• Thu
  • Dec 18, 2014
  • Updated: 9:56am

Volts of confidence

PUBLISHED : Friday, 10 April, 2009, 12:00am
UPDATED : Friday, 10 April, 2009, 12:00am
 

A passing Lamborghini, Ferrari or Porsche is guaranteed to turn heads. Each new model is eagerly awaited by vehicle enthusiasts and wealthy show-offs. Strip away that which is low-slung, sporty and just plain expensive, though, and what the world is really looking forward to in vehicles is electric cars. These are not being produced by the luxury end of the market, but mass-manufacturers like General Motors, Mitsubishi and Toyota and companies with lesser-known names like Tesla, China's BYD and MyCar, which was partly developed by Hong Kong's Polytechnic University.

There is a fever-pitch rush to get all-electric cars onto roads. GM and Toyota have scheduled their offerings for mass release next year. It's all in the name of saving the planet: Being environmentally friendly is the coolest of the cool. Even publicity hungry pop stars are turning up their noses at the Ferrari 599xx, Porsche 911 GT3 and Bentley Continental Supersports to place orders for a far-from-flashy, considerably slower plug-in.

Greenhouse gas emissions from petrol- and diesel-powered vehicles are contributing to global warming. Other toxic exhausts reduce roadside air quality, leading to diseases and chronic illnesses. The more that are taken from the streets and replaced by electric-powered counterparts the better, we are being told. But step back and consider that in many nations, most electricity is produced by coal and oil; the more electric cars being driven in such locations; the greater the levels of pollutants, logic would say.

There are obviously places where electric cars bring the pollution levels down. California comes readily to mind: More than 80 per cent of the power generated for America's most populous state comes from gas or hydro-electricity. France gets almost that figure through equally clean nuclear power. But only a handful of governments have such records and some, like Australia, derive four-fifths of their electricity needs from fossil fuels.

I stumbled across a German study that came to what appears to be devastating conclusions. It found that if 49 per cent of an electric vehicle's power was derived from coal, the emissions of nitrogen and carbon dioxide would be the same as for a petrol car - although the amount of sulfur oxides would increase by a factor of 10. If 100 per cent of the electricity came from coal, electric cars would result in 150 per cent more carbon dioxide, 250 per cent more nitrogen oxides and 2,400 per cent more sulfur oxides.

There is much debate about the calculations. Some people argue that the maths is all but impossible. I much prefer the methods - and conclusions - of British scientist, inventor and educator David MacKay. He has done all the hard work to prove his points that electric vehicles are the future in his free online book, Sustainable Energy - Without the Hot Air.

The Cambridge University professor agreed with my assessment that generally, cars that are wholly driven on electricity make a minimal gain in emissions if coal is the energy source. But that did not defeat the purpose of their use, he said. We should instead take the long view of a future of sustainable energy. That objective is to wean ourselves off fossil fuels so that the electricity grid can be decarbonised.

Dr MacKay's maths goes like this: A standard, average fossil fuel car uses 80 kWh of energy per 100km travelled. An electric vehicle uses 20 kWh, measured at the socket, per 100km. Comparing the energy going in at the fuel tank or socket, a plug-in car is four times more efficient. A power station using fossil fuel is 35 to 40 per cent efficient, but it could be several times more so if it used hydro-electric, thermal, wind and other green means to generate energy.

With today's technology, switching to electric vehicles is only making a modest difference. But we have to agree with Dr MacKay that making the move to electric sooner rather than later starts us in the right direction. Some governments are well on the way to providing environmentally sustainable electricity. We'd do well to follow Dr MacKay's suggested target of 2050 for emission-free transport and energy generation.

Peter Kammerer is a senior writer at the Post

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