sandy mclean, when I read the Hydrogen Economy a few years ago as well as a number of other books on the subject (Smelling the land) I was all excited about the potential of hydrogen.

For instance, planes can fly on hydrogen, and in liquid form - because the energy density per kg is 3x more than aviation fuel -planes could theoretically fly 3x as far. But there's been talk about hydrogen planes since the 70s and only a couple of experimental planes were built but that's it.. Because there is no infrastructure - the US military requirement is that planes need to be able to re-fuel anywhere..

The other point is that hydrogen is simply a storage medium - it doesnt want to exist on its own, you need to make it. One way is steam reforming from methane which releases c02. Another is electrolysis which is really only something like 35% efficient.
So if you are simply using it as a battery - there are better options such as pumping water uphill, compressing air (75% efficiency), flywheels 80% etc..

While fuel cells are also great - platinum is far more scarce and expensive than lithium.

YOu also mentioned storage & transportation - it is hard to contain - there is always some leakage and costs energy to compress & liquify. Pipelines are difficult though not impossible (Germany has some hydrogen pipelines dating from the 1930s)

One possible potential use that might change the infrastructure situation is using hydrogen in superconducting transmission cables -
(Scientific American had an article a couple of years ago) This would minimize electricity loss to resistance, and also the hydrogen would have a dual use - of cooling the cables as well as storage of energy.