Given the attention that green technologies got last year, "green" will very likely be a hot (if not the hottest,.. no pun intended) theme of 2008. In recognition of that trend, the Consumer Electronics Show has established a sustainable technologies pavilion where solution providers like the Singapore-based Horizon Fuel Cell Technologies are stationed showing off innovations such as a pair of fuel cells that turn ordinary tap water into electricity. How is it done?

As can be seen in the video, the process involves what are essentially rechargeable cartridges that you fill with water and insert into devices like Horizon's HydroPak generator. Inside the cartridge is a solution that can pretty much last on a shelf indefinitely until the time comes to activate it. Activation happens when the cannister is filled with water. Once activated, you have about 30 days to use it. The cartridge is inserted into the generator and, according to Horizon's co-founder Taras Wankewycz, the generator can recharge a typical notebook about 8-10 times. He rates the generator at 270 watt-hours of power.

Once a cartridge is spent, you would send it back to the retailer, who in turn would send it back to Horizon, where it would be recharged. Fully charged replacement cartridges will probably cost around $20. Wankewycz says the HydroPak will cost around $400 and targets consumers looking to have emergency sources of power. Whereas the larger $400 HydroPak shown in the video has a regular AC outlet and two USB ports, the smaller unit shown will retail for about $20 and has a single USB port for recharging cell phones, iPods, and the like.