With 12,427 miles of highway, electrifying all of them would be expensive but cheaper than expanding public transit.
By Murray Slovick, Contributing Editor
The world’s first road that allows electric vehicles to recharge as they drive has been installed on 2 km (1.2 miles) of public road just outside Stockholm Sweden.
The road’s builder and sponsor, the eArlanda consortium, explains that energy is transferred from two tracks of rail embedded in the road. As the vehicle moves over the rail, a movable arm on the bottom of an electric car or truck detects its location and moves into contact with it.
The rail is connected to the power grid and divided into 50-m sections, with an individual section powered only when a vehicle is above it. Energy is delivered at 200 kW. When a vehicle stops, the current is disconnected. There’s no electricity on the surface—the electricity is 5-6 cm down from the surface—and eArlanda claims you could walk safely on the track. The system is able to calculate the vehicle’s energy consumption, which enables electricity costs to be determined and charged per vehicle and user.
The system is not unlike slot-car racing, the hobby of racing with miniature autos that are powered by grooves or slots in the track on which they run. The exception is that in the real-life version, the cars are not guided by the slot. In fact, if the vehicle is in the process of overtaking another vehicle, the arm automatically retracts.
Trolley-like overhead conductors were also considered, but rails embedded in the road will cause far less obstruction to the driver’s field of vision, compared with roadside poles for the suspension of overhead cables.
The project, called eRoadArlanda (so named because it’s part of road 893 between the Cargo Terminal at Stockholm’s Arlanda airport and the Rosersberg logistics area), is one of several projects in the Swedish Transport Administration’s pre-commercial procurement for the development of electrified roads.
How Will It Proceed?
The first vehicle to use the electrified road is an 18-ton truck that will be carrying goods for PostNord.
The road will be used for a period of two years to determine how well the installation works under normal traffic conditions in various weather conditions. The investment in the eRoadArlanda project is in line with the Swedish government’s target of creating a fossil-fuel-free transportation infrastructure by 2030.
Sweden has roughly half a million kilometers of roadway, of which 20,000 km are highways. What would it cost to electrify the entire system? The eRoadArlanda consortium has done the math:
Electrifying 20,000 km of roads in Sweden with conductive feeds is expected to cost about SEK 80 billion (about $9.44 billion U.S.). Current vehicle-fuel costs, the consortium estimates, amount to (seven million tons × SEK 6,000) SEK 42 billion ($4.956 billion U.S.) per year before tax. Clean electric power would cost about (25 TWh × SEK 0.4/kW) SEK 10 billion ($1.18 billion per year before tax). Therefore, the savings would be SEK 32 billion ($3.776 billion) per year.
If it’s assumed that electric cars with small batteries cost the same as internal-combustion cars, it would take less than three years to pay for the electrification of the roads. While initially expensive, the cost of electrification per kilometer is said to be 50 times lower than that required to construct an urban tram line.
The Swedish Road and Transport Agency’s National Plan for Electric Roads envisions the project starting with the electrification of the 1,365-km triangle linking Stockholm, Malmö, and Gothenburg.