Knowledge

Keyword: ECAs

paper

The impact of flexible environmental policy on maritime supply chain resilience

Zavitsas, Konstantinos; Zis, Thalis; Bell, Michael G.H.

As policy makers acknowledge the high degree of supply chain vulnerability and the impact of maritime emissions on coastal population health, there has been a consistent effort to strengthen maritime security and environmental regulations. In recent years, overdependence on deeper and wider multinational supply and production chains and lean-optimization has led to tightly integrated systems with little “slack” and high sensitivity to disruptions.

This study considers the impact of Emission Control Areas and establishes a link between environmental and network resilience performance for maritime supply chains using operational cost and SOx emissions cost metrics. The proposed methodological framework analyzes various abatement options, disruption intensities, fuel pricing instances and regulatory strategies. The methodology utilizes a minimum cost flow assignment and an arc velocity optimization model for vessel speed to establish the payoff for various network states. Additionally, an attacker defender game is set up to identify optimal regulatory strategies under various disruption scenarios. The results are complemented by a sensitivity analysis on SOx emissions pricing, to better equip policy makers to manage environmental and resilience legislation. The methodology and findings provide a comprehensive analytic approach to optimize maritime supply chain performance beyond minimisation of operational costs, to also minimize exposure to costly supply chain disruptions.

Transport Policy, Volume 72 / 2018
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paper

Maritime routing and speed optimization with emission control areas

Fagerholt, Kjetil; Gausel, Nora T.; Rakke, Jørgen Glomvik; Psaraftis, Harilaos N.

Strict limits on the maximum sulphur content in fuel used by ships have recently been imposed in some Emission Control Areas (ECAs). In order to comply with these regulations many ship operators will switch to more expensive low-sulphur fuel when sailing inside ECAs. Since they are concerned about minimizing their costs, it is likely that speed and routing decisions will change because of this. In this paper, we develop an optimization model to be applied by ship operators for determining sailing paths and speeds that minimize operating costs for a ship along a given sequence of ports. We perform a computational study on a number of realistic shipping routes in order to evaluate possible impacts on sailing paths and speeds, and hence fuel consumption and costs, from the ECA regulations. Moreover, the aim is to examine the implications for the society with regards to environmental effects. Comparisons of cases show that a likely effect of the regulations is that ship operators will often choose to sail longer distances to avoid sailing time within ECAs. Another effect is that they will sail at lower speeds within and higher speeds outside the ECAs in order to use less of the more expensive fuel. On some shipping routes, this might give a considerable increase in the total amount of fuel consumed and the CO2 emissions.

Transportation Research Part C: Emerging Technologies, Volume 52 / 2015
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Maritime shipping and emissions: A three-layered, damage-based approach

Lindstad, Elizabeth; Eskeland, Gunnar; Psaraftis, Harilaos N.; Sandaas, Inge; Hammer Strømman, Anders

Policy emphasis in ship design must be shifted away from global and idealized towards regional based and realistic vessel operating conditions. The present approach to reducing shipping emissions through technical standards tends to neglect how damages and abatement opportunities vary according to location and operational conditions. Since environmental policy originates in damages relating to ecosystems and jurisdictions, a three-layered approach to vessel emissions is intuitive and practical. Here, we suggest associating damages and policies with ports, coastal areas possibly defined as Emission Control Areas (ECA) as in the North Sea and the Baltic, and open seas globally. This approach offers important practical opportunities: in ports, clean fuels or even electrification is possible; in ECAs, cleaner fuels and penalties for damaging fuels are important, but so is vessel handling, such as speeds and utilization. Globally we argue that it may be desirable to allow burning very dirty fuels at high seas, due to the cost advantages, the climate cooling benefits, and the limited ecosystem impacts. We quantify the benefits and cost savings from reforming current IMO and other approaches towards environmental management with a three-layered approach, and argue it is feasible and worth considering.

Ocean Engineering, Volume 110, Part B, / 2015
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On two speed optimization problems for ships that sail in and out of emission control areas

Fagerholt, Kjetil; Psaraftis, Harilaos N.

This paper deals with two speed optimization problems for ships that sail in and out of Emission Control Areas (ECAs) with strict limits on sulfur emissions. For ships crossing in and out of ECAs, such as deep-sea vessels, one of the common options for complying with these limits is to burn heavy fuel oil (HFO) outside the ECA and switch to low-sulfur fuel such as marine gas oil (MGO) inside the ECA. As the prices of these two fuels are generally very different, so may be the speeds that the ship will sail at outside and inside the ECA. The first optimization problem examined by the paper considers an extension of the model of Ronen (1982) in which ship speeds both inside and outside the ECA are optimized. The second problem is called the ECA refraction problem, due to its conceptual similarity with the refraction problem when light travels across two different media, and also involves optimizing the point at which the ship crosses the ECA boundary. In both cases the objective of the problem is to maximize daily profit. In addition to mathematical formulations, examples and sensitivity analyses are presented for both problems.

Transportation Research Part D: Transport and Environment, Volume 39 / 2015
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