Fuel cells have been just around the corner for over a decade, and that seemingly endless corner has finally been turned. While fuel cells are mainly intended for commercial applications, wartime demands typically give new technologies an opportunity to be developed and put to use more quickly, under more stressful conditions. This leads to more rapid development and adoption of the technology. Fuel cells are just another example of this. In the last few years, fuel cells have been introduced in several military applications, spurred in part by the higher levels of wartime spending.
Fuel cells are now available for UAVs. Fuel cells are a new battery technology that generates four or more times as much electricity per pound as current batteries. Light weight UAVs, from the micros (at under ten pounds) to those weighing two to three times as much, are often powered by batteries. Current batteries give these UAVs an endurance of 30-90 minutes. This is enough to give the users a tactical advantage, and the micro-UAVs have been particularly popular. But if you could keep one of those micro-UAVs up for three hours, instead of one hour, it would be a major, often life-saving, advantage.