Hydrogen has been hyped as the fuel of the future for the last decade or so, but this isn't entirely accurate. Hydrogen does not exist in large natural quantities on Earth. We have to produce hydrogen using some other source of energy, either by extracting it from a fossil fuel or by electrolysis. Hydrogen is simply an energy carrier.
Hydrogen works well in fuel cells but not so well in our current piston engines. Hydrogen burns very hot, very quickly, and needs a lot of room to run. Engines must be redesigned with cylinders five times the volume of a comparable gasoline or diesel engine.
Hydrogen will work well in a properly designed turbine, but it isn't produced in large enough volumes for uses like this. There are no commercial manufacturers of hydrogen turbines in the world at this time.
Hydrogen is an excellent input for a fuel cell. This will probably be where it first makes inroads, being generated in smaller, remote locations where it will be used to firm small supplies of stranded renewables.
Hydrogen is also not pipeline friendly. Nuclear plants eventually fail due to something called neutron fatigue. Having free neutrons passing through materials slowly makes them brittle. Hydrogen is diatomic, two protons and two electrons. It isn't as harsh on metals as a neutron flux, but when containing hydrogen under pressure metal, especially structural steels, experiences what is known as hydrogen embrittlement. Ammonia, on the other hand, is already distributed via a 3,100 mile pipeline in the United States, and is perfectly amenable to pipeline transport.
Hydrogen has 3 isotopes:
Regular H, 1 proton + 1 electron, major component, about 99.99% of what naturally occurs (1 part in 6000).
Dueterium, 1 proton + 1 neutron + 1 electron. A stable isotope, used for special chemistry, and as a moderator in nuke reactors like Canada's Candu reactor. Also used to make hydrogen bombs, and proposed for nuclear fusion reactions. Normally exists as DHO, which can be separated from regular water by careful distillation and/or electrolysis. Harmless.
Tritium, a very dangerous varmit, which has a half life of about 12 years, decomposing into Helium 3 (2 protons, 1 electron) and a beta and a gamma ray. Often formed by the action of neutrons on deuterium in nuke reactors. Really great for making H bombs, N bombs and A bombs, and proposed for fusion reactors (a deuterium + tritium --> helium 4 + neutron + energy). But, with a half life of ~12 years, it's a use it or lose it proposition.
Also, FYI, a "free neutron" has a half life of about 12 minutes. If it gets lodged in a crystal of stainless steel and then decomposes into a proton + electron + gamma rays, lots of energy is released, the crystal has a new component - the H atom (actually, a proton, but not much difference). This is what gives rise to neutron embrittlement of stainless steel and other alloys. Also not good.
Nb41