Electric Public Bus Recharges On The Move
Truth be told, who wouldn’t love to be all green-savvy and cruise around in an environmental-friendly electric car if you could afford it and spare the time to recharge? But then, there is also the fear of running out of power in the middle of a junction, or worse, in the middle of nowhere. Yet, we all agree that electric cars are a great invention. The city of Gumi in South Korea now put all excuses aside and took public transportation to the next level by enabling public buses to run on electric power. What’s new? They do not have to stop to re-”fuel” – not once.
The KAIST Graduate School for Green Transportation, who aim to make green transport Korea’s new growth engine, has developed Online Electric Vehicle (OLEV) buses that can recharge their batteries while being in use. The technology, ranked in Time Magazine’s Top 50 inventions in 2010, basically works like charging mats for smartphones that use electromagnetic induction – simply on a much larger scale. Magnetic charge plates, one embedded in the roadway, one inside the bus, make the current flow and are only “switched on” when they come close to each other.
With a gap of 17 cm between magnet plate to magnet plate there is up to an 85% maximum power transmission efficiency rate that can transfer 20kHz and 100 kW (136 horsepower). The magnet plates under the road take up only 5-15% of the actual road, meaning that roads need not to be completely teared apart to implement the new technology but only small fractions of it. The batteries themselves are only a third of the size of a regular electric car battery so less energy is overall needed.
Gumi is already using this new technology in trams at the Seoul Grand Park amusement park and in shuttle buses on the school campus. In August, Gumi continued their OLEV trial phase with two public buses that actively ran between Gumi train station and the In-Dong district, which covered a distance of 24 km. They continuously want to extend the fleet with implementing ten more public buses by 2015.
Although the OLEV project is the first functioning example of electric vehicles on the move other inductive charging projects have also been successful, such as in Torino, Italy or in Utrecht, Netherlands. Dong-Ho Cho, leader of the team at KAIST says “this is certainly a turning point for OLEV to become more commercialized and widely accepted for mass transportation.” It simply makes sense to equip public buses that take the same roads day by day, always stop-and-go, with a self-sustainable technology.