Amendments to MARPOL Annex VI (Prevention of air pollution from ships) have formally established a North American Emission Control Area (ECA), in which emissions of certain air pollutants from ships are subject to more stringent controls than the limits that apply globally. The ECA will take effect on August 1, 2012, when the US and Canada will begin to enforce the new controls.
This will be the third ECA established by the International Maritime Organization under MARPOL Annex VI; the other two cover the Baltic Sea area and the North Sea area. A fourth—the US Caribbean Sea ECA—is expected to come into effect in 2014 for the waters surrounding Puerto Rico and the US Virgin Islands.
MARPOL Annex VI and ECAs
IMO’s Marine Environment Protection Committee (MEPC) created Annex VI to MARPOL in 1997 to set limits on sulphur oxide (SOx) and nitrogen oxide (NOx) emissions from ship exhausts and to prohibit deliberate emissions of ozone depleting substances (such as CFC). This started with a global cap on the sulphur content of fuel oil. Provisions in the annex allow for special SOx Emission Control Areas (SECAs) to be established with more stringent controls on sulphur emissions. In these areas, ships must use fuel oil with sulphur content drastically lower than the global limit, or use some technological method to limit SOx emissions.
The Baltic Sea is designated as a SOx Emission Control Area in the original annex. Later amendments in July 2005 designated the North Sea as a SOx Emission Control Area, which has been enforced since November 2007.
MARPOL Annex VI was revised in 2008. The main changes were as follows:
- Reduce the global cap on sulphur content in fuel oil to 3.50% (effective January 2012), then progressively down to 0.50 % (effective January 2020)
- Reduce limits applicable in Sulphur Emission Control Areas (SECAs) to 1.00% sulphur content (effective July 2010), being further reduced to 0.10% (effective January 2015)
- Reduce limits on nitrogen oxide (NOx) emissions from marine engines, with the most stringent controls on so-called "Tier III" engines (i.e., those installed on ships after January 2016) operating in Emission Control Areas.
The revised Annex VI also allows for an Emission Control Area to limit emissions on particular groups of air pollutants:
- SOx and particulate matter (PM);
- NOx alone; or
- all three types of emissions from ships (SOx, NOx, and PM)
Thus, the previously established Sulphur Emission Controls Areas have dropped “Sulphur” from the title since the areas may now control nitrogen and particulates as well.
At the time of writing, 136 countries (shaded green above), representing 98% of the world's shipping tonnage, are party to MARPOL, and thus, Annex VI.
Annex VI deals with a long list of pollutants, but those of primary concern are CO2, SOx, NOx and PM. Why is this important?
Sulphur Oxide (SOx)
Sulphur Oxide (abbreviated SOx) combines with moisture in the air to form “acid rain,” which can cause serious damage to plant and animal life, cause paint to peel, corrode steel structures such as bridges, and erode stone statues. Most of eastern Europe from Poland northward into Scandinavia, the eastern third of the United States, and southeastern Canada are significantly impacted by acid rain.
The global fuel sulphur cap of 3.5% implemented in 2011 did not impose an arduous burden for the shipping or bunker supply industries as 3.5% sulphur fuel was widely available. However, the further reduction of that cap to 0.5% in 2020 (and to 0.1% in ECAs in 2015) will effectively make distillate oil impracticable as a fuel for ships.
Nitrogen Oxide (NOx)
Nitrogen Oxide (abbreviated NOx) also combines with water to form damaging corrosive acids, is toxic by inhalation, and is a contributor to smog formation. NOx is produced from the excess air required for complete combustion of fuel oils, which introduces nitrogen into the combustion reactions. At high temperatures, nitrogen in the atmosphere combines with oxygen to form NOx. Limiting NOx production demands the precise control of the amount of air used in combustion.
NOx emission limits are set for diesel engines depending on the engine maximum operating speed, separated in three tiers. Tier I and Tier II limits are global, while the Tier III standards apply only in NOx Emission Control Areas.
Particulate Matter (PM)
Particulate Matter (PM) is smoke or soot emanating from the ship’s exhaust. It is partially burned hydrocarbon material that includes condensed aromatic forms. These molecules include free radicals that can cause respiratory ailments and cancer. On ships, in addition to being a health hazard, PM causes stubborn oily acidic deposits causing corrosion to metal. Smaller particles can be caught by the wind and transported over great distances. Some deposit on and discolor glaciers and ice sheets and this has been associated with the promotion of accelerated ice melt.
There are no explicit PM emission limits. PM emission is directly related to SOx emissions, so reduced SOx emission consequently reduces PM emission.
The North American ECA
On March 26, 2010, IMO’s MEPC adopted amendments to MARPOL Annex VI designating an ECA covering specific portions of US, Canadian and French waters (i.e., Saint-Pierre-et-Miquelon, off the coast of Newfoundland). The ECA runs along North America’s Pacific coast, the Atlantic/Gulf coast and the Hawaiian Islands. It extends up to 200 nautical miles from coasts of the United States, Canada and the French territories, except that it does not extend into marine areas subject to the sovereignty or jurisdiction of other States (like Mexico or the Caribbean nations).
In July 2011, IMO’s MEPC again adopted amendments to MARPOL Annex VI designating an ECA covering certain waters adjacent to the coasts of Puerto Rico and the US Virgin Islands, to be called the US Caribbean Sea ECA. The amendments adopted in July 2011 are expected to enter into force in January 2013, with the new ECA taking effect January 2014.
Experts expect proposals for other ECAs to be submitted to the MEPC in the near future. Most likely candidates are the coastal waters of Mexico and Japan. Norway is also expected to propose an ECA for its coastal waters in the Norwegian Sea, which would be the first ECA in Arctic waters. Proposals for ECAs in the Mediterranean Sea and Straits of Malacca are also expected; however, it will likely be years before it is feasible to meet ECA requirements in these highly trafficked areas.
Avoiding ECAs is not practical for all but smaller feeder shipping lines. Especially with new ECAs expected in the near future, shipping lines will not be able to route vessels away from ECAs, and so they must find a way to comply with ECA requirements. Presently, they have three options:
Diligent fuel switching
Ultra-low sulphur distillate fuel is too expensive to use 100% of the time. Vessels might burn the right fuel in the right place, switching to low sulphur diesel when entering ECAs. But this creates new problems of segregated tankage and is reliant on the ship changing over to the right fuel at the right time.
Exhaust Gas Scrubber (EGS) technology is being considered to remove sulphur and particulate matter from exhaust. It does work, and it would enable the ship to continue using the same fuel in use presently, but it must also be operated in conjunction with Selective Catalytic Reduction (SCR) technology to neutralize NOx. SCR is the injection of ammonia or urea into hot exhaust gas over a catalyst (e.g. titanium dioxide). This converts the NOx back into component nitrogen and oxygen. EGS + SCR is still relatively expensive, and largely untested.
Switch to LNG
There are few LNG-fueled vessels in service, but a full range of approved designs from barges to ultra large container vessels already exist. Major marine engine manufacturers all offer duel fuel (i.e., LNG and distillate fuel oil) or total-LNG fueled engines. LNG-fueled vessels could cost up to 20% more than an equivalent oil fueled vessel, but this premium could be offset by lower operating costs (and may be the only option for complying with ECA requirements after 2015). Though LNG is less costly than fuel oil at the moment, LNG infrastructure is still developing. LNG-fueled vessels have to factor bunkering into route plans, as just a few ports can offer LNG bunker service. Also, LNG just isn’t an option for existing vessels as retrofitting an oil fueled vessel to use LNG is not practical.
The creation of the North American and US Caribbean Sea ECAs was originated (in part) by the US EPA to improve air quality and reduce adverse health effects of air pollution in the US. However, with four ECAs in effect by the end of this year, a large portion of the world’s shipping fleet will be obligated to comply with ECA requirements. And, with more stringent controls on the horizon, the global shipping industry is headed for a major change.