On 14.10.15 22:47, Paul Schlyter wrote:
On Wed, 14 Oct 2015 09:17:57 +0100, Martin Brown
wrote:
I do my daily commute to work and back in my Chevy Volt using
only electricity.
It consumes a mere 200 watts per mile at a cost of less than 1
cent
per mile.

Units! It cannot do any number of watts/mile.

Yes it can! When the car is brand new it runs smoothly and consumes a
number of watts. If you don't maintain the car it will eventually
runt less smoothly and will therefore consumes more watts when
running. The number of watts per mile its power requirement increases
will be a measure of how fast the car deteriorates. Ideally the car's
power requirements would increase by zero watts per mile, in reality
it will increase by some non-zero watts per mile.

It is totally impossible to consume watts.
You are confusing power(watts) and energy(1000 watthours is 1 KWh)

Multiply your watts with time and you have energy(consumption).