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 |
|---|---|---|---|---|---|
| 51 |
EIGER EXPLORER
IMO 9847437
|
50,513 | 2019 |
7.0
|
A |
| 52 |
GAS VENUS
IMO 9876490
|
55,182 | 2021 |
7.0
|
A |
| 53 |
GALAXY RIVER
IMO 9670016
|
54,081 | 2014 |
7.0
|
A |
| 54 |
CORVETTE
IMO 9703837
|
51,620 | 2013 |
7.1
|
A |
| 56 |
SUMMIT RIVER
IMO 9369461
|
52,991 | 2008 |
7.1
|
A |
| 55 |
VEGA SUN
IMO 9793258
|
50,591 | 2017 |
7.1
|
A |
| 57 |
CLIPPER QUITO
IMO 9630755
|
55,047 | 2013 |
7.2
|
A |
| 58 |
CRESQUES
IMO 9702039
|
54,656 | 2015 |
7.2
|
A |
| 59 |
CLIPPER MOON
IMO 9253820
|
44,822 | 2003 |
7.2
|
A |
| 60 |
CORSAIR
IMO 9689926
|
51,620 | 2014 |
7.2
|
A |
| 61 |
BORDA
IMO 9772826
|
44,452 | 2016 |
7.2
|
A |
| 62 |
CLIPPER MARS
IMO 9377078
|
43,544 | 2008 |
7.2
|
A |
| 63 |
LILY PROMENADE
IMO 9809552
|
53,844 | 2019 |
7.2
|
A |
| 64 |
ORIENTAL JUBILEE
IMO 9763813
|
54,520 | 2016 |
7.2
|
B |
| 65 |
VIVIT ALTAIS
IMO 9840879
|
50,703 | 2019 |
7.3
|
B |
| 66 |
CLIPPER POSH
IMO 9656747
|
55,047 | 2013 |
7.3
|
B |
| 67 |
BW ARIES
IMO 9701786
|
54,561 | 2014 |
7.3
|
B |
| 68 |
HELLAS GLADIATOR
IMO 9732503
|
54,376 | 2016 |
7.3
|
B |
| 69 |
ECO SORCERER
IMO 9933468
|
30,062 | 2023 |
7.3
|
B |
| 70 |
NYMFAION LADY
IMO 9926752
|
29,703 | 2023 |
7.3
|
B |
| 71 |
GREEN ENERGY
IMO 9925667
|
30,093 | 2022 |
7.4
|
B |
| 72 |
GENESIS RIVER
IMO 9791224
|
54,149 | 2018 |
7.5
|
B |
| 73 |
INDIANAPOLIS
IMO 9925679
|
30,128 | 2023 |
7.5
|
B |
| 74 |
PASCO STAR
IMO 9247807
|
44,807 | 2003 |
7.5
|
B |
| 75 |
CHRYSOPIGI LADY
IMO 9936537
|
29,703 | 2023 |
7.5
|
B |
| 76 |
HELLAS HERCULES
IMO 9721138
|
54,409 | 2015 |
7.5
|
B |
| 77 |
ALRAR
IMO 9284013
|
44,451 | 2004 |
7.6
|
B |
| 78 |
ECO ENCHANTED
IMO 9945796
|
30,062 | 2024 |
7.6
|
B |
| 79 |
HELLAS VOYAGER
IMO 9869253
|
51,116 | 2020 |
7.6
|
B |
| 80 |
LA CONDAMINE
IMO 9941324
|
29,381 | 2023 |
7.6
|
B |
| 81 |
ASTOR
IMO 9934670
|
30,112 | 2023 |
7.7
|
B |
| 83 |
GREEN POWER
IMO 9927316
|
30,108 | 2023 |
7.7
|
B |
| 82 |
DENVER
IMO 9377236
|
43,563 | 2009 |
7.7
|
B |
| 84 |
PASCO RONI
IMO 9940447
|
29,991 | 2021 |
7.7
|
B |
| 85 |
DORSET
IMO 9470088
|
53,076 | 2011 |
7.7
|
B |
| 86 |
CLIPPER SKY
IMO 9277943
|
44,617 | 2004 |
7.7
|
B |
| 87 |
CLIPPER NEPTUN
IMO 9372432
|
43,508 | 2008 |
7.7
|
B |
| 88 |
ECO MERLIN
IMO 9929194
|
30,062 | 2023 |
7.8
|
B |
| 89 |
MARCELLA
IMO 9934668
|
30,070 | 2023 |
7.8
|
B |
| 90 |
CARTIER
IMO 9924857
|
29,690 | 2022 |
7.9
|
B |
| 91 |
MIRAI
IMO 9929871
|
35,941 | 2023 |
7.9
|
B |
| 93 |
CLIPPER ORION
IMO 9372420
|
43,475 | 2008 |
7.9
|
B |
| 92 |
ECO WIZARD
IMO 9941568
|
30,062 | 2024 |
7.9
|
B |
| 94 |
SAHARA GAS
IMO 9748215
|
28,637 | 2017 |
7.9
|
B |
| 95 |
BARCELONA KNUTSEN
IMO 9401295
|
100,121 | 2010 |
8.0
|
B |
| 97 |
CERRO ALTO EXPLORER
IMO 9940435
|
29,229 | 2023 |
8.0
|
B |
| 96 |
MANTA ANADOLU
IMO 9763045
|
28,460 | 2017 |
8.0
|
B |
| 98 |
PASCO BERKE
IMO 9978028
|
29,175 | 2024 |
8.1
|
B |
| 99 |
GAS TAURUS
IMO 9710385
|
53,765 | 2016 |
8.1
|
B |
| 100 |
YARA FREYA
IMO 9725500
|
28,735 | 2016 |
8.1
|
B |
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.