Most Emission-Efficient Oil 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 2025. 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 |
|---|---|---|---|---|---|
| 1401 |
VS LEIA
IMO 9303730
|
38,461 | 2006 |
7.7
|
E |
| 1402 |
HISTRIA PERLA
IMO 9301287
|
40,471 | 2005 |
7.7
|
E |
| 1403 |
RICH HARVEST
IMO 9908982
|
50,446 | 2021 |
7.7
|
E |
| 1404 |
ATAHUALPA
IMO 9451460
|
46,549 | 2010 |
7.8
|
E |
| 1405 |
BALTIC NARVAL
IMO 9930222
|
24,323 | 2023 |
7.8
|
E |
| 1406 |
HAFNIA SUNDA
IMO 9725639
|
39,067 | 2015 |
7.8
|
E |
| 1407 |
JAN
IMO 9259915
|
35,647 | 2003 |
7.8
|
E |
| 1408 |
ATLANTIC NARVAL
IMO 9930210
|
24,316 | 2023 |
7.8
|
E |
| 1409 |
ETERNAL
IMO 9273351
|
45,915 | 2004 |
7.8
|
E |
| 1410 |
HULDA MAERSK
IMO 9399363
|
37,959 | 2010 |
7.8
|
E |
| 1411 |
MAERSK AEGEAN
IMO 9636644
|
37,538 | 2013 |
7.9
|
E |
| 1412 |
CHAMPION TIMUR
IMO 9288837
|
47,210 | 2005 |
7.9
|
E |
| 1413 |
ASPHALT SYNERGY
IMO 9794159
|
36,771 | 2018 |
7.9
|
E |
| 1414 |
STI HACKNEY
IMO 9686883
|
38,734 | 2014 |
7.9
|
E |
| 1415 |
STAR RIVER
IMO 9815458
|
36,819 | 2018 |
7.9
|
E |
| 1416 |
ETC NEFERTARI
IMO 9399612
|
49,764 | 2011 |
7.9
|
E |
| 1417 |
HISTRIA AMBRA
IMO 9607631
|
40,030 | 2013 |
8.0
|
E |
| 1418 |
SINDRE KNUTSEN
IMO 9905928
|
123,602 | 2022 |
8.0
|
E |
| 1419 |
SEAVALOUR
IMO 9315771
|
46,702 | 2007 |
8.0
|
E |
| 1420 |
MAERSK KAYA
IMO 9431288
|
39,738 | 2011 |
8.1
|
E |
| 1421 |
BISE
IMO 1021702
|
18,644 | 2025 |
8.1
|
E |
| 1422 |
MINERVA JOANNA
IMO 9380386
|
46,924 | 2008 |
8.2
|
E |
| 1423 |
HISTRIA CROWN
IMO 9607629
|
40,390 | 2012 |
8.2
|
E |
| 1424 |
STI FULHAM
IMO 9688374
|
38,734 | 2014 |
8.2
|
E |
| 1425 |
STI BATTERSEA
IMO 9691723
|
38,734 | 2014 |
8.2
|
E |
| 1426 |
OM BORNEO
IMO 9341445
|
29,013 | 2007 |
8.2
|
E |
| 1427 |
TATIANA
IMO 9340128
|
38,396 | 2007 |
8.3
|
E |
| 1428 |
FURE VIKEN
IMO 9980318
|
17,945 | 2024 |
8.3
|
E |
| 1429 |
HENRIETTE MAERSK
IMO 9399349
|
37,985 | 2010 |
8.3
|
E |
| 1430 |
BOW AGATHE
IMO 9393010
|
33,608 | 2009 |
8.3
|
E |
| 1431 |
AGIOS CHARALAMBOS
IMO 9379337
|
50,922 | 2007 |
8.3
|
E |
| 1432 |
CLEAN RAIDER
IMO 9425318
|
49,999 | 2010 |
8.3
|
E |
| 1433 |
BOW ENDEAVOR
IMO 9490325
|
26,197 | 2011 |
8.3
|
E |
| 1434 |
MELORIA
IMO 9292280
|
40,157 | 2006 |
8.4
|
E |
| 1435 |
KRITI
IMO 9270737
|
47,999 | 2004 |
8.4
|
E |
| 1436 |
HENRY MAERSK
IMO 9399351
|
37,933 | 2010 |
8.4
|
E |
| 1437 |
THUN VETTERN
IMO 9971214
|
17,945 | 2024 |
8.4
|
E |
| 1438 |
TIGANI
IMO 9776767
|
112,763 | 2017 |
8.4
|
E |
| 1439 |
HANS MAERSK
IMO 9389497
|
37,961 | 2009 |
8.4
|
E |
| 1440 |
VISION
IMO 9295347
|
37,343 | 2006 |
8.4
|
E |
| 1441 |
FURE VESBORG
IMO 9980332
|
17,948 | 2025 |
8.4
|
E |
| 1442 |
PIS POLARIS
IMO 9426295
|
45,988 | 2010 |
8.5
|
E |
| 1443 |
STI FINCHLEY
IMO 9696565
|
38,734 | 2014 |
8.5
|
E |
| 1444 |
ICE FIGHTER
IMO 9333656
|
70,374 | 2006 |
8.5
|
E |
| 1445 |
HILDA KNUTSEN
IMO 9628300
|
123,166 | 2013 |
8.5
|
E |
| 1446 |
MARIANNA V.V.
IMO 9259707
|
84,999 | 2002 |
8.6
|
E |
| 1447 |
MOUNT MCKINNEY
IMO 9263174
|
40,007 | 2004 |
8.6
|
E |
| 1448 |
WINDSOR KNUTSEN
IMO 9316115
|
160,240 | 2007 |
8.6
|
E |
| 1449 |
STI ROTHERHITHE
IMO 9706475
|
38,734 | 2015 |
8.7
|
E |
| 1450 |
KRITI ROCK
IMO 9392315
|
45,920 | 2008 |
8.7
|
E |
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 2025 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.