Greener Reefers – 10 Frequently Asked Questions

When managed properly, flammability is a property — not a barrier. The natural refrigerant R290 (propane)  can be used safely through proper system design, leak prevention, and technician competence for cooling applications. The Greener Reefers project translates existing positive experience with R290 showcasing that with correct safety standards, risk management, and good installation practices, these systems are as safe as conventional ones.

Many synthetic refrigerants — including HFCs and HFOs such as R134a and R1234yf — are part of the PFAS group (per- and polyfluoroalkyl substances), often called forever chemicals due to their persistence in the environment. PFAS are known from applications such as non-stick coatings in Teflon pans, which have raised concerns due to their health and environmental impacts. The use of R1234yf in car air conditioning, produces high concentrations of these forever chemicals that can already be measured in fresh water, soil and food. Scientific research increasingly highlights concerns about the long-term environmental accumulation and possible health risks. 
In contrast natural refrigerants like R290, R744 (CO₂) and R717 (ammonia) are PFAS-free and do not break down into persistent by-products. They represent a truly sustainable long-term solution that avoids creating new environmental burdens.
 

No single refrigerant fits every application, although natural refrigerants are suitable for all applications. The best option depends on the specific cooling capacity, safety requirements, and operating environment. However, the Greener Reefers project shows that R290 can cover most use cases — offering efficient, climate-friendly and scalable alternatives across container types and temperature ranges.

The commercial refrigeration and heat pump sectors have decades of experience with natural refrigerants. Additionally, the use in electric passenger cars and the increased application for light and heavy-duty trucks shows the potential of R290 and R744 as sustainable refrigerants. Lessons include the importance of phased introduction, safety training, and updated standards to ensure smooth market adoption. These examples show that technological maturity and supply chains already exist — the maritime, transport and mobile air conditioning (MAC) sectors can build on that success.

Safety standards are a means of defining what is safe, acceptable, and certifiable. Many existing standards were developed for older, non-flammable refrigerants and now need to evolve to reflect new, safe system designs with natural refrigerants. Updated standards enable innovation by providing clear frameworks for industry compliance, training, and market entry.

They are absolutely essential. Safe and efficient use of natural refrigerants depends on trained technicians who understand their properties and handling requirements. Higher quality maintenance also decreases leakages of existing cooling applications and reduces their climate harming emissions. The Greener Reefers project invests in capacity building and training modules to ensure technicians can design, install, and service systems responsibly — a cornerstone for any successful transition.

Yes, but the supply chain is still growing. As more countries adopt natural refrigerant technologies, manufacturers and distributors are expanding their portfolios. The Greener Reefers project works closely with suppliers to raise awareness for the upcoming demand of spare parts in the partner countries Costa Rica and South Africa, promoting long-term serviceability and reliability.

R290 as natural refrigerant exceeds energy efficiency compared to synthetic refrigerants, especially under high ambient temperatures. This means lower operating costs and reduced indirect emissions over the system’s lifetime — making the climate and economic case stronger.

Technologies using CO₂ and propane are already being introduced in electric vehicles, offering high efficiency and low climate impact. This shows that natural cooling systems are robust, reliable, and effective even in challenging environments. Proper design and component selection ensure consistent performance under the varying vibration, heat, and pressure typical in maritime or mobile applications. 

The technology is already available — what’s needed now is policy support, investment, and public-private cooperation. Demonstration projects like Greener Reefers are essential for building confidence, while training, standards, and financing mechanisms will turn proven pilots into mainstream adoption.