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Enhancement of Auxiliary Engine Emission Estimating Approach


The advent of AIS has allowed for more accurate estimates of vessel propulsion emissions through the provision of vessel-specific location, time, and speed data that can be linked to individual vessel characteristics allowing for the calculation of kilowatt hours that accounts for the engine operating load for each observation. This approach provides reasonably accurate emission estimates with refined spatial and temporal aspects. The AIS method to estimate propulsion engine emissions tends to provide more accurate and often smaller values than estimates based on previous methods that used more default assumptions. While AIS has improved the accuracy of propulsion emissions estimates, auxiliary emissions estimates, are still based on broad assumptions about power, operating times and engine loads providing less robust estimates. As propulsion emissions are reduced due the use of actual engine operating loads, auxiliary engine emission tend to be greater than or equal to the propulsion emissions; this is particularly an issue for port emissions.

To improve the accuracy of the auxiliary emissions, better methods and additional data are needed. This could include better analysis of vessel type variations in port operations, for example, some vessel types may shut down auxiliary engines while dockside, while others, such as self-unloading vessels in the Great Lakes, may operate at much higher auxiliary power loads. It is anticipated that the auxiliary profiles developed by vessel type could capture many of these types of operational differences.


Better data and methods are needed to improve the quality of auxiliary engine emission estimates. To initiate this study, a methodology based on an expansion of detailed auxiliary engine data is needed; which could be developed using portable emission monitors (PEM) that record engine parametric data alongside emissions data. This information can be analyzed to develop auxiliary engine profiles for each operational mode based on the test data from representative vessel types. These auxiliary engine profiles could be publicly posted, allowing vessel operators an opportunity to review and suggest improvements to the data.


The provision of more accurate emission estimates ensures the development of more effective control initiates as it allows for targeting the emission sources that have the greatest impact on local air quality, specifically port air quality initiatives.

Related Research:

TRID includes a variety of articles about auxiliary engines that use alternative fuels, but no TRB research was identified that better quantified the operation of auxiliary engines.


In order to develop a better auxiliary engine methodology based on detailed engine data, it is necessary to set up a testing program to compile the necessary data for the proposed method. Results from the testing will be analyzed to develop auxiliary engine profiles that can be applied to AIS derived operating mode data to estimate fuel consumption and emissions. To support this the following phases of this project will need to be implemented:

Phase 1 - Planning

· Develop general approach to more accurately estimate auxiliary engine emissions.

· Evaluate required data elements.

· Develop test program to obtain the necessary data to support the proposed methodology.

*Phase 2 - Testing *

· Based on the testing program developed in Phase 1, develop detail test plan for available resources.

· Identify candidate vessels for the study.

· Install PEMs on vessels.

· Implement analysis of collected samples.

· Download operating parameters PEM.

Phase 3 - Analyze Testing Data

· Develop auxiliary engine profiles for each operational mode based on Phase 2 Testing.

· Review available AIS data using AI tools to develop methods to quantify individual vessel operating modes.

*Phase 4 - Methodology *

· Combine auxiliary engine profiles and AI methods developed to quantify operating modes in Phase 3 into a clear set of guidelines that could be used to more accurately estimate emissions.

· Submit the documentation for external review.

· Develop final methodology based on external reviewers comments.

Phase 5 - Outreach

· Post methodology and supporting data on the web.

· Inform agencies and appropriate organizations of the availably of the methodology and supporting data.

· Revisit the methodology in 6 months and consider revisions based on users response to the posting.

· Results from this study should be published by TRB and posted on their website.


Port Authorities, international, federal, state and regional agencies, NGOs, academic researchers and consultants may find results of this study useful, for this reason these groups should be targeted once the methodology and data are ready for public posting.


Port Authorities and agencies such as IMO, USACE, and the U.S. EPA, as well as state and regional agencies, NGO, researchers and consultants may find this methodology helpful in developing accurate emission inventories using AIS data.

Sponsoring Committee:AW030, Marine Environment
Research Period:12 - 24 months
Research Priority:Medium
RNS Developer:Richard Billings
Source Info:California Air Resources Board/ Planning and Technical Support Division, Emission Estimation Methodology for Ocean-going Vessels, May 2008

European Commission DG XI (Environment, Nuclear Safety and Civil Protection), Marine Exhaust Emissions Quantification Study- Mediterranean Sea, 99/EE/7044. December 1999.

Rymaniak, Lukasz; Jacek Pielecha, and Lukasz Brezezinski, Determining NOx Emission from an Auxiliary Marine Engine Based on Operating Conditions, E3S Web Conference, EKO-DOK 2018

US EPA Methodologies for Estimating Port-related and Goods Movement Mobile Source Emission Inventories EPA 420-D-20-001 February 2020.

Van, Thuy Chu; Thomas Rainey; Zoran Ristovski, Ali Pourkhesalian, Emissions from a Marine Auxiliary Diesel Engine at Berth Using Heavy Fuel Oil; 10th Australasian Heat and Mass Transfer Conference at Queensland University of Technology Brisbane, Australia
Date Posted:11/01/2020
Date Modified:01/25/2021
Index Terms:Marine diesel engines, Pollutants, Diesel engine exhaust gases, Estimating, Data analysis,
Cosponsoring Committees: 
Marine Transportation
Data and Information Technology
Freight Transportation

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