WIND ENERGY - Class X Physics

 

WIND ENERGY :

Moving air is called wind. So, the wind possesses kinetic energy and called wind energy . Kinetic energy of wind is utilized for doing work.

Solar 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 comes from the sun in an indirect way.

Windmills :

windmill

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 windmills to pump water  from a well and to grind wheat .

Now a days it is used to generate electricity through wind-powered generators.

Wind-Powered Generators :

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.

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, its shaft also rotates and drives the generator. The generator produces electricity.

The electricity generated by a single wind turbine is quite small (because a single wind turbine can run only a small generator). So, in order to generate 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 electrical energy on a large scale is called a wind enérgy farm.

The small electricity generated by each wind generator is combined together to obtain electricity on a large scale.

Advantage :

• its use does not cause any pollution.
• wind energy is a renewable source of energy which will never get exhausted.

Limitations

(i) Wind energy farms cannot be established everywhere. The wind energy farms can be established only at those places where wind blows for most part of the year.

(ii) The wind required for generating electricity should be strong and steady to maintain the desired level of generation. The minimum wind speed necessary for satisfactory working of a wind generator is about 15 km/h.

(iii) The wind energy farms require a large area of land.

(iv) 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 harnessed, then 45,000 megawatt of electrical power can be generated.

 Some Fact About Wind Energy:

(i)  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.

(ii) The largest wind energy farm established near Kanyakumari in Tamil Nadu can generate 380 MW electricity.

(iii) India is ranked fifth in the world for harnessing wind energy for the production of electricity.

(iv) The first position is occupied by Germany.

(v) Denmark is called the country of 'winds' because more than 25% of the electricity needs of Denmark are met by utilising wind energy.