Editor's note: This article is part of the specialty theme, E-mobility meets the road, by Boyd theme, hosted by GlobalSpec News & Analysis.

As the home of the Nobel Prize and numerous Nobel laureates, Sweden isn’t exactly unfamiliar with innovative thinking and ideas.

This time, Swedish innovation arrives in the form of an electrically charged highway that will top up electric vehicle (EV) batteries while vehicles are moving, a concept known as dynamic charging.

Sweden’s commitment to low emissions transit

Sweden has one of the most ambitious e-mobility goals in the world: 80% of new personal vehicles and half of heavy-duty vehicle sales must be electric. As part of this goal, the government has committed to fully electrifying a 13 mile (21 km) stretch of the E20 highway central to its three largest cities, Stockholm, Gothenburg and Malmö. It could be ready by as early as 2025. The nation’s transport authority, Trafikverket, is currently heavily invested in the problem-solving phase of the endeavor.

It’s a bold decision, but it’s not one that Sweden arrived at without prior research. Pilot projects like the eRoadArlanda have been around since 2017, diving into the practical solutions that would make a real electric highway a practical alternative to stationary charging slots. Looking closer at the technology, they use an in-road charging rail to deliver energy to onboard vehicle batteries on the test track.

Conductive vs. inductive

Undoubtedly, induction charging technologies could be a significant game changer, should they become a viable solution for EVs and e-mobility. However, some key issues exist, such as power efficiency challenges related to coil alignment, interference and roadway contaminants, as well as the weight this equipment adds to each EV.

Sweden has actually had some recent success with conductive rail dynamic charging systems. This, in essence, brings the technology behind slot car racing, to the full-size roadway. eRoadArlanda features an electrified rail that runs along the center of the road. Electric trucks there feature a fold-down conduit to tap into the rail. The trucks get recharged and operators are billed based on the wattage used. Another example exists on Gotland Island e too. Although only for specially modified electric buses and heavy trucks, it underscores Sweden’s passion for a fossil-fuel-free future.

Engineers working on this e-highway still aren't sure if inductive technologies will be ready by the time the road comes to be built. A length like this is a challenging project for engineers. Costs could be prohibitive for adding a whole rail all the way along the highway, but the same could be said for buried induction coils. For all of those copper windings, the roads will need to be dug up to get the coils in place. It’s a major consideration, one that could seriously hamper the project.

E-roads in the equation

E-roads have plenty of skeptics, but there is at least one good reason that they are a viable solution in the e-mobility equation: how they could influence vehicle design.

According to one study conducted by Sweden’s Chalmers University of Technology, EV batteries can be made 70% smaller when vehicle technology is supplemented by e-roads. The smaller batteries work in conjunction with e-road-equipped corridors and traditional charging stations to add meaningful mileage on long trips. This would significantly reduce the battery weight and add EV range as well.

Also consider that as the industrial internet of things (IIoT) begins to reach further into civic infrastructure, this type of available electrical energy on the streetscape will be a basic requirement. E-roads aren't just for cars; they'll likely be key to growing digital networks.

Right now, in e-mobility's rather immature state, the best strategy is based on diversifying charging avenues. So e-roads will continue to be part of the picture. At least until technologies reach comparability with the energy density offered by today's combustion vehicles.

An electric roadmap to the future

A 21-km e-road, imparted with momentum by several pilot projects, is only the beginning. The E20 motorway is testing the practicality of rails and induction coils along its busy corridor, seeking a solution that won’t result in traffic bottlenecks.

Meanwhile, the U.S. is testing the e-road waters. In Detroit, the induction coil approach is being engineered to create an e-road on a downtown street. Utah State University has a similar wireless charging pilot program, although on a smaller scale.

However, Sweden is the first nation to really push the e-road envelope. They’ve already pushed through the growing pains involved with the development of this nascent technology, and now they’re ready to build a whole length of highway.

With their history of innovation and plenty of experience, it should be, as the Swedes say, "Lätt som en plätt." Or, "Easy as a pancake."