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Refrigerated containers enable global trade in perishable goods, but this convenience comes at a significant environmental cost. These intermodal transport units are powered either directly by electricity or by diesel engines, generating significant emissions.
In general, maritime shipping contributes around 3% to global greenhouse gas emissions, making it the sixth-largest emitter, on par with major industrialised nations. While reefers account for only a portion of these emissions, their rapidly growing share represents an increasingly large ecological footprint of the cold chain.
The refrigerated container market—valued at approximately $4.5 billion in 2024—is expected to nearly double to reach $9 billion by 2033 (1), driven by growth in retail, healthcare logistics, and fresh food supply chains.
A single refrigerated container consumes between 4 and 5.8 kW per hour, which equates to approximately 96 to 139 kWh per day. By comparison, a typical US household consumes approximately 30 kWh per day, while an average European household consumes up to 12 kWh—so one reefer unit can consume multiple times what an entire household might in a day.
In container terminals, reefers often account for up to 40% of the facility's total energy consumption. By comparison, container cranes also consume up to 40%, lighting consumes about 12%, and administrative operations consume 8% (2).
Clearly, reefer energy demand is both an operational and environmental pain point, which compounds when multiple reefers arrive simultaneously, triggering sharp energy peaks and inflated utility costs.
Why the Environmental Impact Is Two-Fold
First, there are the indirect emissions generated by generating the energy needed to cool refrigerated containers. This energy often comes from fossil fuel networks or on-board generators, thus contributing to CO₂ emissions.
Secondly, refrigerated containers traditionally use refrigerants with high global warming potential (GWP), including HFCs and other fluorinated compounds. These substances can have a climate impact a thousand times worse than CO₂ if they leak. Although specific data on refrigerated container leaks is scarce, the industry trend is cause for concern: the Green Cooling Initiative, supported by the Green Cooling Initiative, emphasises that more than 1.5 million refrigerated containers are active in global trade, most of which still use outdated refrigerants and inefficient designs (3).
As the world's dependence on refrigerated containers grows, so does their environmental impact. If we do nothing, their emissions and energy consumption will rise in tandem.
Why We Must Act Now
Cost and operational pressures: Uncontrolled energy peaks lead to high bills and strain on infrastructure. Optimising refrigerated container energy use is therefore both climate- and cost-effective.
Sustainability targets: International targets, such as the IMO's goal of reducing shipping emissions by 50% by 2050, require coordinated reductions across all sectors, including cold chain logistics.
Technological readiness: Thanks to smart monitoring, improved insulation, and environmentally friendly refrigerants, the tools to transform reefer operations are already in place—the transition to eco-friendly refrigeration doesn't have to wait.
There are several aspects that make a reefer "green": less energy, cleaner refrigerants, smarter controls, safer handling, and a longer service life. In practice, an environmentally friendly reefer container is one that delivers the required loading climate with minimal lifecycle emissions – from the wattage of shore power it consumes, to the molecules in the refrigerant circuit, to the data systems that ensure efficient operation.
Efficiency First: How Do We Measure an "Economical" Reefer Container?
At terminals, reefers account for a significant portion of the electricity bill; they consume around 40% of all electricity. Connecting large numbers of them simultaneously causes costly peaks in demand. That's why any eco definition starts with kWh saved per box, per day.
Reefer manufacturers do not publish a single, universal efficiency label for all operating conditions. Therefore, it is important to pay attention to aspects such as the measured daily consumption (kWh/day) for typical setpoints and climate zones, as well as the unit's ability to avoid unnecessary defrosting, stabilise the temperature without overshoot, and modulate fans/compressors.
Improvements to design details help; for example, the CO₂-based NaturaLINE from manufacturer Carrier uses a multi-stage compressor to maximise capacity and reduce power consumption at equivalent operating points (4). Standards also play a role. ISO 1496-2 defines specifications and tests for thermal containers, including maximum permissible heat loss rates and functional tests at high ambient temperatures – better insulation and airtightness mean lower energy requirements for the refrigeration unit under real-world conditions.
What to ask vendors/teams: For your common lanes and setpoints, what's the measured kWh/day? Does the controller support variable-speed fans and intelligent defrost? What's the container's tested heat-leakage rate under ISO 1496-2?
Refrigerant Choice: Cutting the "Hidden" Climate Cost
Even efficient machines can leak, and this is where the global warming potential (GWP) of the materials used becomes crucial. Traditionally, HFCs such as R134a have been used, which has a 100-year GWP of 1,530 (i.e., one kilogram of leaked refrigerant warms the planet like 1.53 tons of CO₂). CO₂ (R744), on the other hand, has a GWP of 1—three orders of magnitude lower—and is non-flammable.
Greenhouse Gas (GHG) Protocol
Policy regulations are tightening worldwide. High-GWP HFCs are increasingly being restricted, thus promoting a gradual reduction in their production and use. For operators, this means that the choice of refrigerant impacts compliance risk and long-term costs (including taxes/quotas), as well as sustainability metrics.
Smarter by Default: Remote Monitoring and Control
An environmentally friendly refrigerated container not only has efficient hardware—it remains efficient because it is connected. The ISO 10368 standard defines the interfaces and messaging for remote condition monitoring (RCM) via power lines or other media. This allows terminals and vessels to monitor alarms, setpoints, defrosting processes, and energy consumption without having to climb onto the racks. This interoperability enables the integration of fleets of different brands into a single monitoring layer.
Modern RCM platforms can change setpoints, trigger defrost processes, and perform automatic pre-trips via standard interfaces. This allows data to be integrated directly into energy management and reduces deployments. Reporting from the port industry shows that transparency and reduction in energy consumption increase when this data is presented in dashboards and used to control operating rules.
Why All This Matters Environmentally
More and more field tests and model calculations are yielding results. Scientific and industrial studies show that each additional refrigerated container on board measurably increases the ship's power consumption. This underscores why load management and setpoint discipline are more than just paperwork. In port, proactive RCM plus planning directly solves the previously mentioned problem of the 40% energy share.
The Operational Layer: Green is also How You Use It
Hardware is only half the battle. Standard operating procedures (SOPs) and training ensure further advantages:
Technology is indispensable for modern refrigerated container management and eco-friendly refrigeration. However, it can only achieve its true value in close conjunction with operational discipline. The latest, most accurate sensors may be installed, but if staff are poorly trained or processes aren't aligned, inefficiencies will persist. Conversely, even the best-trained teams can only achieve so much without the right digital tools.
Intelligent Monitoring and IoT: Keeping an Eye on Every Reefer
Traditional terminals have relied on manual checks to monitor the condition of reefers. However, this process is prone to human error and persistent delays. IoT-based monitoring systems enable real-time, 24/7 tracking.
Predictive Maintenance with AI
AI algorithms are increasingly being used to predict failures based on sensor data. Instead of waiting for problems to occur, predictive maintenance analyses vibration, energy consumption, and historical performance to identify anomalies.
Optimised Temperature Setpoints
Many goods have a temperature range within which they can be transported without loss of quality. Even just one degree higher, but still well below the maximum limit, can save significant amounts of energy. AI and decision support tools can suggest optimal temperature setpoints based on cargo type, travel time, and external conditions. When extrapolated to thousands of containers, the difference is enormous.
Energy Management and Smart Grids
Terminals can also optimise their energy consumption by integrating refrigerated containers into smart grid systems:
Operational Practices
Technology enables transparency, but as discussed above, operations influence actual results. Key practices include training programs that ensure all involved personnel understand cargo-specific temperature requirements. Maintaining scheduling discipline reduces idle time by more closely aligning delivery and pickup. The more data shared across the supply chain, the more accurately transportation requirements can be fine-tuned, avoiding unnecessary congestion.
Balancing Technology and Operations
It's tempting to view technology as a panacea, but sustainable reefer container management requires a balance.
Technology without good processes = data overload with little impact.
Processes without technology = blind spots and inefficiencies.
Overall = measurable improvements in energy efficiency, emission reduction, and reliability.
Remote condition monitoring is one of the most important tools for modern reefer container operations and for eco-friendly refrigeration. By combining IoT sensors and real-time alerts, terminals and shipping companies can now monitor the status of every container around the clock. The environmental impact is significant: Greater transparency directly leads to lower energy consumption, less cargo damage, and improved efficiency.
What Remote Monitoring Does
Remote monitoring systems track multiple parameters of each reefer, including:
This data feeds into central dashboards, allowing operators to spot inefficiencies and respond quickly. For example, a reefer's power draw may spike due to blocked airflow or overcooling, triggering an immediate alert.
Reducing Energy Waste
Remote monitoring directly lowers energy consumption by:
Reducing Food Waste
Refrigerated container defects also contribute to indirect greenhouse gas emissions through the disposal of spoiled food. The Food and Agriculture Organisation of the United Nations (FAO) estimates that approximately 14% of the world's food is lost before it reaches retail. Cold chain disruptions—including defective refrigerated containers—are a significant contributor (6).
Food production, transportation, and processing consume energy and resources. When food is thrown away, all associated emissions are essentially "wasted." Landfilling food waste produces methane, a gas with a global warming potential 28 to 36 times greater than CO₂ over 100 years (7). While composting or anaerobic digestion reduces some emissions, they do not completely eliminate CO₂ emissions from production.
Supporting Supply Chain Coordination
Remote monitoring not only optimises the refrigerated container itself but also improves logistics efficiency, which indirectly reduces environmental impact:
Real-World Impact
Ports and shipping lines using remote monitoring report measurable environmental and operational benefits. Let's use a simple calculation example: Across a fleet of 5,000 reefers, a 5% reduction in energy and refrigerator losses translates into roughly 4,000 tonnes of CO₂-equivalent emissions avoided per year.
Eco-friendly reefer operations are not a static challenge. It continues to evolve based on future technology, regulations, and collaboration. What will happen?
AI-Driven Autonomous Refrigeration
Predictive algorithms can already analyse sensor data from reefer containers to predict malfunctions or optimise temperature settings in real-time. In the future, AI-driven autonomous refrigeration systems could also continuously adjust airflow, defrost cycles, and compressor activity with minimal human intervention.
Full Electrification and Integration of Renewable Energies
Decarbonisation efforts are underway worldwide. Diesel generators are increasingly being phased out in favor of partially and fully electric machines and connections. Some ports already operate shore-side power grids powered largely by renewable energy—often produced on-site—so that reefer containers can be powered by green electricity instead of fossil fuels.
The Role of Policy, Regulation, and Industry Cooperation
Policymakers are raising the bar: The EU F-Gas Regulation now calls for a gradual reduction in the use of refrigerants with high global warming potential, such as R-404A, by 2030. Collaboration within the industry, such as the Global Maritime Forum's "Getting to Zero Coalition," is equally important. Terminals that join such frameworks not only comply with current regulations but also help shape the environmentally friendly standards of tomorrow.
Environmentally friendly reefing and occupational safety are more closely linked than many assume. Environmentally friendly practices—such as reducing unnecessary interventions and optimising reefer performance—also mean a lower risk of accidents. When machinery runs efficiently, technicians spend less time near reefers or performing emergency repairs in hazardous environments.
In general, reducing manual intervention improves personnel safety. Remote monitoring and predictive alerts minimise the need for on-site inspections. Due to the high voltage at which reefers operate, their vicinity is dangerous, and it also reduces the risk of common terminal incidents such as slips and accidents involving container handling equipment.
Safety and sustainability, therefore, reinforce each other. By integrating environmentally friendly concepts into refrigerated container operations, terminals create safer workplaces while simultaneously reducing emissions and costs.
Eco-friendly refrigeration is a strategic shift. There are a variety of concrete and actionable ways to reduce the ecological footprint of refrigerated transport: from smarter monitoring and predictive maintenance to energy-efficient technologies, environmentally friendly refrigerants, and a renewable energy infrastructure.
The economic argument is just as compelling as the ethical one. Optimised energy consumption and continuous monitoring reduce costs and maintain the quality and thus the value of goods. Ports that implement environmentally friendly practices also benefit from their reputations – such behaviour is increasingly being demanded by freight forwarders and regulators. This advantage will soon become a prerequisite, so it's impossible to jump on this bandwagon early enough.
The need for action is clear: Terminal operators must prioritise investments in monitoring systems, electrification, and operator training – the decisions made today will determine their business stability.
Delve deeper into one of our core topics: Reefer monitoring
Global Warming Potential (GWP) measures how much heat a greenhouse gas traps in the atmosphere over a set time period relative to carbon dioxide, which has a GWP of 1. It quantifies the climate impact of different gases by considering their ability to absorb heat and how long they remain in the atmosphere. For example, methane has a higher GWP than CO2, meaning it traps more heat per unit mass. GWP helps compare and aggregate emissions for climate policy and carbon footprint calculations, typically using a 100-year timeframe. (8)
Hydrofluorocarbon (HFC) refrigerants are synthetic compounds made of hydrogen, fluorine, and carbon atoms, widely used in air conditioning, refrigeration, and HVAC systems. They replaced ozone-depleting CFCs and HCFCs due to zero ozone depletion potential, but have high global warming potential (GWP). Popular HFC refrigerants include R-134a and R-410A, noted for stability, non-toxicity, and efficiency in cooling applications. Despite environmental benefits over predecessors, their high GWP has led to regulatory phase-downs in favor of more sustainable alternatives. (9)
References:
(1) https://www.businessresearchinsights.com/market-reports/reefer-containers-market-121704
(2) https://jshippingandtrade.springeropen.com/articles/10.1186/s41072-019-0040-y
(5) https://www.mdpi.com/1996-1073/14/15/4456
(6) https://www.fao.org/platform-food-loss-waste/food-waste/food-is-never-waste-coalition/en
(7) https://www.ipcc.ch/report/ar6/wg1/
(8) IPCC (2014). Climate Change 2014: Mitigation of Climate Change. Cambridge University Press.
(9) Calor, John (2020). Refrigeration and Air Conditioning Technology. Delmar Cengage Learning.
Note: This article was partly created with the assistance of artificial intelligence to support drafting.