Eco cars are worse for the environment – at first

The production of battery packs for electric cars and lightweight materials for regular cars is actually worse for the environment than the normal vehicle-manufacturing process, one of the world's biggest car makers, the Volkswagen Audi Group has revealed.

CO2 emissions when producing lithium-ion battery packs and materials such as aluminium, magnesium and carbon-fibre reinforced components – designed to reduce fuel consumption – are actually higher than when processing substitute components made from more common materials such as steel.

Audi uncovered the data as part of is research into making cars more environmentally friendly from 'cradle-to-grave' – not just 'well-to-wheel' – and revealed its findings at an energy conference it hosted in Hamburg at the weekend.

The head of Audi's vehicle development Heinz Hollerweger said: "Well-to-wheel [the environmental cost of mining, refining, transporting and using petrol] is just part of the total lifecycle assessment of a vehicle. Besides fuel and fuel consumption we also have to look at the manufacture and recycling of the vehicle. If we take the holistic approach we call it cradle to grave: production, use and recycling."

Hollerweger said production typically accounted for one third of a vehicle's CO2 output, but that needs to come down if the car industry is to become 'greener'.

"Lightweight construction is only sensible if at the end of the day the actual savings generated in use is higher than the extra energy it required during production. We think this is quite a new mindset," he said.

Audi says it is finding new, more environmentally-friendly ways to manufacture exotic materials in future models.

It says the energy "break-even point" for most cars using advanced materials is between 30,000-80,000km of distance travelled – because that is how long it takes for the reduction in CO2 emissions to be greater than what was expelled during the construction of the car.

But, he said, the new Audi A6's "break even point" was just 5000km because of new manufacturing techniques of lightweight materials, and the use of some recycled metals.

Audi will release its all-new A6 later this week.

The example given at the conference was the new Audi A6 3.0-litre turbodiesel, which is claimed to be 80kg lighter than its predecessor, and 40-50kg lighter than its peers, despite having an all-wheel-drive system.

The Audi data showed that the CO2 output when manufacturing steel was just one-fifth that of the same amount of aluminium and one sixth of the same amount of magnesium (using components designed to do similar functions as a guide).

There was strong incentive to use precious metals because of the weight savings to be made: aluminium is 40 per cent lighter than steel, while magnesium and carbon fibre reinforced materials were 55 per cent lighter than steel.

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