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 |
|---|---|---|---|---|---|
| 51 |
COOL SPIRIT
IMO 9765861
|
16,580 | 2018 |
22.3
|
C |
| 52 |
BARRINGTON ISLAND
IMO 9059614
|
14,140 | 1993 |
22.6
|
C |
| 53 |
GREEN AUSTEVOLL
IMO 8819299
|
6,000 | 1991 |
22.6
|
C |
| 54 |
COOL GIRL
IMO 9194921
|
9,500 | 1999 |
22.6
|
C |
| 55 |
TAGANROGSKIY ZALIV
IMO 9152181
|
9,638 | 1997 |
22.7
|
C |
| 56 |
BALTIC LORD
IMO 9160724
|
12,912 | 2000 |
22.8
|
C |
| 57 |
COOL ROYAL
IMO 9172959
|
12,900 | 2000 |
22.8
|
C |
| 58 |
BALTIC LADY
IMO 9160736
|
12,913 | 2000 |
22.9
|
C |
| 59 |
PERUVIAN REEFER
IMO 8917572
|
11,095 | 1992 |
22.9
|
C |
| 60 |
FRIO CHIKUMA
IMO 9184536
|
8,097 | 1998 |
22.9
|
C |
| 61 |
HELLAS STREAM
IMO 9015187
|
13,930 | 1991 |
22.9
|
C |
| 62 |
ORANGE SEA
IMO 9795971
|
7,737 | 2019 |
23.0
|
C |
| 63 |
ELVIRA
IMO 9202869
|
10,309 | 2000 |
23.0
|
C |
| 64 |
BALTIC SUMMER
IMO 8802090
|
12,350 | 1989 |
23.0
|
D |
| 65 |
SILVER DANIA
IMO 8808604
|
5,353 | 1989 |
23.1
|
D |
| 66 |
GREEN GUATEMALA
IMO 8912144
|
8,583 | 1992 |
23.4
|
D |
| 67 |
DOLE AFRICA
IMO 9046538
|
10,288 | 1994 |
23.7
|
D |
| 68 |
FRIO STAR
IMO 9172947
|
11,014 | 1998 |
23.7
|
D |
| 69 |
DOLE EUROPA
IMO 9046514
|
10,288 | 1994 |
23.7
|
D |
| 70 |
DOLE ASIA
IMO 9046526
|
10,288 | 1994 |
23.8
|
D |
| 71 |
FEGULUS
IMO 9055709
|
10,919 | 1993 |
23.9
|
D |
| 72 |
ATLANTIC ACANTHUS
IMO 9189897
|
11,793 | 1999 |
24.2
|
D |
| 73 |
CROWN SAPPHIRE
IMO 9159115
|
10,334 | 1997 |
24.2
|
D |
| 74 |
BALTIC HOLLYHOCK
IMO 9189902
|
11,788 | 1999 |
24.3
|
D |
| 75 |
SIERRA QUEEN
IMO 9127928
|
7,948 | 1996 |
24.3
|
D |
| 76 |
DOLE AMERICA
IMO 9046502
|
10,288 | 1994 |
24.5
|
D |
| 77 |
ORIENTAL REEFER
IMO 9158549
|
11,016 | 1998 |
24.6
|
D |
| 78 |
BOYANG BERING
IMO 9851191
|
8,251 | 2019 |
24.7
|
D |
| 79 |
CROWN RUBY
IMO 9159103
|
10,338 | 1997 |
25.0
|
D |
| 80 |
BALTIC JASMINE
IMO 9181156
|
10,114 | 1998 |
25.1
|
D |
| 81 |
COLD STREAM
IMO 9051791
|
10,086 | 1994 |
25.1
|
D |
| 82 |
STAR SPIRIT
IMO 9765847
|
16,565 | 2017 |
25.1
|
D |
| 83 |
PACIFIC MERMAID
IMO 9045924
|
10,466 | 1992 |
25.4
|
D |
| 84 |
LOMBOK STRAIT
IMO 9204958
|
15,862 | 2002 |
25.6
|
D |
| 85 |
WILD PEONY
IMO 9191474
|
10,110 | 1998 |
25.7
|
E |
| 86 |
GREEN CRYSTAL
IMO 8920995
|
6,000 | 1992 |
25.8
|
E |
| 87 |
CROWN TOPAZ
IMO 9191498
|
10,318 | 1999 |
25.8
|
E |
| 88 |
CROWN JADE
IMO 9128051
|
10,342 | 1997 |
25.8
|
E |
| 89 |
LUZON STRAIT
IMO 9204960
|
15,867 | 2002 |
25.8
|
E |
| 90 |
ATLANTIC KLIPPER
IMO 9454761
|
15,692 | 2011 |
26.0
|
E |
| 91 |
WILD COSMOS
IMO 9181132
|
10,139 | 1998 |
26.0
|
E |
| 92 |
FRIO AEGEAN
IMO 9172703
|
8,040 | 1998 |
26.3
|
E |
| 93 |
BALTIC PURPLE
IMO 9143099
|
10,379 | 1996 |
26.3
|
E |
| 94 |
BALTIC KLIPPER
IMO 9454759
|
15,609 | 2010 |
26.7
|
E |
| 95 |
GREENSEA BERMEO
IMO 9238703
|
7,614 | 2001 |
26.8
|
E |
| 96 |
BALTIC SPIRIT
IMO 9765873
|
16,727 | 2018 |
27.1
|
E |
| 97 |
GREEN COSTA RICA
IMO 8912120
|
7,726 | 1992 |
27.1
|
E |
| 98 |
CROWN GARNET
IMO 9128049
|
10,334 | 1996 |
27.3
|
E |
| 99 |
GREEN HONDURAS
IMO 8912132
|
7,726 | 1992 |
27.7
|
E |
| 100 |
CROWN OPAL
IMO 9128063
|
10,316 | 1997 |
27.7
|
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 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.