Sustainable road freight transport
How electric heavy-duty vehicles can cover long distances and provide climate-friendly freight transportation
The European Union requires a 15-percent cut in road traffic CO2 emissions by 2025, and 30 percent by 2030. A white paper from the Connected eMobility Corporate Core Technology at Siemens presents two technical solutions – a charging infrastructure from the Future Grids department and the eHighway of Siemens Mobility - that can make a remarkable contribution to meet this goal. Heavy duty vehicles shall be running with electric drives in the future, if possible. An appropriate infrastructure makes it possible that such vehicles can keep up with the CO2-intensive diesel combustion engines.
Hamburg-Nuremberg: a 610-kilometer transport corridor within Germany of federal autobahns A1, A7, A70, and A7321. A route which drivers of heavy-duty vehicles have to cover in a day. When fuel is running low, they fill up with diesel at rest and service areas along the way.
Although this system is working fine around the world, it will no longer be possible in this form in the European Union (EU) in just a few years from now. The reason? The EU has put a binding regulation in place requiring a 15-percent reduction in carbon emissions from road transport by as early as 2025. That figure increases to 30 percent by 2030 – and the EU is aiming to be carbon-neutral by mid-century. That won’t be possible with conventional diesel systems.
With this in mind, a range of alternative drive technologies are currently being developed and discussed. Despite efforts to transport more goods using electrified rail systems, experts still expect the number of commercial vehicles on the roads to increase rather than decrease. Germany’s Oeko-Institut, for example, forecasts that more than half of freight transportation services will still make use of road-based commercial vehicles in the future, despite efforts to switch to rail and ship-based systems. If no improvements are made, that means more emissions, not fewer.
Some 25 percent of the carbon dioxide emitted by road transport in the EU comes from a comparatively small number of vehicles: heavy duty vehicles, in other words freight transport vehicles and buses. “This is where we have the potential to reduce CO2 emissions,” observes Martin Kullmann, Director at Connected eMobility. “Together with colleagues from other Siemens departements - the Future Grids team of Smart Infrastructure and our eHighway colleagues at Siemens Mobility - we have prepared a white paper that shows how we can already find solutions to difficult problems: in this case, enabling the electrification of long-distance heavy freight transport and thus ensuring an emissions-free future.”
Power supply en route
The researchers from Siemens reason that electric drives make the most efficient use of power thanks to a combination of a high efficiency rating and an absence of conversion losses. However, electrified long-distance heavy freight transportation poses major challenges for battery technology. Heavy duty vehicles with electric drvies that are currently being developed are expected to run 500 kilometers or more until they need to be recharged. “It will therefore be necessary to supply additional power to the vehicles while they’re en route”, comments Kullmann. “Based on this premise, we developed two scenarios to illustrate how the two available Siemens technologies could impact on and complement each other on the Hamburg-Nuremberg stretch.”
Near future charging facility
The first scenario illustrates the use of an opportunity charging infrastructure. “Siemens already offers technologies for charging large commercial vehicles at the depot, such as plug-in chargers with liquid-cooled cables and plugs for up to 400 amperes,” says Marcel Rümenapf, who heads Account Management at Future Grids. “The higher the charging capacity, the faster the batteries can be charged. Thus, also large batteries can be sufficiently recharged within the legally requested resting period of 45 minutes, during which the vehicle needs to stand still.” Siemens is planning to enable this opportunity charging not in depots only but also for heavy-duty vehicles that cover long distances. “This is an area where the industry needs to combine its strengths and provide users with uniform solutions,” Rümenapf stresses. “That’s why we’re working closely with manufacturers and other partners in standardization committees, for example.“
This example of a charging facility is based on the expected requirements for 2030: The charging facility of the future will have more than five charging stations with a charging capacity of well over 350 kilowatts. It will also have two stations offering charging capacities of up to one megawatt or higher – in the form of robot-assisted systems in some cases. These will make it easier to manage the large plugs and heavy cables, improving safety when connecting and disconnecting. Some of the peak loads associated with the power required when electric freight vehicles are charging simultaneously will be covered in the short term by stationary battery storage and PV systems. This will help operators of charging facilities to save on grid connection costs thanks to intelligent load management.
Dynamic energy supply via overhead lines
The second scenario outlines the implementation of a Siemens Mobility eHighway: This is where hybrid or battery-powered electric goods vehicles will automatically dock onto overhead lines – similar to electrified trains – using a pantograph while en route on heavily used sections of road. This will supply power to the vehicle while it’s moving – both for the drive system in use and to recharge the battery. Overtaking will still be possible with this system. The technology has already proven itself around the world in numerous pilot projects.
“We made use of our expertise in rail electrification to develop a viable solution for the roads,” comments Hasso Grünjes, Head of eHighway. He notes that the strength of the eHighway lies in the way it combines the efficiency of electric rail systems with the flexibility of freight vehicles to produce a sustainable road-based freight transport system. The use of hybridized vehicles with internal combustion engines would enable the system to be introduced quickly. “If eHighway is installed along the classical long distance routes of heavy-duty vehicles, it solves the question of range for battery-powered freight vehicles. As long as the vehicles are in contact with the overhead line, the battery stays charged and could even be recharged.”
The example illustrated here shows an overhead contact line fed by the medium-voltage grid and running along the autobahn. The substation1 is equipped with medium-voltage switchgear, power transformers, rectifiers, and controlled inverters. The power drawn from the line depends on the drive technology used by the freight vehicles, the size of the fitted battery storage system, and the capacity utilization of the section of line. It’s technically possible to transmit more than 350 kilowatts to the vehicle, part of which can be used to recharge the battery while the vehicle is moving.
At the start of the expansion process, heavily used sections of the route will be electrified and expanded step by step to form a supraregional, national, and pan-European network. The efficiency of the technology will increase with the size of the available network
Requests to the legislative bodies
The white paper concludes that a combined technology landscape with stationary charging points along the route and overhead contact lines to provide a dynamic power supply for moving vehicles constitutes the most economically and environmentally attractive option for the future of road-based heavy duty freight transport within Europe. The authors attach demands to this forecast: Investment must start now on the construction and expansion of a powerful, national power supply infrastructure and grid connections along the long-distance network. The government is called on to put clear strategic and financial stimuli in place to achieve this objective.
Sandra Maria Wild - January 2021
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