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 |
|---|---|---|---|---|---|
| 1351 |
BOW HECTOR
IMO 9363493
|
33,694 | 2009 |
7.0
|
E |
| 1352 |
EAGLE BARENTS
IMO 9676125
|
119,690 | 2015 |
7.0
|
E |
| 1353 |
LOULOULIGHT
IMO 9594901
|
74,986 | 2013 |
7.0
|
E |
| 1354 |
ALPINE LINK
IMO 9478614
|
50,208 | 2010 |
7.0
|
E |
| 1355 |
ILAN
IMO 9282510
|
46,874 | 2004 |
7.0
|
E |
| 1356 |
KAREN MAERSK
IMO 9423712
|
39,708 | 2010 |
7.0
|
E |
| 1357 |
HARDRADA
IMO 9344007
|
45,983 | 2007 |
7.0
|
E |
| 1358 |
BALOS
IMO 9323560
|
40,165 | 2008 |
7.0
|
E |
| 1359 |
OM SINGAPORE
IMO 9341433
|
29,015 | 2007 |
7.0
|
E |
| 1360 |
HISTRIA GEMMA
IMO 9436719
|
40,404 | 2010 |
7.0
|
E |
| 1361 |
MINERVA ANNA
IMO 9298507
|
50,922 | 2005 |
7.0
|
E |
| 1362 |
STAR C
IMO 9411135
|
37,836 | 2009 |
7.0
|
E |
| 1363 |
TWINKLE STAR
IMO 9363780
|
45,750 | 2006 |
7.0
|
E |
| 1364 |
STAMOS
IMO 9592276
|
115,497 | 2012 |
7.1
|
E |
| 1365 |
WHITE PEARL
IMO 9917957
|
36,754 | 2021 |
7.1
|
E |
| 1366 |
MERSINI
IMO 9405899
|
51,753 | 2009 |
7.1
|
E |
| 1367 |
IOANNIS ZAFIRAKIS
IMO 9890587
|
49,999 | 2021 |
7.1
|
E |
| 1368 |
SEAFRONTIER
IMO 9457268
|
48,580 | 2011 |
7.1
|
E |
| 1369 |
HISTRIA AGATA
IMO 9357559
|
40,440 | 2007 |
7.2
|
E |
| 1370 |
OCEAN VENTURE
IMO 9660657
|
49,995 | 2014 |
7.2
|
E |
| 1371 |
T.SUNA
IMO 9652911
|
51,532 | 2012 |
7.2
|
E |
| 1372 |
POLKA
IMO 9422641
|
37,759 | 2009 |
7.3
|
E |
| 1373 |
HISTRIA TIGER
IMO 9396335
|
40,420 | 2008 |
7.3
|
E |
| 1374 |
DARIKA
IMO 9506693
|
51,063 | 2011 |
7.3
|
E |
| 1375 |
TORILL KNUTSEN
IMO 9630030
|
123,166 | 2013 |
7.3
|
E |
| 1376 |
JAG PRERANA
IMO 9321952
|
47,848 | 2007 |
7.3
|
E |
| 1377 |
CLEAN NIRVANA
IMO 9308168
|
50,319 | 2008 |
7.3
|
E |
| 1378 |
ZEAL START
IMO 9379064
|
41,369 | 2009 |
7.3
|
E |
| 1379 |
HISTRIA CORAL
IMO 9301299
|
40,426 | 2006 |
7.3
|
E |
| 1380 |
SAPSAN
IMO 9311713
|
47,496 | 2005 |
7.4
|
E |
| 1381 |
STI POPLAR
IMO 9696589
|
38,734 | 2014 |
7.4
|
E |
| 1382 |
CHEM GUARD
IMO 9261762
|
34,551 | 2002 |
7.4
|
E |
| 1383 |
ROSE I
IMO 9376945
|
37,900 | 2007 |
7.4
|
E |
| 1384 |
PINE MEADOW
IMO 9478688
|
50,171 | 2010 |
7.4
|
E |
| 1385 |
KIRSTEN MAERSK
IMO 9431264
|
39,729 | 2010 |
7.4
|
E |
| 1386 |
CHAMPION POMER
IMO 9455739
|
52,579 | 2011 |
7.4
|
E |
| 1387 |
P. BEVERLY HILLS
IMO 9794068
|
157,285 | 2019 |
7.4
|
E |
| 1388 |
ORFEAS
IMO 9358917
|
73,730 | 2008 |
7.4
|
E |
| 1389 |
JOYCE
IMO 9338814
|
47,344 | 2007 |
7.4
|
E |
| 1390 |
CHAMPION ENDURANCE
IMO 9288813
|
46,803 | 2005 |
7.5
|
E |
| 1391 |
SIRTAKI
IMO 9369887
|
51,442 | 2009 |
7.5
|
E |
| 1392 |
VS LISBETH
IMO 9309978
|
38,492 | 2006 |
7.5
|
E |
| 1393 |
CECH
IMO 9617442
|
42,150 | 2012 |
7.5
|
E |
| 1394 |
HISTRIA GIADA
IMO 9396323
|
40,448 | 2007 |
7.6
|
E |
| 1395 |
VS SPIRIT
IMO 9339636
|
34,671 | 2007 |
7.6
|
E |
| 1396 |
VALVERDE
IMO 9391490
|
50,633 | 2008 |
7.6
|
E |
| 1397 |
MAERSK KATE
IMO 9431276
|
39,756 | 2010 |
7.6
|
E |
| 1398 |
MINERVA ANTONIA
IMO 9380398
|
46,923 | 2008 |
7.7
|
E |
| 1399 |
STI PIMLICO
IMO 9686871
|
38,734 | 2014 |
7.7
|
E |
| 1400 |
MAERSK ADRIATIC
IMO 9636632
|
37,538 | 2012 |
7.7
|
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.