Hi Charlie
On (06 Oct 97) Charlie Young wrote to Alec Cameron...
 CY> I wonder what the total efficiency would be for an electric
 CY> car vs. the traditional gasoline powered car?
 CY> You would have to calculate the energy used digging up the coal,
 CY> transporting it to the power station, transporting it around
 CY> the coal yard, and crushing it.  Then there are blowers and
 CY> other energy hungry devices.  Also you would need to add in
 CY> the losses in the transmission grid.  That is not to say that
 CY> gasoline is the perfect energy source, but maybe not as bad
 CY> as some would have us to believe.
The "calculation" would be wrong every time. Forget grid losses these are
trivial. Let's talk about "total efficiency" as this has real important
HOMEPOWER implications. Then I'll end by talking elec cars.
Start with the energy uses, that are popular in the home.
* TV receiver efficiency very low because the sound output is usually set
at around 0.5 watts and the picture output at about 15 watts but the coal or
oil energy to drive that thru furnace to steam to electricity is way above
that. Here most TV receivers run at about 100 watts input and the typical
overall efficiency of a large 1000MW generating boiler/turbine/generator is
ROUGHLY 33%. So that's about 300 watts of coal consumption to give us 15.5
watts of entertaining light and sound.  Like, total efficiency 100 times 15.5
divide by 300, ie 5%   BAN HOME TV!   Nah!
* Gas or electric cooktop or oven, raise one pound of food thru 300 deg F for
several minutes. Compare the energy absorbed by the food with the heat input
to the kitchen and the cook, and again we are inefficiently burning the 
ossil
fuels. Like, 5% total efficiency.  BAN COOKTOPS AND OVENS?   Nah!
* Refrigerator, deep freeze, airconditioners- none have efficiencies above
40%, the heat released at the condenser greatly exceeds the heat removed.
These cooling devices have the job of removing heat from a cold body and
rejecting it to a hot body. This interfering with nature costs plenty!
Forget lighting. Yes there are smart hi efficiency lamps, but in the huge
majority of homes the lighting energy is trivial compared with the other
loads.
If the overall efficiency of an auto is thought important [by folk who are
wasteful with energy indoors!] then we assume that it would be a Good Thing 
o
use less energy in propelling the auto. Suddenly the problem gets very 
mple-
The surest way to save big on energy for an auto [regardless of what kind of
motor it has] is to do these Un American [and Un Australian] things-
Drive at lower speeds. Cut the engine during major delays. Use smaller
vehicles. Omit the spare wheel. Eliminate heater/ air conditioner and dress
appropriately. At holdups, get your foot off the brake pedal and latch the
handbrake. Keep engine in good tune, don't allow fast idle.  Pump tyres up to
maximum recommended by tyre maker not auto maker. Get that junk out of the
trunk that rides around all the time "in case I need it". Drive thoughtfully
anticipating what acceleration/ braking may be needed. Preferably don't 
rake!
The brake pedal has a great thirst for fuel.
Oh I forgot one important thing. Leave the car at home and walk!!
Cheers.....ALEC
... ........The hasty and the slow meet at the ferry
--- PPoint 1.92
---------------