Maritime service network design with oil-fueled and LNG-fueled mixed vessel fleet under uncertainty: Overview and future research directions

The adoption of Liquefied Natural Gas (LNG) as an alternative fuel for vessels is a critical path to realizing the strategy of shipping decarbonization. Against the backdrop of the increasing promotion of LNG-fueled vessels, the maritime fleet of the shipping company will comprise a mixed fleet of conventional oil-fueled and LNG-fueled vessels in the mid- and long-term. Due to unpredictable trade fluctuations (e.g., the financial crisis), war, global public health emergencies (e.g., the COVID-19 pandemic), and the inherent characteristics of LNG evaporation, the maritime service network design for a mixed vessel fleet typically faces high uncertainty. This paper aims to review the literature on maritime service network design for mixed vessel fleet under uncertainty, including the problems of LNG fleet renewal, LNG bunkering station location, LNG maritime inventory routing, and the collaborative optimization of bunkering location and vessel deployment. The results remark that the following research gaps have not been well addressed: (1) The traditional fleet renewal problem has not considered the impact of government involvement on the fleet renewal decisions, and they have not measured the effects of deferring or implementing earlier of the renewal decision on shipping companies’ revenues; (2) Few studies have addressed the LNG bunkering location and vessel routing problem under uncertainty; (3) There is a lack of research on the dynamic inventory-routing problem, and the existing model formulation and solving techniques are not suitable for large-scale instances; (4) The existing collaborative optimization problems for the location-inventory and vessel deployment are mainly concentrated on the homogeneous vehicle fleet or vessel fleet, and they have not introduced uncertainty into the optimization problems. Finally, we discuss the future directions that we believe are especially important for addressing the aforementioned research gaps. Our research outcomes can help expand the theoretical research of maritime service network design and offer essential research directions for promoting the sustainable development of the port and maritime industries.