Here's a novel concept -- rather than rolling up to a recharge station in the year 2020, plugging your Volt in and reading the latest issue of Esquire while life passes you by, why not swap out a dead fuel cell for a fully rejuvenated one? We can't say for sure the idea will catch on, but it's certainly one that would save Earth-lovin' motorists an awful lot of time. A little-known outfit by the name of Signa is to thank, as the company's new fuel cell-powered bicycle operates using this scheme; riders simply pop in a recyclable 1.5 pound cartridge (where sodium silicide and water mix to create hydrogen power), toss on a pair
