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 |
|---|---|---|---|---|---|
| 101 |
CLIPPER JUPITER
IMO 9699505
|
42,543 | 2015 |
8.3
|
B |
| 102 |
KAUPANG
IMO 9914620
|
29,649 | 2022 |
8.3
|
B |
| 103 |
CLIPPER SATURN
IMO 9699517
|
42,543 | 2015 |
8.3
|
B |
| 104 |
PASCO MARSEL
IMO 9939204
|
29,991 | 2023 |
8.3
|
B |
| 105 |
EAGLE FORD LADY
IMO 9711846
|
28,372 | 2016 |
8.4
|
B |
| 106 |
MANTA BEYOGLU
IMO 9789726
|
28,585 | 2018 |
8.4
|
B |
| 107 |
GASCHEM EUROPE
IMO 9961192
|
29,181 | 2023 |
8.5
|
B |
| 108 |
GUADALUPE EXPLORER
IMO 9926934
|
29,421 | 2022 |
8.5
|
B |
| 109 |
SEASHINE
IMO 9787352
|
28,467 | 2018 |
8.6
|
B |
| 110 |
ECO ARCTIC
IMO 9746683
|
26,798 | 2018 |
8.6
|
B |
| 111 |
ALBERT
IMO 9682447
|
54,354 | 2014 |
8.7
|
B |
| 112 |
SIFNOS LADY
IMO 9903073
|
28,379 | 2021 |
8.9
|
B |
| 113 |
MANTA ANKA
IMO 9666663
|
28,263 | 2013 |
8.9
|
B |
| 114 |
LUIGI GALVANI
IMO 9738246
|
28,543 | 2016 |
9.0
|
B |
| 115 |
TOKYO
IMO 9377248
|
43,538 | 2009 |
9.0
|
B |
| 116 |
RHOURD ENOUSS
IMO 9284025
|
44,399 | 2004 |
9.0
|
B |
| 117 |
YARA AESA
IMO 9725495
|
28,735 | 2016 |
9.0
|
B |
| 118 |
QUEBEC
IMO 9744843
|
28,543 | 2017 |
9.0
|
B |
| 119 |
STIKLESTAD
IMO 9914644
|
29,649 | 2022 |
9.1
|
B |
| 120 |
NORDICO
IMO 9336658
|
29,565 | 2007 |
9.1
|
B |
| 121 |
BERING GAS
IMO 9745536
|
24,244 | 2016 |
9.2
|
B |
| 122 |
SEAMAID
IMO 9892834
|
28,097 | 2021 |
9.2
|
B |
| 123 |
OCEANIC MOON
IMO 9447809
|
26,416 | 2011 |
9.2
|
B |
| 124 |
BW CARINA
IMO 9701798
|
54,561 | 2015 |
9.2
|
B |
| 125 |
KAPELLEN
IMO 9719290
|
29,590 | 2018 |
9.3
|
B |
| 127 |
SEARAMBLER
IMO 9892822
|
28,077 | 2021 |
9.3
|
B |
| 126 |
HELSINKI
IMO 9377224
|
43,601 | 2009 |
9.3
|
B |
| 128 |
ROSILLO EXPLORER
IMO 9940423
|
29,241 | 2023 |
9.3
|
B |
| 129 |
PERMIAN LADY
IMO 9729269
|
28,372 | 2016 |
9.3
|
C |
| 130 |
MARCELLUS LADY
IMO 9722780
|
28,372 | 2016 |
9.4
|
C |
| 131 |
NAVIGATOR EQUATOR
IMO 9714654
|
23,724 | 2019 |
9.4
|
C |
| 132 |
SEATEAM
IMO 9902512
|
28,096 | 2022 |
9.5
|
C |
| 133 |
OCEANIC BREEZE
IMO 9451991
|
26,416 | 2011 |
9.5
|
C |
| 134 |
ECO ICE
IMO 9755646
|
26,798 | 2018 |
9.6
|
C |
| 135 |
ECO FREEZE
IMO 9755658
|
26,417 | 2018 |
9.7
|
C |
| 136 |
KAPRIJKE
IMO 9687485
|
29,639 | 2015 |
9.8
|
C |
| 137 |
NAVIGATOR PHOENIX
IMO 9407330
|
23,640 | 2009 |
9.8
|
C |
| 139 |
HASSI MESSAOUD 2
IMO 9295581
|
44,379 | 2005 |
9.8
|
C |
| 138 |
GAS UTOPIA
IMO 9770531
|
28,672 | 2017 |
9.8
|
C |
| 140 |
KOKSIJDE
IMO 9719305
|
29,543 | 2018 |
9.9
|
C |
| 141 |
SOMBEKE
IMO 9292113
|
29,213 | 2006 |
9.9
|
C |
| 142 |
NAVIGATOR YAUZA
IMO 9761176
|
22,800 | 2017 |
10.0
|
C |
| 143 |
NAVIGATOR TAURUS
IMO 9404807
|
23,328 | 2006 |
10.1
|
C |
| 144 |
CELTIC GAS
IMO 9682265
|
24,281 | 2015 |
10.1
|
C |
| 145 |
HOURAI MARU
IMO 9796585
|
28,894 | 2019 |
10.2
|
C |
| 147 |
NAVIGATOR SCORPIO
IMO 9404792
|
23,333 | 2009 |
10.3
|
C |
| 146 |
NAVIGATOR CASTOR
IMO 9714642
|
23,708 | 2019 |
10.3
|
C |
| 148 |
WARISOULX
IMO 9659139
|
28,590 | 2015 |
10.3
|
C |
| 149 |
KONTICH
IMO 9687502
|
29,461 | 2016 |
10.4
|
C |
| 150 |
BALEARIC GAS
IMO 9682253
|
24,136 | 2015 |
10.5
|
C |
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.