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The return of the coal powered car?


Let me take you back to the year 1788. The Times had just published its first edition, Robert Burns wrote his version of Auld Lang Syne, and up in Yorkshire, Robert Fourness and his cousin James Ashworth, invented a type of steam engine, which could move "travelling carriages of every denomination, without the assistance of a fly". This began an exciting time of steam powered, coal burning cars. However, sadly for many, this era was short lived. Doble, the last steam car manufacturer closed its doors in 1930.

Imagine my surprise when in 2016 I was reading the Telegraph and stumbled across an article that claimed there was a resurgence in these coal powered beauties. However it appeared that the writer had confused coal power with electric power. The article was about the Tesla Model 3.

That's right. The electric Tesla, according to this article (here), is "responsible for heavy air pollution". I was intrigued. Surely these cars, claimed by many to be the solution to increasing global temperatures and overly polluted cities, couldn’t be all that terrible?

I set about investigating two of the article's main claims:

  1. That Electric Cars are "coal-powered cars"
  2. The amount of CO2 emitted by electric cars isn’t that much better than equivalent diesel vehicles

Are electric cars "coal powered cars"?

Yes, and no. Of course in the UK we get some of our electricity from coal, as does every nation in the world. Yet, the proportion is nowhere near enough to claim that powering an electric vehicle from the National Grid makes it coal powered.

Back in the second quarter of 2015, Coal was the third largest contributor to UK power, generating 15.9% of our electricity. However, that proportion has fallen to 5.8% in the second quarter of 2016, a 71.3% reduction overall. The top three producers of electricity in the UK are now gas, nuclear, wind, and solar power. All arguably cleaner than coal.

So if you plugged in your electric car in 2016 your car has been 11.3% coal powered, but 41% Gas powered, 20% nuclear powered and 14% wind and solar powered. In addition, government projections show the mix will change even further with 44% of electricity generated by renewables, and 37% by nuclear power in 2035.

Of course, this is only for the UK. Other countries do use coal to a greater and lesser degree, with China being a big fan. However the article in the Telegraph claims that in "the UK, electric cars would cause the same or more air pollution related deaths than petrol powered cars" due to their use of coal. It would seem this is unlikely.

Do electric cars emit the same amount of CO2 as normal cars?

Now, this took a little more looking into. The Telegraph article compares one diesel car, the Audi A7 and one electric car, the Tesla Model S. It takes into account the amount of CO2 from manufacturing the car and battery, and the emissions from driving the vehicle. It claims that the Tesla will only save 1.2 tonnes of CO2 over a 150,000km lifetime. Not a great prognosis for the electric car. However the article in the Journal of Industrial Ecology that the Telegraph article uses to verify these claims suggests something very different.

The most startling of these is that "when powered by average European electricity, EVs are found to reduce GWP (a proxy created by the study for global warming impact) by 20% to 24% compared to gasoline ICEVs and by 10% to 14% relative to diesel ICEVs". This got me thinking. Could I do my own study based on similar assumptions? The answer after checking my diary was yes, as long as I stayed up too late staring at an Excel screen. So that's exactly what I did.

Rather than looking at just two cars, a rather narrow study, I looked at the Nissan Leaf, BMW i3 and three diesel cars of comparable size, and the same for Tesla Model S.

According to the only study I could find that detailed this, the amount of CO2 emitted during electric car manufacture is 1 tonne of CO2 higher (15%) for small electric cars like the Leaf, and 6 tonnes higher (68% higher) for larger battery vehicles like the Tesla. Pretty big numbers.

Over 150,000km the larger diesel vehicles emitted 22% more CO2 (8.6 tonnes of CO2 more) than their electric equivalent. The smaller diesel cars emit 20% more (5.1 tonnes of CO2 more).

However, 150,000 km isn't that far, amounting to only 93,000ish miles. A more likely lifetime of a car is around 150,000 miles. Using this measure the smaller diesel cars emit 24% more CO2 (8.8 tonnes of CO2 more), and the larger ones 30% more (17.8 tonnes of CO2 more).

"This is all well and good", I can hear you saying, "but I only drive a few miles a year, how long do I have to drive before I can 'offset' the impact of making the battery". Not all that far for the Leaf – only 15,500 miles before the CO2 emissions from the normal cars are the same as your electric car. For the Tesla Model S, it's a quite a bit further at 40,000 miles. According to RAC figures, the average UK mileage per year is 7,900 miles. So if you owned a Leaf it would only take you 1 year and 11 months of driving to offset the CO2 impact of the battery, but for the Tesla, it would take you a wopping 5 years.

There's more to it than just CO2

Although the article focuses on CO2, diesel cars emit other gasses that are pretty harmful. One of these is Nitrogen Oxide (NOx). This gas has been proven to increase the risk of respiratory conditions. Not great for you or I if we happen to be anywhere near a road.

However the EU does limit the levels of NOx emissions through legislation, the latest version of which is Euro 6. Earlier this year DEFRA checked the emissions of 19 cars that comply with the most recent legislation, and looked into their emissions in real world use. Not one of them was below the NOx limit of 80 mg/km. The vehicle with the best results emitted 131 mg/km, the worst vehicle was 14 times over the limit and emitted 1104 mg/km of NOx in the government test.

If you own a small electric car, you're in the green

So if you've just put in your order for an electric car, you've definitely not bought a zero emissions car. Electric cars do emit a significant amount of CO2. However if you're running it in the UK, you are not driving a coal powered car. In fact if you've got a smaller electric car, you can rest assured you're doing your bit for the environment, especially as our electricity production gets greener over the next 20 years.

Electric car drivers - permission to feel smug.