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World’s first road-powered electric vehicle network switches on in South Korea

South Korea has rolled out the world’s first road-powered electric vehicle network. The network consists of special roads that have electrical cables buried just below the surface, which wirelessly transfer energy to electric vehicles via magnetic resonance. Road-powered electric vehicles are exciting because they only require small batteries, significantly reducing their overall weight and thus their energy consumption. There’s also the small fact that, with an electrified roadway, you never have to plug your vehicle in to recharge it, removing most of the risk and range anxiety associated with electric vehicles (EVs).

The network consists of 24 kilometers (15 miles) of road in the city of Gumi, South Korea. For now, the only vehicles that can use the network are two Online Electric Vehicles (OLEV) — public transport buses that run between the train station and In-dong.
Diagram of the SMFIR wireless power transmission technology

Diagram of the SMFIR wireless power transmission technology

Exact details of the system are hard to come by, but we believe that the power is delivered by cables that are around 12 inches (30cm) below the road surface. The power is transmitted wirelessly via Shaped Magnetic Field in Resonance (SMFIR), a technology developed by the Korea Advanced Institute of Science and Technology (KAIST) that essentially runs 100 kilowatts of power through some cables at a very specific frequency (20 kHz in this case), creating a 20 kHz electromagnetic field. The underside of the bus is equipped with a pick-up coil that’s tuned to pick up that frequency, and thus AC electricity is produced via magnetic resonance. (Read: How wireless charging works.) Transmission efficiency is an impressive 85% thanks to the “shaped” part of the technology, which targets the electromagnetic field at the vehicle, so that less energy is lost to the environment.
The relative complexity of a hybrid (top) vs. OLEV

The relative complexity of a hybrid (top) vs. OLEV. The reduced complexity will result in cheaper/lighter/more efficient vehicles.

The OLEV receives 100 kilowatts of power via SMFIR, while maintaining a 17cm gap between the underside of the bus and the road surface. Because each OLEV has a small battery (about one-third the size of the battery in a conventional EV), only small portions of the road (5-15%) need to be electrified. Further increasing efficiency and reducing the radiation received by other road users and pedestrians, the electrified sections only turn on when an OLEV approaches. (In case you do get caught near a strip of electrified road as an OLEV passes by, the level of radiation produced by SMFIR is well within the limits imposed by international EMF standards.)


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