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.<br>
<br><br><br><div class="gmail_quote">2008/5/13 David Lawyer <<a href="mailto:dave@lafn.org">dave@lafn.org</a>>:<br><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
I've submitting the following letter to the editor of the LA times.<br>
Not sure they will print it.<br>
David Lawyer<br>
=======================================================================<br>
Re: "Civilization's last chance", May 11<br>
<br>
The implication that hybrid autos and trains (instead of airplanes)<br>
could make much of a difference in global warming is simply wrong.<br>
<br>
Hybrids use internal combustion engines no more energy-efficient than<br>
the engines on non-hybrids. They also waste a lot of energy converting<br>
the gasoline motor power to electricity, charging a battery, and then<br>
withdrawing energy from the battery to power an electric motor to move<br>
the car. All this energy conversion wastes energy and adds to the<br>
weight of the car. The reason hybrids get good mileage is not because<br>
they are inherently efficient, but because people don't know how to<br>
efficiently drive a non-hybrid and because laws and car design, etc.,<br>
impede one from efficiently driving it.<br>
<br>
To efficiently drive a non-hybrid, one needs to get a "brake specific<br>
fuel consumption map" for their engine, which the auto companies don't<br>
supply. Then use the map to apply the optimal amount of torque at any<br>
given rpm, but autos have no torque meter. Efficient driving will<br>
mean doing a lot of coasting but coasting in neutral is illegal.<br>
<br>
As for trains vs. airplanes, it turns out that they are about equally<br>
energy efficient, and we don't save energy by taking the train. See<br>
the U.S. Dept. of Energy's "Transportation Energy Data Book": edition<br>
26, table 2.14, and account for the fact that about 15% of fuel for<br>
passenger aircraft goes to transport freight in the cargo hold. For<br>
details see my "Fuel-Efficiency of Travel in the 20th Century"<br>
<a href="http://www.lafn.org/%7Edave/trans/energy/fuel-eff-20th-3.html#air_eff" target="_blank">http://www.lafn.org/~dave/trans/energy/fuel-eff-20th-3.html#air_eff</a><br>
</blockquote></div><br>