Hydrogen fuel cell powered bike--its' only byproduct is water.
I can't get a link to work--just go to popsci.com and check out Extreme Machines

Can't pull it up, mwmw.

Who is it made by? Zeppelin Werke a.g.?

I just saw this in the October Pop Sci today. I'm rethinking this whole electric bike thing. It might be a good way for non-cycling spouses to be able to keep up/go the distance with the more experienced cyclist and perhaps learn to love it while pedalling when they can to build up their own stamina.
Regards,
Raymond

But doesn't hydrogen have the nasty habit of exploding easily? I think the last place most people would want to have a mini-Hindenburg is right between their thighs...

Yes it does. Germany couldn't get hold of any helium for the Hindenburg so they used hydrogen instead. Sadly, the rest is history... I agree between my thighs is not where I want a hydrogen bomb! What ever happened to just pedaling?

What happens when the spouse runs out of fuel? Who's gonna ride that anchor back home??

HillaryRose, yep, and that is the big disadvantage mentioned in the little blurb in Popular Science.