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.

Segment rank (2025)

#107 of 106 refrigerated cargos

CO₂ intensity

38.2 g CO₂/dwt·nm

vs segment average (21.89)

+74% higher

Bulk Carrier Container Ship Oil Tanker Chemical Tanker Gas Carrier LNG Carrier General Cargo Vehicle Carrier Refrigerated Cargo Ro-Ro Cargo

Sort 🌱 Greenest first 🔧 Least efficient first — retrofit candidates

Size (DWT)

All sizes < 25,000 DWT 25k – 60k DWT 60k – 100k DWT 100k – 200k DWT > 200,000 DWT

Year

2025 2024

109

vessels ranked

7.59

greenest (g CO₂/t·nm)

22.69

segment median

#	Vessel	Size (DWT)	Built	Length	Main Engine	Carbon intensity — AER (g CO₂/dwt·nm)	Grade
101	SALERNO IMO 9189873	10,447	1998	154 m	Mitsui - 6L60MC	27.9	E
102	SIERRA LAUREL IMO 9163403	5,937	1998	117 m	MAN B&W Diesel A/S - Denmark 7S35MC	27.9	E
103	COOL MAGNUS IMO 9167801	12,906	2000	155 m	Hitachi - 8S50MC	30.2	E
104	SIERRA LARA IMO 9120205	5,970	1996	117 m	Manises Diesel Engine Co. S.A. - Valencia 7S35MC	30.3	E
105	SAVANNA BREEZE IMO 9791274	5,903	2019	128 m	Wartsila Finland Oy 6L-32	31.2	E
106	SAVANNA WIND IMO 9791286	5,102	2020	128 m	Wartsila Finland Oy 6L-32	38.2	E

Page 3 of 3 — 106 vessels

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Engine intelligence

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.

Emission-friendly engine ranking

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.