All current renewable energy sources have one big flaw. They produce energy when the circumstances are right, not when required. Beacause of this they cause issues in the energy grid.
If we could build water cracking facilities at the right scale with the right characteristics, that could help offset the efficiency/cost issues.
And on the issue of high pressure fire bombs, gas powered cars are pretty common here in Europe and those things are pretty safe. There are numerous safety features, not to mention that gas tanks are pretty tough vessels.
Edit: On the topic of fire bombs. I have today learned that one would not want Hydrogen tank in his vehicle.
Everyone comes to this conclusion when you realize how deadly compressed hydrogen is compared to liquid petroleum. Nothing like being burned by fire you can't see.
What losses to we have on the battery end? Transmission line losses (6%), li-ion charge/discharge losses (80-90%), losses due to the fact that the car needs to keep the battery warm/cool depending on outside temperature (pretty high in the winter, regular 120V outlet is not enough to keep the capacity up).
Personally I dismiss hydrogen mostly because I'm frightened by the thought of a bunch of high pressure fire bombs being driven around by drunk people.