Electric road offers flexible charging

19th October 2017
Enaie Azambuja

In recent years, electric roads have emerged as potential alternatives to the heavy and expensive batteries currently needed in electric road vehicles. Now researchers at Lund University in Sweden have developed an even smarter technology – that doesn’t require digging up stretches of road to install the system. Instead, a small conductive rail is laid on top of segments of the road.

”The vehicle has three contact points with the road through which it connects to the power supply. It works much in the same way as a charging pole; except the vehicle charges both while moving and standing still”, explains Mats Alaküla, professor of industrial electrical engineering and automation at Lund University.

The rail is only active when covered by the vehicle, making it a safe option for cities. The system notices when you leave a driving lane and automatically disconnects the “pick up”– reconnecting when you are back. As a driver you wouldn’t notice anything beyond a symbol on your dashboard.

The current challenges for electric vehicles include the large and expensive batteries needed and the limitations in driving range. An electric road solution reduces the need for batteries by up to 80%.

”Modern conventional electric vehicles have a driving range of 300-500 kilometers. With an electric road system covering the national and European road network, you only need a battery range of 50-100 kilometers, to keep you covered if you come to the end of an electric road”, says Mats Alaküla.

For longer distances, around 50% of the national and European road network (e.g 10 out of 20 km on average) needs the rail installed for vehicles to keep running non-stop.

The implementation would be different in cities than in other areas, stresses Mats Alaküla. In cities, the rail would be installed strategically on select road segments, bus stops, loading docks for trucks or waiting lanes for taxis, for example. This way, more complicated areas like intersections or roundabouts can be avoided.

There are alternative solutions currently being developed around the world that are similar in many respects. The key differences with this technology are not having to install anything below the surface, and less points needed where electric power is fed into the system (approximately one per 100 meters.)

”The perfect charging solution is one where you can charge big, small, moving or stationary vehicles – both in a city setting and a countryside setting. Our ambition with this project has been to develop a technique that can do all of that”, says Mats Alaküla.

There is one big unknown, however. Most electric road systems have yet to be tested in the real world, where winter conditions, traffic accidents and repaving of roads occur.

”Ideally, all of these competing technologies would be tested within the next five years, so we can wear them down and see what their strengths and weaknesses are”, says Mats Alaküla. “After that, we will be ready to select the most suitable electric road system for standardisation and extensive dissemination”.

For this system, at least, that process will begin next year – when the city buses in Mariestad in Sweden will start using it. In the longer term, an even bigger challenge remains: the switch from fossil fuel powered vehicles to electric cars may only make environmental sense if the electricity is generated from primarily clean or renewable sources.

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