Alternate sources of Electri. essays

Alternate sources of Electri. essays Alternate Sources of Electricity: Wind Power Wind 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.2 The 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 first law states that the power generated by the turbine is proportional to the wind speed cubed. For example if the wind speed doubles, the power available increases by a factor of eight; if the wind speed triples then twenty seven times more power is available. Therefore a proposed site must have a very fast wind a lot of the time to generate electricity. It is very expensive to deploy lots of wind turbines if each is only going to produce very little electricity. The second law states that the power available is directly proportional to the swept area of the blades. That is the power is proportional to the square of the blade length. For example, doubling the blade length will in...