US EPA proposes emission standards for stationary diesel engines

5 July 2005 | updated 11 July 2005

The US EPA has proposed new emission standards for stationary diesel engines. The proposed standards will reduce emissions of NOx, PM, CO, and HC from new, modified, and reconstructed stationary diesel internal combustion engines. The regulation will require that stationary diesel engines meet the Tier 1-4 emission standards for mobile nonroad engines. The proposed standards would become effective from 11 July 2005—the date the proposed rule was published in the Federal Register—with the exception of Tier 1 compliance that would begin from April-July 2006.

The proposed rule applies to stationary diesel engines such as those used to generate electricity and operate compressors and pumps at power and manufacturing plants. The proposal also covers stationary engines that are used in emergencies to produce electricity and pump water for flood and fire control. As proposed, the rule will affect 81,500 new stationary diesel engines by 2015. Emission reductions will occur gradually from 2005 to 2015. EPA estimated the total nationwide annual costs for the rule to be $57 million in the year 2015.

The rule would take effect in three, increasingly stringent stages:

1. The first stage is a transition period to control emissions from diesel engines built after this rule is proposed but before the 2007 model year.
   • In most cases, the owner/operator would purchase a certified nonroad engine for stationary use and that would be sufficient to comply with the regulatory requirement.
   • The owner/operator could also purchase a non-certified engine. In that case, he would have to demonstrate compliance with the pre-2007 emission limits using manufacturers emissions data or previous test results on a similar engine, or stack test data.
2. Beginning in model year 2007:
   • Engine manufacturers would be required to certify that all new, modified or reconstructed stationary diesel engines meet the emission levels for NOx, PM, CO, and HC that are required for the same size engine and model year for nonroad diesel engines in the Tier 1 through Tier 4 categories, with a few exceptions.
   • Stationary emergency diesel engines would be required to be certified to meet emissions limits through Tier 3 and also Tier 4, however, Tier 4 requirements for them do not require add-on controls such as particulate filters or NOx reduction aftertreatment.
3. Beginning with 2011 model year engines, add-on controls would be required to achieve the emission limits for non-emergency engines (in accordance with the Tier 4 regulation).

The affected engines would also have to switch to low sulfur fuels: no more than 500 ppm sulfur by October 2007, followed by ultra-low sulfur diesel (15 ppm sulfur) by October 2010.

Emissions from stationary engines have not been regulated by federal emission standards (rather, they are subject to a complex patchwork of state and/or local regulations and permit policies). The proposal follows a court settlement that resolved a lawsuit filed against the EPA by Environmental Defense, a New York-based environmental organization. The settlement requires the EPA Administrator to complete a final rule by 28 June 2006.

Source: US EPA (fact sheet | proposed rule)