In article ,
Seraphim writes:
Stephen Harding wrote in news:3F994B53.FACA123
@cs.umass.edu:

Ralph Savelsberg wrote:

Great! However, the big question that very few people seem to be able to
answer (myself included) is where the energy to make the H2 should come
from?

Natural gas. Mix methane (CH4) and very hot steam (H20) to produce Carbon
Dioxide (CO2) and Hydrogen (H2). This is a very well known process, and is
(was?) commonly used in the industrial production of chemicals.

Erm... The Methane comes from where, exactly? Right now there are 2
sources - underground pockets, and Bovine Ddigestive tracts. The
underground sources have teh advantage of being commercially viable,
but incurs the same environmental damage as drilling for petroleum,
adn it's much riskier to store and transport. I'd rather be next to a
nuclear power plant than an LNG storage facility. Since the idea of
cracking Methane to get Hydrogen is to reduce the amount og Co2 being
generated, this method also has no advantages. The C02 is still being
created, It's just occuring at your Hydrogen Generating Plant rather
than in the car engine, or space heater, or whatever. Hydrogen,
whether in gaseous or liquid form, has lousy engery density, as well.
You can gat about 10 times the BTUs (Kilocalories)/gubic ft/meter
[liter/gallon] using kerosene or gasoline. Frankly, you'd be better
off just burning the Methane.


I'm sure you're aware that H2 is not something you can dig up
from the ground. Perhaps our hope should lie with nuclear fusion, though
that's not without its own problems either.
In my opinion H2 not the answer to a possible energy/environmental
crisis. Focussing on H2 is just replacing one problem with another.

There's so dogone much H2 around that its use for energy is almost as
attractive as splitting atoms in the long term.

But yes, those H and O atoms really like to stick together, and the
energy it takes to coax them apart is problematic at the moment.

The energy will always be probematic if water is the only thing used. The
energy it takes to free the hydrogen will be equal to the energy you get by
running it through your fuel cell, assuming that there is no energy is lost
in the process (very unlikely). Now, there are ways around this. You can
introduce something else (like Methane above) which tends to help. Or you
can use 'cheap' energy, like solar or nuclear.

100% efficiency isn't just Very Unlikey, it's Bloody Impossible.
Don't they teach these kids Thermogoddamics any more?

--
Pete Stickney
A strong conviction that something must be done is the parent of many
bad measures. -- Daniel Webster