Solar Energy

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Our world has been in existence for billions of years and throughout all those years we have used the sun for basic energy needs. So why not be able to harness that energy and use it to power things like our homes or our cars? Many scientist have been developing alternate forms of energy called "Green Energy." Green power is the solution to creating a cleaner, sustainable energy system. Renewable energy--power from the sun, wind, plants, and moving water--is a natural way to meet our energy needs and protect the environment. Here are some forms of green energy: • Wind energy converts the power available in moving air into electricity. Wind power does not produce air emissions, generate solid waste, or use water. • Biomass is energy…show more content…
• the need for non polluting and silent sources of electricity; eg tourist sites, caravans and campers • the need for a convenient and flexible source of small amounts of power; eg calculators, watches, light meters and cameras; • the need for renewable and sustainable power, as a means of reducing global warming. Together, these needs have produced a growing market for photovoltaics which has stimulated innovation. As the market has grown, the cost of cells and systems has declined, and new applications have been discovered. To fully understand how solar power energy is created we need to look at how silicon solar cells are made by using either single crystal wafers, polycrystalline wafers or thin films. Single crystal wafers are sliced, (approx. 1/3 to 1/2 of a millimeter thick), from a large single crystal ingot which has been grown at around 1400 °C, which is a very expensive process. The silicon must be of a very high purity and have a near perfect crystal structure. Polycrystalline wafers are made by a casting process in which molten silicon is poured into a mould and allowed to set. Then it is sliced into wafers. As polycrystalline wafers are made by casting they are significantly cheaper to produce, but not as efficient as monocrystalline cells. The lower efficiency is due to imperfections in the crystal structure resulting from the casting process. Almost half the silicon is lost

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