🚀 go-pugleaf

In article <BLACK.92Jan21080323@beach.csulb.edu> black@beach.csulb.edu (Matthew Black) writes:
>I've often heard that electric cars run cleaner than conventional
>gasoline cars.  I believe it!  But what about all the polution
>generated by the electric company?  Electric cars don't eliminate
>polution; they simply move its origin.
>--matt

It's much easier to control pollution from stationary power sources
since they work under relatively constant conditions, as opposed to a
car which may be started cold, started hot, idles, works under part
or full throttle, coasts down hills, may be driven stop and go or at
high speed on the freeway, etc.  For a stationary source the pollution
controls can be optimized for the operating conditions;  there are
so many operating conditions in a car that smog control cannot possibly
be simultaneously optimized for all conditions. 

On the other hand, the stationary source will emit some smog (and I don't
know how much--wish I did), and the roughly the same amount of CO2 for
the same power output (though efficiency is somewhat higher for the
stationary source so the C02 will actually be lower), assuming that the
power is generated by burning fuel.

HOWEVER, you also have to consider the overall efficiency of the electric
car.  First you have to generate the electricity.  Next, you have to 
distribute the power over electrical wires.  Maybe 70% efficiency.  Then
you have to run it through a battery charger.  50% to 80% efficiency,
depending on circuitry (maybe more).  Then you have to charge the batteries
in the electric car.  50% efficiency, or less in cold weather.  Then when
you run the electric car you discharge the batteries.  Another 50% or less.
And there's some power electronics and the motors in the electric car which
add their own efficiencies--let's say 75%.  So the overall efficiency of
converting the electrical power to power at the wheels will be (based on
my guessed numbers):  70% X 50% X 50% X 50% X 75%, or 6.5% efficiency.
Granted, these numbers are guesses, but the savings in smog are going
to have to offset the additional power to be generated at the source of
the electricity for a net gain.

Furthermore, electric cars themselves are not necessarily pollution free.
Most batteries have to vent fumes, which potentially carry some real toxic
components which sould cause their own problems.  For example, lead-acid
batteries will release sulfur dioxide, which will cause acid rain, and som
airborne lead, which is bad news.  Replace every gasoline car with an
electric car and you've got a pollution problem, albeit a different one.  Also
the handling and storage of all these batteries will also be an occupational
hazard.  And every time one of these cars crashes, a bunch of lead (or
equivalent) and strong acid will go into the gutter and down storm drains,
when the battery casings crack, if the driver hasn't been maimed first by
all that acid.  Also, have you ever heard of batteries exploading from
the hydrogen gas?

One more thing to think about with regard to electric cars is that batteries
are awfully heavy, adding much weight without adding to the structure, and
resulting in corresponding lower overall efficiency and also to the chance
of occupant injury in an accident.  

All electric cars I have seen have an extremely limited range (under 100 
milesa, very little power, and few amenities such as air conditioners, power
this and that, etc.  If you replaced the batteries and electric motors with
a gasoline engine of equivalent horsepower, you would probably get well over
100 MPG and pollution would be reduced correspondingly because you would
be burning so little fuel.

Another thought--cost of operation.  An average family size sedan requires
about 30 HP to keep running on the highway.  Using 1 HP = 700 watts (approx),
this is about 21 kw.  On the freeway at 60 MPH you would consume 
21 kw-hr per 60 miles, or 0.35 kw-hr/mile.  This is power at the wheels;  to
get the power consumed you have to divide by the combined efficiency of
charging, power conditioning, and discharging, or 50% X 50% X 50% X 75%, or
9.4% efficiency, resulting in 3.9 kw-hr/mile.  At an average electrical
rate at the meter of $0.10/kw-hr, this comes to $0.39/mile in electric costs.
On the other hand, a car getting 30 mpg would consume 0.03 gallons of gasoline
per mile;  at $1.00/gallon this would come to $0.03 per mile in gasoline
costs.  If you also take into consideration the fact that approximately half
the cost of gasoline consists of local, state and federal taxes, it suddenly
becomes obvious that driving a gasoline powered car is extremely inexpensive.
If in addition you reduced the size and horsepower of the gasoline powered
car to the same level as the electric car, to make a fair comparison, the
cost of operating the gasoline car would be further reduced by a factor of
2 or 3.  Wow!

Electric cars may have their place, but they will not be a panacea.

-- 
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