I remember some time ago this was discussed in 4chins, diy hydrogen production. It was constantly brought that "it wasn't efficient", but I went and threw some math at it, and it appeared to make sense. Mostly, considering you have electricity surplus, like having your own solar panels. And water wasn't worth gold prices. It was a straightforward way to store energy. Note I'm not comparing it to batteries, I haven't done the math in that regard, but hydrogen you can store as easily as storing gasoline, except it is gas. A simple gasoline or diesel engine can work with hydrogen, except with prolonged time, it'll rust. But that doesn't mean that there can't be engines specially designed for this purpose. Granted this is outside of the scope for most people.
All in all I'd like to see you /sci/entists throw math at this and see what happens.
Some people swear this is the ice's green replacement. What do you say?