Monday, 17 January 2011

Electric Vehicles - their time to shine?

In between all of the cuts the new government has been making (with the jury still out on Feed-In Tariffs), one promise which has survived is the £5,000 subsidy offered to buyers of electric vehicles, which was ratified in July last year and implemented in January this year. A list has been produced of all the eligible vehicles – noticeably absent is the Tesla Roadster, although even with a £5k discount this would be beyond the reaches of most!

So the government is directly pushing the purchase of electric vehicles. But how do they stand up to their gas-guzzling cousins? Here we assess their sustainability, from the triple-bottom line of Economy, Environment and Society.


A £5k government subsidy on each vehicle appears generous (although only 9 models are eligible, 6 are yet to be released, and of the three that are, 2 are currently only available for hire). So, the one remaining qualifying car that you can buy today - the Mitsubishi i-MiEV - is advertised as £24,000 after the subsidy. The Nissan Leaf, to be released in March, is the same post-subsidy price. 

Cost of driving the car will be cheaper. The cars will be exempt from tax. Professor David MacKay suggests that an electric car can do 62.5m (100km) on 21kWh electricity - at 10p/kWh, this works out at £2.10, or 3.4pence/mile. The AA suggest that for a petrol car in the equivalent price range, 15.77p/mile is more likely. If the car is used every weekday for 48 weeks for a roundtrip of 60miles to and from work, then the owner would save approximately £1,780/year on fuel costs.


The whole point of these electric vehicles are that they are more environmentally friendly than traditional vehicles. However, it should not be thought that they are zero-carbon, or zero-emission. They have no emissions at end-use, yet, in all likelihood, fuels have been burnt to produce the electricity from which it runs. The cars can only claim to be zero-emission (in operation) if the electricity has been produced from renewable sources (although this simplistic model ignores the impact of life-cycle emissions).

So, there are emissions associated with electric vehicles. But how much? Again, to MacKay - "21kWh per 100 km is equivalent to 105 g CO2 per km, assuming that electricity has a footprint of 500g CO2 per kWh."

Car pages suggest that the average emissions per kilometre figure for new cars is 164gCO2/km. Therefore, electric vehicles emit around 33% less carbon than standard vehicles. But there is more - as electric vehicles will be charged overnight, the efficiency of power plants will increase as demand is increased in period of lull. Further, as decarbonisation of the grid occurs, this figure will decrease, suggesting that electric car owners could travel with no footprint only if they procured their electricity from non-carbon sources. The number of energy companies offering this tariff is increasing all the time.

Of course, energy is still needed to manufacture the car. Boundaries permitting, the only carbon neutral way to travel is by walking (although emissions are released through the manufacture of your shoes - yes I know its becoming a nightmare!)


So the electric cars are expensive, yet cheaper to run and produce less carbon emissions. But would society benefit from their take up? Well, some have voiced concern over the noise of the car - i.e. there isn't any. This could have an impact of children (and adults like myself) who consider all streets to be safe and don't look when they cross the road. I would like to see a study on this if anyone has one! Further, the best electric vehicles can only travel 100km after an 8 hour charge - pretty inflexible, and only really good for short journeys day to day.

But - obviously an increased take-up of electric cars could have benefits elsewhere. It could help people change their other carbon-intensive habits, and persuade them to cut their footprint. Electric cars could lead to greener lifestyles.


The jury is out on electric cars. They are no doubt the future of motoring, although it will be a while before we see standard vehicles made obselete. Like I mentioned in my last post, decarbonising the grid is essential, and will only aid in the environmental benefits of electric vehicles. For now, even with the reduced price, electric vehicles are prohibitively expensive, and for a current 33% improvement on carbon emissions, difficult to justify. But, like all advances in technology, prices will come down and performance will increase. Watch this space (but not whilst waiting - subsidies in Spain last year led to only 200 electric cars being sold out of a predicted 20,000!)

Anthony J.


  1. Nice post, but it is worth noting there is some uncertainty over the 500g/kWh carbon intensity figure with some suggesting it could be much higher:

    The recharging issue is being addressed by entrepreneurs like A Better Place:

    Another really exciting aspect is the ability for electric vehicles to act as storage for renewables in a smart grid:

    Apols for all the links going back to my blog, but I know where the info is there!

  2. Thanks for the info Gareth - nice to have you visiting too, I've been a subscriber to your low carbon agenda newsletter for years.