[Agren]

I've read things here stating that half of all the oil a car uses during its lifetime is used in manufacturing that car, the other half being used for fuel.

This got me thinking about how much oil/energy is really used to manufacture different commodities and raw materials.

Does anyone have any ideas on how to go about finding out? If by chance anyone has actually made calculations like this I'd be very interested in finding out, references and/or links would be very nice

I realise there are problem in knowing when to "stop" in these calculations. I.e. do you include energy used by the guy driving the mining machinery, the energy used by his car and so on. Obviously you can't go on like that, so my idea is to stop at the point of raw materials, e.g. how much oil/energy does it take to create steel, including the energy used in mining the iron ore, but not the energy used by the person running the various machines.

Anyone who can help me out here?

[Licho]

It probably differs car by car.
This study shows that manufacturing consumes about 10% of whole life-cycle energy inputs.

http://www.ilea.org/lcas/macleanlave1998.html

[Licho]

First graph:


Other source:


And this is also very interesting:

Only a marginal amount of the energy consumed by a car is actually used to provide momentum. What remains is lost in exhaust (33%), cylinder cooling (29%), engine friction (13%), transmission and axles (5.5%) and braking (7.5%). Under some climate circumstances, energy is also used to either heat or cool the section of the vehicle occupied by passengers.

[Agren]

Interesting, thanks!

Maybe I did a mistake in specifically mention cars, as I am really interested in this kind of calculations for and and all consumer goods.

So if anyone hogging any info, please help me out

[Bytesmiths]

A fundamental flaw in saying "what percentage of" is that the manufacturing energy costs are fixed; the fuel costs are variable.

Vehicle lifetimes vary considerably, depending on upkeep and accidental damage.

The average auto consumer gets a new vehicle every five years! Thus, to do a meaningful "percentage" comparison, one should only count the "lifetime" of an auto as five years, since, on average, that's how much use a consumer gets for the embedded energy.

<i>(That's not to say that we who only buy vehicles older than five years have no embedded energy cost to those vehicles; it's just that we've been "averaged out" by those people who get a new car as soon as their three-year loan is paid off. :-)</i>

Licho did not cite sources, but I suspect the figures presented came from the auto industry, and assume a much longer lifetime than the average of five years.

[Andy]

I disagree Bytesmiths that using the 5 year initial consumer only is a fair way to determine what percentage of a car's energy use is represented by manufacturing. Most new cars on the road will be around for longer than 5 years, albeit with different owners. To answer the question then means that the average lifetime of the vehicle (not the average time in the hands of the initial customer) must be taken into account. The vehicle does not simply disappear after 5 years. The 5 year old vehicle also has a resale value that represents some kind of remaining embedded energy that 2nd hand customers are purchasing.[CODE]

[Bytesmiths]

I disagree Bytesmiths that using the 5 year initial consumer only is a fair way to determine what percentage of a car's energy use is represented by manufacturing.

I'm afraid I must disagree with you. If the average new vehicle stays with an owner for only five years, that means that a replacement vehicle will be manufactured at the end of that five year period, <b>not</b> at the end of the vehicle's "useful" lifetime.

But don't take my word for it; ask the IRS or any accountant. That's how "depreciation" works. The fact that many of us are driving around in vehicles whose energy cost has been fully depreciated does not change the fact that replacement vehicles continue to be produced, and their embedded energy consumed, on a five-year interval.

The <b>only</b> way to increase the embedded energy per-vehicle cost is for the original purchaser to drive them longer. But that ain't gonna happen any time soon, for obvious reasons.

You simply cannot claim you're using less energy per vehicle just because you make an exponentially increasing quantity of them!

[Mark_i]

on net-energy-affords for producing raw materials/goods/services can be found here

here

It's sponsored by the German Federal Agency for Environment and thereof on German, but it it a very good database.


IF you have to look up certain german words, try it here

www.dict.leo.org