John Biggins sent me a helpful email querying a number in my book's chapter on "Stuff".
I have a question about the embedded energy in a car, which you quote at 76000kWh. That seems awfully high to me. To a first approximation a car is a tonne of steel, with a raw material energy of 6000kWh: an order of magnitude less.The (admittedly biased) Society of Motor Manufacturers & Traders report quote an even lower figure of 2000kWh per car (page 17), which I suspect is probably meant to be simply the energy used per car by the car plant, neglecting materials.
The guardian also wrote about this in 2009 .
They asked a few manufacturers, and arrive at a figures in the ballpark of about 1-4 tonnes of C02 to produce a car, which we might reverse engineer guessing most of the CO2 comes from coal burning in either steel production or electricity generation, to get ballpark figures of probably no more than 10,000kwh per car.
Since these estimates actually differ from your figure by a magnitude, I thought I'd write and ask whether you particularly believe your 76,000kWh figure. Do you have any back-of-the-envelope type way to understand it?
This blog post is where I will record my working on this question. I will aim to justify or adjust my answer within a month, and will add to the book's Errata if necessary. If anyone wants to send me good references on embodied-car-energy to add to my own, please post a comment. Thanks! David