South Korea opened the world’s first road-powered electric vehicle network yesterday, paving the way for other cities around the world to follow.

The 15-mile public transport network on the inner city roads of Gumi City features sub-surface electric cables that magnetically transfer power to the online electric vehicle (OLEV) overhead. The process is wireless thanks to a receiving device installed on the underbody of each OLEV that converts the magnetic fields into electricity.

The public buses are charged on the move and when stationary, thereby eliminating the need to pull over and plug in to a power source.

The technology was developed by researchers at the KAIST Graduate School for Green Transportation as an alternative to using conventional battery storage.

While the buses do carry several small batteries – about a third of the size of a traditional electric vehicle engine – they can easily be charged by drawing on the constant power source 17cm below them.

The network's power system uses segment technology to limit the supply to OLEV buses and switches it off for other vehicles.

Gumi currently has two OLEVs on the network but the city plans to roll out 10 more within the next two years.

One drawback with KAIST’s sub-surface solution is that it requires 15 percent of the road to be replaced in order to fit the power cables. This arguably makes over-head cables, such as those on the San Francisco bus network, easier to implement.

Director of the centre for wireless power transfer technology business development at KAIST, Dong-Ho Cho, said: “This is certainly a turning point for OLEV to become more commercialised and widely accepted for mass transportation in our daily living.”

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