Most Emission-Efficient Refrigerated Cargos
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 |
HELLAS STREAM
IMO 9015187
|
13,930 | 1991 |
21.5
|
C |
| 52 |
ORANGE SEA
IMO 9795971
|
7,737 | 2019 |
21.5
|
C |
| 53 |
EMERALD
IMO 9202857
|
12,375 | 2000 |
21.7
|
C |
| 54 |
BALTIC ERICA
IMO 9194476
|
11,791 | 1999 |
21.7
|
C |
| 55 |
BALTIC PEARL
IMO 9008732
|
10,713 | 1991 |
21.8
|
C |
| 56 |
SWEDISH STREAM
IMO 9030149
|
13,930 | 1992 |
22.2
|
C |
| 57 |
PACIFIC MERMAID
IMO 9045924
|
10,466 | 1992 |
22.3
|
C |
| 58 |
FRIO MARATHON
IMO 8916229
|
7,242 | 1990 |
22.4
|
C |
| 59 |
BALTIC HEATHER
IMO 9181144
|
10,114 | 1998 |
22.4
|
C |
| 60 |
ITALIA STREAM
IMO 9030137
|
13,930 | 1992 |
22.5
|
C |
| 61 |
BALTIC PATRIOT
IMO 9038488
|
10,621 | 1992 |
22.5
|
C |
| 62 |
GREEN BRAZIL
IMO 9045792
|
8,647 | 1994 |
22.7
|
C |
| 63 |
GREEN CRYSTAL
IMO 8920995
|
6,000 | 1992 |
22.7
|
C |
| 64 |
NEDERLAND STREAM
IMO 9015199
|
13,958 | 1991 |
22.8
|
C |
| 65 |
CROWN SAPPHIRE
IMO 9159115
|
10,334 | 1997 |
22.9
|
C |
| 66 |
WATER PHOENIX
IMO 9045168
|
7,947 | 1992 |
23.2
|
C |
| 67 |
GREEN GUATEMALA
IMO 8912144
|
8,583 | 1992 |
23.3
|
C |
| 68 |
DUNEDIN STAR
IMO 9038945
|
11,793 | 1994 |
23.3
|
C |
| 69 |
DOLE AMERICA
IMO 9046502
|
10,288 | 1994 |
23.4
|
D |
| 70 |
WILD PEONY
IMO 9191474
|
10,110 | 1998 |
23.4
|
D |
| 71 |
SIERRA LAUREL
IMO 9163403
|
5,937 | 1998 |
23.6
|
D |
| 72 |
CHARLES ISLAND
IMO 9059626
|
14,140 | 1993 |
23.6
|
D |
| 73 |
COLD STREAM
IMO 9051791
|
10,086 | 1994 |
23.9
|
D |
| 74 |
SILVER DANIA
IMO 8808604
|
5,353 | 1989 |
23.9
|
D |
| 75 |
DOLE EUROPA
IMO 9046514
|
10,288 | 1994 |
23.9
|
D |
| 76 |
CALLISTO
IMO 9073402
|
8,024 | 1993 |
23.9
|
D |
| 77 |
GREEN AUSTEVOLL
IMO 8819299
|
6,000 | 1991 |
23.9
|
D |
| 78 |
BALTIC LADY
IMO 9160736
|
12,913 | 2000 |
24.0
|
D |
| 79 |
INVINCIBLE
IMO 9181170
|
10,358 | 1999 |
24.0
|
D |
| 80 |
WILD LOTUS
IMO 9181168
|
10,139 | 1998 |
24.4
|
D |
| 81 |
BALTIC PURPLE
IMO 9143099
|
10,379 | 1996 |
24.5
|
D |
| 82 |
LAGOON PHOENIX
IMO 9047245
|
8,044 | 1993 |
24.5
|
D |
| 83 |
ORANGE STREAM
IMO 9795983
|
7,738 | 2019 |
24.8
|
D |
| 84 |
FRIO STAR
IMO 9172947
|
11,014 | 1998 |
24.9
|
D |
| 85 |
COOL MAGNUS
IMO 9167801
|
12,906 | 2000 |
24.9
|
D |
| 86 |
SAVANNA BREEZE
IMO 9791274
|
5,903 | 2019 |
25.0
|
D |
| 87 |
GREEN EGERSUND
IMO 8804567
|
6,120 | 1990 |
25.0
|
D |
| 88 |
LOMBOK STRAIT
IMO 9204958
|
15,862 | 2002 |
25.1
|
D |
| 89 |
COOL ROYAL
IMO 9172959
|
12,900 | 2000 |
25.2
|
D |
| 90 |
BALTIC JASMINE
IMO 9181156
|
10,114 | 1998 |
25.2
|
D |
| 91 |
KANO REEFER
IMO 9194957
|
9,566 | 1999 |
25.3
|
D |
| 92 |
WELLINGTON STAR
IMO 8917584
|
11,103 | 1992 |
25.3
|
E |
| 93 |
STAR SPIRIT
IMO 9765847
|
16,565 | 2017 |
25.7
|
E |
| 94 |
ATLANTIC KLIPPER
IMO 9454761
|
15,692 | 2011 |
25.8
|
E |
| 95 |
WILD COSMOS
IMO 9181132
|
10,139 | 1998 |
25.9
|
E |
| 96 |
ELVIRA
IMO 9202869
|
10,309 | 2000 |
26.0
|
E |
| 97 |
PRINCE OF SEAS
IMO 9014444
|
7,387 | 1993 |
26.0
|
E |
| 98 |
BALTIC KLIPPER
IMO 9454759
|
15,609 | 2010 |
26.0
|
E |
| 99 |
CROWN GARNET
IMO 9128049
|
10,334 | 1996 |
26.1
|
E |
| 100 |
CROWN OPAL
IMO 9128063
|
10,316 | 1997 |
26.1
|
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.