Is it time to ditch the trolley buses?

17:00, Jun 01 2012
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ECO-FRIENDLY: This electric bus is part of a world-first initiative by the Seoul Metropolitan Government, which began running a fleet of full-size battery buses on the Mt Namsan circular routes in December. This is the first time that battery electric buses have been used for commercial activities

The pantograph is as much an iconic image of Wellington as the inside-out umbrella, but it's an image that's looking increasingly outdated.

The city's fleet of 60 trolley buses, which cost $27 million and entered service only four years ago, would be coming to the end of their working lives within 10 to 15 years, and we should start thinking now about phasing them out, NZ Bus chief executive Zane Fulljames told Greater Wellington regional councillors last month.

By the end of the decade, he said, technology should exist to allow for a network of battery-powered buses in a city the size of Wellington, which would save the council about $10m a year that it currently spent on maintaining the trolley buses and their network of overhead wires.

Councillors had a real opportunity to build a long-term plan allowing for the transition from trolley buses, to diesel-electric hybrids, to fully electric buses in that time, he said.

Council chairwoman Fran Wilde was all for the idea.

"The sooner the better  we think electric buses would be wonderful for Wellington," she said. "If NZ Bus are considering it, we would encourage them."

Contracts for the trolley buses and the maintenance of the overhead lines would be up for review when they expired in 2017, she said.

The council was reassessing the operation in advance of the review. "The trolleys are quite costly and there would be significant extra funding required if we have to renew the electric power network."

But Mr Fulljames conceded that the self-contained battery bus had not yet been perfected. He urged that, instead of being early adopters, Wellington's transport mandarins should be "smart adopters" and wait until the technology was tried and tested on the world stage.

Since the mid-1990s, the autonomous electric bus has been emerging at a grassroots level on the global mass transit scene.

Small electric bus networks are run in New York, Seoul, Hong Kong airport and in towns and cities around the United States, China, England and Australia.

This week Kuala Lumpur announced it was considering introducing battery-run buses in the next two years  the Malaysian capital is home to more than 7 million people.

The city is looking at buying about 15 buses, at NZ$500,000 each. They have a range of 250km to 300km per charge and would eventually be rolled out to cover the whole city.

Electric buses can now be charged in under 10 minutes and various firms are looking at ways to power them up using solar energy.

The quiet, fumeless buses are often hailed as a zero-emission transport option but are more expensive than diesel buses to produce. The key to their performance is battery protection  a technology yet to be perfected.

Under extreme conditions the batteries can  and do  explode.

Last week a sports car travelling at 180kmh slammed into the back of an electric taxi in southern China, setting the vehicle on fire and killing its three occupants.

Neither the manufacturer nor police have determined yet whether the high-speed impact or the ensuing fire caused the deaths.

Kapiti environmental health researcher James Chappell is excited by the idea of Wellington having a network of battery buses, but has qualms about the technology.

He is about to publish a manual on electrosomatics  the health effects triggered by electric and magnetic fields. The electric bus proposal needed serious research, he said.

Electric cars had what he considered a design flaw  the cable ran under the floor, potentially delivering high levels of "electrosmog" to the bodies of the passengers above.

"When it was suggested we have battery-powered buses, my heart leapt for joy. We would all be better off without those overhead cables and the magnetic field below them.

"But just a minute. Will the coach builders do the same dumb thing  running the cable from the battery under the seats? I hope not. I hope they will consider the health of the passengers and solve this design problem."

Critics also view the electric bus batteries themselves as environmentally unsound, because they are toxic to manufacture and tricky to dispose of.

Mr Fulljames said great inroads were being made into smaller, safer and more sustainable battery technology, especially in Asia.

Meanwhile, there were "really good signs" the technology was emerging globally to the point where fully electric buses could be silently prowling Wellington's streets as early as 2025.

Pros And Cons

Lack of an internal combustion engine means fewer tune-ups and oil changes. However, the skills needed to maintain the sophisticated buses need a more highly trained workforce.

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The buses' quietness is double-edged. Smooth and silent will reduce noise pollution but could mean accidents in a city such as Wellington, which is known for its jay-walkers.

What Is It?

A battery electric bus is powered solely by an onboard rechargeable battery (and is not to be confused with a hybrid electric bus, which has a backup diesel motor to avoid stranding).

The battery electric bus uses electric-powered controllers and a motor instead of an internal combustion engine, and a regenerative braking system harnessing the motor as a generator to return some of the bus's kinetic energy to batteries.

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