Originally Posted by Swift

Hydrogen is a great idea - in theory you could make it from water and when you burn it, you just get water back. But the very big problem, in my opinion, is how to make it.

Currently, most of the hydrogen available is actually made from fossil fuels, usually as a byproduct of the petrochemical industry. But this would be a pointless way to make it if you are trying to decrease the use of fossil fuels or help global warming; you would do better by just burning the coal or oil (as far as total energy out).

One way to make this work would be by making it via a photoelectrochemical process (I actually did research on this in the 80s). Unfortunately, no one has come up with a method with an efficiency even close to commercially viable.

The other way would be thermal-nuclear: using the heat from a nuclear power plant to split the water thermally. I have not seen any particular moves in that direction, at least on a commercial scale.

So, again IMHO, all the work on both hydrogen storage and hydrogen fuel cells (which is how you would "burn" the hyrogen) are putting the cart far in front of the horse.