Overhead cables power electric motor on test truck.
How electric road works
The Swedish Transport Administration is testing an electric road that could minimise the impact vehicles have on the environment. Let us consider how it works. The E16 in Sandviken now hosts a series of roadside posts – 60 metres apart – that span 2km and support power cables which stand about 5.4 metres above the tarmac.
The test vehicle is a large, hybrid-powered, truck. Propulsion comes courtesy of a traditional internal combustion engine that burns diesel, plus an electric motor that requires electricity only. It can, therefore, operate on a standard, non-electric, road.
But this truck has extra features too. As it joins the test road, its pantograph connects to the cables that transfer 750 volts to the vehicle. This energy powers the electric motor that emits no harmful pollutants. What a contrast to the internal combustion engine that also relies on an ever-dwindling supply of fossil fuel.
Electric road maximises potential of hybrid and electric models
On this basis, the electric road solves certain problems. As things stand, a hybrid can be powered by its electric motor only if there is charge in the battery. However, capacity is extremely limited so it often relies on its more polluting, internal combustion, engine.
A fully electric vehicle is more limited. Once its battery is flat, it stops. That is it. Furthermore, the typical recharge time – assuming there is a recharge point available – ranges from 30 minutes to a few hours. Such issues limit practicality and appeal.
The key strength of the electric road is that it enables a hybrid vehicle to travel in non-polluting, electric only, mode as long as it is connected. This, of course, reduces its impact on the environment and public health. Furthermore, a fully electric vehicle has an unlimited range whilst touching the overhead cables.
Director General of The Swedish Transport Administration, Lena Erixon, argued: “Electric roads will bring us one step closer to fossil fuel-free transports, and has the potential to achieve zero carbon dioxide emissions.” She added: “This is one way of developing environmentally smart transports in the existing road network.”
Electric road could have limited shelf life
But Sweden's electric road might only have value short term; at least in its current form. Why? Because every generation of electric vehicle has greater range and faster recharge times than its predecessor. It is, therefore, only a matter of time before they travel (say) 1,500 miles per-charge and refuel within minutes.
On this basis, it seems unlikely such vehicles will require the large, expensive, roadside infrastructure that is now being tested.