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 |
|---|---|---|---|---|---|
| 201 |
ANTIKITHIRA
IMO 9788980
|
14,999 | 2018 |
13.8
|
D |
| 202 |
RHOURD EL ADRA
IMO 9320855
|
19,392 | 2007 |
13.9
|
D |
| 203 |
NISYROS
IMO 9412062
|
26,540 | 2009 |
13.9
|
D |
| 204 |
TRAMMO PARIS
IMO 9792515
|
17,667 | 2017 |
13.9
|
D |
| 205 |
NAVIGATOR GRACE
IMO 9531478
|
16,687 | 2008 |
13.9
|
D |
| 206 |
HAPPY KESTREL
IMO 9543043
|
15,206 | 2013 |
14.0
|
D |
| 207 |
HAPPY PEREGRINE
IMO 9553660
|
14,995 | 2014 |
14.0
|
D |
| 208 |
KALOLIMNOS
IMO 9796705
|
14,999 | 2018 |
14.2
|
D |
| 209 |
HAPPY OSPREY
IMO 9553646
|
15,177 | 2013 |
14.2
|
D |
| 210 |
SAPET GAS
IMO 9922213
|
17,872 | 2022 |
14.3
|
D |
| 211 |
GAS WIDURI
IMO 9590668
|
17,400 | 2011 |
14.7
|
D |
| 212 |
RHOURD EL FARES
IMO 9537044
|
26,353 | 2010 |
14.8
|
D |
| 213 |
TRAMMO MARYCAM
IMO 9409168
|
16,772 | 2009 |
14.9
|
D |
| 214 |
DELTAGAS
IMO 9540003
|
14,999 | 2013 |
15.2
|
D |
| 215 |
GREEN ONE
IMO 9336660
|
29,536 | 2007 |
15.2
|
D |
| 216 |
ZOE SCHULTE
IMO 9675078
|
14,999 | 2015 |
15.3
|
D |
| 217 |
BWEK BEAUTY
IMO 9974589
|
7,138 | 2023 |
15.5
|
D |
| 218 |
GAZ ENERGY
IMO 9458169
|
17,674 | 2010 |
15.5
|
D |
| 219 |
SOPHIA KOSAN
IMO 9374557
|
10,343 | 2008 |
15.9
|
D |
| 220 |
PERTAMINA GAS AMARYLLIS
IMO 9895317
|
57,555 | 2021 |
16.2
|
D |
| 221 |
TAUGAS
IMO 9675080
|
14,999 | 2015 |
16.2
|
D |
| 222 |
HAPPY ALBATROSS
IMO 9675066
|
14,995 | 2015 |
16.3
|
D |
| 223 |
NAVIGATOR LUGA
IMO 9761164
|
19,002 | 2017 |
16.4
|
D |
| 224 |
GAS WALIO
IMO 9590670
|
17,400 | 2011 |
16.6
|
D |
| 225 |
NAVIGATOR EUROPA
IMO 9661807
|
17,005 | 2014 |
16.7
|
D |
| 226 |
NAVIGATOR OBERON
IMO 9671216
|
16,994 | 2014 |
16.8
|
D |
| 227 |
NAVIGATOR UMBRIO
IMO 9704491
|
17,040 | 2015 |
16.8
|
D |
| 228 |
GAZ SYNERGY
IMO 9458157
|
17,739 | 2010 |
16.9
|
D |
| 229 |
GAZ REDSEA
IMO 9264192
|
7,930 | 2002 |
17.4
|
D |
| 230 |
EPIC BONAIRE
IMO 9743253
|
7,198 | 2014 |
17.5
|
D |
| 231 |
GAS HARALAMBOS
IMO 9423126
|
7,331 | 2007 |
17.5
|
D |
| 232 |
EPIC SARDINIA
IMO 9733571
|
9,000 | 2017 |
17.6
|
D |
| 233 |
STELLA KOSAN
IMO 9373591
|
10,316 | 2008 |
17.9
|
D |
| 234 |
GAZ VICTORY
IMO 9458171
|
17,672 | 2010 |
18.0
|
D |
| 235 |
GAZ SERENITY
IMO 9448499
|
17,022 | 2010 |
18.2
|
D |
| 236 |
EPIC BREEZE
IMO 9892808
|
6,827 | 2020 |
18.2
|
D |
| 237 |
STINA KOSAN
IMO 9374569
|
10,348 | 2008 |
18.2
|
D |
| 238 |
GAZ VENTURE
IMO 9506162
|
10,266 | 2011 |
18.4
|
D |
| 239 |
KAZAK
IMO 9739549
|
8,642 | 2014 |
18.8
|
D |
| 240 |
PGC EIRINI
IMO 9800178
|
6,602 | 2018 |
19.0
|
D |
| 241 |
MYGAS
IMO 9694397
|
14,999 | 2017 |
19.0
|
D |
| 242 |
WESTMINSTER
IMO 9520132
|
9,011 | 2011 |
19.1
|
D |
| 243 |
HAPPY CONDOR
IMO 9368780
|
10,355 | 2005 |
19.2
|
D |
| 244 |
PGC STRIDENT FORCE
IMO 9205574
|
8,485 | 1999 |
19.2
|
D |
| 245 |
EPIC BORINQUEN
IMO 9743241
|
7,183 | 2016 |
19.2
|
D |
| 246 |
GAS LISBON
IMO 9267974
|
8,064 | 2002 |
19.3
|
D |
| 247 |
BELGRAVIA V
IMO 9341897
|
9,127 | 2006 |
19.9
|
D |
| 248 |
BEYKOZ
IMO 9558945
|
8,677 | 2009 |
20.0
|
D |
| 249 |
KILBURN
IMO 9664938
|
8,586 | 2013 |
20.4
|
D |
| 250 |
CHEIKH EL MOKRANI
IMO 9324332
|
39,520 | 2007 |
20.4
|
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 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.