August 6th, 2013 date can be recognized as one of the most important days in electric vehicle history, because this day marks the "first time anywhere, electric buses provide public transportation services and are recharged right from the road".
Of course, this historic day was all about two new Online Electric Vehicle (OLEV) electric buses that are now providing public transportation services in the City of Gumi in South Korea, on an inner city route between Gumi Train Station and In-dong district, for a total of 24 km roundtrip.
This project follows the development and operation of commercialized OLEV trams (at an amusement park in Seoul) and shuttle buses (at KAIST campus).
Buses receive 20 kHz and 100 kW of power at an 85% maximum power transmission efficiency rate while maintaining a 17 cm air gap between the underbody of the vehicle and the road surface.
OLEV electric bus in Gumi City
System Shaped Magnetic Field in Resonance (SMFIR) was developed by Korea Advanced Institute of Science and Technology (KAIST), which has been working on it from several years. A 180-kW is operational too.
This is how SMFIR is described by KAIST:
"OLEV receives power wirelessly through the application of the “Shaped Magnetic Field in Resonance (SMFIR)” technology. SMFIR is a new technology introduced by KAIST that enables electric vehicles to transfer electricity wirelessly from the road surface while moving. Power comes from the electrical cables buried under the surface of the road, creating magnetic fields. There is a receiving device installed on the underbody of the OLEV that converts these fields into electricity. The length of power strips installed under the road is generally 5%-15% of the entire road, requiring only a few sections of the road to be rebuilt with the xembedded cables."
The main benefit of this solution is the need for a much smaller battery (about three times less than traditional electric buses require).
KAIST says that magnetic field isn't dangerous for humans:
"The vehicle complies with the international electromagnetic fields (EMF) standards of 62.5 mG, within the margin of safety level necessary for human health. The road has a smart function as well, to distinguish OLEV buses from regular cars—the segment technology is employed to control the power supply by switching on the power strip when OLEV buses pass along, but switching it off for other vehicles, thereby preventing EMF exposure and standby power consumption."
Dong-Ho Cho, a professor of the electrical engineering and the director of the Center for Wireless Power Transfer Technology Business Development at KAIST, stated:
"It’s quite remarkable that we succeeded with the OLEV project so that buses are offering public transportation services to passengers. This is certainly a turning point for OLEV to become more commercialized and widely accepted for mass transportation in our daily living."
If the first two buses operate successfully, Gumi City will put 10 more on the roads by 2015. So, this potentially marks the beginning of completely new era for the public transportation system.