Special Operations Forces (SOF, commandoes and Special Forces) are getting lighter and smaller fuel cells to replace batteries. SOF often go out on long range patrols and stakeouts. They missions use lots of gadgets that need electricity. Typically, a three day mission would require 30-40 pounds worth of batteries. This is being replaced by a single, suitcase size fuel cell unit that weighs less than ten pounds and puts out about 200 watts. You can plug sensors into the fuel cell, or recharge regular batteries. Another important aspect of fuel cells is that, unlike small generators, they make no noise and give off no fumes or heat.
SOF typically are the first to use new equipment, as long as the stuff appears that it will survive in the field. Price is not an issue. By the time the SOF have proved that a new item (usually after some modifications and upgrades) can do the job in a combat zone, the price has come down, and everyone can afford it. At that point, in a few years, fuel cells will be a big help for all infantry, and even mechanized forces. Tanks can haul a fuel cell so that it can have power, quiet power, when it is just sitting, and waiting. Same for all vehicles. Fuel cells are smaller and lighter than conventional generators. The troops appreciate the quiet too, and the absence of fumes.
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.