This looks like a good solution for dealing with portable electronics on a bike
Portable Fuel Cell
And it's much lighter than most external battery solutions for recharging.
So...I'm going to ride my bike to work to save on fuel but use hydrogen "gas" to power my light?
Alright, alright, that's not fair, a lot of people just bike for fun - to be honest, environmental side effects are just a plus for me, not my real motivation to ride.
But even so, I don't really want one. Electricity comes to my home via wires and I don't have to do anything - I just plug in the battery and recharge it. That's it - I don't have to go to the store, don't have to order something online, etc etc. Heck, I always eat fresh fruits/vegetables at the cafeteria because then I don't have to go to the store before going home, and I don't have to throw food out every week because I didn't get around to eating the lettuce or something.
And a fuel cell powered light would be exactly the same - you always end up needing to order more, and since you can't recharge it you always have to carry a spare and stop and change them when they run out. Or - you end up throwing out a lot of half-used ones so you don't have to change the cell in the middle of a ride.
I don't know if we'll see them on bike stuff - we might with weight-weenie racing and such eventually (at the moment that thing only provides a usb amount of power - not a lot I don't think). But I think it would be more annoying than my current battery lights. I don't relish the idea of constantly spending money on new cartridges either - it's pretty impossible to believe they'll be anywhere near as cheap as electricity.
I'm going to hold out for the nuclear one.
Interesting, but if you read a bit further you discover that the 12 Whrs of power that one filled cartridge supplies is equal to around 4 AA NiMH batteries fully charged. (the 1000 AA battery reference in the article refers to the total life of the cartidge including all refills, sort of like the fact that a rechargeable NiMH battery is good for 1000 charge cycles) You would then need to recharge your cartridge or slap in a charged one. For now, it's just a lot cheaper and easier to use rechargeable NiMH batteries -- at about $2 each they are kinda hard to beat.