Australia’s biggest selling electric car, the iMiEV, has sold over 30 units! Photo from

By Nick

The issue of just how much carbon dioxide electric cars emit over their lifetimes has been something that has puzzled me for a while. If electricity generation is fossil fuel derived, could electric cars actually be more damaging to the environment? Or is the electric car more carbon efficient than it’s petrol counterpart and a wise choice. Well, finally someone has crunched the numbers. No longer do we have to wave hands and make conjecture. We have facts, and numbers and statistics with which we can wash away our prejudices and pre-conceived ideas.

So which is it? Better or worse. Turns out its not so black and white. As new research from the Norwegian University of Science and Technology in Trondheim shows. It looks like the paper is open access – hooray!

The construction of electric cars is far more energy intensive than regular cars. Batteries and electric motors are harder to build than fuel tanks and petrol motors. So the carbon cost of these cars is much higher when they reach the garage. Also, electric cars, at the moment, don’t have the life-span of petrol cars, with new batteries and motors needed after a few years.

The work by Hawkins et al, in the Journal of Industrial Ecology shows that, luckily, from production onwards, electric cars are more carbon efficient than petrol ones. The production of electricity used to run the cars produces less carbon than the burning of petrol.

This means that there is a tipping point in the system. When an electric car comes good. At 100,000km, the benefit is no different to that of a diesel car.

By 150,000kms, gains are expected of 10-24% in total carbon output. This is the expected lifespan of a current electric car – for example he Tesla Roadster needs a battery replacement after 100,000 miles (160,000 km)

By 200,000km gains would be 27-29% over petrol and 17-20% over diesel. These are substantial cuts (2% of global carbon emissions), and well worth us making the switch. But not quite as green as perhaps some would make out. Plus the carbon is being produced in places where we have the technology to begin removing it.

There is also an issue of other chemicals. Electric cars also produce more toxic chemicals than regular ones during construction. Whilst this is an issue that ought to be taken into consideration, I’m going to move over it, and focus on the carbon story instead. Apart from making the point that localised production of toxic chemicals in factories may be easier to deal with than the much more dispersed distribution of chemicals into the air in our towns, cities and neighbourhoods that result from the burning of petrol.

But there is a little caveat to this story. They use the European electricity mix as their source of energy. Europe is rapidly investing in solar (Germany), wind (Denmark), geothermal (Iceland) and has a large nuclear industry (France). Renewables are starting to come good in Europe. They’re still a long way off, but its progress. Plus, a lot of the fossil fuel usage comes from Natural Gas, piped from either the North Sea or from Russia and the surrounds.

Here in Australia, things, are unfortunately a long way behind. Despite huge amounts of sunshine and a country large enough for wind to deliver baseline power, Australia’s electricity generation is mostly fossil fuel derived. Worse, this fossil fuel generation comes from dirty, polluting coal. While I don’t have the numbers to know how this adds up, compared to the reasoning of Hawkins et al. I imagine that the best case 24% gains by 100,000km would be largely wiped out.

So as not to end on a sour note, this report does show some promise. And remember, as we move forward, electric car production is likely to come down in carbon cost as technology improves, and who knows, maybe Australia will start to properly invest in renewables. Until then, just remember, cycling helps beat global warming and the obesity epidemic!


BBC report here: