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The search for alternative fuels is a very important research field in the modern word. This research is primarily to replace the fossil fuels which are environmentally harmful as well as depleting and likely to last only for a few hundred years more. One of the alternate fuels which have no environmental pollution is the fuel cell technology. A fuel cell is essentially an energy conversion device like most energy sources but electrochemical in nature. It
uses an external fuel supply and an oxidant that react in the presence of an electrolyte to produce electricity. Fuel cells can operate virtually non-stop by having a continuous in flow of reactants and outflow of reaction produce. This article will bring out the features and applications of the fuel cells and their advantages.
Although similar to the common batteries, they differ in that they need a constant supply of reactant whereas batteries store electro-chemical energy in a closed system. The fuel cell’s electrodes are however, catalytic and stable as compared to those of a battery that react and change during charge and discharge operations.
A fuel cell uses hydrogen as fuel amongst hydrocarbons and alcohols and oxygen as an oxidant amongst chlorine, air or chlorine dioxide. Fuel Cells prove useful as power sources in spacecraft, large parks, rural locations, remote weather and observation stations and also in certain military applications. The major advantages of hydrogen driven fuel cell are compactness, lightweight and no major moving parts.
Types of Fuel Cells: Fuel Cells are of various types and are classified primarily based on their electrolyte usage. This determines the type of chemical reactions that the cell encounters, the type of catalyst used as also the operating temperature of the fuel cell amongst other factors. The Zinc – Air battery, the Metal Hydride Fuel Cell use aqueous alkaline solution (e.g., KOH) as electrolyte, the Reversible and Reformed Methanol Fuel cells use Polymer membrane (ionomer) instead. Fuel cells that use hydrogen and oxygen to produce electricity, heat and water as byproducts are known as regenerative fuel cells.
Uses of Fuel Cells: Fuel Cells find uses in applications such as Auxiliary Power Systems, Base Load Power Plants, Off-grid power supplies, Supplies for Notebook Computers, Portable chargers for handheld devices like PDAs, Mobile phones, etc. The use of fuel cells in automobiles is also under investigation. Hybrid models which incorporate both fuel cells and internal combustion engines have already been developed and tested. However, the technology of fuel cell has not been possible to overcome the energy limits and recharging time of these batteries. Further research on this technology is still continuing all over the world.
Environmental Benefits: Fuel Cells are powered by “clean” fuels like pure hydrogen and produce water as a by-product or “exhaust”. Pollution levels are much less than those of conventional engines when fossil fuels are used in fuel cells. Moreover, polluting substances produced and released by conventional internal combustion engines like nitrogenous and sulfurous oxides are not emitted by fuel cells making them a cleaner alternative if viable for many applications.
