/ Motoring

Are electric cars really emission free?

Green car emitting leaves

Electric cars are grabbing headlines at the moment, with several new launches from major manufacturers like Nissan and Mitsubishi. But their claims of ‘zero emissions’ simply don’t stack up.

We decided to test claims of zero emissions pitting three electric cars against our favourite Best Buy alternatives – we chose diesel models that we knew were pretty thrifty on fuel.

We compared the Suzuki Splash diesel with the Mitsubishi i-MiEV, the VW Golf Bluemotion with the Nissan Leaf and matched up a Smart diesel with a prototype Smart ED (Electric Drive).

Each of the pairings are roughly similar on size – but certainly not on price.

The expense of electric cars

At first glance, all three electric cars are expensive. Even with the government’s £5k grant, the cheapest of the three, the Mitsubishi, is more than twice the price of its diesel equivalent.

And all three have major drawbacks when it comes to limited range, slow charge time and limited places to recharge on the road.

So if you ignore the sizeable price tag and the practical limitations, those who are still keen-to-be-green must try and fathom out whether buying one will earn them tree-hugging brownie points, or whether they’d be better off with a good modern diesel. The answer is far from clear.

Indirect CO2 emissions

It’s true that there are no direct emissions from these cars. So using them in cities will certainly reap significant benefits for the city’s inhabitants, cleaning up the local air no end.

But because almost all electric car owners will use a conventional electricity supply to charge their motors, this will incur a carbon cost from burning fossil fuels.

The figure for the UK’s electricity mix is 544 grams of CO2 per kilowatt hour, according to the Carbon Trust. We used this figure to calculate the CO2 that’s emitted per kilometre, which is now directly comparable to conventional cars.

Nissan Leaf on a leaf

We found that charging the Nissan Leaf produces around 81 grams of CO2 per km, whereas the Volkswagen diesel Golf produces CO2 emissions of around 108g/km (according to our own lab testing). That’s a 25% reduction in CO2 using an electric car instead of a diesel equivalent.

There are more factors

The picture becomes even less clear when you consider that the results don’t account for the extraction, refining or distribution of fuel – whether it be fuel used in power stations, or fuel that comes out of the diesel pump – something pointed out by electric car expert Robert Llewellyn.

Plus, we have more work to do to establish the environmental cost of manufacturing these cars – both the electric ones with their resource-heavy batteries, and conventional cars with their ‘lean manufacturing’ methods.

One thing is for sure – the environmental benefits of electric motoring are less clear-cut once you’ve taken electricity production into account.

It’s this factor, along with the sheer difficulties with charging them, which led us to conclude that the time isn’t right for electric cars – yet. Here’s hoping renewable electricity production will catch up with the cars themselves.


Take all the factors into consideration and electric cars are neither environmentally friendly nor a very practical replacement for ordinary cars. In some applications (e.g. milk floats and mobility scooters) electric power is a good solution.

What we need is incentives to use cars (and public transport) less.

Jeremy says:
6 March 2011

This article – and many of the electric vs fossil fuel car debates – are a little disingenuous when it comes to the comment “The picture becomes even less clear when you consider that the results don’t account for the extraction, refining or distribution of fuel.” Certainly, this muddies the water somewhat, but it does so in favour of EV’s, as power stations burn less refined oil for which less distribution has to be undertaken. Calculations elsewhere swing the pendulum significantly further in favour of EV’s in terms of overall CO2 emissions when attempts are made to factor these issues in.

The supposition is also that none of the electricity is renewably-sourced, for which there are growing choices. Given the emergence of choice, the broader economic and ethical arguments in terms of balance of payments and supporting some of the world’s least likeable regimes when buying petrol should not be disregarded: another wealth transfer to Libya, Iran, or Venezuela anyone? The petrol heads take the addiction as incurable so choose to ignore such considerations altogether, but for how long is this near-sightedness tenable as alternatives emerge?

The debate will become increasingly hypothetical as the regulatory environment is moving rapidly to make direct gasoline-burning engines obsolete, with a marked acceleration of this process from 2015 in the EU. In spite of the current hybdrid / EV hype, longer term most major auto makers and “Big Oil” are still backing fuel cell vehicles which, when using hydrogen extracted from oil and distributed via existing infrastructure (the likely set-up), will result in lower emissions than gasoline burning engines and be less disruptive to the incumbents’ business models.

Few, on the other hand, think that EV’s will be the mainstream unless something major changes with battery technologies. This suits the auto makers and the oil companies very well as EV’s wreck their business models, so don’t expect them to be big advocates of EV’s even if they turn out to be the best thing since sliced bread for consumers.

Notwithstanding, those that think that gasoline-burning engines have much of a future need to understand that they, like smokers, are engaged in a rearguard action. Future generations will probably be incredulous that we frittered away the majority of the wondrous product oil purely for combustion for so long, nor condone the moral compromises we have made to enable us to do so. History will judge. In the meantime, If you’ve ever worried about using plastic bags or whether you’re using recycled paper, be ready for the logical conclusion that the implications of a fill-up when alternatives exist may increasingly render you sleepless!

Paul J. Weighell says:
14 March 2011

The fuel extraction argument does NOT favour EVs as you omit to mention that most electric power in the UK and the US comes from coal so the argument of refined oil v gasoline is largely moot as the CO2 / Sulphur / Particulates etc. etc. from coal skews it all back in favour of nice clean gasoline by comparison. You wanna burn more coal? Get an EV!

Paul J. Weighell says:
14 March 2011

The unreliable sources can never replace the current world use of fossil fuel. At most we have 4% power supplied by the newer intermittent sources and the idea we can scale up to account for another 96% is farcical as the power density of production is woefully small – not to mention that we would still need about 90% of the current supply sources as a standby.

Even if we have 100% of our electric power from these newer cleaner but intermittent sources like wind, solar etc. we still have to back them up with reliable sources. The continuously rated output from wind farms is disappointingly nearer 20% of the possible rated that the sellers quote. Currently each 1gW from a wind farm in the UK still needs a backup of 0.9 gW of conventional power for when the wind doesn’t blow. That raises the cost by a factor of between 3 and 4 as the intermittent sources are already cost more by a factor of at least 2.

I know of no professional engineer that sees a real long-term switch away from fossil fuel other than to appeal to, or to cynically profit by, the pure political decisions to go electric before any of the real supply side problems have been addressed.

UK electricity is produced from coal, with only 14% being Nuclear;
this coal is imported from the 3rd world by oil fired Tankers –
so the carbon footprint argument is bull droppings.

French power is 90% nuclear – so there is less carbon burnt during production, so no need to worry about our nuke plants going up – the French will take us with them anyhow.