Power delivery systems like these have been around since the 1880s, and are still used today. In crowded city centres, overhead wires are the safest way to provide power to buses and trolleys following fixed routes, and they're also the only way to keep high speed intercity trains fed. Vehicles that run on rails harvest electricity from a single overhead wire, using their tracks to complete the circuit, buses and other vehicles with tires need a pair of overhead wires instead.
The overhead wires provide 750V of direct current to the hybrid electric system in the truck through a pair of pantographs. The pantographs can automatically deploy and attach to the wire while the vehicle is traveling at speeds of up to 90km/h, meaning that the truck can seamlessly enter and exit a roadway. The truck itself is a hybrid electric, with a 360 horsepower motor that runs on both biofuel and a 5-kilowatt-hour lithium battery pack that provides enough power to travel about 3km.
Sweden is also testing a different type of electric road, using conductive transfer technology based on an energised rail embedded in the road surface. The rail is exposed, and special ‘shoes’ underneath vehicles can draw energy from it continuously. The rail is only energised when a vehicle passes over it, and “multiple safety barriers” are in place to minimise the risk of accidents.
These roads will be undergoing testing over the next two years. The Swedish government hopes that it will learn enough about what works and what doesn't to help it make informed infrastructure decisions, with the goal of a completely fossil fuel-free vehicle fleet by 2030.
