(Peer version December 10, 2025, i.e. please send feedback to info@transportmeasures.org)

Additional energy use and related GHG-emissions due to temperature control of cargo space  is commonly above general 5% cut-off levels, hence considerable for the common technical applications. The exception are the Cryogenic (CO₂) technique, however with a marginal market share. Hydraulic and alternator techniques increases vehicle fuel consumption.

In general, we recommend use of actual data measured or provided by the supplier when assessing GHG-emissions. If these values cannot be obtained below data can be used as “fall-back” data.

We recommend the use of an average default factor according to below table for different road solutions. There should be no difference between frozen and refrigerated goods due to the fact that the cargo units used differ with regard to insulation. FNA-classed cargo unit with insulation for refrigerated goods and FRC-classed cargo unit with insulation for frozen goods compensate for additional energy use in these two applications.

1. Diesel equipment

This technology includes a small stand-alone diesel engine running a compressor. Based on fuel consumption data per hour from manufacturer and general assumptions on truck fuel use in combination with assumed distances travelled for each type of vehicle results are as below:

A relatively safe assumption is 10-15% GHG-emission increase in road transport

2 Hydraulic driven equipment

This technology rely on the vehicle’s diesel engine using energy from the transmission shaft running the refrigeration unit. Its advantageous is emission performance and energy efficiency corresponding to the vehicle engine although with transmission losses from shaft to the cooling equipment. Its main drawback is the need for an idling engine or plug in of external electricity at stand still of the vehicle.

Our general assumption on additional GHG-emissions is ~10% in road transport.

3. Alternator (generator) driven equipment

This technology relays on the vehicle’s diesel engine using energy from the transmission shaft running the refrigeration unit via an alternator that runs the electric cooling equipment. Its advantageous is emission performance and energy efficiency corresponding to the vehicle engine although with transmission losses from shaft to the cooling equipment. Its main drawback is the need for an idling truck engine or plug in of external electricity at stand still of the vehicle.

Our general assumption on additional GHG-emissions is ~10% in road transport.

4. Eutectic system

This system is based on the usage of various freezing blocks placed in the cargo volume and thereby enabling distribution of refrigerated goods. This technology is rarely used apart for some applications regarding refrigerated dairy goods.

5. Cryogenic systems

The cryogenic system uses liquid carbon dioxide as refrigerant and as a power source for unit evaporator and fans. Stored in a vacuum insulated tank, the cryogenic fluid provides instant cooling capacity.

Life cycle analysis from CIT, Chalmers indicates very low energy use and climate impact from the system. An additional calculation presented below confirms the good environmental performance.

At present this technology is rarely used.

6. General conclusions on thermo equipment

• Cost, performance and reliability and ability to run as stand-alone units are often key criteria’s when choosing technical solutions.
• Extra energy use in conventional techniques (engine, hydraulic and alternator) is additional 10-15% when analysing thermo road transport GHG emissions.
• Alternator and hydraulic solutions seems slightly more energy efficient than conventional stand-alone engine techniques.
• The cryogenic solution is the most energy efficient solution with very good functional performance that in addition can be based on non-fossil electricity, hence no fossil GHG-emissions. At the moment this technique is rarely used as necessary infrastructure is missing, hence its market share is neglectable.

• In average rail and sea container transport we recommend the factor of 1.4, a somewhat higher factor than road transport due to lower relative emissions in these transport modes. For electric train running on green electricity the factor should normally be higher depending on type of electricity used (well-to-tank).

In Ritchie K; From farm to table: An energy consumption assessment of refrigerated, frozen and canned food delivery. A report in draft prepared by Scientific Certification Systems on behalf of the Steel Recycling Institute, California, US they recommend 14 % additions on transport energy.

In Corporate Responsibility Report 2005 J Sainsburys, UK the recommendation is a 15 % addition on transport energy.