[SGVLUG] [OT]Hybrids and trains (was fuel prices and the dollar)

[Dan Borne]

I applaud your letter, I think it is a good thing to say especially since
the only thing I hear about conservation of any sort is people driving a
Toyota Prius (which is a quite flawed method of "conservation" when one
considers that around 70% of the energy a car produces is used to push the
air past the front of the vehicle and it has one of the largest drags
thereof) . I am still confused thought how a plane is more efficient than a
train; doesn't a jet engine burn 10, 11 gallons of fuel a second.



2008/5/13 David Lawyer <dave at lafn.org>:

> I've submitting the following letter to the editor of the LA times.
> Not sure they will print it.
>                        David Lawyer
> =======================================================================
> Re: "Civilization's last chance", May 11
>
> The implication that hybrid autos and trains (instead of airplanes)
> could make much of a difference in global warming is simply wrong.
>
> Hybrids use internal combustion engines no more energy-efficient than
> the engines on non-hybrids.  They also waste a lot of energy converting
> the gasoline motor power to electricity, charging a battery, and then
> withdrawing energy from the battery to power an electric motor to move
> the car.  All this energy conversion wastes energy and adds to the
> weight of the car.  The reason hybrids get good mileage is not because
> they are inherently efficient, but because people don't know how to
> efficiently drive a non-hybrid and because laws and car design, etc.,
> impede one from efficiently driving it.
>
> To efficiently drive a non-hybrid, one needs to get a "brake specific
> fuel consumption map" for their engine, which the auto companies don't
> supply.  Then use the map to apply the optimal amount of torque at any
> given rpm, but autos have no torque meter.  Efficient driving will
> mean doing a lot of coasting but coasting in neutral is illegal.
>
> As for trains vs. airplanes, it turns out that they are about equally
> energy efficient, and we don't save energy by taking the train.  See
> the U.S. Dept. of Energy's "Transportation Energy Data Book": edition
> 26, table 2.14, and account for the fact that about 15% of fuel for
> passenger aircraft goes to transport freight in the cargo hold.  For
> details see my "Fuel-Efficiency of Travel in the 20th Century"
> http://www.lafn.org/~dave/trans/energy/fuel-eff-20th-3.html#air_eff<http://www.lafn.org/%7Edave/trans/energy/fuel-eff-20th-3.html#air_eff>
>
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