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Thursday, March 01, 2007

Hydrogen is NOT a practical source of energy

Hydrogen is not, repeat, not, a practical source of energy. The reason is plainly laid out in a recent article in The New Atlantis.

As the author says, almost all of the Hydrogen on earth is combined with some other element, and the only way Hydrogen can serve as a source of energy is if it is not so combined. In order to free it, it is necessary to apply energy, and, because of the second law of thermodynamics, it takes more energy to separate the Hydrogen from, say, Oxygen, than we would get back by re-combining the two in, say, an automobile.

The chemistry in what follows is simplified greatly.

Hydrogen + Oxygen gives off energy. Lots of it. But you have to have the reactants to carry out this equation.

Just in case anyone hasn't thought of it, it also takes energy to obtain energy from petroleum -- it must be found, tapped, shipped, refined, and stored. But we get more energy from petroleum than it takes us to do all of this. The reason is because the Hydrogen in hydrocarbons does not need to be free in order to serve as a fuel. It's the same Hydrogen, but combining Oxygen with the Hydrogen in hydrocarbons gives off energy. Not as much as if free Hydrogen were combined with Oxygen, but, with hydrocarbons, we don't have to free it. The fuel + Oxygen reaction gives off energy. Hydrogen in hydrocarbons is in a form that can combine with Oxygen without being freed first. Photosynthesis, done freely for us by plants, using the energy of the sun's light, combines Hydrogen with Carbon to make organic matter, which was the source of hydrocarbons and other fossil fuels.

Hydrogen, like gasoline, can be a carrier of energy -- stored until needed. But the article claims that it isn't even very good at that. (See also the Wikipedia article on the Hydrogen Economy.)

There are probably some uses of Hydrogen fuel cells that would be practical. But they won't solve our energy problems.

Hydrogen, used another way, might solve our fuel problems. That would be in a fusion reactor, a tamed Hydrogen bomb. We don't seem to be very close to making that practical yet, and, so far, we aren't using ordinary Hydrogen, but a heavy isotope thereof, in such reactors (and also in Hydrogen bombs.)

Thanks for reading.

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