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Re: FW: Gas or Electric



A few points that seem to have been missed in this discussion:
--The human pollutant exposure difference between the gas and electric
lawn mower is quite remarkable.  In the instance of the gas lawn mower,
the emission is uncontrolled and very near where the human user is
breathing.  The exposure to the user from pollutants emitted from the
engine is quite significant (even with newer mowers).  These mowers are
usually operated in urban areas, so neighbors receive a lower, but
potentially meaningful, exposure.  In the instance of the electric lawn
mower, the emissions are from a power source generally distant from
people, with significant air pollution controls that greatly reduce
pollutant emissions per amount of energy used.  The health benefits
clearly lay on the side of the electric lawn mower.
--Most electric lawn mowers have cords.  This means no batteries (and
resulting energy loss and pollution), but the inconvenience of the
cord.  Our corded electric mower works just fine for our small lawn, but
it would be a pain on a large lawn.
--The pollution from the electricity generation depends on the
generation source.  This varies regionally.  For example, in California,
much of the electricity is generated by renewable, hydro, and natural
gas power plants; we have relatively little coal and oil.  This causes a
lower air pollutant emission per kilowatt hour than you'd see in the
midwest, where coal fired power plants supply most of the power.
--In general, electric motors (which are very efficient) and an electric
power source provide more efficient use of fuel than a gasoline engine. 
Although I'm not sure how reliable the statistic is, I've been told that
my electric car (a Honda EV, which is a very freeway capable short
minivan) uses fuel at the equivalent of about an 80 mpg gasoline power
car.

Also, I should correct a misconception in a previous posting:  electric
motors are notable for their significant torque.  The problem is that
the motors were (and some still are) undersized for the application in
question (e.g., initial electric lawn mowers).

Since most lawn mowing is in urban areas, I think that a life cycle
analysis will show that the electric mower is far superior
environmentally, primarily because of the human exposure issues.

Kelly Moran
TDC Environmental