Welcome to European Tribune. It's gone a bit quiet around here these days, but it's still going.
Note: "plug-in hybrid". Anyway, most journeys for most vehicles are short.
by Colman (colman at eurotrib.com) on Thu Sep 13th, 2007 at 10:34:56 AM EST
[ Parent ]

Yep. I think fully electric (or plug-in) vehicle are likely, because, as you say, most of journeys are

There's a calculation which is seldom made :
only 3% of the solar energy is converted to chemical potential energy in a plant and then 2/3 of this energy is spilled in conventional motors so that a biofuel + heat engine line has a yield of 1% (and I'm considering that no energy has been necessary to obtain biofuel).

Solar panel convert 15% of the solar energy into electricity. 1/3 is lost when using batteries. Since the yield of an electrical motor is around 90%, then 9% of the solar energy is converted into movement. Ok, a lot of energy is required to make the solar panels (4 years of their production is necessary to fabricate the next panel).

So... I don't believe in conventional motors. Nowhere except for long journeys - because of the energetic density of fuel.

by Renard (scio at free point fr) on Thu Sep 13th, 2007 at 11:26:33 AM EST
[ Parent ]
by Laurent GUERBY on Thu Sep 13th, 2007 at 02:34:02 PM EST
[ Parent ]
Interesting enough, indeed.  Thanks for those links.

I guess that the speaker for tesla motors wasnt fully impartial. However, the figures are striking. Even if they are overestimated by one order of magnitude, electric motors are even more interesting than what I thought.

I think he has forgotten some phenomena (electricity transport, for instance) and that he underestimates the average cost of using batteries. Anyway, this is interesting. Partial, but interesting.

by Renard (scio at free point fr) on Thu Sep 13th, 2007 at 04:21:47 PM EST
[ Parent ]
Yes of course Telsa Motors is not neutral, but they did cite their sources and the few numbers I went after on google were within reasonable bounds of what the paper said.

Electricity transport is not that costly (around 95% efficient IIRC) and also not mandatory (eg local production).

Batteries are of course the current hot topic (cost and storage capacity per mass/volume), but some EV models have in car fuel-burning generator that generate electricity to extend range.

by Laurent GUERBY on Fri Sep 14th, 2007 at 06:56:23 AM EST
[ Parent ]
I do not disagree with the figures - I'm just saying they choose the "best ones", and not the more realistic ones.

From wikipedia :

The nickel cadmium and nickel metal-hydride designs have efficiencies of around 66%.[43] However, modern lithium designs have almost negated this wastage as they can have efficiencies of around 99%.[44]

But are the latter batteries really available ? It may be more reasonable to assume a 66% yield instead. This is what I usually do. :) With the idea that it is possible to have a much better yield using "modern" design.

by Renard (scio at free point fr) on Fri Sep 14th, 2007 at 07:47:34 AM EST
[ Parent ]
Tesla (and many others) use Lithium-Ion batteries of course, expensive but best Wh/kg. The battery is usually the single most expensive component of EV, some vendor lease the battery.

The Modec van uses Zebra batteries with charge-discharge effiency above 90% (IIRC).


Even with NiMH AA batteries, 66% is near the absolute worst :).

by Laurent GUERBY on Fri Sep 14th, 2007 at 01:17:24 PM EST
[ Parent ]


Occasional Series