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 |
|---|---|---|---|---|---|
| 302 |
MIKELA P.
IMO 9440382
|
158,007 | 2009 |
2.9
|
A |
| 301 |
SILVERWAY
IMO 9742912
|
157,781 | 2017 |
2.9
|
A |
| 303 |
NISSOS IOS
IMO 9886770
|
157,447 | 2021 |
2.9
|
A |
| 307 |
POPI SAZAKLIS
IMO 9817494
|
157,610 | 2018 |
2.9
|
A |
| 306 |
OLYMPIC FRIENDSHIP
IMO 9745251
|
158,885 | 2017 |
2.9
|
A |
| 305 |
SIENA
IMO 1030404
|
158,932 | 2025 |
2.9
|
A |
| 304 |
TORM HOUSTON
IMO 9904883
|
115,414 | 2022 |
2.9
|
A |
| 308 |
SPYROS
IMO 9877171
|
158,081 | 2020 |
2.9
|
A |
| 309 |
SEA RAPTOR
IMO 9356751
|
50,343 | 2007 |
2.9
|
A |
| 311 |
AURA M
IMO 9595333
|
156,245 | 2020 |
2.9
|
A |
| 310 |
SEAVIOLET
IMO 9790983
|
158,480 | 2015 |
2.9
|
A |
| 317 |
BALTIC LOYALTY
IMO 9411953
|
317,441 | 2010 |
2.9
|
A |
| 316 |
DINO
IMO 9923994
|
157,010 | 2022 |
2.9
|
A |
| 315 |
FREUD
IMO 9804461
|
157,620 | 2018 |
2.9
|
A |
| 314 |
STELLA
IMO 9461776
|
164,714 | 2011 |
2.9
|
A |
| 313 |
SONANGOL CABINDA
IMO 9575589
|
157,747 | 2013 |
2.9
|
A |
| 312 |
VICTORY VENTURE
IMO 9773040
|
114,456 | 2017 |
2.9
|
A |
| 318 |
SEAMAGIC
IMO 9997969
|
113,947 | 2025 |
2.9
|
A |
| 320 |
CAPE ANTIBES
IMO 1054632
|
114,000 | 2025 |
2.9
|
A |
| 319 |
EFFIE MAERSK
IMO 9682978
|
158,295 | 2017 |
2.9
|
A |
| 321 |
JIAOLONG
IMO 9379208
|
159,021 | 2009 |
2.9
|
A |
| 323 |
GENEVA STAR
IMO 1028528
|
158,000 | 2025 |
2.9
|
A |
| 322 |
OTTOMAN EQUITY
IMO 9404950
|
150,545 | 2008 |
2.9
|
A |
| 324 |
FRONT SIENA
IMO 9832250
|
149,999 | 2019 |
2.9
|
A |
| 325 |
NISSOS SIFNOS
IMO 9884045
|
157,447 | 2020 |
2.9
|
A |
| 327 |
NORDIC HAWK
IMO 9749491
|
158,594 | 2016 |
2.9
|
A |
| 326 |
COBALT NOVA
IMO 9534028
|
299,989 | 2011 |
2.9
|
A |
| 329 |
SHENLONG
IMO 9379210
|
159,021 | 2009 |
3.0
|
A |
| 328 |
FAIRWAY
IMO 9590319
|
160,250 | 2013 |
3.0
|
A |
| 333 |
COSTAS P
IMO 9934321
|
157,010 | 2023 |
3.0
|
A |
| 332 |
MARAN HERMES
IMO 9761346
|
156,458 | 2017 |
3.0
|
A |
| 331 |
LENI P.
IMO 9594133
|
158,640 | 2010 |
3.0
|
A |
| 330 |
NAVIG8 PROVIDENCE
IMO 9947378
|
109,995 | 2023 |
3.0
|
A |
| 334 |
DELTA SKY
IMO 9410181
|
166,092 | 2009 |
3.0
|
B |
| 337 |
EVRIDIKI
IMO 9318137
|
167,295 | 2007 |
3.0
|
B |
| 339 |
ZEUS
IMO 9886378
|
159,153 | 2021 |
3.0
|
B |
| 336 |
PATMOS I
IMO 9800245
|
156,917 | 2018 |
3.0
|
B |
| 335 |
MONTE UDALA
IMO 9785823
|
156,341 | 2018 |
3.0
|
B |
| 338 |
FRONT ULL
IMO 9600932
|
157,000 | 2014 |
3.0
|
B |
| 345 |
ECO WEST COAST
IMO 9902811
|
157,668 | 2021 |
3.0
|
B |
| 348 |
CAPE BENAT
IMO 9406013
|
156,642 | 2010 |
3.0
|
B |
| 344 |
PLATA EAST
IMO 9410997
|
297,007 | 2010 |
3.0
|
B |
| 347 |
NISSOS ANTIMILOS
IMO 9895226
|
157,447 | 2021 |
3.0
|
B |
| 346 |
MOTELE OLA
IMO 9399492
|
156,852 | 2009 |
3.0
|
B |
| 343 |
MONTESTENA
IMO 9585883
|
159,372 | 2012 |
3.0
|
B |
| 342 |
LORAX
IMO 9903413
|
109,990 | 2022 |
3.0
|
B |
| 341 |
PLATANOS
IMO 9825477
|
114,578 | 2019 |
3.0
|
B |
| 340 |
ATHENS SPIRIT
IMO 9594793
|
158,529 | 2012 |
3.0
|
B |
| 350 |
JILL GLORY
IMO 9959917
|
115,415 | 2021 |
3.0
|
B |
| 349 |
ASIA
IMO 9905318
|
163,111 | 2022 |
3.0
|
B |
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.