Electrifying heavy-duty transport does not necessarily have to start with the tractor unit. Michael W. Nimtsch, Managing Director of the German company Trailer Dynamics, sees the trailer as the missing piece in the drivetrain transition. We spoke with him about the opportunities offered by electric trailers.
Founded in 2018, Trailer Dynamics is a startup specialising in semi-trailers equipped with their own electric powertrain. The system reacts to the driving behaviour of the coupled tractor unit and is designed to support its propulsion system – whether diesel, gas, battery-electric or fuel cell – by reducing the load on the tractor.
Technically, the Aachen-based company is already well advanced. Around two dozen pre-series vehicles are currently on the road, and the company has carried out a number of field tests with well-known logistics partners. Most recently, Trailer Dynamics secured a €25 million loan from the European Investment Bank. But how is the start-up progressing on its path to scaling?
In an interview with electrive, Managing Director Michael W. Nimtsch discusses the often overlooked role of the semi-trailer in the transition to zero-emission freight. He also explains the technical concept behind the eTrailer, the regulatory challenges facing the technology, and how the electrified trailer performs in terms of payload and operating costs.
According to Nimtsch, the benefits go beyond reducing CO₂ emissions. While decarbonisation is a key advantage, the technology also promises significant efficiency gains – an argument that tends to resonate strongly with logistics operators.
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Mr Nimtsch, do you remember the moment when you first realised that the electrification of heavy-duty transport does not necessarily have to start with the tractor unit?
Yes, I came across the idea for Trailer Dynamics in a pitch as a startup investor in 2018. I subsequently met with my later co-founder Abdullah Jaber, the technical brain and inventor behind Trailer Dynamics. What he explained to me was very compelling. However, in 2018, we were primarily focused on reducing diesel consumption, rather than coupling with electric trucks.
What is the idea behind an eTrailer?
The idea is to develop a plug-in vehicle that overcomes the rolling resistance of the trailer and thus reduces fuel consumption or increases the range of the tractor unit. Plug-in in the sense of being easy to couple and independent of the manufacturer.
When a diesel tractor is coupled with an eTrailer, the combination effectively becomes a plug-in hybrid. How much diesel can actually be saved in practice?
Here is a rewritten version in the concise, factual tone typical of electrive.com interviews:
This is currently our most relevant use case, as more than 95 per cent of all semi-trailer tractors are still diesel-powered. The actual savings depend heavily on factors such as route topography, driver behaviour and payload.
To illustrate this, let’s look at two extremes. If a truck is travelling almost empty on a motorway without gradients and with little stop-and-go traffic, fuel consumption may already be relatively low – around 22 litres per 100 kilometres. In such a scenario, the additional savings from the eTrailer are comparatively limited, at roughly 30 per cent.
The picture changes on more demanding routes. On hilly terrain with frequent stop-and-go traffic and heavy loads, fuel consumption can exceed 30 litres per 100 kilometres. In these conditions, the eTrailer can reduce diesel use by up to 50 per cent.
On average, we see savings of around 40 per cent. This is why selecting the right routes together with the customer is a key part of the deployment strategy. The same logic also applies when the eTrailer is paired with a battery-electric truck to extend its driving range.
Let’s look at electric trucks in combination with the eTrailer: How much does the range increase?
Standard battery-electric semi-trailer tractors achieve between 350 and 450 kilometres – again, depending on the type of route. In combination with the eTrailer, we consistently achieve 800, possibly 900 kilometres, because we carry almost exactly the same power pack that the semi-trailer tractor has at the front, again at the rear. This results in these significant range increases.
What do you say to those who point out that drivers have to take a break after four and a half hours anyway?
Breaks in relation to battery charging times are a topic in themselves. One key question currently being debated is whether charging a vehicle’s battery counts as working time under labour law. This issue needs to be taken into account when planning routes.
What matters in our case is that the driver can simply take their regular break. Thanks to the extended range made possible by the eTrailer, additional charging stops during long-haul operations can often be avoided. This means there is no need to interrupt operations to search for an available charging point and wait for the charging process to finish.
For many logistics use cases, this time saving can be a significant advantage.
Now, the eTrailer contains more technology than a conventional semi-trailer. How much more does an eTrailer cost compared ?
The most expensive component of our trailers is the batteries, which is why we offer them modularly. We start at 180 kWh, offer 367 kWh or go up to 550 kWh, depending on the customer’s use case. The prices for the eTrailer start at around 140,000 to 150,000 euros with a smaller battery – depending on the trailer type and equipment – and go up to 200,000 to 220,000 euros with the largest battery.
That is, of course, a significant figure for a logistics provider.
Electric mobility in heavy-duty transport is still more expensive than diesel. For this reason, we currently offer our eTrailers almost exclusively through rental or leasing models. To support this approach, we cooperate with all major leasing and rental providers.
Let’s return to the technology itself: what are the key components of the eTrailer?
The eTrailer from Trailer Dynamics features an electric axle with two motors and transmissions on board, with each wheel being individually controlled. In addition, there are the batteries and the entire drivetrain control via the kingpin. These are the three major components. The core competence of Trailer Dynamics is clearly the drivetrain control. Motors and batteries can be sourced externally, but the art lies in combining them sensibly, safely and functionally to supportively drive the vehicle. The necessary software and sensor technology – that is what sets us apart.
The battery capacity can reach up to 550 kWh. Why does the eTrailer need such a large battery?
That is pure physics: Around 60 per cent of the rolling resistance of the entire vehicle is attributed to the trailer alone, with 40 per cent to the semi-trailer tractor. To provide meaningful support, this rolling resistance must be overcome. Because we want to drive, reduce CO₂, and lower consumption or increase range at the front, we need these large batteries and the energy they provide, and therefore also these powerful electric motors.
And does the trailer also charge regularly at the charging station?
Yes, just like the electric truck, via the standard CCS2 plug. Currently, up to 350 kW DC charging power is possible. If the industry standard increases or megawatt charging becomes established, we can adjust upwards.
The obvious question is: how does the additional drivetrain affect payload?
Electric mobility in commercial vehicles inevitably adds weight. Depending on the battery option, the additional drivetrain components – including the battery – increase the weight by around 2.2 to 5.5 tonnes. So yes, there is an impact on payload.
At the same time, the EU is working on regulatory exemptions for electrically powered commercial vehicles to compensate for this loss of payload. Regulation therefore plays an important role in this context.
From our perspective, it ultimately makes little difference whether the additional weight stems from the electric truck itself or from the eTrailer. Electrification increases the weight of the overall vehicle combination.
In what way does it not matter?
In the future, the two vehicles – the truck and the trailer – will merge. So, in 10, 20 to 30 years, this separation between truck and trailer will probably no longer exist. Instead, a single vehicle will emerge – autonomously controlled and likely without any driver’s cab.
Returning to the present: which trailer types are currently part of your portfolio?
We currently offer eBox trailers and will add the eCurtainsider this year, which is particularly in demand in Germany. We will also introduce an electric refrigerated trailer in the second half of the year. E-Mega trailers are also planned. These are the four major types of trailers we want to offer.
You also advertise making the eTrailer smart. What does that mean?
With electrical energy available on board, a range of new functions becomes possible. For example, the system can power the refrigeration unit, monitor the cargo area, optimise the use of cargo space or determine the load weight.
Another key aspect is predictive drivetrain control. By analysing data such as traffic conditions, weather and charging availability, the system can anticipate how the vehicle will behave along the route. Evaluating this data can help both the driver and fleet management operate the vehicle more efficiently.
How challenging is it to make the eTrailer compatible with tractor units from different manufacturers and with all types of propulsion?
This is extremely demanding. The solution lies in the kingpin, where we absorb the forces occurring there, convert them into digital signals and send them to the vehicle control unit, which in turn controls the electric axle in the trailer in real time in a functionally safe manner. It is very important to note: we are legally prohibited from pushing; we are only allowed to support.
Now, the systems must of course recognise: Where did the force or movement come from? Was it just a pothole? Or a kerb? Or is it a request for support? Developing this, calibrating it and solving it through algorithms is what we have safely demonstrated in the eTrailer over the past few years.
Where do you stand with road approval?
In 2024, the EU enabled type approval for eTrailers. Since we currently offer the eTrailer from Trailer Dynamics in a pre-series stage – meaning we are still developing it – we are currently working with so-called individual operating permits, which entail no restrictions. Approvals on this basis are already possible in Germany and Denmark, and presumably soon in Sweden.
However, we are also working in parallel with the EU to ensure that the eTrailer can be approved across Europe. This would, of course, be a huge step forward for us, as we have recently received customer enquiries from Austria, for example.
Which target markets are you particularly interested in?
We are currently seeing particularly strong demand from Scandinavia, which is not surprising given the comparatively low electricity prices in the region. Austria and Switzerland offer attractive subsidies, while electricity in France is also cheaper than in Germany. In general, lower electricity costs are a key factor.
In my view, electric mobility in freight transport would scale much faster if energy prices were reduced. That said, our focus is fundamentally on the entire European market.
Over the past few years, you have conducted numerous trials and analyses with logistics companies and manufacturers. How strong is the interest from the industry?
First, we need to differentiate the industry: Retail and industry increasingly have their own climate neutrality goals and are thus pushing their logistics partners to decarbonise. Often, these players do not have their own fleet but work with logistics providers who they urge to save emissions. Both levels are our target group.
The industry – i.e., the clients – definitely have great interest. Our test calendar is full: we are conducting one customer field test after another. Logistics is also gradually approaching the topic. In this area, there are some frontrunners who, alongside the logistics process suitability of the eTrailer, primarily focus on TCO and liquidity.
And how do you plan to convince cost-conscious logistics providers on a broad scale?
We always talk a lot about CO₂ reduction – a major strength of eTrailer technology. But we should also talk about increasing efficiency, for example, in terms of the time savings already mentioned: I am faster than before. Or in terms of transparency. CO₂ reduction and increased efficiency: both go hand in hand and add value.
Trailer Dynamics recently secured a €25 million loan from the European Investment Bank. Is this the moment when scaling really begins?
We have been selling to rental companies since autumn 2024, and they rent the vehicles on to customers. So, the vehicle is clearly available for purchase. We want to sell around 100 to 150 vehicles this year. These are fully functional pre-series vehicles. By the end of 2027 or beginning of 2028, we plan to move into full-scale production.
And what production capacity are you aiming to achieve?
We at Trailer Dynamics are not trailer manufacturers but system suppliers. We supply our eKits to trailer manufacturers. Last year, for example, we began supplying the eKit to Krone. Krone then integrates the eComponents and completes the eTrailer in its production halls. We also collaborate with Chereau, a French trailer manufacturer. In principle, we want to establish connections with all European trailer OEMs and offer our eKit.
And what is the difference between pre-series and series production in terms of kit supply?
We are still developing our kit in parallel, and for 2027/2028, we expect to be ready for series production – to have a vehicle that can then be type-approved. The eTrailer can then be produced in large quantities. At the moment, as mentioned, all vehicles are on the road with individual operating permits. Since we are still developing the eTrailer until it is ready for series production, type approval does not yet make sense.
What do you say to critics who argue that choosing an eTrailer as the ‘easier’ option could slow down the full electrification of freight transport?
Yes, we hear that again and again, especially from politicians. What do I say in response? First, one must simply acknowledge reality: We have over two million registered semi-trailer tractors in Europe, of which over 95% are diesel. And they will remain so for the next 20 years.
The current reality is a diesel reality. We can, of course, continue to let these vehicles operate as dirty as before. Or, alternatively, use the eTrailer to decarbonise this existing diesel fleet. Secondly, we are not preventing the battery-electric vehicle; we are improving it by increasing its range and thus making emissions-free freight transport possible for long distances.
How open are Germany and Europe to eTrailer technology?
Trailer OEMs, truck OEMs, logistics providers and the industry are all engaging with eTrailer technology, or the eTrailer is already in daily use. The eTrailer will come; we are certain of that. The process will unfold as it does with all new technologies: first, the new technological approach is gradually adopted, and at some point, it will more or less become the standard.
The actual value creation, the actual transport, takes place in the trailer, not in the semi-trailer tractor. The electrified semi-trailer will increasingly come into focus.
Mr Nimtsch, thank you very much for the conversation!
