Korean Road Wirelessly Charges New Electric Buses

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Electric vehicles still have limited range, expensive batteries, and few charging stations. While mainstream manufacturers seek to improve battery tech, the Korea Advanced Institute of Science and Technology (KAIST) has a different idea. Who needs big batteries and stations when the road itself can charge vehicles?

In July, two new buses began public service in the South Korean city, Gumi. The buses, or online electric vehicles (OLEVs), travel a road like a wireless cellphone charging mat—only, this particular mat is 7.5 miles long and cost $4 million to build.

How does it work? The buses are inductively charged throughout the route by 180 kW power sources periodically embedded in the road. KAIST says just 5% to 15% of an already existing road needs to be rebuilt to convert it into a wireless charger.

Each power source connects to the grid and is selectively turned on or off as a bus approaches and leaves. When on, the source produces a magnetic field that wirelessly transfers energy to a receiver underneath the bus. The magnetic field is converted back into an electric current and sent to the battery and motor.

KAIST’s approach was first developed by researchers at the University of California, Berkeley. But the scientists worried strong electromagnetic fields might have adverse health effects and abandoned the idea. (A problem KAIST says they’ve solved—their vehicles fall within international standards for health and safety.)

Wired electric trolley bus.

Wired electric trolley bus.

KAIST says their buses convert up to 85% of the power sent from the embedded source. Their batteries are about a third the size of a typical electric car battery, thus reducing weight and cost, yet they needn’t ever stop to charge. If all goes well, ten more KAIST buses will be added to the route by 2015.

Wireless power transmission has a long history. Of course, Nikola Tesla is the godfather of wireless power. Tesla wanted to send electricity wirelessly from central power stations using giant Tesla coils, and he even filed a patent for an inductive electric railway system.

Tesla’s ideas didn’t catch on—our thoroughly wired world is testament to that—but the dream of wireless power has never really gone away, and it’s finding a new market in electric vehicles and public transportation.

Indeed, a fleet of inductively charged buses have prowled the streets of Turin and Genoa, Italy for over a decade. But the Italian buses aren’t charged along their route, like the KAIST buses. And that’s what makes the Korean system unique.

When KAIST president Suh Nam-Pyo spoke at the system’s first test site, an amusement park in Seoul, he boldly claimed, “The potential for application [of this technology to public transport systems] is limitless. I dare say this is one of the most significant technical gains in the 21st century.”

So, are road-charged wireless vehicles the wave of the future?

Although the prospect of a continuously juiced car sounds lovely, inductive roads on a grand scale probably aren’t realistic. The private sector can buy and build discrete charging stations, but the government has a monopoly on roads—and it’s already difficult to marshal funds to rebuild older pieces of infrastructure. Even for governments who subsidize electric cars, upgrading and maintaining a nationwide network of inductive roads would be a different story altogether.

In all probability, political support would be hard to win before electric car tech goes mainstream. But lacking an alternative, wide adoption of electric cars requires manufacturers improve batteries and build charging stations—at which point, there’d be little need for inductive roads, and the issue would be a non-starter in legislatures.

But what about on a smaller, more specialized scale, like along heavily traveled public transportation routes in cities? That seems more likely. Electric trolley buses are ubiquitous around the world. While they reduce noise and pollution, they also draw energy from a bristling nest of wires overhead. By limiting required funding and promising to beautify a few urban areas in the process, KAIST’s inductive roads would be an easier political sell, and may well take root in a city or two—maybe more.

Image Credit: KAIST, Ibou69100/Wikimedia Commons

Discussion — 5 Responses

  • AntonOfTheWoods August 25, 2013 on 2:05 pm

    The principle has been in use in Bordeaux, France for their tram system for around a decade now. There were some pretty annoying outages while they got the moisture problems sorted (there is a big river that runs through the city) but it’s pretty solid now. It cost LOTS to develop but it has meant that much of the city has trams and no overhead lines. In fact, the system is a hybrid one – in the city centre where the overhead lines would be an eyesore the system uses induction and in the suburbs it uses overhead lines so the project costs were kept down. 99% of people in Bordeaux are over the moon about it…

  • John Doe August 26, 2013 on 12:48 am

    But are we going on the right track or electric vehicles need more than thier fair share of new research? Read this article to know more: http://spectrum.ieee.org/energy/renewables/unclean-at-any-speed

  • John Doe August 26, 2013 on 12:49 am

    But are we on the right track for a green future? Read this article and find out why it is a Clear no. http://spectrum.ieee.org/energy/renewables/unclean-at-any-speed

  • Ian Ayers August 28, 2013 on 4:26 am

    I think you might be missing the potential of this technology. As you point out, electric vehicles that are hooked up to a wire (trains, metros, buses, trollies) have been ubiquitous and quite successful for a long time, while battery-only vehicles have had very limited success despite the enormous amount of effort that has gone into their development. Governments would not have to install and maintain the charging infrastructure. Lots of private companies (electric utilities, cable TV, water companies) currently install and maintain systems under the public streets. Systems like Kaist’s could grow organically, starting with bus systems, then letting taxis use the system with appropriate expansion into taxi stands and routes, then urban delivery services, and so on. Each new user group inducing and financing an incremental expansion. If electric batteries don’t improve and drop in price fast enough, I think something like OLEV is inevitable.

  • Muhammad Saeed December 19, 2013 on 3:18 am

    Ref PM / EVCE / 2013 / 12 / 01
    Dated Dec. 19, 2013
    Sub.. Arrangements for setting up Road for Electric Vehicle Charging
    Dear Sir,
    We are going to establish a fleet of Electric buses for operation in various cities of Pakistan. These Electric buses will be operated with in the city, as City Bus.
    Further, we are going to establish a facility for the manufacturing of Electric cars, electric rickshaw and electric motorcycle.
    It has been brought in to our knowledge that you manufacture, install, construct the roads for electric vehicle charging, based on wireless and based on physically of charging wires.
    We have plan to start with, initially food major cities of Pakistan. Total requirements of these roads will be 20, initially.
    You are requested to kindly forward us, Full Corporate Offer, Duly sported by the following information
    1 – Ex-factory price of the each road setup,
    2 – Fright charges up to Karachi roads,
    3 – Cost of the sea insurance
    4 – Cost of the installation / construction of this road in Pakistan
    5 – usual / normal length of the road
    6 – Time required for charging of Electric bus and of electric car
    7 – All other required information. After receiving your offer we may plan to visit you.
    Thanks and Regards
    Muhammad Saeed
    Cell +92-332-5440-965

    참조 PM / EVCE / 2013 / 12 / 01
    2013년 12월 19일 일자
    하위 .. 충전 전기 자동차 를위한 도로 를 설정 하기위한 장치
    친애하는 각하,
    우리는 파키스탄 의 여러 도시 에서 작동을 위해 전기 버스 의 함대 를 구축 할 것입니다. 이 전기 버스는 시내 버스 로 , 도시에서 함께 운영 됩니다.
    또한, 우리는 전기 자동차 , 전기 인력거 와 전기 오토바이 의 제조 시설을 설립 할 것입니다.
    그것은 당신이 , 제조, 설치 , 무선 을 기반으로 물리적으로 전선을 충전 기반으로 전기 자동차 충전을위한 도로 를 건설 우리의 지식 에서 가져왔다 .
    우리는 시작 하는 계획 , 파키스탄 의 초기에 음식 의 주요 도시 가있다. 이 도로 의 전체 요구 사항은 처음에 20 이됩니다.
    당신 이 친절하게 , 전체 기업의 제안 을 우리에게 전달하도록 요청 하는 정당 은 다음과 같은 정보에 의해 자랑 해 보였다
    1 -각 도로 설치 의 전 공장 가격,
    2 – 공포 요금 카라치 도로 까지 ,
    3 – 바다 보험의 비용
    4 – 파키스탄 이 도로의 설치 / 건축 비용
    5 – 도로의 보통 / 보통 길이
    6 – 전기 버스 와 전기 자동차 의 충전 에 필요한 시간
    7 – 다른 모든 필요한 정보를 제공합니다. 당신의 제안 을받은 후 우리는 당신 을 방문 할 수 있습니다.
    감사합니다 감사합니다
    무하마드 사이드
    휴대 +92-332-5440-965