31 March 2009

The United States and Canada have submitted a proposal to the UN’s International Maritime Organization (IMO) to designate specific portions of US and Canadian coastal waters as an Emission Control Area (ECA). The ECA is to be designated for the control of NOx, SOx, and PM emissions from ocean-going ships.

The proposed area of the ECA includes waters adjacent to the Pacific coast, the Atlantic/Gulf coast and the eight main Hawaiian Islands. The proposed ECA would extend 200 nautical miles (230 miles, 370 km) from the coastal baseline, except that it would not extend into marine areas subject to the sovereignty, sovereign rights, or jurisdiction of any State other than the United States or Canada. The proposed ECA does not include the Pacific US territories, the western (unpopulated) Hawaiian Islands, the US territories of Puerto Rico and the US Virgin Islands, the Aleutian Islands and Western Alaska, and the US and Canadian Arctic.

In October 2008, the IMO adopted new standards to control exhaust emissions from ships. The member states of IMO agreed to amend Annex VI to the International Convention on the Prevention of Pollution from Ships (MARPOL), adopting new Tier II and Tier III NOx emission standards and new fuel sulfur controls. The most stringent of these new emission standards apply to ships operating in specially designated Emission Control Areas:

  • Beginning in 2015, fuel used by all vessels operating in ECAs cannot exceed 0.1% (1000 ppm) fuel sulfur. This requirement is expected to reduce PM and SOx emissions by more than 85%.
  • Beginning in 2016, new engines on vessels operating in ECAs must meet Tier III NOx emission standards. These engines will have to use emission controls that achieve an 80% reduction in NOx emissions, relative to Tier II standards applicable in global waters.

In most cases, ships already have the capability to store two or more fuels. However, to meet the 2015 requirement of 1,000 ppm fuel sulfur, some vessels may need to be modified for additional distillate fuel storage capacity. As an alternative to using low sulfur fuel, ship operators may choose to equip their vessels with exhaust gas scrubbers which would absorb and remove sulfur from the exhaust.

The Tier III standards are expected to require high efficiency NOx aftertreatment, such as selective catalytic reduction (SCR), on new ocean-going ship engines. Other emission technologies considered for meeting the IMO Tier II/III standards include water injection and exhaust gas recirculation.

In the USA and Canada combined, the ECA is expected to reduce emissions of NOx by 23%, PM2.5 by 74%, and SOx by 86% below current levels. The overall cost of the ECA is estimated at $3.2 billion.

Two SOx Emission Control Areas are currently designated by the IMO, including the Baltic Sea and the North Sea. The US/Canada ECA would become the word’s first NOx ECA.

In parallel to the ECA proposal, EPA is developing standards for Category 3 marine diesel engines (i.e., engines of over 30 liters displacement per cylinder), similar in stringency to the Tier III NOx standards that will apply to all engines in the ECA. The agency plans to issue the Notice of Proposed Rulemaking in Spring 2009 and finalize it by December 2009.

Source: US EPA