We’re all still waiting for a usable fuel cell solution, but maybe we’re a step closer. PolyFuel just announced that their latest fuel stack can deliver up to 500 Watts per liter. Now, we don’t want to carry a liter of methanol with us, so PolyFuel has a 111cc fuel stack that provides 56 Watts of power. That would get me a little more runtime on my UMPC that I get with the extended battery. The fuel stack isn’t all that big either: this photo shows it off at 8.8 x 4.5 x 2.8 centimeters. The efficiency of the stack is helped by sandwiching fuel cell membranes, electrodes, and bipolar plates to provide the most fuel and air to the stack’s internal surface areas. Too bad these run on methanol and not methane; we have plenty of that around the house thanks to the numerous cows in the area.