I may have a misunderstanding of hydrogen fuel cells, isn't hydrogen driven through a catalytic converter and combusted?
I take that back, I was mistaken about how the energy was captured, its not thermal its creating current from the splitting of H2 gas and separating the electrons off. In this case, how is that any different than just using batteries? I suppose the only benefit would be "charge" time where you just refill the hydrogen rather than recharging a battery in its place. It'd still be far less energy efficient than just using batteries. If we make the splitting process more efficient and it takes 1.1 joules to get 1 joule worth of hydrogen. Then you get a 50% efficiency from the fuel cell, wouldn't you have been better off just taking that 1.1 joules, putting it into a battery at negligible loss, and running a 80% efficient electric motor?
I'm all for clean energy, I'm particularly pro nuclear, but I'd be perfectly content if we increased our solar/wind/hydro/tidal/geothermal power instead. I'm not "against" hydrogen. I just don't think its a practical option.
Batteries aren't very energy dense. It takes hundreds of kg of batteries to equal the same amount of energy as a tank of compressed hydrogen.
Batteries are about 10x more expensive than hydrogen tank / fuel cell combination (per kwh). Fuel cells have more durability than li-ion batteries (so longer lifetimes without having to replace the systems).
Technically, fuel cells can get up to 60% currently. As we find better catalyst for PEM fuel cells, it's theoretically possible to hit 95-99.99%.
Both technologies do use an electric motor, so that drive-train remains the same, allowing you to take advantage of features such as regenerative braking.
The problem really with batteries is the energy density... there's absolutely no way you're going to be able to compete with a battery (or capacitor) against compressed hydrogen in terms of energy / weight.
If we had magic super batteries, I'd say "sure, let's skip the step of hydrogen", but we've been working with battery technology for like 2000 years. While battery energy technology is getting better and better, it's not even close to the energy density than compressed hydrogen gives.
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I think hydrogen is the best solution going forward, as it requires way less resources to create the hydrogen tank and PEM fuel cell than what it takes to make a li-ion battery. Also, production of hydrogen can be done cleanly with a nuclear reactor (steam biproduct -> hydrogen instead of massive cooling towers to reclaim water).
Hydrogen can be used in many applications... cars, boats, and even planes. There's no way we're going to be able to fly a jet with batteries. Batteries are just simply too heavy for the energy they hold.
Why do people fear hydrogen so much? It's literally safer than gasoline. It may seem that several myths were spread throughout the public (probably by big-oil).
Perhaps the dangers are a bit overinflated. But we do have a rather dramatic example of how hydrogen could be dangerous.
Perhaps you should read the wikipedia article. Most individuals died from jumping. Out of the 85 people onboard, only 35 people died. And there's no evidence anyone died due to the hydrogen. This thread covered the hindenburg hydrogen myth several times now... which shows you hadn't read before posting.
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