NOVELTY - A fuel cell comprises proton exchange membrane; anode housing having anode feed passage (115) and anode waste passage; cathode housing having 2 cathode through passages; three-dimensional anode having surface to volume ratio of 50-5000 cm2/cm3; and three-dimensional cathode. The anode housing and proton exchange membrane together define an anode chamber containing the anode within the anode housing.    USE - For stacked fuel cell.    ADVANTAGE - The microbial fuel cell may function in aerobic or anaerobic environments, can be 10-100 times smaller than traditional microbial fuel cells (with the potential in the design to be shrunk to 103 to 104 times smaller), and has been shown to generate continuous power for weeks. This design may be scalable, enable several cells to be efficiently stacked in three-dimensional (3D) for wiring series or parallel circuits, and allow for complex and highly porous 3D conducting structures to be added to the anodic and cathodic chambers, creating orders of magnitude higher surface area electrodes than currently disclosed designs.    DETAILED DESCRIPTION - The fuel cell comprises proton exchange membrane; anode housing having anode feed passage and anode waste passage; cathode housing having 2 cathode through passages; three-dimensional anode having surface to volume ratio of 50-5000 cm2/cm3; and three-dimensional cathode. The anode housing and proton exchange membrane together define an anode chamber containing the anode within the anode housing. The cathode housing and proton exchange membrane together define a cathode chamber containing the cathode within the cathode housing. The anode feed passage and anode waste passage are each coupled to the anode chamber and to the cathode through passage. INDEPENDENT CLAIMS are also included for:    (1) a stacked fuel cell comprising the fuel cells and electrical lead(s); and    (2) a method of generating power comprising providing the fuel cell; placing in the anode chamber bacteria capable of donating electrons to the anode upon exposure to a fuel; and circulating an anode solution through the anode feed line, the anode chamber, the anode waste line, and the cathode through passages.    DESCRIPTION OF DRAWING(S) - The figure is a schematic view of the stacked fuel cell.    Anode through passage (115)    Leads (125)