Wind Energy The sun’s radiation heats up different parts of the earth at different rates, mostly during the day and night, but also when different surfaces (example, water and land) absorb or reflect at different rates. This causes areas of the atmosphere to warm differently. Hot air rises, reduncing the atmospheric pressure at the earth’s surface, and cooler air is drawn in to replace it, thus resulting in wind. Air does have mass and when it is in motion, it contains the energy of that motion called “kinetic energy”. This kinetic energy can be used to power wind turbines, engines and many other things. Solar Energy Energy derived ultimately from the sun. It can be divided into direct and indirect categories. Most energy sources on Earth are forms of indirect solar energy, although we usually don’t think of them in that way. Coal, oil and natural gas derive from ancient biological material which took its energy from the sun (via plant photosynthesis) millions of years ago. All the energy in wood and foodstuffs also comes from the sun. Movement of the wind (which causes waves at sea) and the evaporation of water to form rainfall which accumulates in rivers and lakes, are also powered by the sun. Therefore, hydroelectric power and wind and wave power are forms of indirect solar energy. Direct solar energy is what we usually mean when we speak of solar power – it is the use of sunlight for heating or generating electricity. greenenergydevelopment.org/windsolar.html
Posted on: Mon, 11 Nov 2013 07:57:55 +0000
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