Electric trucks: megawatt chargers could change the business
Developments in tractor units and the charging infrastructure suggest that battery-powered trucks will prevail over competing drive systems.
Mercedes is on tour in Europe with the e-Actros 600. The tractor unit with a 621 kilowatt-hour traction battery can weigh a total of 42 tons with trailer instead of the usual 40 tons.
(Image: Daimler Truck)
- Christoph M. Schwarzer
The charging station, which was installed by the Technical University of Munich (TUM) and MAN Truck & Bus as part of the NEFTON research project, has an output of 1000 kilowatts or one megawatt. The aim is to enable heavy goods vehicles to drive electrically. Not with overhead lines, where a test route between Hamburg and Lübeck will be discontinued at the end of the year. Not with hydrogen-powered fuel cells, as Hubert Aiwanger, Minister of Economic Affairs of the State of Bavaria, who was present at the NEFTON presentation in Plattling, Bavaria, would like. Instead, the heavy trucks, which have been increased in weight from 40 to 42 tons, will be powered by batteries. There is every indication that this solution will prevail. The lever for implementation is the standardized Megawatt Charging System (MCS).
The world of trucks ticks a little differently to that of cars. It is well known that battery electric commercial vehicles work on short distances in distribution transport. But what about when it comes to traveling from Granada to Essen or from Hanover to Katowice? Here, the statutory driving times determine the daily routine: the driver may only be at the wheel for 4.5 hours at a time. He must then take a 45 minute break. In any case, driving times are not for the faint-hearted, as a glance at the EU regulations for professional drivers shows.
621 kWh in the Mercedes e-Actros
In theory, these 45 minutes should be enough to sufficiently charge the traction battery in the tractor unit. One example is the Mercedes e-Actros 600, series production of which will start at the end of the year: The LFP cells in the e-Actros hold up to 621 kWh. Initial practical tests of these and similar vehicles, including loaded semi-trailers, show consumption values of between 90 and 120 kWh/100 km.
What many electric car drivers know from home is already commonplace at the depots of large haulage companies: their own filling station. If this is electric in the future, a heavy combination could start with a full battery. Assuming a pessimistic power consumption of 120 kWh/100 km, 360 km would be covered in 4.5 hours of driving time at a speed of 80, and the traction battery in the e-Actros would still be around 30 percent charged at the charging stop.
Bottleneck charging infrastructure
How many kilowatt hours the tractor units from MAN and Mercedes, Volvo or Scania can actually charge during the prescribed break will soon be revealed in practice. Mercedes is initially communicating a charging capacity of 400 kW for the e-Actros 600; later, the megawatt that is being researched in the NEFTON pilot project should be feasible. The situation is similar at Milence, a joint venture between Daimler Truck, the Volvo Group and Traton with MAN and Scania: the basic network has an output of 400 kW, which will later be increased to almost 1.5 megawatts.
In view of the increasing charging rates for passenger cars, there is no reason why traction batteries in trucks should not be able to absorb more and more electrical energy within a certain time window. How many driving profiles can this not cover? Due to a lack of sufficient field tests, it is not possible to say exactly, but it is likely that the bottleneck will be less the electric tractor units and trailers - those with a cooling function need a little more energy - but the infrastructure.
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350 locations with up to 2400 charging points
The National Control Center for Charging Infrastructure, a federally owned limited company owned by the Ministry of Transport, has dealt with this in detail. For example, toll data was analyzed to identify ideal locations. According to calculations by the National Centre for Charging Infrastructure, 350 locations are required to establish a fast-charging network for trucks in Germany. 130 of these should be located at so-called unmanaged service areas. These are the simple parking spaces where trucks are currently parked in order to comply with rest periods. In total, 1800 to 2400 charging points must be installed at the 350 locations. They need lots and lots of power. If we assume that battery-electric heavy-duty trucks will also become established on long-distance routes, even the connection to the medium-voltage grid is likely to be too meagre in many cases; high-voltage is preferred. Incidentally, the railroads have been demonstrating for decades that it is possible to provide a great deal of electrical power for driving.
Ensuring competition for traction current
The National Charging Infrastructure Control Center has identified another aspect that is very important for the function: the billing system. Berlin is not amused by the current situation at car charging points, where the formation of an oligopoly leads to excessive prices. To prevent a similar disaster with trucks, the National Control Center wants to establish functioning competition for charging electricity from the outset. This is based on three different billing options: Firstly, ad-hoc charging, where payment is made directly via a payment terminal without a contract. This model is particularly interesting for the operators (charge point operators or CPOs) because the electricity is marketed directly and there are no middlemen. There will also be e-mobility providers (EMP), similar to those for cars. Truckers have a contract with which they can pay anywhere.
Pass-through model with infrastructure charge
The third model is the new transit model. The haulier has a contract with an electricity supplier. The CPO in turn receives an infrastructure charge for operation and transmission. The federal government sets the amount of this infrastructure charge. This can work because a lot of land on the highways belongs to the state. The federal government can link the allocation of these sites to the condition of transit. Heavy, electric commercial vehicles are exempt from the toll until the end of 2025. Will the haulage industry embrace electric driving? That will be a question of cost: if there is a realistic prospect that it will be cheaper to run on electricity than on diesel fuel, the diesel engine will be finished. There are signs that this is exactly what is happening.
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(emw)