Costs of Emission Reduction Technologies for Category 3 Marine Engines

In December 2007, the Environmental Protection Agency (EPA) published an Advanced Notice of Proposed Rulemaking to enact more stringent exhaust emission standards for engines on ocean going vessels. New nitrogen oxides (NOx) and sulfur oxides (SOx) exhaust emission standards were discussed for engines on Category 3 marine vessels. Two new tiers of NOx standards have recently been adopted by the International Maritime Organization (IMO). Tier II NOx standards are roughly 20 percent lower than the existing Tier I NOx standards set by the IMO in Annex VI. To meet these standards, in-cylinder emission control approaches such as electronically controlled high pressure common rail fuel systems, turbocharger optimization, compression ratio changes and electronically controlled exhaust valves could be used. Tier III NOx standards which only apply in designated Emission Control Areas are roughly 80 percent below Tier I NOx standards and would likely require exhaust aftertreatment such as selective catalytic reduction (SCR). Other approaches that may be considered to reduce NOx emissions from Category 3 vessel engines are exhaust gas recirculation and water technologies such as direct water injection or fumigation. In addition to these NOx standards for new Category 3 marine vessel engines, standards were adopted by the IMO for NOx limits for existing engines due to the very long life of ocean going vessels and the availability of known in-cylinder technical modifications such as slide valve fuel injectors and injection timing retard that provide significant and cost-effective NOx reductions. It is believed that engines built in 1990 through 1999 are compatible with these lower NOx components. The standards require that engines would need to be modified to achieve a 20 percent reduction in NOx emissions from their existing baseline emission rates. Reductions in SOx and PM are expected to be met primarily through two approaches. The first would be to operate the engines on a lower sulfur distillate fuel. Category 3 marine engines typically operate on heavy fuel oil with a sulfur content of 2.7 percent. Significant SOx and PM reductions could be achieved using distillate fuels with a sulfur content of 0.1 percent. Fuel costs will be estimated through a separate effort. However, costs due to vessel modifications will be considered here. This report includes descriptions of baseline and likely emission control technologies expected to be used to meet Tier II and Tier III emission standards, the lower sulfur fuel requirement for designated Emission Control Areas, as well as the related costs for application, usage, and maintenance of these technologies.


  • English

Media Info

  • Media Type: Digital/other
  • Edition: Final Report
  • Features: Figures; Photos; References; Tables;
  • Pagination: 58p

Subject/Index Terms

Filing Info

  • Accession Number: 01531903
  • Record Type: Publication
  • Report/Paper Numbers: EPA-420-R-09-008
  • Contract Numbers: EP-C06094; Work Assignment No. WA1-8
  • Files: TRIS
  • Created Date: Jul 7 2014 9:49AM