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Many ways to cut ship NOx emissions

Establishing NOx Emission Control Areas would significantly reduce ship NOx emissions by 2040 – introducing economic instruments could cut emissions faster and further.

A new study has given projections of ship NOx emissions in the Baltic Sea, the North Sea and the English Channel up to 2040, and estimated the potential of various measures to reduce NOx emissions from international shipping.

Ships emit significant amounts of air pollution, including sulphur dioxide (SO2), nitrogen oxides (NOx) and small particles (PM2.5), causing serious damage to health and the environment. As a result of both EU and global regulations, sulphur emissions from ships are expected to gradually come down, but there is currently no regulation that will ensure any significant cuts in their NOx emissions.

The only existing regulation of NOx from international shipping is in Annex VI of the MARPOL Convention under the International Maritime Organization (IMO). However, the NOx emission standards in this regulation solely apply to newly constructed ship engines, and the currently (since 2012) applicable Tier II standard accomplishes just a modest 15 to 20 per cent emission reduction compared to an unabated Tier I engine.

There is however a stricter Tier III standard that requires emission reductions of about 80 per cent compared to a Tier I engine, but this applies only to newly built ships in designated NOx Emission Control Areas (NECA) which currently only exist in North America.

While the Tier II standard can be achieved by internal engine modifications that adjust combustion parameters, bigger changes are needed to reach the Tier III standard.

There are several different abatement options for reducing emissions of NOx from marine engines, including:

  • Exhaust gas after-treatment, where the main option is selective catalytic reduction (SCR).
  • Combustion modification using techniques such as exhaust gas recirculation (EGR) or methods where water is introduced in the engine.
  • Switching from marine fuel oils to, for example, liquefied natural gas (LNG) or methanol.
  • Reduced fuel consumption, e.g. through slow steaming.

According to the study, SCR, EGR and using LNG as fuel can all reduce NOx emissions to Tier III levels. Of these, SCR has the longest history of marine applications, LNG is increasingly being used as a marine fuel, and while EGR is said by engine manufacturers to live up to the standard, so far there is limited data from practical applications.

In terms of costs, EGR and the SCR have comparable costs per kg of NOx reduced, while the costs for LNG depend largely on whether an existing ship is rebuilt or the LNG system is installed on a new ship – the latter being considerably less costly than the former. Fluctuations in the LNG price also affect the potential return on investment.

In order to analyse the potential for reducing NOx emissions from shipping, the study made new projections of emissions up to 2040 in the Baltic Sea, the North Sea and the English Channel. Regarding activity levels, ship traffic was assumed to increase by 1.5 per cent per year for all ship types except container ships, where the increase was set at 3.5 per cent per year. The average lifetimes of ships were assumed to stay the same up to 2040, i.e. 25 to 28 years.

Expected improvements in transport efficiency will result in lower fuel consumption for comparable volumes of freight transport, and in this study efficiency is assumed to increase between 1.3 and 2.25 per cent per year for the different ship types. The authors point out that these values are quite optimistic and result in fuel consumption that is stable over time despite an increase in ship traffic.

Projections were given for two scenarios – one business-as-usual (BAU), i.e. with no NOx Emission Control Area (NECA), and another with a NECA in place from 2021.

Current (2015) emissions were estimated to amount to 830,000 tonnes of NOx. Under the BAU scenario, emissions in 2040 are expected to come down by about 14 per cent, to 715,000 tonnes. Assuming that a NECA is in place from 2021, emissions in 2040 would instead be reduced by nearly two-thirds, to 306,000 tonnes.

In addition to estimating the impact of a NECA, the study evaluated several policy instruments that could be implemented in addition or as an alternative to the NECA. These policy instruments would address NOx emissions from the entire fleet, not only from newly built ships.

Three policy instruments were shortlisted as the most promising for use in addition or as an alternative to a NECA:

The first option is a levy that ships have to pay for NOx emissions in the area. The revenue from the levy would be used to fund the uptake of NOx abatement measures in the sector.

The second option requires ships to reduce their speed by 15 per cent under the baseline speed when sailing in the area. As an alternative compliance option, the ships that prefer to stick to their baseline speed can pay a levy, depending on their NOx emissions in the area. The income from this levy would be used to fund NOx abatement measures in the sector.

The third option is a stand-alone levy that ships have to pay for their NOx emissions in the area. The revenue from this instrument is assumed to go to the member states and not to be earmarked.

These three instruments were evaluated regarding their NOx reduction potential and the associated costs for the sector if the levy rate was either set at €1, €2 or €3 per kg NOx. It was found that two of the three instruments were better at meeting the two criteria, firstly a levy & fund and secondly regulated slow steaming combined with a levy & fund.

Introducing a levy & fund instrument could quickly and significantly reduce ship NOx emissions. In 2025 emissions could be cut by two-thirds (67%) in the case of no NECA and by 61 per cent with a NECA in place (see table). In 2040, reductions would amount to about 70 per cent in the absence of a NECA, and about 30 per cent if a NECA is established. This is roughly twice the reduction achieved with regulated slow steaming combined with a levy & fund if the baseline speed is reduced by 15 per cent. However, costs for the sector of a levy & fund are also roughly twice the costs of regulated slow steaming combined with a levy & fund.

Table: NOx emissions from international shipping in the Baltic Sea, the North Sea and the English Channel 2005–2040 (thousand tonnes).


Expressed in tonnes, this means that even with a NECA in place, the use of economic instruments could cut annual NOx emissions by about 400,000 tonnes on average throughout the 2020s. For comparison, this is more than the total land-based NOx emissions of Sweden, Denmark and Finland combined, which in 2014 amounted to 385,000 tonnes.

Because the Tier III NECA standard applies only to newly built ships and ships have a very long lifetime, the introduction of economic instruments such as a levy & fund would provide a very useful complement to the NECA, by also ensuring significant emission cuts in the short term. Assume, for example, that a levy & fund is adopted and put into practice in the Baltic Sea and the North Sea in 2021, this would achieve an accumulated additional emission reduction over the ten years up to 2030 amounting to nearly four million tonnes of NOx.

Christer Ågren

The study “NOx controls for shipping in EU seas” (June 2016) was commissioned by Transport & Environment and prepared jointly by the consultants IVL Swedish Environmental Research Institute and CE Delft.

Figure: NOx emissions from international shipping in the Baltic Sea, the North Sea and the English Channel 2005–2040 under a) business-as-usual (BAU); b) a NOx emission control area (NECA), and; c) a NOx levy and fund system.

Figure: NOx emissions from international shipping in the Baltic Sea, the North Sea and the English Channel 2005–2040 under a) business-as-usual (BAU); b) a NOx emission control area (NECA), and; c) a NOx levy and fund system.

Big benefits of cleaner marine fuel

Air quality in coastal areas improved significantly in 2015 after stricter sulphur limits for marine fuels were introduced in the North Sea and the Baltic Sea.

In several countries bordering the North Sea and the Baltic Sea, concentrations of sulphur dioxide (SO₂) have come down by 50 per cent or more in 2015 compared to previous years, according to a recent study by the Dutch research consultancy CE Delft conducted on behalf of the German environmental group NABU (Nature and
Biodiversity Conservation Union).

The study has investigated the experiences of the first year of applying stricter marine fuel sulphur standards in the Sulphur Emission Control Area (SECA) covering the North Sea and the Baltic Sea. It focussed on air quality, socio-economic effects, impacts on business, and on compliance and enforcement.

As from 1 January 2015 the maximum sulphur content of marine fuels used in SECAs was reduced by 90 per cent, from 1.0 to 0.1 per cent. The resulting health benefits of better air quality were estimated to amount to between €4.4 and 8 billion.

This can be compared to the cost to the maritime sector of moving to low-sulphur marine gas oil (MGO) in the North Sea and the Baltic Sea, which was estimated at €2.3 billion.

The researchers conclude that the health benefits of lower emissions of SO₂ and particulate matter (PM) were between 1.9 and 3.5 times higher than the increase in fuel costs, which means that the benefits of introducing the new regulations clearly outweighed the cost.

Before its implementation, there were industry concerns that the stricter fuel standard would significantly increase fuel costs and that there would be problems with the availability of low sulphur fuels. There were also concerns about impacts on the industry, such as closures of companies or services, and potential shifts towards road transport. The lack of effective surveillance schemes to ensure compliance and enforcement were also subject to debate.

The study found that the availability of MGO has proven to be sufficient and that the price of MGO actually decreased – the latter mainly as the result of reduced oil prices in general. However, the MGO price decreased more sharply than the price of heavy fuel oil (HFO) and automotive diesel. In fact, by the end of 2015, the price of 0.1 per cent sulphur MGO was at the same level as the price of high-sulphur HFO was at in the beginning of 2015.

No significant shifts towards road transport were found for RoRo transport, which is regarded as the market segment that is most sensitive to a modal shift.

Moreover, no company or service closures, nor any decrease in cargo turnover in Northern European ports, was found that could be clearly linked to the introduction of the stricter sulphur standard.

Interestingly, some shipping companies reported a financial record year for the year 2015 and established new services.

According to data for 2015 from the European Maritime Safety Agency (EMSA), between three and nine per cent of the ships were non-compliant in the Baltic Sea and North Sea, respectively. It should be noted that countries typically use a margin of up to 20 per cent above the legal threshold during control in ports for reporting deficiencies and 50 per cent for applying sanctions.

It is believed that the rate of noncompliance on the open seas might be significantly higher, but the limited data available does not allow any firm conclusions.

More and better data are needed in order to estimate the actual compliance rate on the open seas. In addition, fuel sampling needs to be intensified in 2016 in order to meet the required 30–40 fuel samples per 100 administrative inspections, as required by EU legislation.

It is recommended that there should be further development of monitoring and control techniques, including control on the open seas, to improve the effectiveness of the inspection regime. The authors also recommend that countries apply sanctions that are proportionate to the economic benefits of non-compliance.

Christer Ågren

Sources: CE Delft press release and Ends Europe Daily, 20 April 2016

The study: “SECA Assessment: Impacts of 2015 SECA marine fuel sulphur limits” (April 2016).

By CE Delft, the Netherlands. Downloadable at:

Potential for shore-side electricity

AcidNews June 2015

Connecting ships at berth to onshore power will provide health and environmental benefits by reducing air pollution, greenhouse gases and noise.

A recent study by Ecofys on behalf of the European Commission’s DG CLIMA has investigated the potential for shore-side electricity (SSE) in Europe, including the barriers to implementation, and provides recommendations on policy action that the Commission could take to accelerate the implementation of SSE in European harbours.

When at berth, ships typically burn fuel oil in their auxiliary engines to generate electrical power for communications, lighting, ventilation and other onboard equipment. Ships may also burn fuel oil in boilers, for instance to  supply hot water and heating and to prevent the heavy fuel oil from solidifying.

This combustion of fuel oil results in emissions of air pollutants, including the main greenhouse gas, carbon dioxide, in the port areas, which are often located in or near cities. SSE is an option for reducing unwanted environmental impacts of ships at berth.

According to the study’s mapping of the health benefits of SSE, ports in the UK, France, Belgium, the Netherlands, Germany, Denmark, Sweden, Italy, Greece and the Mediterranean islands would gain large benefits from NOx reductions.

Concerning SO2, the biggest benefits of SSE are to be found in the Mediterranean area, Ireland and the western part of the UK.

Current SSE projects show that there can be a business case for all parties, says the study. The initial investment for ship owners and in ports is substantial, but can be recouped from lower operating costs.

Furthermore, huge benefits have been documented in terms of reductions in noise and air pollutant emissions.

The study estimates that if all seagoing and inland ships in European harbours in 2020 were to use SSE to cover their energy demand at berth, they would consume 3,543 GWh annually, equivalent to 0.1 per cent of the electricity consumption of Europe as a whole in 2012. In general, the increase in demand is not seen as problematic for the electricity grid, especially considering that expanding the use of SSE is a medium to long-term process.

The study: Potential for Shore Side Electricity in Europe (January 2015). By Ecofys, the Netherlands.

Downloadable from:

Efficiency standards for ships too easy to meet

AcidNews June 2015

CE Delft has released a study, commissioned by Brussels-based NGOs Seas at Risk and Transport & Environment, which calculated the Estimated Index Values (EIVs) of new ships built between 2009 and 2014, and concluded that the majority of container and general cargo ships built in recent years already meet the IMO’s Energy Efficiency Design Index (EEDI) standards set for 2020.

Of the ships in the study that were built in 2014, some 34 per cent of container ships and 43 per cent of general cargo ships also met the EEDI target for 2030.

The study confirms that the EEDI targets need substantial revision since the current standards fall short on reflecting best practice or the pace with which improvements in efficiency can be brought about.

The study identified a large variation in the EIV of ships of similar type and size, indicating that large additional fuel savings and associated reductions in CO2 emissions would be possible if all ships were built to the best available designs and technologies.

The EIV improvements have coincided with increases in average design speed and decreases in main engine power for a number of ship categories, which suggests an improvement in hull or propulsion efficiency. The findings also suggest that, if design speeds were kept constant, larger improvements in design efficiency would have been possible.

More information at:

Shipping emissions associated with increased cardiovascular hospitalizations

•Nickel and vanadium in PM10 are indices of shipping air pollution.
•Nickel and vanadium were associated with elevated cardiovascular hospitalizations.
•Nickel appeared to correspond better than vanadium to cardiovascular health.
•Controlling residual oil emissions is important in port cities.


Previous studies have suggested nickel (Ni) and vanadium (V) as the likely constituents that are partially responsible for health effects associated with particulate matter pollution. The authors aimed to examine the effects of Ni and V in PM10, the indices of shipping emissions, on emergency hospitalizations for cardiovascular diseases (CVD) in Hong Kong. Daily PM10 speciation data across six monitoring stations in Hong Kong during 1998–2007 were collected. Generalized additive Poisson models with single-day lags were used to estimate the excess risks of emergency hospital admissions for CVD associated with Ni and V, after adjusted for major PM10 chemical species and criteria gaseous pollutants. The excess risks for inter-quartile range (IQR) increases of Ni and V on the same day and previous six days (lag0 ∼ lag6) were estimated. Ni in PM10 was associated with a 1.25% (95%CI: 0.81–1.68%) increase of total emergency CVD admissions on the same day, while lag0 V was associated with a 0.95% (95%CI: 0.55–1.35%) elevated CVD admissions. The associations were not sensitive to the further adjustment for co-pollutants. Ni appeared to correspond better than V to cardiovascular health. Controlling shipping emissions from residual oil combustion in the port cities like Hong Kong is particularly important.


Health risks of shipping pollution have been ‘underestimated’

One giant container ship can emit almost the same amount of cancer and asthma-causing chemicals as 50m cars, study finds

Britain and other European governments have been accused of underestimating the health risks from shipping pollution following research which shows that one giant container ship can emit almost the same amount of cancer and asthma-causing chemicals as 50m cars.

Confidential data from maritime industry insiders based on engine size and the quality of fuel typically used by ships and cars shows that just 15 of the world’s biggest ships may now emit as much pollution as all the world’s 760m cars. Low-grade ship bunker fuel (or fuel oil) has up to 2,000 times the sulphur content of diesel fuel used in US and European automobiles.

Pressure is mounting on the UN’s International Maritime Organisation and the EU to tighten laws governing ship emissions following the decision by the US government last week to impose a strict 230-mile buffer zone along the entire US coast, a move that is expected to be followed by Canada.

The setting up of a low emission shipping zone follows US academic research which showed that pollution from the world’s 90,000 cargo ships leads to 60,000 deaths a year and costs up to $330bn per year in health costs from lung and heart diseases. The US Environmental Protection Agency estimates the buffer zone, which could be in place by next year, will save more than 8,000 lives a year with new air quality standards cutting sulphur in fuel by 98%, particulate matter by 85% and nitrogen oxide emissions by 80%.

The new study by the Danish government’s environmental agency adds to this picture. It suggests that shipping emissions cost the Danish health service almost £5bn a year, mainly treating cancers and heart problems. A previous study estimated that 1,000 Danish people die prematurely each year because of shipping pollution. No comprehensive research has been carried out on the effects on UK coastal communities, but the number of deaths is expected to be much higher.

Europe, which has some of the busiest shipping lanes in the world, has dramatically cleaned up sulphur and nitrogen emissions from land-based transport in the past 20 years but has resisted imposing tight laws on the shipping industry, even though the technology exists to remove emissions. Cars driving 15,000km a year emit approximately 101 grammes of sulphur oxide gases (or SOx) in that time. The world’s largest ships’ diesel engines which typically operate for about 280 days a year generate roughly 5,200 tonnes of SOx.

The EU plans only two low-emission marine zones which should come into force in the English channel and Baltic sea after 2015. However, both are less stringent than the proposed US zone, and neither seeks to limit deadly particulate emissions.

Shipping emissions have escalated in the past 15 years as China has emerged as the world’s manufacturing capital. A new breed of intercontinental container ship has been developed which is extremely cost-efficient. However, it uses diesel engines as powerful as land-based power stations but with the lowest quality fuel.

“Ship pollution affects the health of communities in coastal and inland regions around the world, yet pollution from ships remains one of the least regulated parts of our global transportation system,” said James Corbett, professor of marine policy at the University of Delaware, one of the authors of the report which helped persuade the US government to act.

Today a spokesman for the UK government’s Maritime and Coastguard Agency accepted there were major gaps in the legislation. “Issues of particulate matter remain a concern. They need to be addressed and we look forward to working with the international community,” said environment policy director Jonathan Simpson.

“Europe needs a low emission zone right around its coasts, similar to the US, if we are to meet health and environmental objectives,” said Crister Agrena of the Air Pollution and Climate Secretariat in Gothenburg, one of Europe’s leading air quality organisations.

“It is unacceptable that shipping remains one of the most polluting industries in the world. The UK must take a lead in cleaning up emissions,” said Simon Birkett, spokesman for the Campaign for Clean Air in London. “Other countries are planning radical action to achieve massive health and other savings but the UK is strangely inactive.”

The calculations of ship and car pollution are based on the world’s largest 85,790KW ships’ diesel engines which operate about 280 days a year generating roughly 5,200 tonnes of SOx a year, compared with diesel and petrol cars which drive 15,000km a year and emit approximately 101gm of SO2/SoX a year.

Shipping by numbers
The world’s biggest container ships have 109,000 horsepower engines which weigh 2,300 tons.

Each ship expects to operate 24hrs a day for about 280 days a year

There are 90,000 ocean-going cargo ships

Shipping is responsible for 18-30% of all the world’s nitrogen oxide (NOx) pollution and 9% of the global sulphur oxide (SOx) pollution.

One large ship can generate about 5,000 tonnes of sulphur oxide (SOx) pollution in a year

70% of all ship emissions are within 400km of land.

85% of all ship pollution is in the northern hemisphere.

Shipping is responsible for 3.5% to 4% of all climate change emissions

• This article was amended on 25 August 2015 to correct the number of deaths per year attributed to pollution from the world’s 90,000 cargo ships.