When we look for the best ways to protect are environment, the answers are often complicated. Take for example the electric car. On the face of it, an electric car would seem to be far less polluting than a petrol or diesel one. After all, the car itself produces zero emissions, so it must be better, right? Well, in terms of direct emissions from the car, yes it is.

But the full picture is more complicated than this.  A recent study comparing  electric and conventional cars, authored by the Norwegian University of Science and Technology looked at the total environmental impacts of cars driven for 150,000km (93,205.7 miles) has shown that in some cases, electric vehicles are actually worse for the planet.

They found that some electric vehicles have almost double the impact on climate change as conventional cars during their manufacture, mostly because of the raw materials and energy required to make lithium-ion batteries.

Of course, things improved as soon as the cars started to be driven, but how much of an improvement there was depended on how the electricity that charged the electric cars’ batteries was being produced.  The study took into account the environmental impacts of drilling for oil, refining it and transporting it to filling stations, as well as the impacts of actually burning petrol or diesel in cars.  But it also took into account what kind of fuel was being used in the power stations that provided the electricity.

In countries where the electricity was being generated from coal-fired power stations, the benefits of electric vehicles were greatly reduced.  In the UK in 2012, almost 40% of our electricity came from coal-fired power stations, as the cost of gas rose higher and coal was therefore used more, as it was cheaper.  In terms of climate change, coal is about the worst fuel we could be using.  Gas is cleaner, but more expensive.  In countries like China, where almost all of their power comes from coal fired power stations, electric vehicles were actually found to be more polluting than conventional ones!In countries where more energy is generated from renewable sources – hydroelectricity, solar, wind and tidal power, using electric vehicles does significantly reduce climate change causing emissions.

Using what the study calls ‘average European electricity’, the benefits of using an electric vehicle for 150,000km range from a 10-14% improvement in overall greenhouse gas emissions over diesel fuelled cars and a 20 to 24% improvement over petrol cars.   The study found that if the electric cars were driven further in their lifetime – say 200,000km, their overall benefits in terms of greenhouse gas emissions increased as well to 17-20% compared with diesel cars and 27-29% compared with petrol  powered cars.

Using just coal-fired power, electric vehicles were found to produce 17-27% more greenhouse gas emissions than diesel or petrol ones over 150,000km.

In the UK, the benefits of electric cars are at the low end of ‘average European electricity’ at the moment, because so much of our energy comes from coal.  However, by 2020, just 11% of our energy is planned to be generated from coal, meaning that the benefits of using electric vehicles will increase in the coming years.

You can read the full report here.

So when it comes to green matters, there is very little in the way of black and white.  We need to burn less fuel, and it would be great to find a no-carbon transport alternative, but at the moment, electric cars are not only very costly and very rare (only 0.1% of new cars sold in the UK last year were electric), but how much benefit they can deliver to the environment depends on which country they are being used in and how that country produces its energy.  And that doesn’t even touch on their sometimes limited range, lack of charging stations etc.  As new technology develops and as the UK reduces its climate changing emissions, electric vehicles may well come into their own.  But we’re not at that point yet.  And then you have to consider HOW we reduce our emissions.  If it’s through nuclear energy, well, that’s another can of worms altogether, and one I’m not about to open today.

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