"David Hill" wrote in message
...
Franz asked "..... Why not mount windmills directly on every car?
......"

It was not I who asked that, but let it be........

Why bother when most cars have their alternators doing nothing most
of their
journey, they could be used to charge up a 2nd battery, If you think
of how
much potential electricity could be produced each day from our
traffic, cars
and lories etc, it would add up to a lot, and with no extra fuel
used.

Sorry David, but there is no such thing as a free lunch in the energy
world.
Firstly, the amount of energy stored in a car battery is very tiny.
Secondly, it is not deposited in the battery for free. Petrol is
burnt to achieve it.

Alternatively, make all vehicles petrol/electricity combined so that
the
electricity produced would go to power the car in urban situations,
thus
saving fuel and co2 emissions.

That does not save any fuel whatsoever. Not even one tiny little
smidgeon. *All* the energy of which you talk has come from burning
fuel.

Also.What about a microwave powered engine.

That's a new one to me. How does it work? Where does the microwave
energy come from? Did you know that not all of the electrical energy
applied to a magnetron is converted into microwaves? And klystrons
are even less efficient? And that converting microwave energy into
heat and subsequently into mechanical energy is only about 30%
efficient, at best?

Franz