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 |
|---|---|---|---|---|---|
| 1251 |
COROSSOL
IMO 9395331
|
106,898 | 2010 |
5.9
|
D |
| 1252 |
SCOTT SPIRIT
IMO 9466142
|
109,334 | 2011 |
5.9
|
D |
| 1253 |
ROMEOS
IMO 9326897
|
74,992 | 2008 |
5.9
|
D |
| 1254 |
JAG PRIYANKA
IMO 9658379
|
50,026 | 2013 |
5.9
|
D |
| 1255 |
FRIDA KNUTSEN
IMO 9905916
|
123,602 | 2022 |
5.9
|
D |
| 1256 |
ANAFI WARRIOR
IMO 9370848
|
107,593 | 2005 |
5.9
|
D |
| 1257 |
HIGH MARINER
IMO 9812755
|
51,492 | 2017 |
5.9
|
D |
| 1258 |
VELOS FORTUNA
IMO 9347310
|
47,286 | 2007 |
5.9
|
D |
| 1259 |
SILVER EBURNA
IMO 9718416
|
49,737 | 2016 |
5.9
|
D |
| 1260 |
STI MARVEL
IMO 9829473
|
47,499 | 2017 |
5.9
|
D |
| 1261 |
HAFNIA AFRICA
IMO 9467811
|
74,539 | 2010 |
5.9
|
D |
| 1262 |
MINERVA VIRGO
IMO 9307827
|
49,990 | 2006 |
5.9
|
D |
| 1263 |
UNIQUE GUARDIAN
IMO 9540821
|
50,475 | 2012 |
6.0
|
D |
| 1264 |
PIS SUMATERA
IMO 9645798
|
51,622 | 2011 |
6.0
|
D |
| 1265 |
CL GEORGE ELIOT
IMO 9943360
|
49,355 | 2023 |
6.0
|
D |
| 1266 |
LARGO ATOM
IMO 1034747
|
49,740 | 2025 |
6.0
|
D |
| 1267 |
CAPOEIRA
IMO 9327011
|
73,400 | 2008 |
6.0
|
D |
| 1268 |
LARGO EMERALD
IMO 9935935
|
49,999 | 2023 |
6.0
|
D |
| 1269 |
LARGO SEA
IMO 9746279
|
49,990 | 2016 |
6.0
|
D |
| 1270 |
KANALA
IMO 9425552
|
49,997 | 2010 |
6.0
|
D |
| 1271 |
ASTROLIGHT
IMO 9724714
|
45,999 | 2017 |
6.0
|
D |
| 1272 |
HANSA SEALEADER
IMO 9367712
|
47,463 | 2008 |
6.1
|
D |
| 1273 |
SCHWYZ
IMO 9905605
|
37,764 | 2021 |
6.1
|
D |
| 1274 |
HISTRIA DIONE
IMO 9800805
|
40,000 | 2020 |
6.1
|
D |
| 1275 |
KOUROS
IMO 9374507
|
49,999 | 2008 |
6.1
|
D |
| 1276 |
FLORENCE
IMO 9333242
|
47,999 | 2006 |
6.1
|
D |
| 1277 |
FRANK LIGHT
IMO 9724726
|
45,999 | 2017 |
6.1
|
D |
| 1278 |
EVRIDIKI
IMO 9358929
|
73,740 | 2008 |
6.1
|
D |
| 1279 |
CL MARGUERITE DURAS
IMO 9943358
|
49,357 | 2023 |
6.1
|
D |
| 1280 |
HAFNIA PACIFIC
IMO 9810226
|
49,686 | 2017 |
6.1
|
D |
| 1281 |
OVERSEAS SUN COAST
IMO 9862944
|
50,332 | 2019 |
6.1
|
D |
| 1282 |
LAKSHMI
IMO 9428865
|
50,192 | 2009 |
6.1
|
D |
| 1283 |
HELLESPONT PROTECTOR
IMO 9351452
|
73,821 | 2007 |
6.1
|
D |
| 1284 |
PELICAN MARINER
IMO 9905423
|
50,177 | 2020 |
6.1
|
D |
| 1285 |
LUCTOR
IMO 9479840
|
50,383 | 2011 |
6.1
|
D |
| 1286 |
ANLAN
IMO 9346859
|
110,295 | 2007 |
6.2
|
D |
| 1287 |
LYSIAS
IMO 9397511
|
49,999 | 2008 |
6.2
|
D |
| 1288 |
ALBARO
IMO 9326873
|
74,998 | 2007 |
6.2
|
D |
| 1289 |
SAFEEN BARONESS
IMO 9460576
|
105,335 | 2011 |
6.2
|
D |
| 1290 |
ZOBU START
IMO 9367724
|
47,186 | 2008 |
6.2
|
D |
| 1291 |
GERAKAS
IMO 9399894
|
49,997 | 2009 |
6.2
|
D |
| 1292 |
YAS
IMO 9439785
|
50,251 | 2009 |
6.2
|
D |
| 1293 |
NAVE PYXIS
IMO 9697430
|
49,998 | 2014 |
6.2
|
D |
| 1294 |
CLEAN MOXIE
IMO 9422512
|
49,999 | 2010 |
6.2
|
D |
| 1295 |
PEARL LIGHT
IMO 9724685
|
45,999 | 2017 |
6.2
|
D |
| 1296 |
PACIFIC COBALT
IMO 9788617
|
49,886 | 2020 |
6.3
|
D |
| 1297 |
ASOPOS
IMO 9309253
|
61,286 | 2006 |
6.3
|
D |
| 1298 |
CEPOLIS
IMO 9590905
|
48,020 | 2011 |
6.3
|
D |
| 1299 |
TURMOIL
IMO 9479838
|
50,358 | 2011 |
6.3
|
D |
| 1300 |
CHARLINE
IMO 9476812
|
50,436 | 2009 |
6.3
|
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.