The PEM fuel cell consists of four parts, the anode, the catalyst, the Proton Exchange Membrane, and the cathode, shown in the picture below. The anode is the negative part of the fuel cell, which separates the hydrogen molecules into electrons, used to power something on an outside circuit, and positively charged ions. The catalyst is the "splitter" that separates the protons and electrons from the hydrogen molecules. It is usually platinum in a powder form, sparsely "sprinkled" on a thin cloth or carbon paper, and it is like a boundary between the Proton Exchange Membrane and the cathode and anode. The Proton Exchange Membrane (PEM) is the electrolyte, the part of a fuel cell that helps the reactions occurring in a fuel cell, used in the PEMFC. This area of the fuel cell attracts only the positively charged ions, rejecting the electrons. The cathode is the positive part of the fuel cell, in which the oxygen molecules are split into two negatively oxygen atoms. Those negatively charged atoms also attract the positively charged ions across the PEM. Then when the positively charged ions combine with the negatively charged oxygen atoms along with the electrons that reentered the fuel cell after traveling through an exterior circuit, a water molecule (H20) is formed, which happens to be the fuel cell's only emission. The animation below shows how a fuel cell works.
That one reaction, one process, only creates 0.7 volts so to gather enough sufficient voltage, multiple fuel cells are grouped together to create a fuel stack. However, there are several other types of fuel cells as well besides the PEMFC. They include the Phosphoric-acid Fuel Cell (PAFC) which is more suited for small standing generators, the expensive Alkaline Fuel Cell (AFC) which has been operated since the 1960's in the United States space program and needs pure hydrogen and oxygen in order to maintain its life span, the less expensive Molten Carbonate Fuel Cell (MCFC) which is suited for larger standing generators, and the more costly Solid Oxide Fuel Cell (SOFC) which is suited for much larger and substantial generators that supply power to plants, factories, and towns. This fuel cell technology may sound all amazing and terrific, but there is one major downside to the fuel cell, hydrogen, the important part in powering the fuel cell. Hydrogen is not in relatively adequate amounts like gasoline and petroleum and in addition, the costly hydrogen is complicated to store. However, other resources like natural gas can be converted to hydrogen through a reformer, but it is inefficient. Another downside is that fuel cells are extremely expensive, and many consumers refuse to pay as much as it costs now. (Manufacturers are still trying to reduce the price of a five kilowatt fuel cell below $30,000 compared to a regular six kilowatt gasoline house generator which costs $1,400!)
Two major things can benefit from the fuel cell, the automobile as well as households. A fuel cell powering an automobile has been approached aggressively by several manufacturers, like General Motors. Their concept auto, dubbed the Hy-Wire, shown below, incorporates a 94 kilowatt fuel cell stack, but with the auto's compressed hydrogen tanks that can only reach 5,000 psi, the range of the drivable Hy-Wire is only eighty miles. However, GM expects to compress the hydrogen even more to 10,000 psi to increase the range of the Hy-Wire and if everything flows correctly, they plan to hit production around 2010.
Manufacturers have been working on reducing the cost of fuel cells from $30,000 for a five kilowatt fuel cell to around $5,000 for the same five kilowatt fuel cell so that it would be affordable to many consumers to use fuel cells to power their households or at least some of parts of the household. Unfortunately, no manufacturers have been able to reduce the price so low, and some estimates say that it will take seven to ten years to reduce the prices. Until then, only experiments and ideas can be performed and considered. Some energy utilities say that instead of placing a fuel cell in every home, the utilities will actually group many fuel cells in one area, distributing the power throughout the houses in the area. Here are some neat predictions by Polydyne, a company that focuses on fuel cell economics, CEO Peter B. Bos: By 2006 to 2010, one percent of households in the U.S. will be powered by fuel cells, a few years after that four year period, fifty percent of U.S. households will be powered by fuel cells, and the most striking of all predictions, Bos says that by 2031, 99 percent of U.S. households will be powered by fuel cells. Now that only happens if fuel cell prices actually decrease and the consumers are even interested.
The fuel cell is definitely a piece of promising technology, with its efficiency and clean emissions, and it is absolutely an option for a future mass-production power source. First, though, the prices of fuel cells have to decrease and the availability of hydrogen to consumers has to be relatively easy to procure, like gasoline today. Until then, though, the idea of mass-production of fuel cells to consumers might just stay as a concept to be worked on and discussed.
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