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 |
|---|---|---|---|---|---|
| 1451 |
STI ACTON
IMO 9696553
|
38,734 | 2014 |
8.7
|
E |
| 1452 |
FURE VALO
IMO 9983097
|
17,949 | 2025 |
8.7
|
E |
| 1453 |
CUMBIA1
IMO 9436343
|
50,213 | 2010 |
8.7
|
E |
| 1454 |
KINGSTON
IMO 9420863
|
38,341 | 2009 |
8.7
|
E |
| 1455 |
NV ATHENA
IMO 9527075
|
21,166 | 2011 |
8.7
|
E |
| 1456 |
YURIY KUCHIEV
IMO 9804033
|
52,292 | 2019 |
8.7
|
E |
| 1457 |
ZAPPHIRE
IMO 9391957
|
47,329 | 2010 |
8.8
|
E |
| 1458 |
MAERSK KATARINA
IMO 9431290
|
39,723 | 2011 |
8.8
|
E |
| 1459 |
STARLIGHT I
IMO 9377664
|
37,824 | 2007 |
8.8
|
E |
| 1460 |
AMBER BEE
IMO 9316608
|
40,083 | 2004 |
8.8
|
E |
| 1461 |
SOUTHERN PUMA
IMO 9792008
|
26,071 | 2016 |
8.8
|
E |
| 1462 |
MAERSK KARA
IMO 9374428
|
38,396 | 2008 |
8.8
|
E |
| 1463 |
ANDROMEDA
IMO 9315795
|
39,378 | 2007 |
8.8
|
E |
| 1464 |
FURE VICTORIA
IMO 9983968
|
17,951 | 2025 |
8.9
|
E |
| 1465 |
VALTELLINA
IMO 9384136
|
37,481 | 2008 |
9.0
|
E |
| 1466 |
VALSESIA
IMO 9385178
|
37,481 | 2008 |
9.0
|
E |
| 1467 |
HENNING MAERSK
IMO 9389526
|
38,001 | 2010 |
9.0
|
E |
| 1468 |
SAN FELIX
IMO 9314868
|
37,312 | 2007 |
9.0
|
E |
| 1469 |
IDI
IMO 9307982
|
46,858 | 2007 |
9.1
|
E |
| 1470 |
KRITI EPISKOPI
IMO 9340104
|
38,500 | 2006 |
9.1
|
E |
| 1471 |
SAM MAJESTY
IMO 9308144
|
50,338 | 2007 |
9.2
|
E |
| 1472 |
THE BLACKSMITH
IMO 9659660
|
31,289 | 2013 |
9.2
|
E |
| 1473 |
M BRISTOL
IMO 9299434
|
29,050 | 2005 |
9.2
|
E |
| 1474 |
SEAEXPRESS
IMO 9344019
|
45,976 | 2007 |
9.2
|
E |
| 1475 |
FORTUNE
IMO 9379325
|
50,922 | 2008 |
9.2
|
E |
| 1476 |
SEACOD
IMO 9352315
|
40,559 | 2006 |
9.2
|
E |
| 1477 |
FURE VANGUARD
IMO 9963360
|
17,942 | 2024 |
9.2
|
E |
| 1478 |
VALGARDENA
IMO 9384124
|
37,481 | 2008 |
9.2
|
E |
| 1479 |
AEGEAS
IMO 9315800
|
39,378 | 2007 |
9.2
|
E |
| 1480 |
STI BRIXTON
IMO 9686869
|
38,734 | 2014 |
9.3
|
E |
| 1481 |
SUMER
IMO 9314856
|
37,258 | 2007 |
9.3
|
E |
| 1482 |
MINERVA GRACE
IMO 9305855
|
50,922 | 2005 |
9.3
|
E |
| 1483 |
SOUTHERN SHARK
IMO 9821299
|
26,051 | 2018 |
9.3
|
E |
| 1484 |
ALKEA
IMO 9425502
|
36,207 | 2009 |
9.3
|
E |
| 1485 |
LEANDER FISHER
IMO 9878058
|
34,724 | 2022 |
9.3
|
E |
| 1486 |
BOSPOROS
IMO 9315903
|
39,589 | 2007 |
9.3
|
E |
| 1487 |
SUNNY C
IMO 9470959
|
37,857 | 2010 |
9.3
|
E |
| 1488 |
SAN MARCOS
IMO 9425540
|
50,120 | 2010 |
9.3
|
E |
| 1489 |
SOUTHERN XANTIS
IMO 9883493
|
25,887 | 2020 |
9.4
|
E |
| 1490 |
GEA
IMO 9292591
|
39,999 | 2005 |
9.4
|
E |
| 1491 |
VALCADORE
IMO 9384112
|
37,481 | 2008 |
9.4
|
E |
| 1492 |
SEAMARLIN
IMO 9380489
|
40,549 | 2007 |
9.4
|
E |
| 1493 |
BYZANTION
IMO 9315898
|
39,589 | 2007 |
9.5
|
E |
| 1494 |
DICTADOR
IMO 1055430
|
18,416 | 2025 |
9.5
|
E |
| 1495 |
COSTANZA M
IMO 9436680
|
40,042 | 2009 |
9.5
|
E |
| 1496 |
HTM DEFENDER
IMO 9346445
|
63,495 | 2008 |
9.5
|
E |
| 1497 |
GRACE ROMAVICTOR
IMO 9629926
|
49,990 | 2012 |
9.5
|
E |
| 1498 |
BORIS SOKOLOV
IMO 9817315
|
51,416 | 2018 |
9.5
|
E |
| 1499 |
FURE VITEN
IMO 9898204
|
17,999 | 2021 |
9.5
|
E |
| 1500 |
FURE VEN
IMO 9983102
|
17,945 | 2025 |
9.5
|
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.