A fuel cell, reportedly the nation's first powered by methane gas from rotting garbage, was introduced by Southern California Edison Co. and the Los Angeles Department of Water and Power. The fuel cell, which operates quietly and without combustion, reportedly could supply power to 25 homes. DWP resource development engineer John Pepper said it is made up of a layer of phosphoric acid between two electrodes. The methane gas passes over one of the electrodes and air or some other oxygen-carrying medium passes over the other. The gas is collected from a landfill through a series of pipes. The cell is in the experimental stage at an undisclosed site in the City of Industry.