Most Emission-Efficient Chemical 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 |
|---|---|---|---|---|---|
| 1301 |
BASARAN BAYRAK
IMO 9932165
|
8,127 | 2022 |
16.9
|
E |
| 1302 |
WAVEPOWER
IMO 1043097
|
8,524 | 2025 |
16.9
|
E |
| 1303 |
VIOLETA THERESA
IMO 9354571
|
8,817 | 2006 |
16.9
|
E |
| 1304 |
MUT OZT
IMO 9382114
|
7,915 | 2007 |
16.9
|
E |
| 1305 |
OWL 6
IMO 9340350
|
13,006 | 2007 |
16.9
|
E |
| 1306 |
MRC LINA
IMO 9462299
|
8,280 | 2010 |
17.0
|
E |
| 1307 |
ATA OCEAN
IMO 9373929
|
9,942 | 2007 |
17.0
|
E |
| 1308 |
PECHORA STAR
IMO 9488322
|
13,021 | 2011 |
17.1
|
E |
| 1309 |
SELENKA
IMO 9447067
|
10,745 | 2009 |
17.1
|
E |
| 1310 |
CYAN ORCA
IMO 9542908
|
9,131 | 2007 |
17.2
|
E |
| 1311 |
LISA ESSBERGER
IMO 9295438
|
8,617 | 2005 |
17.2
|
E |
| 1312 |
HULIN
IMO 9447043
|
10,745 | 2008 |
17.2
|
E |
| 1313 |
ALICE THERESA
IMO 9478303
|
7,874 | 2010 |
17.2
|
E |
| 1314 |
W WEST
IMO 9383651
|
8,025 | 2008 |
17.2
|
E |
| 1315 |
LIESEL ESSBERGER
IMO 9272761
|
8,571 | 2004 |
17.2
|
E |
| 1316 |
EVA HONGKONG
IMO 9800001
|
19,861 | 2017 |
17.3
|
E |
| 1317 |
RITA IEVOLI
IMO 9846471
|
15,882 | 2023 |
17.3
|
E |
| 1318 |
SCOT BREMEN
IMO 9260835
|
8,211 | 2003 |
17.3
|
E |
| 1319 |
DONIA
IMO 9442914
|
7,702 | 2008 |
17.4
|
E |
| 1320 |
MONA SWAN
IMO 9371804
|
11,348 | 2006 |
17.4
|
E |
| 1321 |
MERCURIUS
IMO 9816531
|
7,998 | 2019 |
17.4
|
E |
| 1322 |
CHARLOTTE THERESA
IMO 9400708
|
11,403 | 2008 |
17.4
|
E |
| 1323 |
JETTE THERESA
IMO 9406582
|
11,383 | 2009 |
17.4
|
E |
| 1324 |
BISCAY
IMO 9474450
|
11,161 | 2008 |
17.5
|
E |
| 1325 |
SCOT HAMBURG
IMO 9255799
|
8,241 | 2002 |
17.5
|
E |
| 1326 |
SCOT BERLIN
IMO 9255804
|
8,254 | 2003 |
17.5
|
E |
| 1327 |
TARNBRIS
IMO 9372652
|
11,288 | 2007 |
17.6
|
E |
| 1328 |
SONGA RUBY
IMO 9444479
|
17,604 | 2008 |
17.6
|
E |
| 1329 |
XT HONESTY
IMO 9576832
|
18,187 | 2022 |
17.6
|
E |
| 1330 |
KATTEGAT
IMO 9432866
|
11,299 | 2008 |
17.6
|
E |
| 1331 |
SCOT STUTTGART
IMO 9274549
|
8,184 | 2006 |
17.7
|
E |
| 1332 |
GRIFFIN T
IMO 9390537
|
10,778 | 2008 |
17.8
|
E |
| 1333 |
SATURNUS
IMO 9816529
|
7,998 | 2018 |
17.8
|
E |
| 1334 |
SHANNON STAR
IMO 9503926
|
13,023 | 2010 |
17.8
|
E |
| 1335 |
CAROLINE THERESA
IMO 9428449
|
7,884 | 2009 |
17.8
|
E |
| 1336 |
BOSNIA
IMO 9445643
|
13,210 | 2008 |
17.8
|
E |
| 1337 |
SLOMAN HERMES
IMO 9466738
|
16,418 | 2012 |
17.8
|
E |
| 1338 |
ODOARDO AMORETTI
IMO 9361031
|
15,000 | 2012 |
17.9
|
E |
| 1339 |
DUZGIT DIGNITY
IMO 9581019
|
8,488 | 2014 |
17.9
|
E |
| 1340 |
KARINA THERESA
IMO 9428451
|
7,871 | 2009 |
17.9
|
E |
| 1341 |
MILANO
IMO 9286059
|
37,305 | 2005 |
17.9
|
E |
| 1342 |
NQ VICTORIA
IMO 9344174
|
8,824 | 2006 |
17.9
|
E |
| 1343 |
DOMENICO IEVOLI
IMO 9334430
|
10,015 | 2006 |
18.0
|
E |
| 1344 |
ELLEN ESSBERGER
IMO 9272747
|
8,571 | 2004 |
18.0
|
E |
| 1345 |
SONGA AURORA
IMO 9373632
|
16,651 | 2008 |
18.1
|
E |
| 1346 |
TERNVIND
IMO 9425356
|
11,258 | 2008 |
18.1
|
E |
| 1347 |
NORDIC
IMO 9438444
|
11,530 | 2008 |
18.2
|
E |
| 1348 |
PLEVNE
IMO 9340908
|
11,321 | 2007 |
18.2
|
E |
| 1349 |
CARIBE LUNA
IMO 9352133
|
13,157 | 2006 |
18.3
|
E |
| 1350 |
AYSEN STAR
IMO 9419199
|
12,552 | 2010 |
18.3
|
E |
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.