An Engine Load Monitoring Approach for Quantifying Yearly Methane Slip Emissions from an LNG-Powered RoPax Vessel
Liquefied natural gas (LNG) is increasingly used as a marine fuel due to its capacity to significantly reduce emissions of particulate matter, sulfur oxides (SO<sub>x</sub>), and nitrogen oxides (NO<sub>x</sub>), compared to conventional fuels. In addition, LNG combustion pro...
Saved in:
| Main Authors: | , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2025-07-01
|
| Series: | Journal of Marine Science and Engineering |
| Subjects: | |
| Online Access: | https://www.mdpi.com/2077-1312/13/7/1379 |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| _version_ | 1849733044171177984 |
|---|---|
| author | Benoit Sagot Raphael Defossez Ridha Mahi Audrey Villot Aurélie Joubert |
| author_facet | Benoit Sagot Raphael Defossez Ridha Mahi Audrey Villot Aurélie Joubert |
| author_sort | Benoit Sagot |
| collection | DOAJ |
| description | Liquefied natural gas (LNG) is increasingly used as a marine fuel due to its capacity to significantly reduce emissions of particulate matter, sulfur oxides (SO<sub>x</sub>), and nitrogen oxides (NO<sub>x</sub>), compared to conventional fuels. In addition, LNG combustion produces less carbon dioxide (CO<sub>2</sub>) than conventional marine fuels, and the use of non-fossil LNG offers further potential for reducing greenhouse gas emissions. However, this benefit can be partially offset by methane slip—the release of unburned methane in engine exhaust—which has a much higher global warming potential than CO<sub>2</sub>. This study presents an experimental evaluation of methane emissions from a RoPax vessel powered by low-pressure dual-fuel four-stroke engines with a direct mechanical propulsion system. Methane slip was measured directly during onboard testing and combined with a year-long analysis of engine operation using an Engine Load Monitoring (ELM) method. The yearly average methane slip coefficient (<i>C</i><sub>slip</sub>) obtained was 1.57%, slightly lower than values reported in previous studies on cruise ships (1.7%), and significantly lower than the default values specified by the FuelEU (3.1%) Maritime regulation and IMO (3.5%) LCA guidelines. This result reflects the ship’s operational profile, characterized by long crossings at high and stable engine loads. This study provides results that could support more representative emission assessments and can contribute to ongoing regulatory discussions. |
| format | Article |
| id | doaj-art-355ddbe2002a407a94943d4aca7f489e |
| institution | DOAJ |
| issn | 2077-1312 |
| language | English |
| publishDate | 2025-07-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Journal of Marine Science and Engineering |
| spelling | doaj-art-355ddbe2002a407a94943d4aca7f489e2025-08-20T03:08:09ZengMDPI AGJournal of Marine Science and Engineering2077-13122025-07-01137137910.3390/jmse13071379An Engine Load Monitoring Approach for Quantifying Yearly Methane Slip Emissions from an LNG-Powered RoPax VesselBenoit Sagot0Raphael Defossez1Ridha Mahi2Audrey Villot3Aurélie Joubert4ESTACA, ESTACA’Lab—Paris Saclay, 78180 Montigny-Le-Bretonneux, FranceESTACA, ESTACA’Lab—Paris Saclay, 78180 Montigny-Le-Bretonneux, FranceIMT Atlantique, CNRS, GEPEA, UMR 6144, 4 rue Alfred Kastler, 44307 Nantes, FranceIMT Atlantique, CNRS, GEPEA, UMR 6144, 4 rue Alfred Kastler, 44307 Nantes, FranceIMT Atlantique, CNRS, GEPEA, UMR 6144, 4 rue Alfred Kastler, 44307 Nantes, FranceLiquefied natural gas (LNG) is increasingly used as a marine fuel due to its capacity to significantly reduce emissions of particulate matter, sulfur oxides (SO<sub>x</sub>), and nitrogen oxides (NO<sub>x</sub>), compared to conventional fuels. In addition, LNG combustion produces less carbon dioxide (CO<sub>2</sub>) than conventional marine fuels, and the use of non-fossil LNG offers further potential for reducing greenhouse gas emissions. However, this benefit can be partially offset by methane slip—the release of unburned methane in engine exhaust—which has a much higher global warming potential than CO<sub>2</sub>. This study presents an experimental evaluation of methane emissions from a RoPax vessel powered by low-pressure dual-fuel four-stroke engines with a direct mechanical propulsion system. Methane slip was measured directly during onboard testing and combined with a year-long analysis of engine operation using an Engine Load Monitoring (ELM) method. The yearly average methane slip coefficient (<i>C</i><sub>slip</sub>) obtained was 1.57%, slightly lower than values reported in previous studies on cruise ships (1.7%), and significantly lower than the default values specified by the FuelEU (3.1%) Maritime regulation and IMO (3.5%) LCA guidelines. This result reflects the ship’s operational profile, characterized by long crossings at high and stable engine loads. This study provides results that could support more representative emission assessments and can contribute to ongoing regulatory discussions.https://www.mdpi.com/2077-1312/13/7/1379engine load monitoringLNGmethane sliponboard measurementyearly emission |
| spellingShingle | Benoit Sagot Raphael Defossez Ridha Mahi Audrey Villot Aurélie Joubert An Engine Load Monitoring Approach for Quantifying Yearly Methane Slip Emissions from an LNG-Powered RoPax Vessel Journal of Marine Science and Engineering engine load monitoring LNG methane slip onboard measurement yearly emission |
| title | An Engine Load Monitoring Approach for Quantifying Yearly Methane Slip Emissions from an LNG-Powered RoPax Vessel |
| title_full | An Engine Load Monitoring Approach for Quantifying Yearly Methane Slip Emissions from an LNG-Powered RoPax Vessel |
| title_fullStr | An Engine Load Monitoring Approach for Quantifying Yearly Methane Slip Emissions from an LNG-Powered RoPax Vessel |
| title_full_unstemmed | An Engine Load Monitoring Approach for Quantifying Yearly Methane Slip Emissions from an LNG-Powered RoPax Vessel |
| title_short | An Engine Load Monitoring Approach for Quantifying Yearly Methane Slip Emissions from an LNG-Powered RoPax Vessel |
| title_sort | engine load monitoring approach for quantifying yearly methane slip emissions from an lng powered ropax vessel |
| topic | engine load monitoring LNG methane slip onboard measurement yearly emission |
| url | https://www.mdpi.com/2077-1312/13/7/1379 |
| work_keys_str_mv | AT benoitsagot anengineloadmonitoringapproachforquantifyingyearlymethaneslipemissionsfromanlngpoweredropaxvessel AT raphaeldefossez anengineloadmonitoringapproachforquantifyingyearlymethaneslipemissionsfromanlngpoweredropaxvessel AT ridhamahi anengineloadmonitoringapproachforquantifyingyearlymethaneslipemissionsfromanlngpoweredropaxvessel AT audreyvillot anengineloadmonitoringapproachforquantifyingyearlymethaneslipemissionsfromanlngpoweredropaxvessel AT aureliejoubert anengineloadmonitoringapproachforquantifyingyearlymethaneslipemissionsfromanlngpoweredropaxvessel AT benoitsagot engineloadmonitoringapproachforquantifyingyearlymethaneslipemissionsfromanlngpoweredropaxvessel AT raphaeldefossez engineloadmonitoringapproachforquantifyingyearlymethaneslipemissionsfromanlngpoweredropaxvessel AT ridhamahi engineloadmonitoringapproachforquantifyingyearlymethaneslipemissionsfromanlngpoweredropaxvessel AT audreyvillot engineloadmonitoringapproachforquantifyingyearlymethaneslipemissionsfromanlngpoweredropaxvessel AT aureliejoubert engineloadmonitoringapproachforquantifyingyearlymethaneslipemissionsfromanlngpoweredropaxvessel |