Electric roads are key to Sweden’s target of slashing greenhouse gas emissions from domestic road transport by 70 percent.
However, to achieve just a 20 percent cut by 2020, the country needs to lower emissions by one million tons a year between now and 2030. By 2035, the government wants to find 3,000 kilometers of roads with heavy traffic that can be adapted for electrification. The Swedish Transport Administration, Trafikverket, has been identifying suitable roads and so far, four solutions have been tested.
At the first site, an overhead power line charged trucks via pantographs mounted on their roofs. The four-year test period — along two kilometers of the E16 highway close to Sandviken in central Sweden — ended in 2020.
The second option is the eRoad Arlanda project, a two-kilometer section of the road between Stockholm’s Arlanda Airport and the Rosersberg logistics center. Vehicles use a movable arm to pick up electricity from an electric rail embedded in the road. The test began in 2018.
A third alternative is a conductive connection between the electric road and the vehicle through a pick-up under the vehicle. The pick-up connects to the road by sliding along electric rails laid on top of the road, efficiently transmitting power and charging the vehicle’s batteries. This solution is being trialed between 2020 and 2022 in the Evolution Road project in Lund, southern Sweden, using a city bus as the main test vehicle.
Fourthly, the Smartroad Gotland focuses on a 1.6-kilometer-long electric road between the airport and town center of Visby on the Baltic Sea Island of Gotland. It is an inductive system where receivers pick up electricity under the vehicle’s chassis from a copper cord sunk into the road. The three-year test ends in 2022.
The electric road concept will be most suitable for long-distance transport on the roads with most traffic. The incentive to invest in vehicles for electric roads will depend on the share of goods transported on these roads, and it is estimated that the volume should be 40 percent or more to make this solution profitable.
To these electric road projects, Trelleborg supplied tailor-made sealing solutions, including a special EPDM material with very low conductivity. The seals have to provide a reliable sealing function against water ingress into the rail system and maintain electric conduction to the pick-up connection area. It’s a very demanding application not only due to the wear caused by the pickup device under the test vehicles, but also from the usual non-electric traffic on the road. The sealing has to withstand very harsh weather conditions, with road temperatures ranging from minus 40 degrees Celsius during the coldest part of the winter to more than 60 degrees Celsius on the hottest summer days.
Ethylene Diene Propylene Monomer (EPDM) sheeting is one of the most versatile types of rubber sheeting and best suited for outdoor applications. It is highly resistant to wear and tear, even in the most aggressive external conditions such as steam, UV rays, ozone, saltpeter or extreme weather. EPDM sheeting also maintains its properties under a wide range of temperatures, making it ideal for general industry and construction, automotive, marine and outdoor applications. The EPDM sheeting used in the electric road projects was tailor-made for the application. Source