On 1 January 2015, the sulphur requirements in Emission Control Areas will be reduced to just 0.10%.
Although air pollution from ships does not have the direct cause and effect associated with, for example, an oil spill incident, it causes a cumulative effect that contributes to the overall air quality problems encountered by populations in many areas, and also affects the natural environment, such as though acid rain.
MARPOL Annex VI, first adopted in 1997, limits the main air pollutants contained in ships exhaust gas, including sulphur oxides (SOx) and nitrous oxides (NOx), and prohibits deliberate emissions of ozone depleting substances.
SOx and particulate matter emission controls apply to all fuel oil, as defined in regulation 2.9, combustion equipment and devices onboard and therefore include both main and all auxiliary engines together with items such boilers and inert gas generators. These controls divide between those applicable inside Emission Control Areas (ECA) established to limit the emission of SOx and particulate matter and those applicable outside such areas and are primarily achieved by limiting the maximum sulphur content of the fuel oils as loaded, bunkered, and subsequently used onboard. These fuel oil sulphur limits (expressed in terms of % m/m – that is by weight) are subject to a series of step changes over the years, regulations 14.1 and 14.4:
Outside an ECA established to limit SOx and particulate matter emissions:
4.50% m/m prior to 1 January 2012
3.50% m/m on and after 1 January 2012
0.50% m/m on and after 1 January 2020
Inside an ECA established to limit SOx and particulate matter emissions:
1.50% m/m prior to 1 July 2010
1.00% m/m on and after 1 July 2010
0.10% m/m on and after 1 January 2015
The ECA established are:
1. Baltic Sea area
2. North Sea area
3. North American area (which extends up to 200 nm from the coasts of the continental US & Canada
4. United States Caribbean Sea area
Most ships which operate both outside and inside these ECA will therefore operate on different fuel oils in order to comply with the respective limits. In such cases, prior to entry into the ECA, it is required to have fully changed-over to using the ECA compliant fuel oil, regulation 14.6, and to have onboard implemented written procedures as to how this is to be undertaken. Similarly change-over from using the ECA compliant fuel oil is not to commence until after exiting the ECA. Compliance can also be obtained by using ECA compliant fuel at all times.
Ship owners should be aware that MARPOL Annex VI Reg 4.1 allows the use of alternative compliance measures provided that the vessels flag administration certifies that these installations are “at least as effective in terms of emissions reductions as that required”.
Within 200 miles of shore, strict emission limits of exhaust gas are supported by EU and US EPA regulators and enforcement will be carried out by various governmental organizations.
The new compliance rules will apply to all vessels operating within any ECA. For ship owners there are two options to meet the requirements of the SOx emissions regulations:
Option 1: Switch to an alternative fuel with the correct sulphur content
Option 2: Install a scrubber to remove sulphur from the exhaust fumes following combustion
Scrubbing systems remove the sulphur content of fuel from the exhaust gases after they’ve been burnt, meaning vessels can go on using their existing fuel.
The process of scrubbing exhausts has been used since the 1930s in industrial plants and marine vessels. The scrubbing process uses a fluid containing alkaline material which can absorb SOx and neutralise it. After this process the clean exhaust gases are released and the resulting waste product, or sludge, is stored on board and transferred on shore.