Now TfL is taking that a step further by introducing wireless charging for buses, with a new trial due to start next year.

The plan is to keep the city’s buses fully powered up, even when they are in use, without any fumbling with unwieldy charging cables involved.

“We are very conscious of our environmental impact, both in terms of local air quality and also CO2,” says Mike Weston, director of buses for TfL. “We’re seeing a lot more interest in the full electrification of buses, and this is not just in the UK but across Europe and many parts of the world.”

Wireless charging



TfL is investigating “opportunity charging” – grabbing a battery top-up wherever you can. Like many of us with plugging in our smartphones whenever we see a spare socket, the buses can also grab small top-ups quickly and easily, which will allow them to run without the diesel generator for longer.

“Many of our double-deckers will run for 19 to 20 hours per day,” says Weston. “If we put enough batteries on the bus to have enough energy for that, we would have no room for passengers. So we have to look at other ways of creating an electric bus.”

One of those ways is to charge the buses wirelessly. When the bus gets to a terminus it will be parked over an induction pad, which will transfer power to the bus, at the rate of about 10kW every five minutes.

The basic technology is similar to the way an electric toothbrush charges without needing direct electrical contact. The bus will have to be parked fairly accurately over an induction coil in the ground, which will match with one installed on the bottom of the bus.

The gap between the two needs to be about six inches (15cm), so the bus will “kneel” – lowering the suspension just like it does to allow easy access for passengers. That means the driver is not required to get out of the bus and plug it in with a cable, which can add valuable minutes of charging time.