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 |
|---|---|---|---|---|---|
| 202 |
STARWAY
IMO 9900801
|
157,551 | 2022 |
2.6
|
A |
| 201 |
AEGEAN DREAM
IMO 9645425
|
158,888 | 2016 |
2.6
|
A |
| 200 |
NORDIC HUNTER
IMO 9921075
|
157,037 | 2022 |
2.6
|
A |
| 205 |
ENERGY TRIUMPH
IMO 9817614
|
157,470 | 2018 |
2.6
|
A |
| 204 |
YASA POLARIS
IMO 9907457
|
158,224 | 2022 |
2.6
|
A |
| 206 |
FRONT SUEZ
IMO 9831830
|
157,270 | 2017 |
2.6
|
A |
| 208 |
DR IRENE TSAKOS
IMO 9993755
|
156,838 | 2025 |
2.6
|
A |
| 207 |
MONTE URBASA
IMO 9785835
|
156,400 | 2018 |
2.6
|
A |
| 209 |
PACIFIC
IMO 9912141
|
158,405 | 2022 |
2.6
|
A |
| 211 |
TAIPAN
IMO 9996393
|
159,076 | 2024 |
2.6
|
A |
| 210 |
NISSOS KOUFONISSI
IMO 9895214
|
157,447 | 2021 |
2.6
|
A |
| 212 |
NEW COMFORT
IMO 9706413
|
313,999 | 2016 |
2.6
|
A |
| 214 |
FRONT CLIPPER
IMO 9759771
|
157,351 | 2017 |
2.6
|
A |
| 213 |
FOLEGANDROS
IMO 9793753
|
159,221 | 2018 |
2.6
|
A |
| 216 |
NISSOS TINOS
IMO 9886782
|
157,447 | 2021 |
2.7
|
A |
| 218 |
OCEANIS
IMO 9532757
|
320,780 | 2011 |
2.7
|
A |
| 215 |
FRONT CORAL
IMO 9743203
|
157,522 | 2017 |
2.7
|
A |
| 217 |
ALDANA
IMO 9809368
|
156,670 | 2018 |
2.7
|
A |
| 219 |
MARAN HERCULES
IMO 9761360
|
157,755 | 2014 |
2.7
|
A |
| 222 |
GREENWAY
IMO 9900796
|
157,327 | 2022 |
2.7
|
A |
| 221 |
MONTE ULIA
IMO 9803285
|
156,424 | 2019 |
2.7
|
A |
| 220 |
NORDIC AQUARIUS
IMO 9818216
|
157,338 | 2018 |
2.7
|
A |
| 224 |
SFL SABINE
IMO 9799874
|
115,711 | 2017 |
2.7
|
A |
| 223 |
POPI P
IMO 9934319
|
157,010 | 2023 |
2.7
|
A |
| 225 |
NEPTUNE MOON
IMO 9784013
|
150,000 | 2019 |
2.7
|
A |
| 227 |
FEARLESS WARRIOR
IMO 1028736
|
156,885 | 2025 |
2.7
|
A |
| 226 |
SONANGOL CAZENGA
IMO 9766310
|
156,899 | 2017 |
2.7
|
A |
| 228 |
DELTA MARINER
IMO 9579573
|
157,638 | 2013 |
2.7
|
A |
| 230 |
TAQAH
IMO 9501174
|
316,373 | 2012 |
2.7
|
A |
| 229 |
BOUBOULINA
IMO 9298753
|
163,759 | 2006 |
2.7
|
A |
| 232 |
MARLIN SHIKOKU
IMO 9841627
|
156,573 | 2019 |
2.7
|
A |
| 231 |
FRONT CRYSTAL
IMO 9743186
|
157,409 | 2017 |
2.7
|
A |
| 233 |
FRATERNITY
IMO 9416733
|
157,714 | 2009 |
2.7
|
A |
| 235 |
SEA AMBER
IMO 9772931
|
158,455 | 2016 |
2.7
|
A |
| 234 |
ARIADNE
IMO 9973834
|
114,905 | 2024 |
2.7
|
A |
| 236 |
MARAN HOMER
IMO 9761372
|
156,458 | 2017 |
2.7
|
A |
| 241 |
MARAN PHOEBE
IMO 9868156
|
157,946 | 2020 |
2.7
|
A |
| 240 |
DELTA EURYDICE
IMO 9700706
|
157,031 | 2015 |
2.7
|
A |
| 239 |
EAGLE SAN ANTONIO
IMO 9594822
|
157,849 | 2012 |
2.7
|
A |
| 238 |
SPEEDWAY
IMO 9749506
|
158,594 | 2017 |
2.7
|
A |
| 237 |
FRONT CHALLENGER
IMO 9759745
|
157,407 | 2016 |
2.7
|
A |
| 243 |
SFL FRASER
IMO 9874258
|
158,060 | 2018 |
2.7
|
A |
| 242 |
STENA SUEDE
IMO 9579042
|
158,824 | 2011 |
2.7
|
A |
| 245 |
SEA SHELL
IMO 9773947
|
158,409 | 2015 |
2.7
|
A |
| 244 |
EVA MAERSK
IMO 9682992
|
158,468 | 2017 |
2.7
|
A |
| 248 |
MARLIN SANTORINI
IMO 9835836
|
156,587 | 2019 |
2.7
|
A |
| 247 |
DILONG SPIRIT
IMO 9390628
|
159,021 | 2009 |
2.7
|
A |
| 246 |
KANARIS 21
IMO 9889942
|
156,921 | 2021 |
2.7
|
A |
| 250 |
MINERVA KALLISTO
IMO 9853008
|
113,000 | 2019 |
2.8
|
A |
| 249 |
OTTOMAN COURTESY
IMO 9788708
|
152,544 | 2017 |
2.8
|
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.