Most Emission-Efficient Chemical Tankers
Ships ranked by AER (Annual Efficiency Ratio) — grams of CO₂ emitted per tonne of deadweight carried one nautical mile (g CO₂/dwt·nm), the IMO carbon-intensity metric behind the CII rating — from official EU MRV emissions data for reporting year 2024. Lower is greener. Pick a segment and size class to see the greenest vessels first.
| # | Vessel | Size (DWT) | Built | Carbon intensity — AER (g CO₂/dwt·nm) | Grade |
|---|---|---|---|---|---|
| 351 |
BOW TRIUMPH
IMO 9669902
|
49,622 | 2015 |
6.5
|
B |
| 352 |
BOW SUMMER
IMO 9215270
|
49,592 | 2005 |
6.5
|
B |
| 354 |
SEA LA BAMBA
IMO 9470909
|
46,093 | 2009 |
6.5
|
B |
| 353 |
SC MERCURY
IMO 9746188
|
33,985 | 2016 |
6.5
|
B |
| 356 |
ARDMORE ENTERPRISE
IMO 9654555
|
49,452 | 2013 |
6.5
|
B |
| 355 |
ARDMORE ENCOUNTER
IMO 9654579
|
49,477 | 2014 |
6.5
|
B |
| 357 |
ELECTA
IMO 9416824
|
51,117 | 2009 |
6.5
|
B |
| 358 |
ARREBOL
IMO 9939565
|
49,996 | 2024 |
6.5
|
B |
| 359 |
CHAMPION PULA
IMO 9341146
|
46,927 | 2006 |
6.5
|
B |
| 363 |
ELKA DELOS
IMO 9259290
|
44,598 | 2000 |
6.5
|
B |
| 362 |
ELKA COSMOS
IMO 9655602
|
49,990 | 2015 |
6.5
|
B |
| 361 |
RHAPSODY
IMO 9810666
|
34,766 | 2020 |
6.5
|
B |
| 360 |
GRANDE RIVIERE
IMO 9733686
|
30,732 | 2015 |
6.5
|
B |
| 365 |
HIGH FIDELITY
IMO 9689146
|
49,990 | 2014 |
6.6
|
B |
| 364 |
CELESTE I
IMO 9250488
|
46,350 | 2003 |
6.6
|
B |
| 366 |
CHEM RAMBLAS
IMO 9937995
|
33,374 | 2024 |
6.6
|
B |
| 367 |
MARITIME TRANQUILITY
IMO 9848338
|
49,999 | 2020 |
6.6
|
B |
| 368 |
ZEFYROS
IMO 9515917
|
50,155 | 2013 |
6.6
|
B |
| 371 |
MARI INNOVATOR
IMO 9909572
|
49,999 | 2021 |
6.6
|
B |
| 370 |
SEAWAYS CREST
IMO 9387920
|
51,510 | 2009 |
6.6
|
B |
| 369 |
ATLAS
IMO 9538177
|
37,866 | 2014 |
6.6
|
B |
| 373 |
CHEM NICHOLAS
IMO 9374416
|
38,396 | 2007 |
6.6
|
B |
| 372 |
FPMC 30
IMO 9581679
|
50,489 | 2012 |
6.6
|
B |
| 374 |
AQUILA
IMO 9692258
|
49,075 | 2015 |
6.6
|
B |
| 375 |
CHEMROAD ZENITH
IMO 9926300
|
35,777 | 2022 |
6.6
|
B |
| 376 |
MAHADAH SILVER
IMO 9718777
|
45,923 | 2016 |
6.6
|
B |
| 377 |
HORIZON ATHENA
IMO 9407378
|
50,242 | 2008 |
6.6
|
B |
| 378 |
QUARTZ
IMO 9694361
|
49,999 | 2015 |
6.6
|
B |
| 381 |
SEAWAYS CITRON
IMO 9380362
|
49,999 | 2007 |
6.7
|
B |
| 380 |
CHEMROAD AQUA
IMO 9790610
|
35,678 | 2018 |
6.7
|
B |
| 379 |
CLEAROCEAN MORITZ
IMO 9695834
|
49,737 | 2016 |
6.7
|
B |
| 382 |
STENA IMPRESSION
IMO 9667461
|
49,776 | 2015 |
6.7
|
B |
| 383 |
MOSTAR
IMO 9313474
|
51,274 | 2007 |
6.7
|
B |
| 386 |
VINJERAC
IMO 9489194
|
49,999 | 2011 |
6.7
|
B |
| 385 |
NAVIG8 EXCEL
IMO 9973901
|
49,127 | 2024 |
6.7
|
B |
| 384 |
STAR KESTREL
IMO 9321940
|
51,228 | 2008 |
6.7
|
B |
| 387 |
GREAT KAPPA
IMO 9873656
|
49,282 | 2020 |
6.7
|
B |
| 388 |
AGIOS NIKOLAOS IV
IMO 9464364
|
37,557 | 2010 |
6.7
|
B |
| 389 |
ELKA DELPHI
IMO 9705902
|
49,990 | 2015 |
6.7
|
B |
| 390 |
HARBIYE
IMO 9396787
|
50,553 | 2008 |
6.8
|
B |
| 391 |
MTM WESTPORT
IMO 9317858
|
32,044 | 2005 |
6.8
|
B |
| 392 |
KRITI BAY
IMO 9418573
|
50,998 | 2006 |
6.8
|
B |
| 394 |
FPMC 31
IMO 9831696
|
49,731 | 2019 |
6.8
|
B |
| 397 |
HAFNIA AMMOLITE
IMO 9727534
|
38,506 | 2015 |
6.8
|
B |
| 396 |
STOLT COURAGE
IMO 9296731
|
32,858 | 2004 |
6.8
|
B |
| 395 |
CHAMPION CONTEST
IMO 9272199
|
47,171 | 2005 |
6.8
|
B |
| 393 |
STOLT CALLUNA
IMO 9744893
|
32,771 | 2017 |
6.8
|
B |
| 400 |
HAFNIA VIOLETTE
IMO 9690626
|
49,126 | 2015 |
6.8
|
B |
| 399 |
ARDMORE EXPLORER
IMO 9654581
|
49,494 | 2014 |
6.8
|
B |
| 398 |
ELLIE M II
IMO 9307994
|
46,784 | 2007 |
6.8
|
B |
Which engines power the greenest fleets?
The main engine is the single largest CO₂ source on board — typically well over 80% of a ship's emissions come from propulsion. We aggregated this ranking the other way around: every engine design is scored by the measured carbon intensity of the vessels carrying it, licensee-built units merged under their design brand. The verdict from the 2024 data — modern dual-fuel designs like MAN B&W's ME-GI and WinGD's X-DF families, together with EGR/SCR-abated and ultra-long-stroke G-type engines, consistently power the most emission-friendly ships in service.
AER (Annual Efficiency Ratio) = annual CO₂ emissions ÷ (deadweight × distance sailed), the IMO carbon-intensity metric used for CII ratings. It is built only from measured CO₂, distance and deadweight — not the self-reported cargo transport-work figure, which is unreliable. Implausible outliers (top 2% per segment) are excluded. Grade A–E reflects each vessel's rank within its segment. Source: EMSA THETIS-MRV.