Numerical Modeling of Air Pollutants and Greenhouse Gases Emissions in Intermodal Transport Chains

Abstract

This paper discusses the most attractive emission compliance options (emission abatement technologies and cleaner fuels) in intermodal transport chains that include short sea shipping. Most studies on emissions-based transport chain comparisons have estimated high levels of nitrogen and sulfur oxide emissions in maritime transportation, decreasing its competitiveness. However, the consequences of regulatory and technological developments and the integration of maritime transport in intermodal transport chains have not yet been considered in detail. In order to address this research gap, a numerical model for computing emissions from different transport modes in an intermodal transport network, under the effect of these developments, is presented that is based on bottom–up emission factors that depend on the fuel type, engine type, and operational profile of each vehicle. Different emissions scenarios are chosen for specific unimodal and intermodal routes (short sea shipping-based) between Portugal and northwestern Europe. Conclusions are drawn on estimated values of air pollutant emissions and greenhouse emissions, in CO2-eq per unit of cargo, in each scenario. These results allow the identification of the most environmentally friendly transport chains, thus supporting the development of adequate transport policies.

The Impact of the Internalization of External Costs in the Competitiveness of Short Sea Shipping

“…Figure 3 shows the values of each external cost type in the total external costs calculated for each transport chain per trailer. The most favourable alternative for this corridor, in terms of external costs, seems to be the intermodal SSS-based route E through Rotterdam and making use of a freight train to Manheim, followed closely by the other two SSSbased intermodal alternatives B and C. The intermodal rail-based alternative D sees its competitiveness reduced by the large external costs associated with air pollutant emissions associated with the use of a diesel locomotive for which emission standards are lower when compared to other inland modes [15]. The diesel freight train is the current solution used in the railway connection between the Iberian Peninsula and the other EU countries.…”

“…An activity-based methodology is used to estimate fuel consumption and emissions, using the most recent consumption patterns and emission factors for each mode, and was described in a previous paper [15]. The change in speed due to congestion and its impact in fuel consumption is considered, depending on the congestion level assigned to each link.…”

“…This corridor has been studied before [14] and its interest remains as there are significant volumes of trade between the Iberian Peninsula and the central European countries and the peripheral location of those countries can easily drive the modal shift from road to sea. Detailed results for emissions using these transport chains have been published before [15].…”

“…A Ro-Ro cargo ship is considered for maritime links (main dimensions: Lbp = 180 m, B = 27 m, T = 7.5 m) having a deadweight of 13,535 t, a capacity of 239 trailers fully loaded, equipped with a medium-speed diesel engine with 12,000 kW, using VLSFO (0.5%S) outside the emission control area (ECA) in the North Sea and 0.1%S fuel inside the ECA, and 1270 kW of auxiliary power. The average time spent in each (origin and destination) port, when applicable, is 6 h. In the port the main engine is switched off but the auxiliary engines are kept running at 40% load [15].…”

“…The numerical results presented in this paper are based on a generalpurpose computational tool developed to estimate the internal and external costs in any transport corridor forming part of the Trans-European Transport Network (TENT-T). The numerical model has been presented before [13,14] and a detailed methodology is used for the estimation of the fuel consumption and emission quantities, which includes the effect of congestion in speed, the impact of new fuels and abatement technologies, particularly in maritime transport, and is based on the most recent emission inventories for all transport modes [15].…”