Electric buses in China - Wikimedia Commons
The World Health Organisation has added the exhaust from diesel to the World Health Organisation's list of most carcinogenic substances this week.It is now ranked alongside arsenic, asbestos, formaldehyde, mustard gas and plutonium as a major health hazard.
It was reported in the NZ Herald that although diesel emissions were previously classed as “probably carcinogenic” WHO agency working group chairman Christopher Portier said definitely yesterday that "diesel engine exhaust causes lung cancer in humans. The agency said there was also a "positive association" between diesel exhaust and a greater risk of bladder cancer. It noted that large numbers of people were exposed to diesel fumes in everyday life, at work and elsewhere. It reaffirmed an assessment of petrol exhaust as "possibly carcinogenic to humans".
I have been driving heavy trade diesel vehicles every working week (though not every day in recent years) for almost all of the last 35 years. Ooops! I imagine any person who drove buses for the Christchurch Transport Board in the 1970s will never forget those pre-dawn mornings wading through a knee-deep fug of diesel fumes created by 150 plus 25 year old AEC buses left idling all night on frosty nights, to avoid key components (such as valves on the compressed air interlock system) freezing up!! The fuel costs were cheaper than the breakdown/won't start factor, even if the real cost was pollution. Biking to work I could often smell the whiff of diesel a block away. The local Catholic College next door were very upset by the remnants of this "below the knees cloud" drifting into their yard!
The AEC "Mark IV" buses in Colombo St, Christchurch 1960s; grand old
workhorses but farting out a fug of diesel fumes where ever they went
I don't think anyone exposed to diesel fumes would ever imagine for one moment that they were harmless, that there would be some risk has always been taken for granted. Like all these other "long term exposure" risks of modern life one has to take them with a grain of salt. Sure it pays to act sensibly but also know that almost everything we do carries some risk (electro-magnetic effects from cell phones etc may turn out to have far worse long term residual degeneration effects). I am not aware of a massive lung or bowel cancer death syndrome amongst former workmates, or the thousands of truckies (and how does one separate the diesel from the long hours sitting in driving jobs, also said to foster cancer below?). Stats might show a distinct blip but I won't be losing too much sleep about having to add "diesel" to the 101 things that may end the life of someone my age.
This said society's, governments, city councils, have to act responsibly to minimise risks and such a serious classification can not be dismissed lightly. The writing may well be on the wall for the use of diesel in built-up areas, commercial and residential, for delivery trucks and - of course - buses.
However, the timing is not inappropriate because there is much to suggest the standard diesel engine, however much improved, will no longer be a mainstay of urban bus fleets in a decade or two.
Many major car manufacturers are involved in partnerships with bus manufacturers etc, seeking to create the most effective, fully electric, quickly rechargeable buses. A factor of course is that much of the technology developed, refined and trialled on urban buses (doing high mileage in easily monitored situations) can subsequently be applied or adjusted from trucks and cars.
Perhaps some of tomorrow’s buses may hybrids, combining electricity with a gas or diesel motor. Mostly these now appear to be built according to the same concept developed by John Turton of Designline in Ashburton, NZ, late last century. That is having the diesel or gas motor not to directly run the vehicle, alternating with the electric motors, but rather to power an electricity generator as a top up to the electricity regenerated from braking. This requires a much smaller fuel engine and fuel usage and keeps the bus essentially fully electrically driven. A factor for these vehicles is that it allows the buses to sit quietly and generate no fumes in traffic queues.
Mercedes have combined some of these same principles and technologies with hydrogen fuel cell buses being tested in European cities, as noted in this report from Power Engineering webmag;
Compared with previous fuel-cell buses tested from 2003, the new Citaro FuelCell Hybrid offers significant innovations, with a lithium-ion battery pack charged by braking energy recovery, electric motors in the wheel hubs, electrified power take-off units and more advanced fuel cells. The cells have a service life of at least five years, or 12,000 operating hours. ……The new FuelCell bus is a further development of Mercedes' BlueTec hybrid buses, which derive their electric power from a diesel generator. In the new set-up, the diesel engine and generator are ditched and the fuel cells generate the electricity for the drive motors, without producing any emissions, while also reducing tare weight. The improved fuel-cell components and the hybridisation with lithium-ion batteries result in a reduction in hydrogen consumption of almost 50 per cent for the Hybrid compared with the previous generation
An earlier model Mercedes Citaro Fuel Cell bus in London. The photographer that contributed this Wikimedia commented; "Note the exhaust, which because this is a fuel cell vehicle is (according to the boffins) pure water vapour". [Hmmm, Is that not also an emission?]
However breakthroughs in the last five years in batteries that can be recharged in less than ten minutes would seem to be the real driver of a major shift to electric buses.
General Motors are working in the USA with the Proterra Eco-liner, several buses being trialed on normal timetable work in small cities on the foothills on the edge of Los Angeles. A Press release a year ago illustrates the potential operating economies of fully electric buses (my bolding)
Proterra's EcoRide™ BE-35 battery electric bus is averaging up to 24 mpg (diesel equivalent) in service, a more than 600-percent improvement over a typical diesel bus. Using technology developed by Proterra, the lightweight, composite-body bus recharges in about 10 minutes.
Mitsubishi Heavy Industries is in a four way group working with major North American bus builder New Flyer and other local organisations up in Winnipeg, Manitoba, also to develop a bus suitable for the North American market. The first prototype hit the road just this week and the Provincial Premier launching the bus aptly noted that this "is the future of public transport
But it is perhaps the Chinese that are furthermost down the track, hundreds of fully electric buses now in service in various cities. The biggest electric bus producer BYD is now selling electric buses across the Globe, their speciality the Iron Phosphate battery which is said to be totally biodegradable.
Swedish heavy vehicle giant Volvo is working with Chinese to produce electric buses under the Sunwin brand name. In April the city of Qingdao (population approx 8 million) began building a drive through power station specifically for the recharging of electric buses, notably the 180 fully electric twelve metre long articulated buses it plans to use, some of these operating through a tunnel under a bay, without producing exhaust fumes.
Chen Gang, deputy chief engineer of the project said, “Electric buses can get recharged in the station’s recharging system, and the battery replacement work will be operated by a robot. The bus battery status is monitored by the real-time monitoring center, which takes charge of the battery replacement.” The average replacement interval for each bus is about eight minutes. The power station can recharge six buses at the same time, and the worn out batteries will be retrieved for further processing.
However not every electric bus operation needs to be implemented at the level of Qingdao's fleet and charging plant. Check out this BBC report (and You Tube) on a small Warwickshire, UK, bus operator, 40 years in the business but obviously keen to taste the future before he retires.
And sooner or later Wellington's relatively new trolley buses will need to be retired and the colourful but old fashion network of overhead wires is looking distinctly redundant, according to a recent "Dominion-Post" report "Is it time to Ditch the Trolley Buses"
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.
However perhaps a timely reminder that there is no perfect solution to high density humanity challenges belongs to a health researcher, quoted in the same article
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.
As Hank Williams sung "No matter how we struggle and strive nobody gets out of this world alive".
Strangely beautiful in an ugly way, the tensioned wires of Wellington trolleybus system give an old fashioned busyness to Wellington's landscape but are likely to be a very redundant technology within a few years