Despite improvements to the vehicles' engine technology, carbon dioxide emissions produced by road freight transport rose from 39.3 million tonnes to 47.4 million tonnes between 1995 and 2019. According to the research project StratES managed by the Heilbronn University of Applied Sciences, the target of a 15 per cent reduction in CO2 emissions by 2025 is no longer achievable simply by improving the efficiency of conventional diesel drives. This is a clear indicator that we must find alternative drives for trucks. But what are the options?
Hydrogen offers a distinct advantage, particularly when it comes to range. However, it is likely to be some time before a comprehensive supply of green hydrogen and a secure infrastructure are available.
What about battery-powered lorries? Currently limited to around 200-300 kilometres in range, e-trucks are a particularly attractive transport option in metropolitan areas. This emission-free drive goes some way to reducing emission values in heavily built-up cities, thus improving the quality of life. While diesel-powered trucks for e.g. rubbish disposal often disturb residents’ sleep, e-trucks are virtually silent. This means that local authority and construction traffic can shift to night-time operating hours, removing some of the burden on the already heavy city traffic during the day.
Lower energy and maintenance costs, which make up a large proportion of the running costs of conventional transport, mean that there is also potential to make savings. These savings and the subsidised purchases of such vehicles mean that the higher costs of an electric fleet can be recouped relatively quickly.
Emission-free, quiet and efficient: e-trucks in Munich.
Waste Management Munich (AWM) carried out a test run to investigate the potential of the Volvo FE Electric. This roll-off tipper has been used to dispose of waste at recycling centres in the city since November 2020. ‘The vehicle is trickle charged overnight at a 22kWh charging station located in the carport. To increase its daily range, the roll-off tipper is also charged during the driver's legally prescribed break times at a 150 kWh quick-charging station. A type 2 connection means that it is technically possible to charge the vehicle at a universal charging station,’ explains the company spokesperson.
Both drivers and residents in the city appreciate the quieter streets. Instead of engine noise, it is now the significantly quieter hydraulic system that can primarily be heard when the bins are picked up and emptied.
The only aspect that AWM is critical of is the battery: ‘It has a capacity of 200 kWh, which enables a maximum range of just 120 kilometres. But we are currently working closely with Volvo to adjust and optimise the operating conditions. We’re also discussing our experiences with this roll-off tipper with colleagues in other local authority companies,’ says AWM.
Long-distance transport: further development work needed
Other technical issues needed to enable further development of e-trucks aside from the battery are being tackled by the University of Kassel. To this end, the university set up a new large-scale test stand at the end of 2020, which enables it to test electric drive systems on everything from vans to heavy lorries in realistic conditions.
‘With a continuous ouput of 1650 kw, the dynamic test stand can replicate various road conditions. In addition to inclines, the test stand allows us to test more complex parameters, such as the effect that uneven contact with the ground has on tyres in slippery conditions. Thanks to its range of capabilities, the test rig for vehicle drives is a truly unique asset in this research field at the moment,’ explains test stand manager Prof. Michael Fister.
The changing load profiles place different demands on the vehicle over long distances, the information from which will influence further development. Transferring existing electric drives used in cars to commercial vehicles is simply not possible. To meet both the torque and speed requirements simultaneously, high power reserves are required, which increase weight, energy consumption and therefore costs.
Battery-powered trucks with a single-speed transmission like those in e-cars, for example, experience significant limitations on inclines, explains Prof. Fister. The Scale-e-Drive project initiated by the Federal Ministry of Transport and Digital Infrastructure is also taking advantage of the Kassel test stand to work on optimising the efficiency and system weight of the drives used in e-trucks.
Fully automated data collection at the test stand
At the test bench of the Institute for Propulsion and Vehicle Technology, Department of Mechantronics, the team headed by Prof. Fister is therefore investigating new ways to ensure quicker gear changes in lorries. Shortening the duration of traction interruption while changing gear could lead to a reduction in the loss of power. ‘As the loads are potentially constantly changing throughout the journey, collecting the necessary data for development is very time-consuming. Thanks to the fully automated test stand, we can go through several weeks' worth of data and thus speed up our research,’ says Fister.
The Mercedes Benz plant in Kassel also benefits from the efficient test bench and the scientific expertise of the university and uses the test bench within the framework of their partnership. As the competence center for commercial vehicle axles of Daimler Truck AG, the Mercedes-Benz plant in Kassel will also manufacture axles for the new eActros in the future. The battery-electric truck for heavy distribution transport will go into series production this year.
Solid state batteries for the future
There could be a solution to the heavy weight and low range issue posed by lorry batteries. Solid state batteries like those that Volkswagen aims to produce in collaboration with the US battery start-up company Quantumscape in Salzgitter may be the revolution that is needed. The solid state battery can be charged more quickly, which means that the service life of a solid state battery is significantly longer than that of a lithium-ion battery. In addition, the solid state battery requires less space and weighs less in comparison. The quicker that this technology can be installed as standard in cars, the more it will also start to be used for lorries and achieve the required ranges necessary for long-distance transport. The hope then is that huge progress in decarbonisation will be made.
‘E-trucks are a good way to reduce CO2 emissions and noise in inner cities. We offer the option to convert lorries used in distribution transport in all kinds of ways. Electric battery-driven vehicles of up to 26 tonnes can achieve ranges of up to 300 kilometres in short-distance freight transport. Over the past six years, Orten Electric Trucks has electrified 300 commercial vehicles that have since covered six million miles between them.’
Robert E. Orten, Managing Partner, Orten Electric Trucks
‘Electric vehicles are particularly climate friendly for short to medium distances. As an SME, we consider our core task to be emission-free heavy goods transport. The e-mobility market is not necessarily driven by size, but by innovativeness, flexibility and the ability to look beyond the present.’
Serhat Yilmaz, Chief Marketing & Business Development Officer, Framo
‘It is a myth that battery-powered drives are not suitable for long-distance freight. Using batteries instead of heavy diesel components does not significantly reduce payload and they can be recharged during the driver’s mandatory breaks. Battery-electric trucks generally have the lowest cost, lowest emissions and offer by far the highest CO2 bang for the buck.’
Andreas Kammel, Senior Manager Alternative Drives and Autonomous Driving, Traton
‘Our axle drive has the potential to help achieve a breakthrough where electric lorries are concerned because it opens up new possibilities for vehicle manufacturers in terms of range, load, driving performance, vehicle layout as well as in industrial production. With 7.5 tonne lorries, we can achieve a range of over 200 kilometres, which is far more than is typically required in the urban environment. And with a payload of over three tonnes at that. As the drive is integrated directly into the axle, we save a lot of weight, which balances out the additional weight of the batteries.’
Markus Schell, Managing Partner, BPW Bergische Achsen KG
- Alternative Drives