Renewable Energy Sources are those energy sources which are not destroyed when their energy is harnessed. Human use of renewable energy requires technologies that harness natural phenomena, such as sunlight, wind, waves, water flow, and biological processes such as anaerobic digestion, biological hydrogen production and geothermal heat. Amongst the above mentioned sources of energy there has been a lot of development in the technology for harnessing energy from the wind.
Wind is the motion of air masses produced by the irregular heating of the earth’s surface by sun. These differences consequently create forces that push air masses around for balancing the global temperature or, on a much smaller scale, the temperature between land and sea or between mountains.
Wind energy is not a constant source of energy. It varies continuously and gives energy in sudden bursts. About 50% of the entire energy is given out in just 15% of the operating time. Wind strengths vary and thus cannot guarantee continuous power. It is best used in the context of a system that has significant reserve capacity such as hydro, or reserve load, such as a desalination plant, to mitigate the economic effects of resource variability.
The maximum value of CP according to Betz limit is 59.3%. For good turbines it is in the range of 35-45%.
The tip speed ratio (A) for wind turbines is the ratio between the rotational speed of the tip of a blade and the actual velocity of the wind. High efficiency 3-blade-turbines have tip speed ratios of 6-7.
The total capacity of wind power on this earth that can be harnessed is about 72 TW. There are now many thousands of wind turbines operating in various parts of the world, with utility companies having a total capacity of 59,322 MW. The power generation by wind energy was about 94.1GW in 2007 which makes up nearly 1% of the total power generated in the world. Globally, the long-term technical potential of wind energy is believed to be 5 times current global energy consumption or 40 times current electricity demand. This would require covering 12.7% of all land area with wind turbines. This land would have to be covered with 6 large wind turbines per square kilometer.
Some 80 percent of the global wind power market is now centered in just four countries—which reflects the failure of most other nations to adopt supportive renewable energy policies. Future market growth will depend in large measure on whether additional countries make way for renewable energy sources as they reform their electricity industries.
India has a vast supply of renewable energy resources. India has one of the world’s largest programs for deployment of renewable energy products and systems 3,700 MW from renewable energy sources installed.
The wind flows due to the moving automobiles is utilized by the wind turbine blade. This is a system in which the energy waste sources. The wind power is converted into the mechanical rotation. Then this rotation is then converted into electrical power output.
This electrical output is then stored in a battery or the generated power is directly connected to grid.
- Rural areas of the country where there is no electricity board.
- Isolated areas like a forest.
- High power grids can be connected.
- And hence we achieved following advantages over conventional system
- Clean source of energy.
- Renewable source of enegy.
- Longer and maintenance free life.
- Low response at low sunlight.
- Initial cost is high.
- It is interrupted source of energy.