Re: End of airliner evolution?

Date:         08 Dec 96 04:12:39 
From: (Paul Keller)
Organization: North Carolina State University
References:   1 2 3 4
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In article <>,
 <> wrote:
>On 21 Nov 96 03:02:20 , (Woodhams) wrote:
>> (Tim Russell) writes:
>>>H2 powered jets are not new it was tested in the 50'a.
>>>I read a quote that H2 was a "terrific fuel for turbines"
>>of fossil fuels to use is greater. Some alternative energy sources
>>(e.g. windmills on ocean buoys) have troubles linking to the
>>electricity grid, so for these it may make sense to store the energy
>>by electrolizing hydrogen out of water, and have ships come to empty
>>the hydrogen tanks every so often.
>Great idea! Non-constant power sources used to create H2 and then use
>the hydrogen to produce a constant supply of electricity. Solar is
>another example of a power source that is at it's peak at the wrong
>time. Highest power demand is at the dinner hour but here in Canada
>the sun is down by 5PM in the winter. Store up the daytime power in
>the form of H2 and generate the power when it's needed.
>  I admit that storing H2 in even large aircraft would be a problem
>but fossel fuels will not last forever.
>Any other sugestions from anyone? What will be the next jet fuel?

This business about powering airliners using H2 has come up before on
this board, and, I'm sorry, but I really must put an end to the idea.
Quite simply, unless global warming causes the CO2 emissions from
airliners to become a _very_ serious concern, then, if you're old
enough to read this, this won't happen in your lifetime, and not your
children's, or grandchildren's, or...and even the possibility of
airliner CO2 emissions becoming a concern is highly unlikely as well.
As others on this board have noted before, airliner CO2 emissions are
a mighty small contribution to total CO2 emissions.  If global warming
does become a concern, there are much bigger sources to reduce for far
less money than what you'd get by powering airliners with H2.
Powering airliners with H2 to combat global warming may also be the
wrong thing to do if it's not done correctly.  See below.

We'll be using JET-A, or some very similar hydrocarbon fuel in
airliners for a good long time to come.  It's only a question of where
are these fuels are going to come from.  Working from fifteen-year old
memories of seminars on synthetic fuels, it's possible to liquefy coal
at a cost of around US$50/barrel in 1980 dollars.  With crude from the
Middle East selling for $20/barrel, that's not economically
competitive, so it isn't being down right now.  In fact, no one right
now is even doing much work on synfuels simply because there aren't
any near-term prospects for a sustained increase in crude oil prices.
Nonetheless, the technology is there and available if we ever want it.
The world currently has hundreds of years of coal reserves, so that
that's one fossil fuel which isn't going to run out real soon.  There
are similarly large reserves of oil shales and tar sands which could
be refined as well, and at similar prices, which are plenty low enough
to eliminate H2 from any serious consideration.

If, after hundreds of years, we still need hydrocarbon fuels to power
airliners, and after that long a time I wouldn't consider that a
given, there is still biomass, which produces methane, which can also
be converted into heavier hydrocarbon fuels.

Something most here don't seem to realize is that most, if not nearly
all, industrial H2 is not produced by electrolyzing water, which is
horrendously expensive (and another reason why you won't see it
powering airplanes anytime soon).  Rather, it is produced by steam
reforming of coal.  Basically, you spray hot steam on coal, and get H2
and CO out of the reaction.  This is the old water gas reaction.  The
H2 is then refined and sold to industrial users.  The CO gets disposed
of, so all you're really doing with this process is burning coal to
produce H2.  Doesn't help the global CO2 emissions at all if you're
producing the H2 this way.

Paul Keller