EPA’s new diesel-emissions rules set Tier 4 standards for 2014

The U.S. Environmental Protection Agency has announced new, far-reaching marine diesel-emission standards.
The new rules, issued in March, finalize a three-part program applying to marine diesel engines below 30 liters per-cylinder displacement. The new rules:
• establish the first national standards for existing marine diesel engines larger than 600 kw when they are remanufactured
• set near-term Tier 3 standards for new marine engines beginning in 2009
• establish Tier 4 standards to take effect in 2014 for new marine engines above 600 kw, based on high-efficiency catalytic after-treatment technology.
The overall environmental challenges for the marine engine manufacturers and shipowners continue to be reduction of SOx (oxides of sulfur, mainly SO2), particulate matter (particulates of carbon, fuel, lubricant ash, hydrocarbons and sulfates), NOx (oxides of nitrogen) and CO2.
According to the EPA, the new standards will result in a 90 percent reduction in particulates and an 80 percent cut in NOx from Tier 4 engines.
Jed Mandel, president of the Engine Manufacturers Association, said meeting the standards will require further technological advances, particularly in after treatment. The engine manufacturers are committed to developing the needed technologies, he said, while noting that “the marine environment imposes significant challenges in terms of safety, reliability needs, vessel space, weight constraints and engine operating temperatures.”
Those equipment design challenges are acknowledged by the EPA, which stated in 2007, “Since 2003 we have continued to gain a greater understanding of the technical issues and assess the continuing efforts of manufacturers to apply advanced emission control technologies to these engines.”
The EPA and the International Maritime Organization had also concluded that more “information was expected to come to light” that would affect the final standards.
Geoff Conrad, general manager at Cummins Inc., said, “This rule establishes difficult stretch goals for the industry but we are prepared to meet the challenge.”
According to the IMO, rule proposals by the EPA to the IMO’s Marine Environmental Protection Committee were “designed to offer substantial reductions in the most problematic emissions from ships while allowing the shipowner to decide what technologies or fuels offer the most cost-effective means of compliance.”
After-treatment developments may be critical to meeting the emission goals. After-treatment technologies under development for both distillate and residual-fuel engines include catalyst technology such as particulate filters and urea-based selective catalytic reduction. A seawater scrubber technology being tested is designed to remove SOx and particulates. A new regulatory challenge, according to the EPA, will involve disposal of emissions removed from the exhaust gases and certification requirements for the after-treatment equipment.

“With implementation of this rule, clean diesel is no longer an oxymoron, but a proven, efficient, cost-effective and clean technology,” said Cummins’ Conrad.

By Professional Mariner Staff