South Korea tries recharging road to power vehicles

South Korea's top technology university has developed a plan to power electric cars through recharging strips embedded in roadways that use a technology to transfer energy found in some electric toothbrushes.

The plan, still in the experimental stage, calls for placing power strips about 20 cm (8 inches) to 90 cm (35 inches) wide and perhaps several hundred meters long built into the top of roads.

Vehicles with sensor-driven magnetic devices on their underside can suck up energy as they travel over the strips without coming into direct contact.

If we place these strips on about 10 percent of roadways in a city, we could power electric vehicles, said Cho Dong-ho, the manager of the online electric vehicle plan at the Korea Advanced Institute of Science and Technology.

The university has built a prototype at its campus in Daejeon, about 140 km (90 miles) south of Seoul, for electric-powered golf carts and is working on designs that would power cars and buses.

The system that can charge several vehicles at once would allow electric cars and buses to cut down on their battery sizes or extend their ranges.

The non-contact transfer of electricity, also called inductive charging, works by magnets and cables on the underside of the vehicle making a connection with the current in the recharging strip to receive power as they travel over it.

It is employed in some brands of electric toothbrushes that are sealed and water resistant, which do not need to be plugged into anything but use a magnetic connection to receive energy while resting in a cradle.

The recharging strips, which are attached to small electrical stations, would be laid in places such as bus lanes and the roads running up to intersections so that vehicles could power up where traffic slows down, Cho said.

The system will be tested later this year for use in the bus systems of Seoul and other South Korea cities while some of the country's automakers are also cooperating in the project.

Unlike electric lines used for trams, vehicles do not need to be in constant contact with the strips and a person can touch the lines without receiving a shock.

The system so far has proven safe to humans and machinery, Cho said.

The cost of installing the system is an estimated 400 million won ($318,000) per kilometer of road. Electricity is extra.