Sustainable journey: the urgency of zero-emission temperature controlled trailers

Keeping products at the right temperature is increasingly important. The current diesel-powered solution is not meeting the sustainability goals we aspire to in the mobility sector, which is why TIP is actively looking into electrical Trailer Refrigeration Units (TRU) that can operate with zero emission.

Trailer refrigeration units

Global warming calls for industry change

The European Union calls upon major industries to invest in sustainable solutions. For logistics services, this means we strive to cut carbon emissions to reverse the effect of climate change.

Scientists agree that temperature rise is inevitable, even if we reach our goals. ‘The coldest summer of the rest of our lives’, society has started calling it. An increasingly hot climate means a growing dependency on good refrigeration for medicine and especially food since these products are increasing in value due to more intense weather, growing population and more global health challenges.

Temperature-controlled trailers in transportation will need to be relied on even more in the future. The current TRUs are keeping the products at the right temperature and are meeting our requirements, but these high-performance engines are still fuelled by diesel, which ironically adds to the problem it will be asked to rectify in the future. Hence, it does not make sense to retain the status quo where valuable customer goods are kept cool by an engine that adds to the global warming problem.

It is remarkable that the EU has set very strict limits on diesel powered truck-engines, but has not (yet) regulated the emissions of the reefers in the trailers. It is TIP’s goal to stay ahead of these possible restrictions and integrate innovation on time.


Electrify the on-board Temperature Control

If the mobility sector is gradually electrifying its engines, then why stop at the propulsion of the vehicle? The TRU can be made electric to operate on the onboard power supply. The benefits of such sustainable innovation would contribute to emission reduction goals and cleaner, quieter cities, all while reducing the dependency on facilities and costs for fuel on-board.

The core element of the re-design of a temperature-controlled trailer is to electrify the TRU. To supply the engine with sufficient power, an advanced battery system should be mounted to the trailer. This battery needs to be charged efficiently to make the concept reliable and viable.

infographic battery


The eTRU, an accessible alternative

The core of the solution is electrifying the TRU and its engine. These are currently already available and go by the name ‘eTRU’. Using electricity powered fans and cooling/heating systems, the first models that TIP put on trial in 2022 have a modified Thermo King engine (Advancer A400) that can keep the freight chilled at temperatures down to -25°C  (source: TIP Group).


A new kind of battery designed to perform for the entire duration of the journey 

The lightweight specialised battery system from Maxwell and Spark, with its 70 kilowatt-hours (kWh), can run the TRU completely on electricity during working hours and is optimal and has to have a sufficient output for the duration of the transport. Additionally, it has the margin to stand still without being able to charge on the net. A lot of innovation is still happening in this sector to make it more efficient.


Charged on the net 

It is common that the batteries are charged via a cable and a three-phase power connection to the grid. For the logistics sector, this could happen during the loading and unloading of freight or when drivers are on a break. At the moment, using only a high capacity battery pack is more cost-effective and can be retrofitted into our existing trailers. However, there are ways to charge power on-board, such as:


  • Additional charge with an energy axle

Currently, in cold chain services, trailers can generate their own electricity with kinetic energy via a special axle. Using a generator, the fridge can run while the vehicle is in motion and charge in-built batteries that allow the trailer to be cooled or heated while stationary for up to 90 minutes. This ensures a renewable source and zero-emissions but also reduces the reliability of charging facilities and lowers costs.


  • Charged with solar panels

Solar panels would have the same benefits whilst generating energy from solar power. It is a more popular solution that has yet to be proven in the trailer industry.


The first step to sustainable change

In the Netherlands, TIP’s first trial of several months has successfully been rounded up in July 2022. Two trailer units ran completely electric to safely transport Ben & Jerry’s for Unilever across the Dutch autumn roads. The temperature-controlled transport kept freight chilled down to -25°C by using only green energy. Each unit saves up to 25 tons of CO2 per year, contributing to lower emissions in the transportation sector. The overall benefits of this improvement would be a cleaner and more efficient trailer solution.


Next steps to reach sustainable goals

After the success of the first trial, TIP and Unilever looked at the results and assessed what was needed to make future units even better. In the summer of 2022, they had four trailers in use on the hot summer roads of the Netherlands. The roadmap is optimistic; once these trailers have proven their abilities, the technology can be rolled out across a larger fleet. Eventually, TIP hopes to inspire the wider sector to collaborate, in order to make impactful sustainable improvements.


Let’s innovate now!

It has become clear for the logistics sector that the temperature-controlled distribution network needs to innovate towards trustworthy zero-emission solutions. Relying on outdated diesel engines is no longer viable. Current battery-based solutions show promising results, but there is still much to gain in the on-board generation of power to secure energy-efficiency and become more independent.

It is an exciting proposition to electrify the cold chain for many parties, from shippers to carriers and equipment providers, lowering costs while improving quality of life and fighting climate change on a large scale.