Vehicles powered by underground cable? Korea's top tech institute is serious about it. For one thing, batteries would be lighter and cheaper
Auto companies around the world are touting plug-in hybrid and all-electric vehicles. In South Korea, researchers are working on an experimental alternative they say could revolutionize the way vehicles will be powered. A group of 55 scientists and engineers at the Korea Advanced Institute of Science & Technology, the country's top technology university known as KAIST, is working on designs for a shuttle service at a Seoul amusement park where vehicles will be driven with power transferred by magnetic induction from cables buried underground.
The shuttle service, due to begin a test run in November and open for public use next spring, will be the first time the technology will be used for public transportation. Under the university's plan, electricity-powered cars don't need to be equipped with heavy and bulky batteries that are too expensive for most consumers.
That's because electric cars will be continuously charged while running on roads embedded with power strips. "Given the need to cut down emissions, electrification of the power train appears inevitable," says Cho Dong Ho, director of KAIST's Institute for Information Technology Convergence, who is heading the project dubbed Online Electric Vehicle (OLEV). Cho claims magnetic induction technology would be "the most convenient and cost-effective" way to usher in an era of electric vehicles. KAIST researchers point out that it also resolves such problems associated with battery-powered vehicles as short driving range and long charge time.
Overcoming the Ground-Clearance Issue
There are a number of questions to be addressed, and so it could take years for OLEV to become commonplace. But KAIST scientists have reported significant progress since the university first demonstrated the technology in February with a converted golf cart at its campus in Daejeon, 140km south of Seoul.
One major challenge is to gain high efficiency of power transfer without the car coming into direct contact with the supply. When KAIST proposed the idea to Korean President Lee Myung Bak in February, the magnetic device under the demonstration car was only 1cm above the ground and sucked up 80% of power from cables embedded in the road. Researchers managed to widen the gap to 12cm—the minimum requirement for vehicles in most countries—in August when the university ran an OLEV bus on its campus, but the efficiency dropped to 60%. It has since improved efficiency to 72% even as it widened the gap to 17cm. "The biggest hurdle has been removed as we passed the 70% efficiency requirement," crows Cho.
Another big question is cost. Project coordinator Song Min Choul at KAIST argues that laying power strips underground would be less costly than building charging stations in big cities where real estate prices are exorbitantly high. "Investing in charging stations in cities doesn't make any business sense as electricity prices are too cheap to recoup investment," Song says.
Moreover, the OLEV system needs only one-fifth the size of the bulky batteries typically used, saving on advanced battery materials. That's because batteries will be charged while on the go or trapped in a traffic jam. Researchers at KAIST figure Korea needs to place underground charging strips beneath 30% of its roads to make the system work across the country. In other words, alleys and smaller roads in residential areas don't need underground power cables.
Working Toward a Seoul Bus Test
Skeptics abound. The magnetic charging technology is not new but has not been commercialized since a similar test was made at the University of California-Lawrence Berkeley National Lab some two decades ago, according to critics. KAIST engineers respond that since then no serious research has taken place for the technology as oil prices stayed affordable until recently.
Doubts linger over whether the system could be put into practice even if results are satisfactory in lab environments. Kim Pil Soo, who teaches automobile engineering at Daelim University College at Anyang, just south of Seoul, notes that power-transfer efficiency drops dramatically once the gap widens between power strips and receiving devices on vehicles' undersides. "Cars move from left to right and it's tough to stay on course to receive energy properly," Kim says. "It could work on a track but results will be totally different on open roads."
The Korean government, however, is prepared to give it a trial. The central government, which in May allocated $21 million for initial research this year on the project, is also reviewing another request for $83 million for next year's experiments as part of President Lee's plan to spur economic growth through green technologies. In addition, the Seoul metropolitan government set aside $832,000 to test the shuttle service at the city's amusement park. "If the shuttle service proves successful, the next step is to test the system on bus lanes in select routes," says Yu Jun Su, an official responsible for managing the city's air quality.
KAIST's target is to attract commercial investments from 2012 for gradual adoption of the system over 30 years or so. "Of all the solutions dreamed up to end emission problems without making drivers give up heating, air-conditioning, or worry about recharging batteries, OLEV appears to be the best path so far," says Cho.