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 |
|---|---|---|---|---|---|
| 749 |
HAIGUI
IMO 9505821
|
114,900 | 2013 |
3.8
|
C |
| 751 |
SAMOS
IMO 9486934
|
104,649 | 2010 |
3.8
|
C |
| 755 |
VST AMARA
IMO 9742211
|
109,990 | 2017 |
3.8
|
C |
| 754 |
NAVIG8 PROMISE
IMO 9791298
|
109,992 | 2015 |
3.8
|
C |
| 753 |
STI CONNAUGHT
IMO 9697600
|
109,999 | 2013 |
3.8
|
C |
| 756 |
SERTANEJO SPIRIT
IMO 9637715
|
154,233 | 2013 |
3.8
|
C |
| 758 |
ARCHANGEL
IMO 9302592
|
163,216 | 2006 |
3.8
|
C |
| 757 |
STI OXFORD
IMO 9697595
|
109,999 | 2015 |
3.8
|
C |
| 759 |
PACIFIC RAWAN
IMO 9772022
|
109,999 | 2017 |
3.8
|
C |
| 765 |
KMARIN RELIANCE
IMO 9683025
|
109,466 | 2016 |
3.8
|
C |
| 764 |
ALFA ALANDIA
IMO 9752797
|
106,324 | 2016 |
3.8
|
C |
| 763 |
ELANDRA BAY
IMO 9821691
|
115,674 | 2018 |
3.8
|
C |
| 762 |
STI LAVENDER
IMO 9838254
|
109,999 | 2019 |
3.8
|
C |
| 761 |
KWK EXCELSUS
IMO 9728411
|
114,716 | 2016 |
3.8
|
C |
| 760 |
SEA SAPPHIRE
IMO 9935600
|
156,669 | 2022 |
3.8
|
C |
| 768 |
NISSOS CHRISTIANA
IMO 9694658
|
114,264 | 2015 |
3.8
|
C |
| 766 |
SAMOS
IMO 9772345
|
158,000 | 2018 |
3.8
|
C |
| 767 |
ALFA BALTICA
IMO 9696773
|
106,373 | 2015 |
3.8
|
C |
| 770 |
SELIGER
IMO 9402263
|
115,126 | 2009 |
3.8
|
C |
| 769 |
SWORD
IMO 9783631
|
104,027 | 2018 |
3.8
|
C |
| 771 |
AMADES
IMO 9903126
|
112,708 | 2022 |
3.8
|
C |
| 772 |
MINERVA DOXA
IMO 9304617
|
159,438 | 2007 |
3.8
|
C |
| 773 |
VELOS AMBER
IMO 9571038
|
74,902 | 2010 |
3.8
|
C |
| 775 |
JAG LAXMI
IMO 9568196
|
105,525 | 2012 |
3.8
|
C |
| 774 |
ATLANTIC JADE
IMO 9892987
|
109,325 | 2019 |
3.8
|
C |
| 777 |
PIS KERINCI
IMO 9838242
|
109,994 | 2019 |
3.8
|
C |
| 776 |
STI SPIGA
IMO 9708148
|
109,999 | 2015 |
3.8
|
C |
| 778 |
CIELO DI HOUSTON
IMO 9791860
|
74,999 | 2019 |
3.9
|
C |
| 779 |
AFRODITI
IMO 9452880
|
166,164 | 2011 |
3.9
|
C |
| 781 |
STI ORCHARD
IMO 9690834
|
109,999 | 2014 |
3.9
|
C |
| 780 |
MARETA
IMO 9537927
|
115,795 | 2013 |
3.9
|
C |
| 782 |
STI CONDOTTI
IMO 9690810
|
109,999 | 2013 |
3.9
|
C |
| 783 |
STI RAMBLA
IMO 9730880
|
109,999 | 2017 |
3.9
|
C |
| 784 |
ZUMBI DOS PALMARES
IMO 9453810
|
157,055 | 2007 |
3.9
|
C |
| 787 |
SUNDA
IMO 9806146
|
79,902 | 2019 |
3.9
|
C |
| 786 |
STI GLADIATOR
IMO 9722170
|
109,999 | 2017 |
3.9
|
C |
| 785 |
PROTEUS ELSIE
IMO 9923451
|
109,999 | 2023 |
3.9
|
C |
| 789 |
AL DASMA
IMO 9653446
|
109,719 | 2014 |
3.9
|
C |
| 788 |
STI SANCTITY
IMO 9719707
|
109,999 | 2013 |
3.9
|
C |
| 794 |
PROTEUS BOHEMIA
IMO 9923437
|
109,999 | 2020 |
3.9
|
C |
| 793 |
AL AGAILA
IMO 9415404
|
164,787 | 2009 |
3.9
|
C |
| 792 |
NAMRATA
IMO 9401154
|
105,830 | 2008 |
3.9
|
C |
| 791 |
EAGLE KLANG
IMO 9417892
|
107,481 | 2010 |
3.9
|
C |
| 790 |
SAND
IMO 9379612
|
115,878 | 2009 |
3.9
|
C |
| 795 |
BANIYAS
IMO 9838228
|
109,994 | 2017 |
3.9
|
C |
| 800 |
SPETSA
IMO 9337004
|
150,265 | 2008 |
3.9
|
C |
| 799 |
IONIC ANASSA
IMO 9779795
|
114,718 | 2016 |
3.9
|
C |
| 798 |
ALBERT
IMO 9843572
|
113,095 | 2019 |
3.9
|
C |
| 797 |
MAERSK CAPRI
IMO 9786140
|
49,919 | 2018 |
3.9
|
C |
| 796 |
ADVANTAGE SUMMER
IMO 9419890
|
156,527 | 2010 |
3.9
|
C |
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.