Moving air is called wind. Wind has a energy. The energy possessed by wind is due it's high speed (or motion). So, the wind kinetic energy. It this kinetic energy of wind which is utilised for doing work. Solar energy (or sun's energy) is responsible for the blowing of wind. Wind blows due to the uneven heating of earth by the sun in different regions. So, wind energy coms from the sun in an indirect way.
The energy of wind is harnessed by using a windmill. A windmill consists of big sized, table fan like blades which are fixed over the top of a tall pole in such a way that they are free to rotate. When the fast moving wind strikes on the blades of windmill, it makes them rotate continuously.
The rotatory motion of the windmill is then used to do mechanical work through a shaft connected to the rotating blades.
In the past, wind energy was used through windmill to pump water (or life water) from a well and to grind wheat into flour. This happened as follows: When the blades of windmill rotate by the force of wind, a shaft connected to them also rotate. This rotating shaft was made to run a water pump to lift water from a well by a suitable mechanism.
It could also turn the mill stones of a flour mill.The traditional use of wind energy has now been modified by the improvement in technology to generate electricity through wind powered generators. This is explained below:
Wind Generator
The windmill used for generating electricity is called a wind turbine, and the complete set up of generating electricity by using wind energy is called 'wind generator'. We will now describe wind powered electric generator in somewhat detail.
A wind Generator which is used to generator electricity by using wind energy is shown in picture. When the fast moving wind strikes the blades of wind turbine, then the wind turbine starts rotating continuously. The shaft of wind turbine is connected to a small generator. When the wind turbine rotates, it's shaft also rotates and drives the generator. The generator produces electricity.
The electricity generator by a single wind turbine is quite small (because a single wind turbine can run only a small generator). So, in order to generator a large amount of electricity, a large number of wind turbines are erected over a big area of land. Such a set up of having a large number of wind turbines working at a place to generate electricity energy on a large scale is called a wind energy farm. The small electricity generated by each wind generator is combined together to obtain electricity on a large scale.
An important advantage of using wind energy for generating electricity is that it's use does not cause any pollution. Another advantage is that wind energy is renewable source of energy which will never get exhausted.
As long as the sun keeps shining, the wind will keep blowing and provide us energy. The increased use of wind energy for generating electricity will help us conserve fossil fuels (like coal, petroleum and natural gas) so that they may last longer. Moreover, wind energy is available free of cost!
Some of the limitations of harnessing wind energy for generating electricity are free follow:
- Wind energy farms cannot be established everywhere. The wind energy farms can be established only at those places where blows for most part of the year.
- The wind required for generating electricity should be strong and steady to maintain the desired level of generation. The minimum wind speed for satisfactory working of a wind generator is about 15 km/ h. This is not always so.
- The wind energy farms require a large area of land.
- The setting up of wind energy farms is very expensive.
The wind power potential of our country is estimated to be about 45,000 MW. This means that if India's wind energy is fully generated. At present we are generating more than 1025 MW of electricity from wind energy.
This is going to increase soon when some more wind energy farms start working. The largest wind energy farms established near Kanyakumari in Tamil Nadu can generate 380 MW electricity. India is ranked fifth in the world for harnessing wind energy for the production of electricity. The for harnessing wind energy for the production of electricity.
The first position is occupied by Germany Dermark is, however first position is occupied by Germany Denmark is however called the country of 'winds' because more than 25% of the electricity needs of Denmark are met by utilising wind energy.
