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 |
|---|---|---|---|---|---|
| 151 |
SEAWAYS TYBEE
IMO 9734642
|
300,960 | 2015 |
2.5
|
A |
| 154 |
ADVANTAGE SMOOTH
IMO 9999620
|
157,782 | 2023 |
2.5
|
A |
| 153 |
ANDROMEDA
IMO 9352561
|
321,300 | 2008 |
2.5
|
A |
| 152 |
SEAPASSION
IMO 9783734
|
299,700 | 2017 |
2.5
|
A |
| 155 |
GRAND AMBITION
IMO 9909807
|
299,988 | 2021 |
2.5
|
A |
| 156 |
ALMI ODYSSEY
IMO 9579559
|
157,787 | 2013 |
2.5
|
A |
| 158 |
COSFLOURISH LAKE
IMO 9783356
|
308,151 | 2017 |
2.5
|
A |
| 157 |
ENERGY DELOS
IMO 9994565
|
158,091 | 2025 |
2.5
|
A |
| 159 |
HOMERIC
IMO 9819844
|
157,000 | 2019 |
2.5
|
A |
| 160 |
FRONT CASCADE
IMO 9769829
|
157,434 | 2017 |
2.5
|
A |
| 164 |
LOIRE
IMO 9761516
|
157,463 | 2016 |
2.5
|
A |
| 163 |
FRONT SAVANNAH
IMO 9831828
|
157,270 | 2019 |
2.5
|
A |
| 162 |
YUAN BEI HAI
IMO 9843352
|
158,840 | 2021 |
2.5
|
A |
| 161 |
RHYTHMIC
IMO 9819856
|
159,196 | 2019 |
2.5
|
A |
| 165 |
EAST LOYALTY
IMO 9537745
|
323,183 | 2011 |
2.5
|
A |
| 166 |
ATLANTIC
IMO 9912139
|
158,337 | 2022 |
2.5
|
A |
| 168 |
MARAN LYNX
IMO 9534016
|
318,833 | 2011 |
2.5
|
A |
| 167 |
SEA BEAUTY
IMO 9806627
|
156,634 | 2016 |
2.5
|
A |
| 171 |
CANOPUS VOYAGER
IMO 9897846
|
115,589 | 2021 |
2.5
|
A |
| 170 |
AEGEAN MARATHON
IMO 9745225
|
158,913 | 2016 |
2.5
|
A |
| 169 |
FRONT SANTIAGO
IMO 9831842
|
157,270 | 2019 |
2.5
|
A |
| 172 |
MARAN ORPHEUS
IMO 9868168
|
157,946 | 2020 |
2.5
|
A |
| 173 |
SYDNEY SPIRIT
IMO 9594781
|
158,542 | 2012 |
2.5
|
A |
| 176 |
STENA SUNSHINE
IMO 9585900
|
159,039 | 2013 |
2.5
|
A |
| 174 |
SONANGOL KULUMBIMBI
IMO 9938482
|
157,663 | 2023 |
2.5
|
A |
| 175 |
OLYMPIC FIGHTER
IMO 9745263
|
158,932 | 2014 |
2.5
|
A |
| 177 |
MARLIN SICILY
IMO 9835848
|
156,563 | 2017 |
2.5
|
A |
| 180 |
ARGEUS I
IMO 1025485
|
155,352 | 2025 |
2.5
|
A |
| 179 |
COSWISDOM LAKE
IMO 9727194
|
308,018 | 2016 |
2.5
|
A |
| 178 |
PRIMEWAY
IMO 9817626
|
157,470 | 2018 |
2.5
|
A |
| 181 |
YASA SCORPION
IMO 9643271
|
313,998 | 2013 |
2.6
|
A |
| 183 |
MIAOULIS 21
IMO 9886641
|
158,081 | 2021 |
2.6
|
A |
| 182 |
ELANDRA EAGLE
IMO 9792474
|
157,554 | 2017 |
2.6
|
A |
| 184 |
ATLANTIC PRINCESS
IMO 9899363
|
156,828 | 2021 |
2.6
|
A |
| 186 |
FRONT CRUISER
IMO 9797230
|
157,215 | 2020 |
2.6
|
A |
| 185 |
BLUE NOVA
IMO 9534846
|
298,000 | 2011 |
2.6
|
A |
| 187 |
WEST LOYALTY
IMO 9537757
|
314,000 | 2011 |
2.6
|
A |
| 192 |
MINERVA EVROPI
IMO 9785237
|
159,000 | 2015 |
2.6
|
A |
| 191 |
FRONT SILKEBORG
IMO 9832274
|
158,006 | 2019 |
2.6
|
A |
| 190 |
SONANGOL RANGEL
IMO 9575541
|
157,755 | 2011 |
2.6
|
A |
| 189 |
DELTA HELLAS
IMO 9406673
|
157,583 | 2009 |
2.6
|
A |
| 188 |
IPANEMA
IMO 9996410
|
158,413 | 2022 |
2.6
|
A |
| 194 |
FRONT SEOUL
IMO 9831854
|
157,270 | 2019 |
2.6
|
A |
| 193 |
YUAN DONG HAI
IMO 9843338
|
158,677 | 2020 |
2.6
|
A |
| 198 |
HERCULES I
IMO 9723124
|
300,000 | 2017 |
2.6
|
A |
| 199 |
CYAN NOVA
IMO 9534004
|
318,663 | 2011 |
2.6
|
A |
| 197 |
NORDIC CYGNUS
IMO 9818228
|
157,526 | 2018 |
2.6
|
A |
| 196 |
ENERGY DIONE
IMO 9995973
|
158,091 | 2025 |
2.6
|
A |
| 195 |
FRONT COSMOS
IMO 9769817
|
157,528 | 2017 |
2.6
|
A |
| 200 |
ZENITH SPIRIT
IMO 9404845
|
159,952 | 2009 |
2.6
|
A |
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.