The Greener Reefer Transition Alliance, led by the German Society for International Cooperation (GIZ), has introduced a free online simulator enabling shipping companies and logistics operators to compare emissions and costs across refrigerants used in maritime containers on real-world trade routes. The Reefers Emissions & Cost Savings Simulator was developed in collaboration with the Hapag-Lloyd Center for Shipping and Global Logistics (CSGL) at Kühne Logistics University (KLU), with support from the International Climate Initiative and Germany's Federal Ministry of the Environment. The tool arrives as the maritime industry faces mounting regulatory pressure to phase out high-GWP (global warming potential) refrigerants from reefer containers - units that, despite comprising only 15% of the global container fleet, contribute a disproportionately large share of shipping's refrigerant-related emissions.
Regulatory Pressure Mounts on Maritime Refrigerants
Approximately 96% of refrigerated containers currently use R134a, a synthetic refrigerant with a GWP of 1,430, according to a SINTEF analysis published in late 2025. Refrigerant leaks from reefers accounted for an estimated 3.7 million metric tons of CO₂-equivalent emissions in 2018 alone, according to a Greener Reefer Transition Alliance white paper. At the international level, the IMO agreed in July 2023 to a strategy for reducing greenhouse gas emissions from ships, targeting 20-30% reduction by 2030, 70-80% by 2040, and net-zero by 2050 compared to 2008 levels. In Europe, the EU Emissions Trading System now covers 70% of emissions from international voyages and 100% of intra-EU voyages as of 2026, adding direct carbon costs that further incentivize refrigerant transitions.
The broader HFC phasedown under the Kigali Amendment to the Montreal Protocol and the U.S. AIM Act - which mandates an 85% reduction in HFC production and consumption by 2036 - is compressing timelines for fleet operators across transport modes.
Simulator Details and Cost Findings
The simulator allows users to select a vessel by IMO number, specify cargo type, container size, load, route, and market prices for refrigerants and fuel. It accounts for each route's ambient temperature, vessel technical specifications, refrigerant charge, and leak rate. Outputs include direct and indirect greenhouse gas emissions, trifluoroacetic acid (TFA) emissions - relevant due to growing regulatory scrutiny of PFAS - and carbon abatement costs per kilogram of CO₂-equivalent avoided.
Modeling results presented during an alliance webinar showed significant cost differentials. Switching from R452A to propane (R290) could save approximately $1,200 per container per year. Compared to R290, annual costs per container were roughly $50 higher for CO₂ (R744), $350 higher for R134a and R1234yf, $450 higher for R513A, $1,000 higher for R404A, and $1,200 higher for R452A, according to NaturalRefrigerants.com reporting on the alliance's data.
Gordon Wilmsmeier, Director of CSGL at KLU, stated that "natural refrigerants can turn decarbonization into a strong business case."
R290 Proof-of-Concept Advances
The simulator complements physical hardware development under the broader Greener Reefers project. GIZ and Thermo King, a brand of Trane Technologies, are developing a proof-of-concept R290 refrigerated container, with a planned test involving a Costa Rican fruit producer. The €2.9 million project targets completion by April 2026 and aims to establish safety standards and performance validation for propane-based marine containers. University of Valencia modeling indicated that the R290 design cuts power consumption by 7% compared to Thermo King's R134a baseline reefer at 30 Hz compressor operation, with potential energy savings of up to 24% at lower frequencies, according to Thermo King's Santiago Martinez.
Outlook
The alliance's white paper concluded that adopting R290 in 50% of new reefers by 2050 could achieve significant greenhouse gas savings, with an additional 20% reduction in indirect emissions possible through improved insulation and logistics. As carbon pricing mechanisms expand and HFC phase-downs accelerate globally, fleet-level decision-support tools that quantify the total cost of refrigerant transitions are positioned to influence capital allocation across the cold-chain sector.
