Figure 7.7. Parts (a) and (b) illustrate the basic principle of a fuel cell. The cell consists of two electrodes sandwiched around an electrolyte. Oxygen passes over one electrode and hydrogen over the other, generating electricty, heat, and water. Hydrogen is sent into one side of a proton exchange membrane (PEM), which splits it into a proton and an electron. The hydrogen proton travels through the membrane [Follow the arrows in part (b)], while the electron enters an electrical circuit, creating a DC electrical current. On the other side of the membrane, the proton and electron are recombined and mixed with oxygen from room air, forming water. Because there is no combustion in the process, there are no emissions other than that of water, making fuel cells an extremely clean and renewable source of electricity. [Part (a) courtesy of Fuel Cell 2000 (Breakthrough Technologies Institute), Washington, DC, part (b) courtesy of Ballard Power Systems, Burnaby, British Columbia, Canada.] Part (c) shows a 25-W fuel cell, with a stack of three cells. The voltage from a single cell is about 0.7 V, enough for a common lightbulb. When cells are stacked in a series, the operating voltage increases to 0.7 V multiplied by the number of cells stacked. (Photo courtesy of the U.S. DOE National Renewable Energy Lab., Golden, CO.) Part (d) shows a 5-kW fuel cell, with its assembly of many individual cells locked together. This large cell is manufactured by Plug Power, Latham, NY. (Photo courtesy of the U.S. DOE's National Renewable Energy Laboratory, Golden, CO. Warren Gretz, Photo credit.) Part (e) shows a Plug Power stacked fuel cell installed in a stationary electric power unit. [Photo courtesy of Fuel Cell 2000 (Breakthrough Technologies Institute), Washington, DC.]
Was this article helpful?
Do we really want the one thing that gives us its resources unconditionally to suffer even more than it is suffering now? Nature, is a part of our being from the earliest human days. We respect Nature and it gives us its bounty, but in the recent past greedy money hungry corporations have made us all so destructive, so wasteful.