This article is part of our special report Air Quality 2013.
SPECIAL REPORT / In the Belgian port of Zeebrugge one spring day, a hulking cargo ship waiting to make its 36-hour run to the Swedish port of Gothenburg sat as a model for European and international efforts to reduce vessel emissions.
The German-built Schieborg Delfzijl is one of the first cargo vessels built to comply with the International Maritime Organisation (IMO) standard for nitrogen oxides (NOx), using a catalytic reduction system. The IMO standards apply for new vessels starting in 2016.
The vessel’s catalytic technology uses urea, which is produced from the synthesis of ammonia and carbon dioxide, to reduce nitrogen pollutants. NOx gases are produced from fuel combustion and contribute to ozone and acid raid.
Although the systems can remove 95% of NOx emissions, they are costly to install in older ships and is less effective at lower engine temperatures, such as when vessels are approaching ports or operating inside harbours.
"In places you want to use it you can't," said Onno Steenweg, superintendent of Wagenborg Shipping B.V. in the Netherlands, which operates the 13-year-old Schieborg Delfzijl.
International efforts to reduce emissions
Whether in harbours or on the open sea, the shipping industry has come under the microscope to reduce pollution and faces a 2016 deadline under the IMO’s Marpol convention to slash NOx emissions.
The treaty requires an 80% reduction in NOx emissions from 2000 levels in some coastal areas, and has also set caps on sulphur dioxide (SO2), carbon and other pollutants.
In some busy European ports, including Rotterdam and Gothenburg, shipping companies get discounted port dues for using catalytic systems, scrubbers and cleaner-burning engines. At Zeebrugge, the Schieborg Delfzijl and other vessels use dockside electricity connections to cut the need to run fuel-fired generators while loading and unloading.
The European Union has also put more attention on reduce marine pollution after years of efforts to control emissions from industries, power plants and road transport. Ships have traditionally been big polluters because they use heavier, less refined fuels that are cheaper to burn but more caustic for the air.
EU environment ministers agreed in October 2012 to cut the maximum sulphur content of shipping fuels by 90% to 0.1% in restricted Sulphur Emission Control Areas, which include some of Europe's busiest waters. The rules take effect in 2015.
Outside the controlled areas, the IMO limit of 0.5% will be mandatory in EU waters by 2020. That compares with the current 3.5% for cargo vessels and 1.5% for passenger ships.
SO2, emitted when sulphur-containing fuels are burned, is a principle cause of acid rain.
Under the new EU legislation, shipping companies that use exhaust-gas cleaning systems, or “scrubbers”, will be able to use fuels with higher sulphur content as long as SO2 emissions stay under the agreed limit.
During debates on the SO2 legislation, the European Sea Ports Organisation, a shipping industrial group, argued that higher costs associated with low-sulphur fuel and retrofitting ships with pollution filtration systems could hurt an industry that was already struggling from a lethargic global economy. The group also expressed concern that it could backfire environmentally, encouraging a modal shift back to road transport in coastal areas.
Shippers are facing similar retrofits of older ships to accommodate the catalytic technology and urea storage tanks that are needed to reduce NOx emissions. Adding the catalytic system and storage tanks in a vessel’s cramped engine compartment can be costly, potentially several million euros, shipping officials say.
Good for the environment
Nonetheless, Steenweg acknowledged that "from an environmental point of view, it is better to have [NOx filtration] than not.”
Transport and Environment, a Brussels campaign group, also says tougher rules on shipping emissions are worth it, estimating that air pollution from international shipping accounts for 50,000 premature deaths in Europe per year.
The group also estimates that applying the IMO standards for nitrogen and sulphur emissions to shipping would save up to €34 billion per year in health costs.
“These savings do not take into consideration the benefits for ecosystems and the environment as a whole if acidification and other negative consequences of air pollution were reduced,” the group says.