h. Economic savings reached €628,028 for early arrivals, while late arrivals incurred potential losses of €351,770. Overall, autonomous JIT could improve punctuality, economic performance, and sustainability, but requires early data, real-time integration, digital port infrastructure, and stakeholder coordination.