Lower speed – less emissions?

Ships in the Mediterranean Sea have reduced their speed by more than 30 per cent since 2008, which has led to a 45 per cent cut in average ship NOx emission factors.

Lowering the speed of ships – also known as slow steaming – became more widespread from 2008 because shipping companies needed to cut costs by saving on fuel, as fuel prices had doubled over just a few years, and to reduce overcapacity, as transport demand fell due to the global economic recession. In practice, slow steaming means reducing the speed of a vessel from about 20–25 knots to 16–19 knots. As a result, fuel use and accompanied fuel costs for ship voyages are cut significantly. In addition, emissions of air pollutants, such as sulphur dioxide (SO₂) and nitrogen oxides (NOx), and of the greenhouse gas carbon dioxide (CO₂) decrease sharply with reduced ship speed.

Using satellite measurements, a group of researchers have analysed changes in European ship NOx emissions between 2005 and 2012, looking at four European shipping lanes in the Mediterranean, Bay of Biscay, North Sea, and Baltic Sea.

Their results show that European ship NOx emissions increased by about 15 per cent from 2005 to 2008. This increase was followed by a reduction of some 12 per cent in 2009 – a result of the global economic downturn in 2008–2009, after which emissions remained relatively stable from 2009 to 2012.
The impact of slow steaming was estimated for shipping in the Mediterranean Sea. Observations of ship passages through the Suez Canal and satellite-derived ship densities suggest that ships in the Mediterranean have reduced their speed by more than 30 per cent since 2008. Ship average NOx emissions increased from 2005 to 2008, then decreased by 46 per cent from 2008 to 2009, to stay relatively constant, at 30 per cent below the 2005 levels, in the years from 2009 onwards.

The lower ship NOx emission factors from 2009 coincide with the implementation of slow steaming in 2008–2009. The fact that average emission factors per ship have remained low since 2009 indicates that slow steaming has remained a common practice in the Mediterranean Sea.
According to the study, the implementation of slow steaming in 2009 contributed to offsetting the 2005–2007 increase in ship NOx emissions, but the relative contribution of the shipping sector to total European NOx emissions still increased from 11 per cent in 2005 to 14 per cent in 2012.
So in spite of the implementation of slow steaming, the emission estimates suggest that one in seven of all NOx molecules emitted in Europe in 2012 originated from the shipping sector, up from one in nine in 2005.

The study concludes that the growing share of the shipping contribution to overall European NOx emissions suggests a need for the shipping sector to implement additional emission abatement measures.

Christer Ågren
Study: “Ships going slow in reducing their NOx emissions: changes in 2005–2012 ship exhaust inferred from satellite measurements over Europe” (July 2015). By K F Boersma, G C MVinken and J Tournadre. Published in Environmental Research Letters 10 (2015) 074007. Link: http://iopscience.iop.org/1748-9326/10/7/074007

In this issue

1.5°C target adequate for Paris agreement

The 2°C goal for global warming is inadequate. Risks increase significantly between 1.5 and 2°C, a UN review of climate targets concludes.

Editorial: The road from Paris

At the UN climate conference in December 2015 in Paris, 196 countries will hopefully adopt a new global agreement for strong greenhouse gas reductions.

Environment MEPs want stricter air pollutant caps

Member states should meet stricter 2025 and 2030 air pollution reduction targets and mercury should also be included in the National Emission Ceilings directive, says the Parliament’s Environment Committee.

A future based on 100 % renewable energy for all is achievable

Greenpeace has launched the new edition of the popular Energy [R]evolution report “How to Achieve 100% Renewable Energy for All by 2050”.

Film:1.5 Stay Alive

AirClim has co-published a 50-minute documentary and Caribbean music film about climate change in the coastal zones of the Caribbean Region.

Exposing the role of coal in Europe – launch of European Coal Map

There is now a comprehensive overview of existing and planned coal power plants that also displays key information on pollution and health impact, presented by the Climate Action Network (CAN).

Deal on pollution from medium combustion plants

While EU-wide application of readily available emission abatement techniques would reduce NOx emissions from these plants by more than 80 per cent by 2025, the new directive will deliver less than half of this reduction.

Weak EU coal pollution standards carry high costs

Draft new EU emission limits for coal-fired power stations are so weak that they could result in health damage, including the loss of over 23 million working days, which would cost over €52 billion between 2020 and 2029.

140 000 life-years lost each year in London because of air pollution

Inclusion of the impact of nitrogen dioxide for the first time suggests that more than twice as many people as previously thought die prematurely from air pollution in London.

Lower speed – less emissions?

Ships in the Mediterranean Sea have reduced their speed by more than 30 per cent since 2008, which has led to a 45 per cent cut in average ship NOx emission factors.

Emissions keep on slowly shrinking

Air pollutant emissions from land-based sources are continuing to fall slightly, but considerably slower than before. Some of the reductions on land are also countered by rising emissions from international shipping.

Pledges for the 2015 UN climate agreement

South Korea plans to cut emissions by 37 percent by 2030, and China plans to boost renewables. As the Paris conference approaches, countries are submitting their plans for greenhouse gas reductions.

Dirty diesel cars tested

Emissions tests on 32 Euro 6 diesel passenger cars from ten different manufacturers and with different abatement technologies show that most cars fail to meet the NOx emissions standards under more realistic driving conditions.

Lignite villages have been needlessly destroyed

Lignite has a low energy output and requires huge quantities to be mined, which has a devastating impact on landscapes and settlements. Even so, many countries are still committed to the fuel.

EU air pollution emissions still exceeded

Ten EU countries breached at least one of their air pollutant emission ceilings in 2013, preliminary data from the European Environment Agency (EEA) shows.

Main menu

Lower speed – less emissions?

In this issue

1.5°C target adequate for Paris agreement

Editorial: The road from Paris

Environment MEPs want stricter air pollutant caps

A future based on 100 % renewable energy for all is achievable

Film:1.5 Stay Alive

Exposing the role of coal in Europe – launch of European Coal Map

Deal on pollution from medium combustion plants

Weak EU coal pollution standards carry high costs

140 000 life-years lost each year in London because of air pollution

Lower speed – less emissions?

Emissions keep on slowly shrinking

Pledges for the 2015 UN climate agreement

Dirty diesel cars tested

Lignite villages have been needlessly destroyed

EU air pollution emissions still exceeded

Publications

Food for Thought

Northern forests, climate change and the UNFCCC

EU climate targets aligned with the Paris agreement’s 1.5°C objective

Baltic Sea Offshore Wind Collaborative-Learning project

Air pollution in Europe and children’s health

Climate Change: A Himalayan Odessey

No further discussion needed. The agreed global goal is to limit temperature rise to 1.5°C

Fossil-free electricity 2021

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