Several options for cutting ships’ emissions

A mix of regulatory measures, such as emission control areas and fuel efficiency standards, combined with market-based instruments, is the best way of reducing air emissions from shipping, according to a report published by the European Commission's Joint Research Centre (JRC) in December.

The report describes a wide variety of options for reducing emissions of both “traditional” air pollutants and of greenhouse gases (GHG), and provides an assessment of the emission abatement potential of each of these measures.

Application of the technological measures outlined in the report could reduce shipping emissions of sulphur dioxide (SO2) and fine particles (PM) by 90 per cent, nitrogen oxides (NOx) by 80 per cent, and carbon dioxide (CO2) by 70 per cent.

Data on cost-effectiveness, expressed as the cost per tonne of avoided pollutant emission, is shown for a number of measures. Regarding SO2, fuel switching from 2.94 per cent sulphur heavy fuel oil (HFO) to 0.5 per cent sulphur fuel oil is estimated to cost €1,300/tonne, while switching from 2.94 per cent sulphur HFO to 0.1 per cent sulphur marine gas oil (MGO) would cost €3,600-4,300/tonne. If sea water scrubbing is used instead, costs are estimated at €310-550/tonne of SO2.

All three options would also to a varying degree reduce PM emissions, but it appears as if all of the cost for the fuel switch and scrubber operation, respectively, is allocated solely to the reduction in SO2.

Application of selective catalytic reduction (SCR) can reduce NOx emissions by 90-95 per cent, at an estimated cost of between €200 and €800 per tonne, depending on factors such as the size of the ship and if the equipment is added to a newly built ship or retrofitted to an existing one.

The JRC points out that to achieve significant reductions of air emissions, fuel- and engine- related technological solutions should be supplemented with other measures. Market-based options addressing both regional and global measures should therefore also be investigated. As an example, the report includes an analysis on how the introduction of market-based policies, such as a GHG Emission Trading Scheme (ETS) for the shipping sector at international level, could be used.

When analysing data and methodologies available to estimate air emissions from ships, the JRC concludes that limited availability of data on shipping movements complicates the design and assessment of air emission reduction strategies. But it suggests that combining data sources could reduce uncertainties.

Christer Ågren

The report "Regulating air emissions from ships: the state of the art on methodologies, technologies and policy options", can be found here.

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