Log in | Subscribe | RSS feed

What’s New

US EPA proposes amendments to marine engine emission standards

26 August 2019

The US Environmental Protection Agency (EPA) proposed to amend its marine diesel engine emission standards to delay the Tier 4 emission requirements for high-power marine diesel engines that are used in high-speed commercial vessels such as lobster fishing boats and pilot boats. The proposal also includes a technical correction to the US marine diesel fuel program.

The proposal has been issued to address concerns by boat builders, to allow for continued installation of Tier 3 engines for certain vessels because suitable Tier 4 engines are not available. The existing marine emission regulations define Tier 4 standards—which were expected to require the use of SCR aftertreatment for NOx control—phased in from 2014 to 2017, depending on engine power. Some boat builders have informed EPA, said the agency, that there are no certified Tier 4 engines with suitable performance characteristics for the vessels they need to build, specifically for high-speed commercial vessels that rely on engines with rated power between 600 and 1,400 kW that have high power density.

The EPA is proposing that implementation of the Tier 4 standards for certain categories of engines and vessels would occur in two phases:

The proposed changes to the marine diesel fuel program are intended to align US regulations with the international IMO regulations. The proposed changes clarify that US refiners can legally distribute global marine fuel up to the 5,000 ppm (0.5%) sulfur limit, which will facilitate the implementation of the 2020 IMO marine fuel standard.

While the 0.5% sulfur fuel is allowed in global shipping, it is not allowed in the US coastal waters—which are designated an IMO Emission Control Area (ECA) where fuels of maximum 0.1% sulfur must be used—or in land-based diesel engines. The proposed changes include several conditions intended to ensure that the 0.5% sulfur fuel is not diverted for use in the United States, including documentation requirements to help ensure compliance.

The EPA will accept comments beginning when the Proposed Rule is published in the Federal Register. A public hearing is scheduled for September 20, 2019 in Maine.

Source: US EPA