Great benefits of NOx reductions in the North Sea

Of the total ship emissions in the North Sea, an estimated 97 per cent are released within 100 nautical miles (185 kilometres) from the shore. Photo: Andreas Adelmann/flickr.com/ CC BY-NC-ND

The health benefits of establishing a North Sea NECA are up to seven times higher than the costs and would provide total annual net benefits to society of up to €1646 million in 2030.

The costs and benefits of creating a nitrogen emission control area (NECA) in the North Sea and the English Channel have been analysed in two recent studies. Establishing such a control area would mean that ships built from 2016 onwards are required to emit 75 per cent less nitrogen oxides (NOx), resulting in substantial benefits for health and nature.

Annex VI of the MARPOL Convention of the International Maritime Organization (IMO) provides an opportunity for countries to apply for designation of emission control areas (ECAs). The Baltic Sea and the North Sea (including the English Channel) have already been designated for several years as sulphur emission control areas (SECAs), and since August 2011 the North American coastal sea area (extending 200 nautical miles from the shore) has been a combined sulphur and nitrogen ECA.

At a meeting of the Helcom Commission in early March this year, the countries surrounding the Baltic Sea finalised their application to the IMO for making the Baltic Sea a NECA, but they have yet to agree on when to actually submit their application.

Reducing NOx emissions from ships in the North Sea would bring substantial benefits to both public health and the environment. This is the main conclusion from the two new studies by the Netherlands Environmental Assessment Agency and the Danish Environmental Protection Agency, both jointly commissioned by the eight countries bordering the North Sea, that have analysed the costs and benefits of creating a NECA in the North Sea and the English Channel, from 2016 onwards. Both studies looked at the situation in 2030 and how this would differ with or without a NECA.

The North Sea is one of the busiest seas in the world, with more than 20,000 ships registered as operating there in 2009. According to the new studies, emissions of NOx from these ships were estimated to amount to 472,000 tons that same year. It should be noted, however, that some other emission inventories for that same sea area have resulted in significantly higher figures of between 650,000 and 785,000 tons of NOx.

Of the total ship emissions in the North Sea, an estimated 97 per cent are released within 100 nautical miles (185 kilometres) from the shore and 32 per cent within 12 nautical miles.

A baseline scenario for estimating North Sea shipping in 2030 was constructed in which  ship activities are expected to continue to grow at annual growth rates of 3.5 per cent for container ships and 1.5 per cent for other types of ship, resulting in a 54 per cent increase in ton-kilometres between 2009 and 2030. It was further assumed that ship transport efficiency will improve by 1 per cent per year on average, that new ships (those built after 2010) will comply with the global IMO Tier II emission standards, and that some of the newly built ships will use liquified natural gas (LNG) as their main fuel.

Under this baseline scenario, NOx emissions in 2030 would come down by about five per cent to 446,000 tons. By contrast, in the same time period land-based emissions in the EU27 are expected to be more than halved under a baseline scenario (i.e. assuming only implementation of already adopted legislation).

To assess the environmental impacts of NOx emission control, two scenarios were developed. The main NECA scenario assumes that all ships built after 2016 and operating in the North Sea will comply with the IMO´s Tier III NOx standards, thus reducing their emissions by approximately 75 per cent as compared to the Tier II standards. By 2030, this scenario would reduce total North Sea NOx emissions by about 30 per cent as compared to the baseline, down to 317,000 tons. The limited overall emission reduction is a result of the slow turnover rate of ships, which usually have a life-length of 25–30 years.

To illustrate a situation where all ships in the North Sea meet the Tier III standards by 2030, an additional scenario (MFR) was constructed. Here, the resulting emissions would come down to 146,000 tons, nearly 70 per cent below the 2030 baseline level.

Looking at the health and environmental impacts in 2030 it was concluded that NOx emissions from North Sea shipping in line with the baseline scenario will be responsible for between 1 and 5 per cent of country-average PM concentrations, resulting in about 18,300 years of life years lost in that year. The highest contribution to average PM concentrations is found in the Netherlands and the UK with 7 and 6 per cent, respectively.

Contribution to country-average nitrogen dioxide (NO₂) concentrations will range from 7 to 24 per cent in the North Sea countries, highest in the Netherlands and Denmark. Contribution to nitrogen depositions, which enhance eutrophication and acidification and result in damage to biodiversity, ranges from 2 to 5 per cent, and is highest in Norway and Denmark.

In the NECA scenario these contributions would come down by about one third, and in the MFR scenario they would be cut by two thirds, as compared to the baseline. The lowered ship NOx emissions will also reduce damage to health and vegetation from ground-level ozone.

To protect people’s health there are binding EU air quality standards for maximum allowed concentrations of NO2 and PM, and many member states are currently facing infringement proceeding for failing to achieve those standards. Since the emissions from ships are carried by winds towards the densely populated areas on land, the establishment of a North Sea NECA would help to improve air quality.

The total monetised health benefits of a North Sea NECA were estimated to amount to between €443 million and €1928 million annually in 2030 – the range given depends primarily on the choice of valuation method. Benefits to ecosystems were not monetised and thus not included in these figures, but they are quantitatively described in the Dutch study report.

According to the studies, the Tier III standards (a 75 per cent NOx reduction compared to Tier II) can be achieved by three different currently avilable techniques, namely exhaust gas de-NOx systems (also known as Selective Catalytic Reduction, SCR); exhaust gas recirculation (EGR); or the use of liquefied natural gas (LNG) instead of conventional fuel oils. Of these, SCR – which can reduce NOx emissions by up to 95 per cent – is the most proven technology with more than 500 SCR systems already installed on ships.

The costs of a North Sea NECA were estimated to amount to €282 million annually in 2030. This implies an abatement cost of €1878 per ton of NOx reduced, which is up to 3–4 times higher than some other estimates. This relatively high abatement cost is explained, at least partly, by the fact that there is a high share of transit traffic in the North Sea. Sensitivity analyses show that if more sea areas around the EU were to become NECAs, the cost for the North Sea NECA could be more than halved.

Impacts on freight rates are expected to be only marginal and are therefore unlikely to lead to a shift towards land-based transportation modes.

Comparing the estimated monetised health benefits and costs for 2030 results in a total annual net benefit to society of between €161 million and €1646 million, which means that the benefits are between 1.6 and 6.8 times larger than the costs.

It is expected that the North Sea countries will meet this autumn to discuss the outcome of these two studies and possible next steps towards getting the North Sea designated as a NECA.

Christer Ågren

Assessment of the environmental impacts and health benefits of a nitrogen emission control area in the North Sea (June 2012). Published by PBL Netherlands Environmental Assessment Agency.
Economic impact assessment of a NOx emission control area in the North Sea (June 2012). Published by the Danish Ministry of the Environment, Environmental Protection Agency.

Figure: Contribution from shipping in 2030 to average annual PM_2.5 concentrations, average annual NO₂ concentrations and average annual N depositions.