Most Emission-Efficient Gas Carriers
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 2024. 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 |
|---|---|---|---|---|---|
| 251 |
CHELSEA
IMO 9392250
|
9,127 | 2005 |
20.5
|
D |
| 252 |
THETAGAS
IMO 9368792
|
10,264 | 2008 |
20.8
|
D |
| 253 |
GAS DIAMOND
IMO 9806732
|
6,407 | 2018 |
21.2
|
E |
| 254 |
EPIC SALINA
IMO 9733569
|
8,982 | 2017 |
21.2
|
E |
| 255 |
GAZ INTERCEPTOR
IMO 9291224
|
6,539 | 2006 |
21.3
|
E |
| 256 |
HELENA KOSAN
IMO 9342396
|
8,555 | 2007 |
21.3
|
E |
| 257 |
GAZ EXPLORER
IMO 9506150
|
10,266 | 2010 |
21.3
|
E |
| 258 |
EPIC BALI
IMO 9519523
|
6,022 | 2010 |
21.4
|
E |
| 259 |
GAZ PROVIDENCE
IMO 9448504
|
17,022 | 2010 |
21.5
|
E |
| 260 |
GASCHEM RHONE
IMO 9401570
|
7,341 | 2008 |
21.6
|
E |
| 261 |
GAZ CONCORD
IMO 9506174
|
10,313 | 2011 |
21.9
|
E |
| 262 |
ALEXANDRA KOSAN
IMO 9342413
|
8,586 | 2008 |
22.0
|
E |
| 263 |
CORAL IVORY
IMO 9207039
|
6,875 | 2000 |
22.0
|
E |
| 264 |
SYN ACRAB
IMO 9251781
|
9,328 | 2003 |
22.0
|
E |
| 265 |
GAS ESCO
IMO 9507752
|
7,207 | 2012 |
22.1
|
E |
| 266 |
HAPPY PENGUIN
IMO 9623996
|
8,643 | 2013 |
22.4
|
E |
| 267 |
EPSILONGAS
IMO 9202039
|
6,175 | 2000 |
22.6
|
E |
| 268 |
TRISTAR DANA
IMO 9506186
|
7,879 | 2010 |
22.6
|
E |
| 269 |
GAZ HORIZON
IMO 9572563
|
6,519 | 2011 |
22.7
|
E |
| 270 |
EPIC BORACAY
IMO 9521588
|
6,519 | 2007 |
22.8
|
E |
| 271 |
GAS FORTUNE
IMO 9774898
|
6,420 | 2016 |
22.9
|
E |
| 272 |
PGC TAORMINA
IMO 9800166
|
6,612 | 2017 |
23.1
|
E |
| 273 |
GAZ DYNAMIC
IMO 9612844
|
6,044 | 2011 |
23.2
|
E |
| 274 |
GREMIO
IMO 9699256
|
6,486 | 2014 |
23.3
|
E |
| 275 |
CHRISTOPH SCHULTE
IMO 9368778
|
10,309 | 2007 |
23.4
|
E |
| 276 |
CLAMOR SCHULTE
IMO 9220809
|
9,174 | 2002 |
23.4
|
E |
| 277 |
EPIC BORNEO
IMO 9519535
|
6,028 | 2010 |
23.4
|
E |
| 278 |
GASCHEM MOSEL
IMO 9274379
|
7,407 | 2007 |
23.4
|
E |
| 279 |
GAS AEGEAN
IMO 9545209
|
10,390 | 2012 |
23.7
|
E |
| 280 |
GAZ FRATERNITY
IMO 9448487
|
17,022 | 2010 |
24.1
|
E |
| 281 |
GASCHEM SHINANO
IMO 9269271
|
7,413 | 2007 |
24.1
|
E |
| 282 |
GASCHEM CARIBIC
IMO 9371684
|
9,305 | 2011 |
24.2
|
E |
| 283 |
KNEBWORTH
IMO 9624809
|
8,584 | 2012 |
24.7
|
E |
| 284 |
CHEIKH BOUAMAMA
IMO 9324344
|
39,483 | 2008 |
24.8
|
E |
| 285 |
CGAS JAGUAR
IMO 9578024
|
4,980 | 2012 |
25.0
|
E |
| 286 |
KAPPAGAS
IMO 9215141
|
6,211 | 2001 |
25.1
|
E |
| 287 |
HAPPY PELICAN
IMO 9618850
|
8,610 | 2012 |
25.2
|
E |
| 288 |
ECO NICAL
IMO 9746774
|
6,407 | 2016 |
25.2
|
E |
| 289 |
TRISTAR SHAMAL
IMO 9506198
|
7,879 | 2008 |
25.6
|
E |
| 290 |
EPIC BEATA
IMO 9580182
|
6,513 | 2011 |
25.7
|
E |
| 291 |
ZETAGAS
IMO 9623984
|
8,641 | 2013 |
25.8
|
E |
| 292 |
NAVIS
IMO 9260366
|
6,017 | 2002 |
25.8
|
E |
| 293 |
SYN ANTARES
IMO 9512848
|
9,230 | 2014 |
25.9
|
E |
| 294 |
CORAL PEARL
IMO 9425253
|
8,602 | 2009 |
26.1
|
E |
| 295 |
GAZ UNITED
IMO 9511650
|
10,314 | 2011 |
26.4
|
E |
| 296 |
CORAL SHASTA
IMO 9254941
|
10,770 | 2003 |
26.6
|
E |
| 297 |
CORAL PATULA
IMO 9425241
|
8,570 | 2009 |
27.1
|
E |
| 298 |
DOROTHEA SCHULTE
IMO 9618862
|
8,643 | 2013 |
27.2
|
E |
| 299 |
PGC ARATOS
IMO 9251779
|
9,329 | 2003 |
27.6
|
E |
| 300 |
CGAS PANTHER
IMO 9578000
|
4,994 | 2012 |
27.8
|
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 2024 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.