It's not easy being green II

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ELECTRIC cars could produce higher emissions over their lifetimes than petrol equivalents because of the energy consumed in making their batteries, a study has found.

An electric car owner would have to drive at least 129,000km before producing a net saving in CO2. Many electric cars will not travel that far in their lifetime because they typically have a range of less than 145km on a single charge and are unsuitable for long trips. Even those driven 160,000km would save only about a tonne of CO2 over their lifetimes.

The British study, which is the first analysis of the full lifetime emissions of electric cars covering manufacturing, driving and disposal, undermines the case for tackling climate change by the rapid introduction of electric cars.

The Committee on Climate Change, the UK government watchdog, has called for the number of electric cars on Britain's roads to increase from a few hundred now to 1.7 million by 2020.

Britain's Department for Transport is spending $66 million over the next year giving up to 8,600 buyers of electric cars a grant of $7700 towards the purchase price. Ministers are considering extending the scheme.

The study was commissioned by the Low Carbon Vehicle Partnership, which is jointly funded by the British government and the car industry. It found that a mid-size electric car would produce 23.1 tonnes of CO2 over its lifetime, compared with 24 tonnes for a similar petrol car. Emissions from manufacturing electric cars are at least 50 per cent higher because batteries are made from materials such as lithium, copper and refined silicon, which require much energy to be processed.

Many electric cars are expected to need a replacement battery after a few years. Once the emissions from producing the second battery are added in, the total CO2 from producing an electric car rises to 12.6 tonnes, compared with 5.6 tonnes for a petrol car. Disposal also produces double the emissions because of the energy consumed in recovering and recycling metals in the battery. The study also took into account carbon emitted to generate the grid electricity consumed.