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 2025. 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 |
|---|---|---|---|---|---|
| 1 |
ORANGE STAR
IMO 9564384
|
36,994 | 2011 |
7.6
|
A |
| 2 |
ORANGE SKY
IMO 9228370
|
26,863 | 2000 |
8.5
|
A |
| 3 |
CITRUS VITA BRASIL
IMO 9491836
|
34,966 | 2009 |
10.5
|
A |
| 4 |
ORANGE OCEAN
IMO 9675391
|
22,918 | 2014 |
10.7
|
A |
| 5 |
ORANGE BLOSSOM 2
IMO 9675406
|
22,874 | 2014 |
10.7
|
A |
| 6 |
CARLOS FISCHER
IMO 9230995
|
43,067 | 2002 |
12.5
|
A |
| 7 |
OURO DO BRASIL
IMO 9018646
|
19,519 | 1993 |
13.0
|
A |
| 8 |
ORANGE WAVE
IMO 9057123
|
16,700 | 1993 |
14.0
|
A |
| 9 |
ICE GRACE
IMO 8706777
|
14,932 | 1988 |
14.8
|
A |
| 10 |
PACIFIC REEFER
IMO 9179268
|
17,283 | 1999 |
16.1
|
A |
| 11 |
ACONCAGUA BAY
IMO 9019652
|
11,581 | 1992 |
16.1
|
A |
| 12 |
ORANGE FROST
IMO 9797656
|
8,726 | 2018 |
16.4
|
A |
| 13 |
ATLANTIC REEFER
IMO 9179256
|
17,178 | 1998 |
16.5
|
A |
| 14 |
RUNAWAY BAY
IMO 9019640
|
11,581 | 1992 |
16.8
|
A |
| 15 |
ORANGE STRAIT
IMO 9795995
|
7,737 | 2019 |
17.1
|
A |
| 16 |
IVAR
IMO 8819938
|
16,950 | 1990 |
17.3
|
A |
| 17 |
SWEDISH STREAM
IMO 9030149
|
13,930 | 1992 |
18.3
|
A |
| 18 |
COTE D IVOIRE EXPRESS
IMO 9983994
|
14,547 | 2024 |
18.4
|
A |
| 19 |
SENEGAL EXPRESS
IMO 9984015
|
14,567 | 2025 |
18.4
|
A |
| 20 |
CAMEROUN EXPRESS
IMO 9983865
|
14,565 | 2024 |
18.5
|
A |
| 21 |
ORANGE ICE
IMO 9797917
|
8,751 | 2018 |
18.7
|
A |
| 22 |
AUTUMN STREAM
IMO 9038323
|
13,981 | 1993 |
18.7
|
B |
| 23 |
COOL EXPRESS
IMO 9836878
|
22,715 | 2018 |
18.8
|
B |
| 24 |
GHANA EXPRESS
IMO 9984003
|
14,552 | 2025 |
19.1
|
B |
| 25 |
COSTA RICAN STAR
IMO 9150822
|
14,726 | 1998 |
19.4
|
B |
| 26 |
CALA PEDRA
IMO 9164782
|
16,090 | 2000 |
19.6
|
B |
| 27 |
COOL EXPLORER
IMO 9836880
|
23,169 | 2019 |
19.6
|
B |
| 28 |
REGAL BAY
IMO 9053658
|
10,520 | 1993 |
19.6
|
B |
| 29 |
BALTIC SPRING
IMO 8909070
|
12,350 | 1991 |
19.7
|
B |
| 30 |
CARIBBEAN STAR
IMO 9150810
|
14,726 | 1997 |
20.0
|
B |
| 31 |
CALA PULA
IMO 9164768
|
16,090 | 1999 |
20.0
|
B |
| 32 |
CHARLES ISLAND
IMO 9059626
|
14,140 | 1993 |
20.1
|
B |
| 33 |
ORANGE STREAM
IMO 9795983
|
7,738 | 2019 |
20.1
|
B |
| 34 |
CALA PINO
IMO 9164756
|
16,090 | 1999 |
20.2
|
B |
| 35 |
EMERALD
IMO 9202857
|
12,375 | 2000 |
20.3
|
B |
| 36 |
COTE D'IVOIRIAN STAR
IMO 9172478
|
14,815 | 1998 |
20.4
|
B |
| 37 |
SEIN TOPAZ
IMO 9047245
|
8,044 | 1993 |
20.5
|
B |
| 38 |
DUNCAN ISLAND
IMO 9059638
|
14,140 | 1993 |
20.6
|
B |
| 39 |
DITLEV
IMO 8819926
|
16,950 | 1990 |
20.8
|
B |
| 40 |
HOOD ISLAND
IMO 9059640
|
14,140 | 1994 |
20.9
|
B |
| 41 |
CALA PALMA
IMO 9164770
|
16,090 | 2000 |
21.1
|
B |
| 42 |
KANO REEFER
IMO 9194957
|
9,566 | 1999 |
21.1
|
B |
| 43 |
BALTIC ERICA
IMO 9194476
|
11,791 | 1999 |
21.3
|
C |
| 44 |
DUNEDIN STAR
IMO 9038945
|
11,793 | 1994 |
21.4
|
C |
| 46 |
ALBEMARLE ISLAND
IMO 9059602
|
14,160 | 1993 |
21.4
|
C |
| 45 |
COLOMBIAN STAR
IMO 9172480
|
13,900 | 1998 |
21.4
|
C |
| 47 |
STAR COURAGE
IMO 9765859
|
16,543 | 2017 |
21.6
|
C |
| 48 |
GREEN BRAZIL
IMO 9045792
|
8,647 | 1994 |
21.8
|
C |
| 49 |
PRINCE OF SEAS
IMO 9014444
|
7,387 | 1993 |
22.0
|
C |
| 50 |
ITALIA STREAM
IMO 9030137
|
13,930 | 1992 |
22.2
|
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 2025 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.