A fully electric bus is being tested on a demanding urban route in Milton Keynes
Developers of schemes to provide more environmentally friendly buses on city streets have said that support from government grants and awards has been crucial in allowing them to bring their ideas to fruition at a time when subsidies for green technology are being questioned.
Vantage Power, which has developed a hybrid diesel-electric powertrain that can be retrofitted to existing buses, was the recipient of £40,000 from Shell’s Springboard awards earlier this year, and has also received a grant from the government-backed Technology Strategy Board. The company is also backed by individual investors. Vantage Power was set up by Alex Schey, an engineer, after he left university.
“Several things conspired to mitigate the effect of the recession on hybrid buses – the main thing being the green bus fund, run by the government to subsidise the purchase of hybrid and electric buses,” Schey told PE.
“The government covered the cost of the difference between buying a new conventional bus and buying a hybrid.”
The company is focusing on four double-decker models, which Schey says represent more than half of the UK bus fleet. Vantage’s system is in a prototype phase, but full-scale manufacturing is expected in 2015. A bus can be retrofitted in a day, Schey claimed. “The concept of hybrid retrofitting is quite new and we are bringing a lot of innovation to that,” he said.
Fuel savings are comparable to the best-in-class hybrid systems on the road today, equating to about £20,000 a year, according to Vantage. Developing hybrid solutions for single-decker buses is much less economic than for double-deckers, Schey said, as they use comparatively smaller amounts of fuel. “That will happen only when the components we use come down in price, and that will take time.” Ultimately, there could be purpose-built buses using Vantage’s technology.
While the battery cells for the technology are being imported, Schey said the company was proud that about 80% of components, including the diesel engine, motors and inverters, were being sourced in the UK.
Vantage’s B320 powertrain is based on a series hybrid architecture. Unlike conventional vehicles, the combustion engine is disconnected from the wheels and acts solely as an electrical generator. This generator, also known as a range extender, charges an energy storage device such as a battery, which then powers an electric motor fitted to a conventional axle and differential.
The company’s business model means that bus operators effectively pay a monthly fee for use of the powertrain that is less than the amount saved through using less fuel, said Schey.
In Milton Keynes, meanwhile, trials are under way of the city’s first fully electric bus, supported by the local council and several partners, including engineering firm Arup, UK manufacturer Wrightbus, and bus operator Arriva. The bus, which is being trialled on a 15-mile route, is being inductively, or wirelessly, charged to top up its batteries at each end of the journey.
Jamie Talbot, a chartered mechanical engineer at Arup, said that it was possible to charge the buses in this way without affecting their timetable. The scheme is said to be the first of its type in Britain.
“The buses are plugged in overnight, so start the morning on a full charge,” Talbot explained. “What the inductive charging system allows us to do is give a boost to the battery over the day. If this technology was not available, we would have to have a huge battery to run the service over the day.” The batteries would be prohibitively expensive and take up a lot of space, Talbot added.
The vehicle is based on the Wrightbus Streetlight platform. Wrightbus has developed electric Streetlight buses before, but without inductive charging technology. “It has had to change a number of things to do this,” said Talbot.
The electric buses will go into service in the new year, making their debut on route 7, which runs between Wolverton and Bletchley.
In the meantime, bus operator Arriva is running a training programme to familiarise drivers with the new technology, which includes not only how to drive the vehicle, but also how to recharge wirelessly at each end of the route, and how to maximise the battery’s performance.
Paul Adcock, area managing director of Arriva, said: “Electric buses have huge potential, and we’re exploring how they can help us take better care of the environment without compromising passenger service. With the help of the project collaborators, we’ll be monitoring the buses closely over the next five years.”
John Miles, Arup consultant and engineering research professor at Cambridge University, who will be tracking the buses’ performance, said: “These electric buses will be expected to do everything a diesel bus does, so they won’t be getting any preferential treatment. They will be operating on a demanding urban route, and that’s all part of the trial’s aim – to prove that electric buses can be tough as well as green.”