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1. Hi
   Today’s topic is about renewable energy as a worthy addition to the world’s energy portfolio. There are various types of alternative sources energy, namely, solar, wind, geothermal, bio-mass and biofuel. Solar, wind and geothermal energy are renewable sources of energy in the wise that, they are not depletable like fossil energy. Suffice it to say that, the source of wind energy is the sun. By definition wind is air in motion. This motion of the air results when the sun heats the air particles such that a temperature differential exists between layers of air particles resulting in a difference in air density between the layers, thus resulting in a random motion of air particles between colder layers of air and warmer layers of air. Thus, a pressure gradient ensues which results in the flow of air particles from regions of high pressure to regions of low pressure and hence the wind. Solar energy by itself is direct energy from the sun. Two forms exist; solar thermal energy resulting from direct heating of a medium by the sun and solar electricity resulting from the conversion of the sun’s ultraviolet rays into electricity by a photoelectric cell. Geothermal energy is actually energy from geological sources like heat extracted from hot ground waters deep down the earth’s surface.