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 |
|---|---|---|---|---|---|
| 1001 |
OTIS
IMO 9408217
|
156,719 | 2010 |
4.6
|
D |
| 1002 |
FLAGSHIP ORCHID
IMO 9456939
|
74,577 | 2012 |
4.6
|
D |
| 1003 |
LYRIC CAMELLIA
IMO 9730933
|
109,999 | 2016 |
4.6
|
D |
| 1004 |
ADVANTAGE SUN
IMO 9513141
|
156,644 | 2012 |
4.6
|
D |
| 1005 |
FAITHFUL WARRIOR
IMO 9750062
|
149,992 | 2016 |
4.6
|
D |
| 1006 |
SOLAR MADELEIN
IMO 9882413
|
49,990 | 2020 |
4.6
|
D |
| 1007 |
DELTA BLUE
IMO 9601235
|
158,322 | 2012 |
4.6
|
D |
| 1008 |
PIURA PACIFIC
IMO 9983889
|
49,805 | 2024 |
4.6
|
D |
| 1009 |
HAFNIA CATERINA
IMO 9688427
|
49,999 | 2015 |
4.6
|
D |
| 1010 |
ABU DHABI-III
IMO 9489027
|
105,131 | 2011 |
4.6
|
D |
| 1011 |
MARAN ATLAS
IMO 9414022
|
105,071 | 2009 |
4.6
|
D |
| 1012 |
PGC ALEXANDRIA
IMO 9336505
|
74,996 | 2006 |
4.6
|
D |
| 1013 |
HAFNIA SHENZHEN
IMO 9863223
|
74,999 | 2020 |
4.6
|
D |
| 1014 |
ALIAI
IMO 9884813
|
50,315 | 2021 |
4.6
|
D |
| 1015 |
LARGO EXCELLENCE
IMO 9935923
|
49,999 | 2023 |
4.6
|
D |
| 1016 |
STAVANGER PEARL
IMO 9839090
|
49,999 | 2020 |
4.6
|
D |
| 1017 |
ALICANTE
IMO 9527855
|
115,707 | 2013 |
4.6
|
D |
| 1018 |
RAFFLES HARMONY
IMO 9607734
|
105,405 | 2013 |
4.6
|
D |
| 1019 |
AQUALEGEND
IMO 9592240
|
115,571 | 2010 |
4.6
|
D |
| 1020 |
BRIOLETTE
IMO 9524982
|
104,588 | 2011 |
4.6
|
D |
| 1021 |
LIRICA
IMO 9302982
|
150,205 | 2006 |
4.6
|
D |
| 1022 |
LEYTE SPIRIT
IMO 9484089
|
109,670 | 2011 |
4.6
|
D |
| 1023 |
PROTEUS PHILIPPA
IMO 9923425
|
109,999 | 2022 |
4.6
|
D |
| 1024 |
PORTOFINO
IMO 9564671
|
74,905 | 2010 |
4.6
|
D |
| 1025 |
GAMSUNORO
IMO 9677313
|
105,638 | 2014 |
4.7
|
D |
| 1026 |
CHRYSALIS
IMO 9437684
|
115,867 | 2010 |
4.7
|
D |
| 1027 |
MAERSK TACOMA
IMO 9708617
|
49,828 | 2015 |
4.7
|
D |
| 1028 |
GRIMSTAD
IMO 9336402
|
105,850 | 2007 |
4.7
|
D |
| 1029 |
OLAVO BILAC
IMO 9547697
|
114,700 | 2018 |
4.7
|
D |
| 1030 |
PACIFIC ANNA
IMO 9772010
|
109,999 | 2015 |
4.7
|
D |
| 1031 |
UOG IOANNIS V
IMO 9485629
|
73,338 | 2008 |
4.7
|
D |
| 1032 |
MARGARITA
IMO 9426594
|
74,998 | 2008 |
4.7
|
D |
| 1033 |
ADVANTAGE PORTO CERVO
IMO 9794850
|
74,000 | 2019 |
4.7
|
D |
| 1034 |
EAGLE BALDER
IMO 9833113
|
128,427 | 2020 |
4.7
|
D |
| 1035 |
SEA PUMA
IMO 9802176
|
114,560 | 2019 |
4.7
|
D |
| 1036 |
ORIENT INNOVATION
IMO 9793387
|
49,997 | 2017 |
4.7
|
D |
| 1037 |
MAERSK CALLAO
IMO 9786152
|
49,919 | 2018 |
4.7
|
D |
| 1038 |
ST. CLEMENS
IMO 9790361
|
49,998 | 2017 |
4.7
|
D |
| 1039 |
AEGEAN HARMONY
IMO 9338917
|
115,824 | 2007 |
4.7
|
D |
| 1040 |
ATHINA
IMO 9884253
|
49,999 | 2020 |
4.7
|
D |
| 1041 |
BANI YAS
IMO 9487249
|
74,913 | 2010 |
4.7
|
D |
| 1042 |
MARI BOYLE
IMO 9732979
|
49,999 | 2016 |
4.7
|
D |
| 1043 |
AQUILA L
IMO 9829411
|
49,999 | 2018 |
4.7
|
D |
| 1044 |
PENELOP
IMO 9325908
|
115,091 | 2006 |
4.8
|
D |
| 1045 |
HAFNIA COUGAR
IMO 9675494
|
49,999 | 2014 |
4.8
|
D |
| 1046 |
PROMITHEAS
IMO 9305611
|
117,055 | 2006 |
4.8
|
D |
| 1047 |
ALQADISIA
IMO 9343352
|
115,577 | 2008 |
4.8
|
D |
| 1048 |
UOG HERMES
IMO 9550694
|
73,410 | 2009 |
4.8
|
D |
| 1049 |
LARGO ALPHA
IMO 1031109
|
49,834 | 2025 |
4.8
|
D |
| 1050 |
ADAM
IMO 9826732
|
113,226 | 2018 |
4.8
|
D |
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.