20 Mar 07
According to a VW-sponsored report, manufacturing accounts for 27-30% of a car's total CO2 footprint. Substantial yes, but it means the bulk of the carbon was emitted after the car was delivered to its first owner.
In the UK, the Society of Motor Manufacturers and Traders estimates that the energy needed to build an average car in Britain during 2005 translated to 600kg of CO2. Honda in the US reckons its figure is 810kg. Not much considering that an average UK car emits 2.8 tonnes of CO2 over 10,000 miles.
That's not the whole story, of course. Production of the raw materials is estimated to account for nearly three quarters of the car's production footprint, especially if the steel is produced in a country with heavy coal use, such as India.
The CO2 from electricity consumption is another tricky element in the calculation. If you're not sure about the source of the electricity, it's difficult to assign a CO2 figure to it. VW 'decided not to report such emissions' in its latest sustainability study for that reason, which is fair enough, but it is a significant omission; Honda estimates electricity amounted to 70% of all its factory energy consumption in America.
The figures are coming down. The British CO2-per-car figure of 600kg has come down from 1.1 tonnes in 1999, says the SMMT. It's this ability to reduce CO2 emissions at source that has led to calls for car companies to carbon-trade instead of forcing them to chase ever lower fuel consumption figures. An ultra low-emission car factory is every bit as desirable as a hybrid supermini.
