Electric bus

Milton Keynes tries out inductively charged electric buses

The city of Milton Keynes is introducing wirelessly charged electric buses in an initiative that is expected to reduce bus running costs by £12-15k per year.

Eight organisations led by a subsidiary of Mitsui & Co Europe have signed a five-year collaboration agreement that will see diesel buses replaced by all-electric vehicles on one of the main bus routes in the city by summer 2013.

Eight electric buses will run on the number 7 route in Milton Keynes seven days a week, removing approximately 500 tonnes of tailpipe CO2 emissions per year as well as 45 tonnes of other noxious tailpipe emissions. The route currently transports over 775,000 passengers a year over a total of 450,000 miles.

The new vehicles will be able to recharge their batteries wirelessly through the day, which means that they will be capable of carrying the equivalent load of a diesel bus.

The buses will charge when power transmitted from a primary coil buried in the road is picked up by a secondary coil on the bus. 10 minutes parked over a coil will replenish two thirds of the energy consumed by the bus’s route. The primary coils will be placed at three points on the bus route, and the buses will charge in the time scheduled for driver breaks at the end of the route.

While inductive charging is new to the UK bus market, it has already been proven in Italy. About 30 electric buses in Genoa and Turin have been using Conductix-Wampfler’s IPT (Inductive Power Transfer) technology since 2002. The company says that with regular interim charging, fleet operators can buy cheaper buses with smaller, lighter batteries in which the cell chemistry is kept healthy by more-frequent, but shorter charging cycles.

The trial was planned and will be managed by Mitsui-Arup joint venture MBK Arup Sustainable Projects (MASP), and is a partnership between: Mitsui subsidiary eFleet Integrated Service; Milton Keynes Council; bus operator Arriva; manufacturer Wrightbus; technology supplier Conductix-Wampfler; Western Power Distribution; Chargemaster and SSE.

MASP’s ultimate aim is use the data collected by the Milton Keynes trial to demonstrate the economic viability of low-carbon public transport. This data could be used to kick-start electric bus projects in other towns and cities worldwide.

John Miles, who initiated the trial from Arup, said: “What makes this project different from other electric bus schemes is the wireless charging system. The Milton Keynes buses will be able to cover a heavily-used urban route because they are able to charge for 10 minutes at the beginning and end of each cycle without interrupting the timetable. This means that for the first time, an electric bus will effectively be able to do everything a diesel bus can do, which is a significant step forwards to a cleaner, quieter, public transport system.”

Noriaki Sakamoto, managing director, Mitsui Europe, said: “Since the withdrawal of the subsidy for diesel buses, we can see that the cost of diesel bus operations will rise significantly. This, coupled with the anticipated reduction in the cost of batteries and electric drive systems for buses, as well as the introduction of wireless charging during the day, means that the electric bus is now a real contender in the future of public transport. Innovation and trials are urgently needed to find a new way forward and Mitsui, as a business enabler, is happy to back this initiative because we can see the long-term benefit.”

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