Vessel routing and scheduling under uncertainty in the liquefied natural gas business

Liquefied natural gas (LNG) is natural gas transformed into liquid state for the purpose of transportation mainly by specially built LNG vessels. This paper considers a real-life LNG ship routing and scheduling problem where a producer is responsible for transportation from production site to customers all over the world. The aim is to create routes and schedules for the vessel fleet that are more robust with respect to uncertainty such as in sailing times due to changing weather conditions. A solution method and several robustness strategies are proposed and tested on instances with time horizons of 3-12 months. The resulting solutions are evaluated using a simulation model with a recourse optimization procedure. The results show that there is a significant improvement potential by adding the proposed robustness approaches. (C) 2012 Elsevier Ltd. All rights reserved.