TECHNOLOGY FOCUS - ELECTRICAL POWER AND ENERGY - Preferred Components: The fuel cell layer is a thin flat construction or a thin curvilinear construction. The unit fuel cells are disposed parallel to each other horizontally around the central axis. They may be disposed parallel to each other forming a tube and oriented parallel to the central axis of the tube. A first unit fuel cell may be disposed at a first angle to an adjacent unit fuel cell and a second unit fuel cell may be disposed at a second different angle to the first unit fuel cell. A first group of the unit fuel cells is formed into a first group of parallel unit fuel cells and a second group of unit fuel cells is formed into a second group of parallel unit fuel cells. The first group of the unit fuel cells is disposed at an arbitrary angle to the second group of unit fuel cells. The fuel cell has a three-dimensional shape, preferably cylindrical, prismatic, box-like or irregular. At least one of the fuel cells is oriented to form the fuel plenum. At least one of the first and second unit fuel cells conform to the shape of the fuel plenum. The oxidant plenum is enclosed by a structure (40) open to ambient atmosphere. The structure may be a closed container. The fuel plenum is enclosed by a closed container. The fuel cell layer comprises 2-50000 (preferably 2-100) unit fuel cells. At least one process layer comprises an ion-conducting material or an electronically conductive material. The ion-conducting material comprises a proton exchange membrane, an electrolyte-filled micro-porous structure and/or a liquid electrolyte trapped in a mesh. Each perimeter barrier comprises a material that prevents the uncontrolled mixing of fuel and oxidant. Preferred Dimensions: The fuel cell layer has a thickness of 1 nm to 2 cm. The overall length of the fuel cell layer is 1 mm to 100 cm. The overall width of the fuel cell layer is 1 mm to 50 cm. The overall thickness between the front face and the back face of the fuel cell layer is 100 nm to 5 cm. The fuel cell layer comprises a variable thickness.    TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Materials: The oxidant comprises air, oxygen, mixtures of inert gas and oxygen.    TECHNOLOGY FOCUS - METALLURGY - Preferred Materials: The electronically conductive material may comprise a metal or a filled metal composite.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Materials: The fuel comprises hydrogen, hydrogen from reformate, methanol, ethanol, formic acid, and/or ammonia.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Materials: The oxidant comprises air, oxygen, mixtures of inert gas and oxygen.    TECHNOLOGY FOCUS - POLYMERS - Preferred Materials: The electronically conductive material may comprise a filled micro-structure of polymer, a filled epoxy composite, or a graphite composite.