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US EPA proposes emission standards for Category 3 marine engines

2 July 2009

The US EPA published Notice of Proposed Rulemaking for Control of Emissions from New Marine Compression-Ignition Engines at or Above 30 Liters per Cylinder (Category 3 engines). The proposed Tier 2 and Tier 3 emission standards are consistent with the IMO Marpol Annex VI regulations.

The proposed near-term Tier 2 standards for newly built engines would apply beginning in 2011 and would require more efficient use of current engine technologies, including engine timing, engine cooling, and advanced computer controls. The Tier 2 standards would result in a 15 to 25% NOx reduction below the current Tier 1 levels.

The proposed long-term Tier 3 standards would apply beginning in 2016 and would require the use of high efficiency aftertreatment technology such as selective catalytic reduction to achieve NOx reductions 80% below the current levels.

In March, US and Canada proposed to establish an IMO emission control area (ECA) along their shorelines. Under the Annex VI provisions, fuel used by all vessels operating in ECAs cannot exceed 0.1% (1000 ppm) fuel sulfur beginning in 2015.

EPA proposed a change to the diesel fuel program that would forbid the production and sale of marine fuel oil above 1,000 ppm sulfur for use in the waters within a US ECA and internal US waters and allow for the production and sale of 1,000 ppm sulfur fuel for use in Category 3 marine vessels. The current EPA diesel fuel program sets a sulfur limit of 15 ppm that will be fully phased-in by December 1, 2014 for nonroad, locomotive, and marine fuels. Without the proposed change, fuel with a sulfur content of up to 1,000 ppm could be used in Category 3 marine vessels, but it could not be legally produced in the US after June 1, 2014.

In addition to the NOx emission limits, EPA proposed standards for emissions of HC and CO from new Category 3 engines. EPA did not propose a standard for PM emissions for Category 3 engines. However, significant PM emissions benefits will be achieved through the ECA fuel sulfur requirements. EPA also proposed to require engine manufacturers to measure and report PM emissions.

Source: US EPA