US EPA adopts new emission standards for Category 3 marine engines

22 December 2009

The US Environmental Protection Agency (EPA) has finalized a rule setting more stringent emission and fuel standards for large US-flagged ships. The regulation—applicable to Category 3 marine engines (per cylinder displacement ≥ 30 liters)—harmonizes with international Tier 2 and Tier 3 standards adopted by the IMO.

The final near-term Tier 2 standards for newly built engines will apply beginning in 2011 and will require more efficient use of current engine technologies, including engine timing, engine cooling, and advanced computer controls. The Tier 2 standards will result in a 15 to 25% NOx reduction below the current Tier 1 levels. The final long-term Tier 3 standards for newly built engines will apply beginning in 2016 and will require the use of high efficiency emission control technology such as selective catalytic reduction to achieve NOx reductions 80% below the current levels.

In addition to the NOx emission limits, EPA adopted HC and CO emission standards from new Category 3 engines. No standard has been adopted for PM emissions from Category 3 engines. However, significant PM emission benefits will be achieved through the ECA fuel sulfur requirements that will apply to ships that operate in areas that affect US air quality, said the EPA.

While IMO Tier 2 standards are applicable in all waters, the more stringent IMO Tier 3 standards are applicable only in waters designated as Emission Control Areas (ECA). In March 2009, US and Canada proposed to establish an IMO ECA along their shorelines. The IMO will vote on the adoption of the US-Canadian ECA in March 2010. Once the ECA is established, it will also trigger more stringent fuel sulfur requirements—under the IMO Annex VI provisions, fuel used by all vessels operating in ECAs cannot exceed 1% (10,000 ppm) sulfur beginning in 2010, and 0.1% (1000 ppm) sulfur from 2015. However, SOx scrubbers are allowed in lieu of low sulfur fuel.

Compared to the EPA proposal, the final rule provides more flexibility in complying with the fuel sulfur requirements. Vessels may now use other methods, such as SOx scrubbers, to achieve SOx emissions reductions equivalent to those obtained by the use of low sulfur fuel. Several additional flexibilities apply to vessels operated on the Great Lakes and Saint Lawrence Seaway: the low sulfur requirements can be deferred—subject to availability of 1% S fuel in 2010 as well as economic hardship provisions—and are not applicable to steamships.

Source: US EPA