Routing and scheduling of RoRo ships with stowage constraints

Roll-on/Roll-off ships are used for international transport of vehicles and other rolling equipment. We consider the problem where a ship sails between two geographical regions, picking up cargo in the first and making deliveries to the second. Several variations are considered with optional cargoes, flexible cargo quantities, and ship stability restrictions. Decisions must be made regarding the route and schedule of the ship as well as the stowage of cargo onboard. The problem is modeled as a mixed integer program, which has been solved using Xpress. In addition, a tailor made heuristic procedure is built using components from tabu search and squeaky wheel optimization. Extensive computational results are presented, showing that the heuristic is able to handle realistically sized problem instances.     

The effectiveness of a European speed limit versus an international bunker-levy to reduce CO2 emissions from container shipping

In the fight to reduce CO₂ emissions from international shipping, a bunker-levy is currently under consideration at the International Maritime Organization (IMO). Faced with the inability of the IMO to reach an agreement in the short term, the European Commission is now contemplating a unilateral measure of a speed limit for all ships entering European Union (EU) ports. This paper argues that this measure is counterproductive for two reasons. Firstly, because it may ultimately generate more emissions and incur a cost per ton of CO₂ which is more than society is willing to pay. Secondly, because it is sub-optimal compared to results obtained if an international bunker-levy was to be implemented. These elements are illustrated using two direct transatlantic services operated in 2010.     

Use of an ANP to prioritize managerial responsibilities of maritime stakeholders in environmental incidents: An oil spill case

While maritime pollution is often caused at the operational level, the causes can generally be traced back to shortcomings in the ship–shore interface and to poor communication among stakeholders. Here, the environmental responsibilities of maritime stakeholders are systematically analyzed and quantified using an analytic network process. This approach ensures that the most important dependencies and feedbacks among the responsibilities which is applied to a real marine situation (an oil spill) to validate the theoretical basis. A number of latent links between stakeholders’ responsibilities and the catastrophic impacts of the spill are identified.     

Effect of a speed reduction of containerships in response to higher energy costs in Sulphur Emission Control Areas

The objective of this paper is to explore the possible consequences of the future low-sulphur fuel requirements in Sulphur Emission Control Areas (SECA) on vessel speed, from the standpoint of the container shipping industry. Rational energy use, speed reduction, and revenues are closely related in the container shipping sector because speed reductions may provide substantial energy and cost savings. The operators could consider reducing their speed in SECA in order to save on fuel that will become relatively expensive. However, to maintain a weekly frequency without adding new ships, such a behaviour implies that the required speed at sea outside the SECA area increases. This paper aims to investigate if such a difference in speed is cost-effective, and if the increase in speed outside SECA may result in an increase in CO₂ emissions of the total cycle. We propose a cost model that estimates the cost-minimising combination of speeds inside and outside SECA, and the resulting CO₂ emissions of the liner service. Applying this model to representative liner services serving North Europe, we find that differentiating speed accordingly slightly decreases total costs and increases CO₂ emissions in a similar way. The results are sensitive to the price of low-sulphur fuels, the part of the cycle in SECA and the number of ships deployed in the service.     

Airline ambidextrous competition under an emissions trading scheme – A reference-dependent behavioral perspective

This study presents a reference-dependent Hotelling model for analyzing airline competition in pricing and green transportation investment, as well as the resulting financial performance under the European Union emission trading scheme. One feature of the proposed methodology is that it embeds psychological benefits/costs of consumers to characterize consumer attitudes to the increases in airline fare adjustments and improvements in green transportation. This study then investigates the equilibrium solutions for airfare adjustment and green transportation investment margins in different scenarios. The analytical results reveal specific operational conditions under which a cost-efficient airline can gain supreme competitive advantage by increasing both airfare and green transportation investment margins beyond the increases made by competitors under the emission trading scheme, whereas certain specific conditions may favor a cost leadership strategy. Conversely, a cost-inefficient airline can compete with a cost-efficient airline in both market share and profitability using the green transportation investment-differentiation strategy, particularly when consumers perceive the airfare difference as equaling the increased psychological benefit induced by the airline’s green effort.