Volvo is developing an electric truck system that uses power lines built into the surface of the road.
It has built a 400-metre long track at its testing facility in Hällered outside Gothenburg and the company has been researching the system since last autumn.
Volvo is working with Alstom on the idea which entails two power lines built into the surface of the road along the entire length of the road. A current collector in contact with the power lines will be located on the truck.
The lines are sectioned so that live current is only delivered to a collector mounted at the rear of, or under, the truck if an appropriate signal is detected.
As an additional safety measure, the current flows only when the vehicle is moving at speeds greater than 37 mph.
Mats Alaküla, Volvo’s expert on electric vehicles and professor at Lund University, said: “The vehicle is equipped with a radio emitter, which the road segments can sense. If an electric vehicle passes a road segment with a proper encrypted signal, then the road will energize the segments that sense the vehicle.”
Volvo’s electric truck
Research currently focuses on transferring the electric current from the lines in the road into the truck so Volvo is using a standard FH12 tractor unit with a diesel engine.
There’s no electric motor installed at the moment. When the collector comes into contact with the power lines, 750v of direct current is delivered and routed to a water-cooled heating element that has a similar power requirement to an electrically-driven truck.
The collector has been designed to track the power rails, even when the vehicle is not directly over the middle of the contact lines.
Volvo reckons it will be some years before the system is perfected. Future research involves the continued technical development of the current collector, electric motor and the control systems required. It also involves road construction, road maintenance, electricity supply along the roads and various payment models, etc.
“A lot of years remain before this is on our roads,” says Mats Alaküla, “But, if we are to succeed in creating sustainable transport systems, we must invest significantly in research now. I am convinced that we will find a cost-efficient way to supply electricity to vehicles in long-distance traffic and we have already come a long way in our research.”