[LINK] Electric vehicles and generation

[Karl Auer]

> The limit is ultimately how far a body X kg can travel using Y kW of 
> power, how much you can carry in the batteries, and electricity 
> distribution practicalities (how many houses can be fitted with 70-amp 
> circuits).

It runs deeper than that.The real question in all this (apart from the
question of why we need to use energy travelling) is the *kind* of
energy we use. Fossil fuels are finite and they pollute (even the
so-called "bio" alternatives, although renewable, still burn into CO2
etc).

Electricity does that too, if it is generated via burning something, but
it doesn't have to. Electricity can come from many other sources -
solar, wind, tide, nuclear etc, and these have far smaller "footprints".

Hybrid cars reduce fuel usage chiefly by using the energy more
carefully. An electric car with a small onboard petrol generator, for
example, doesn't burn lots of fuel starting or accelerating. Because
speed can be controlled electrically rather than mechanically, you save
on gearboxes, clutches etc, all of which waste energy. Brakes can
recover some energy, or at least stop using it when slowing rather than
accelerating. WAY less energy goes into heating up (and then having to
cool) the motor. Although the batteries are heavy, you don't have an
engine block, and many components that add weight to a normal car can be
much lighter (drive train) or omitted entirely (like motor cooling,
gearbox etc).

So the equation is more complicated than just kilowatt hours.

Regards, K.

-- 
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Karl Auer (kauer at biplane.com.au)                   +61-2-64957160 (h)
http://www.biplane.com.au/~kauer/                  +61-428-957160 (mob)