The Oil Drum: Australia/New Zealand | A Twelve-Step Plan to End Oil Addiction

86 comments on A Twelve-Step Plan to End Oil Addiction

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DaveMart on May 26, 2008 - 4:59am

Hi EP,
Thanks for putting some figures on the energy required to produce cars.
I think it is worth pointing out that the energy to manufacture is largely non-oil based too, as that is our current pinch-point.
I'm just wondering if it is possible to narrow the figure down at all for the manufacture of electric vehicles rather than hybrids, as the weight saving reductions possible in this technology are very large.
I know you will be aware of them, but for the benefit of others who may be browsing this thread, most of the stuff you need for a conventional car can be thrown out, and importantly it is good economics to switch to lighter materials, using carbon fibre and so on instead of steel.You would though tend to use more aluminium, which comes at high energy cost.
The weight savings multiply into even less energy cost in production, as you don't need such beefy suspension where you have a lighter engine, and the engine needs to be less powerful where the body weight is lower, and so on round in a circle.
In view of these savings, would a guesstimate of 80GJ be likely in the right ball-park for a 4-5 seater EV?

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AlanfromBigEasy on May 26, 2008 - 5:49am

The weight savings multiply into even less energy cost in production, as you don't need such beefy suspension where you have a lighter engine, and the engine needs to be less powerful where the body weight is lower, and so on round in a circle

True enough, but range in EVs creates a multiplicative effect.

Design passenger cabin, add suspension, motor and batteries to go 40 km. Light weight (less than comparable ICE by a few kg). Marketing comes in screaming, we need at least 120 km range !

OK, triple batteries, increase suspension and motor size to move more kg. OOPs, with added weight of batteries and other, range is only 80 km. Increase batteries by another 50%, .... closer. One ends up with x6 batteries to x3 range, and almost double the overall weight, but heavier than a ICE car. (VERY rough calcs to make a point).

Other solutions ? Downsize from 4-5 passenger compartment to 2 or even 1 passenger compartment.

One engineering optimization leads you to a "hybrid
car", the eBike. Passenger/motor works with battery (one can afford high tech batteries for such an efficient mode) and a very small electric motor to give extended range.

Another engineering optimization may lead to a 2 passenger titanium EV (titanium, unlike carbon fiber, can be recycled) with fabric seats, charcoal heater, no air conditioner. Expensive structure but fewer expensive batteries. Minimal parasitic loads and weight.

Best Hopes for Adapting Society to Engineering Reality,

Alan

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DaveMart on May 26, 2008 - 6:11am

You are of course correct that with current batteries weight savings for the set-up I specified, with 4-5 seats are not possible.
I was trying to illustrate how important weight is to EV's and overstated my case.

I used the example of carbon fibre purely as one example, but a number of composite solutions are possible.
The Th!nk car is highly recyclable, unfortunately I do not have information on what they have used in the structure.

I suspect that cost considerations will lead to many EV's being designed with very limited range to get people to work, even lead-acid batteries with capacitors might do for this, and the cost is way lower than lithium batteries.

For the record I don't see EV's attaining universal coverage anytime soon, but the better off are likely to have the option - nothing like our current, or perhaps I should say the US's current, car based culture though.

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