Mannheim, Germany, and Gumi, South Korea, recently joined a growing list of cities outfitting electric buses with "induction charging" — a wireless technology that charges their batteries on the go. The advance remains in its trial phase in the United States, but will get a major public debut early next year in Long Beach, California. The city's transit authority has contracted to install the system on 10 buses on a route that runs downtown.
"I think we're on the verge of seeing much larger adoption," says Michael Masquelier, chief executive at WAVE, which develops the charging system. "We have somewhere between 10 and 20 additional opportunities in cities in the U.S. that we're working on to deploy. There's a tremendous amount of interest."
The wireless system works when one charging pad is attached to the bottom of an electric bus and another is planted in the road at a key point along the transit route. After the bus stops over the pad in the road, the induction charge sends power to the battery via a wireless transfer that can travel across several inches of airspace. A few minutes later — depending on the size of the battery — the bus is ready to resume its route.
The system offers multiple advantages to traditional electric bus charging. Chief among them is that a wireless bus doesn't have to be taken off the road to get a full charge from a depot. It can last the full transit cycle of 16 hours by stopping over the charging pad a couple times during the day, says Masquelier, whereas a traditional electric bus must be replaced halfway through its cycle by another bus with a full battery.