Re: Hydrogen is not the answer
You're forgetting about the important bit: energy availability.
The thing about stand-by diesel generators, or the hydrogen fuel cells Microsoft has been testing, is that you can spin them up quite fast, and on demand.
You see, wind turbines generate electricity whenever there's wind, but that doesn't necessarily match with when you need electricity, so using this "excess" electricity to produce hydrogen, which you can then quickly turn back into electricity when you need more electricity, is actually a pretty clever idea.
TL; DR: Neither is a great use of energy, but diesel and hydrogen are good ways to store energy and have it available as electricity in a moment's notice.