Alternate sources of Electri.
Alternate Sources of Electricity: Wind PowerWind is created from an unequal heating of the earths atmosphere therefore wind is an indirect form of solar energy. Convection currents, which occur due to the fact that warm air rises and cooler air drops, produces this cycle of air or wind. Some of the suns energy directly heats the air but mostly the heat is transferred form the earth into the atmosphere. "Between 1 - 2% of the solar radiation that reaches the Earth is converted into energy in the wind."1.Seasonal variations in the speed and direction of the wind result from the seasonal changes angle of the Earths spin relative to the Sun. Daily variations are caused by the different speeds of heating different surfaces, for example land and oceans heat up at different speeds.2The force excreted by wind on a propeller or some sort of mechanical instrument is used to create motion. Thus converting mechanical energy into electrical is not a problem. The process is the reverse of an electric motor which uses a magnet to force the shaft to spin. Likewise if the shaft spins it will induce a magnetic field thus providing electricity. "There are three basic physical laws governing the amount of energy available from the wind. The fir
The system can be shut down to avoid damage, mechanical breaks could be used or the angle of the rotor compared to the wind direction can be changed to decrease the area, which the wind hits. However coal burning produces a large about of greenhouse gases and not last forever. The lower speed, called the 'cut in speed' is generally 4 - 5 ms-1, as there is too little energy below this speed to overcome system losses. "The second law states that the power available is directly proportional to the swept area of the blades. This can be implemented in three different ways. It is very expensive to deploy lots of wind turbines if each is only going to produce very little electricity. Compared to coal power plants which can rely on constant output the wind generators may produce a satisfying out one season and be inoperable the in the next. More efficiency can be achieved if a generator is designed for lower speeds in the areas it is going to be used. For example, doubling the blade length will increase the power by four times, and tripling the blade length will increase the power by nine times. Ten Mile Lagoon has 9, 225kW wind turbines, generating a total of 2MW. Although harnessing the kinetic energy of the wind is a very good source of energy as it is renewable in the sense that no natural resource is being used up it cannot compare to the output of a coal power plant. A proposed solution is to connect all the sites of wind generation into a grid which in turn will reduce the complications of variable wind speeds greatly as it is unlikely that all or none of the stations will have high wind speeds or no wind. Wind powered machines provide a source of renewable energy that is appropriate and cost effective in some circumstances. "Practical wind turbines are designed to work between certain wind speeds.
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Acceptance Essays
