Fuel cells hold great promise as an emission-free way to power cars and other vehicles, but range is the bottleneck. Without a national infrastructure to support fuel cell re-fueling, drivers are pretty much stuck to a network of local charging stations. That could change fairly rapidly, if a test under way by the Department of Defense bears out. In cooperation with several DoD agencies and the car manufacturer GM, the U.S. Army has just launched a pilot fleet of 16 vehicles powered by hydrogen fuel cells in Hawaii. That\'s small potatoes compared to the tens of thousands of vehicles owned by DoD, but according to the Army it\'s the largest military fleet of fuel cell vehicles in the world. The new fleet is stationed at Fort Shafter in Honolulu on the island of Oahu. The choice of Hawaii as a location to test fuel cell vehicles underscores the military’s tactical need to develop alternative fuels that can be produced on or near Department of Defense facilities. Hawaii is the most fossil fuel dependent state in the U.S., and imports account for about 90 percent of its petroleum consumption. \"Our pursuit of alternative energy is closely tied to our commitment to continually adapt to an ever-changing security environment,\" explained George Ka\'iliwai, the Army\'s Director of Resources and Assessment for U.S. Pacific Command in a press statement. \"Defense relationships and military approaches alone can\'t solve all of our energy challenges, but they underpin the initiatives we\'re taking within the Department of Defense to reduce the dependence on foreign sources of energy.\"