Ship Emissions: Logistics and Other Tradeoffs

This paper takes a look at various tradeoffs that are at stake in the goal for reduced ship emissions and may impact the costeffectiveness of the maritime logistics chain and presents some models that can be used to evaluate these tradeoffs. The reason for investigating such tradeoffs is that measures to reduce such emissions may possibly have ramifications as regards the logistical supply chain, and vice-versa. The broad spectrum of measures that are involved in the drive to reduce emissions generally depends on the type of emissions that are studied. In this paper we focus on operational measures that have a direct link to logistical operations, and investigate related tradeoffs. The focus is mainly on CO2 and SO2 emissions. Measures such as reduction of speed, change of number of ships in the fleet, and possibly others, will generally entail changes (positive or negative) in overall emissions, but also in other logistics and cost-effectiveness attributes such as intransit inventory and other costs. Industry circles have also voiced the concern that low-sulphur fuel in SECAs (these are the so-called ‘sulphur emissions control areas’ that exist in some parts of the world- for instance the Baltic and the North Sea) may make maritime transport (and in particular short-sea shipping) more expensive and induce shippers to use land-based alternatives (mainly road), even though shifting cargo from land to sea is an important policy goal. A reverse shift of cargo from sea to land might ultimately increase the overall level of CO2 emissions along the intermodal chain. Models to investigate such problems are developed and some examples are presented.