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From: graner@ut-ngp.UUCP (Nicolas Graner)
Newsgroups: net.physics
Subject: Re: Hydrogen powered vehicles
Message-ID: <1503@ut-ngp.UUCP>
Date: Thu, 28-Mar-85 00:14:08 EST
Article-I.D.: ut-ngp.1503
Posted: Thu Mar 28 00:14:08 1985
Date-Received: Sun, 31-Mar-85 02:33:39 EST
Organization: U.Texas Computation Center, Austin, Texas
Lines: 37

Mike Augeri recently said in net.physics:

> With regard to hydrogen fueled vehicles, let me make an observation.
> 
> [...] their calculations indicated it
> would take the power output from two (2) nuclear power plants of current
> capacity to provide the energy required to produce enough hydrogen to fuel
> just the aircraft that fly out of O'Hare Field in Chicago!
> [...]
> Now, you may dispute the numbers (quite frankly, I do)
> [...]
> does anyone have some numbers on how much
> hydrogen would be necessary to replace today's gasoline-powered automobiles
> with an equivalent number of hydrogen-fueled automobiles (just the USA of
> course)?  How much energy would it require to produce that amount of
> hydrogen?

    I don't think it makes much sense to compare directly hydrogen
to gasoline. We use gasoline as a source of energy: energy coming
from the Sun millions of years ago was stored in the ground and
we can now retrieve it and use it for (almost) free (except for minor
economical considerations :-)
.
    Since there is no hydrogen stored on earth, we have to produce
it by decomposing water. And when it is used in an engine, it 
re-creates water, releasing the energy that was consumed to produce it.
Therefore hydrogen should only be considered as a *storage*, not a 
*source* of energy - very much like a battery.

    I have no idea how efficient this process is compared to a
conventional battery, either in terms of released energy/stored energy
or of stored energy/mass, but the above statistics suggest that it
is pretty low.

Nic.                      {ihnp4,seismo,...}!ut-ngp!graner

*If Murphy's law can go wrong, it won't*