The adoption of natural refrigerants like propane (R290) and CO2 (R744) in refrigerated maritime containers – known as reefers – represents a “crucial step” in the decarbonization of the global shipping industry, according to a white paper published by the Greener Reefer Transition Alliance.
The paper – Accelerating the Transition to Climate and Environmentally Friendly Reefers – highlights that replacing HFCs and HFOs with natural alternatives could “drastically cut” the industry’s direct greenhouse gas emissions. It could also avoid the environmental and human health risks associated with f-gases, many of which are per- and polyfluoroalkyl substances (PFAS) and degrade into trifluoroacetic acid (TFA), a persistent pollutant.
Beyond emission reductions, propane offers comparable performance to conventional refrigerants.
“The adoption of propane in reefer containers is a game-changing opportunity to decarbonize the sector,” the paper says. “Adopting R290 in just 50% of new reefers by 2050 could achieve significant [greenhouse gas] savings.”
The report also estimates that the industry could reduce indirect (energy-related) emissions by up to 20% through improvements in insulation, temperature control and logistics, particularly when deployed in conjunction with natural refrigerants.
Co-developed with the Kuehne Climate Center and GIZ (German Society for International Cooperation), the white paper will be presented during a webinar taking place on April 29 at 9 am CEST.
“The adoption of propane in reefer containers is a game-changing opportunity to decarbonize the sector.”
Greener Reefer Transition Alliance
Barriers to adoption
Despite natural refrigerants already being widely used in supermarkets, cold storage and industrial processing, their adoption in the shipping industry is hindered by a number of technical, regulatory and market challenges, the paper highlights.
Overcoming these barriers will require a holistic approach that integrates technological advancements, international and national policy frameworks, capacity-building programs and innovative finance mechanisms, it adds.
“By leveraging proven technologies from other industries, we can drive meaningful change in refrigerated shipping,” the Greener Reefer Transition Alliance said in a LinkedIn post.
To support the development of propane-based reefers, GIZ has partnered with Thermo King – a brand of Trane Technologies that manufactures refrigerated containers – to develop a proof of concept unit. With a completion date of April 2026, the Greener Reefers Project also seeks to develop safety standards, performance modeling and validation for propane refrigerated marine containers.
Decarbonizing shipping
Globally, shipping is responsible for around 3% of greenhouse gas emissions, and, while reefers make up just 15% of the world’s container fleet, they represent a disproportionately high share of the industry’s emissions due to their reliance on high-GWP refrigerants and leakage rates that can reach 25%.
In 2018 alone, refrigerants leaked from reefers accounted for an estimated 3.7 million metric tons of CO2e emissions.
With demand for refrigerated containers growing at approximately 8% annually through 2030, and the sector working to align with international climate commitments – including the IMO’s 2023 GHG Reduction Strategy, the Kigali Amendment and the EU F-gas Regulation – the report emphasizes that swift adoption of sustainable refrigeration is no longer optional.
“Companies that embrace natural refrigerants and energy-efficient technologies will lead the charge toward a cleaner, more competitive industry,” the paper says. “Those that hesitate risk being left behind in a rapidly evolving regulatory and market landscape.”
