Wind Energy

WIND ENERGY

Moving air is called wind. Energy recovered from the force of wind is called wind energy. Energy possessed by the wind is due to its high speed. Kinetic energy of the wind is converted into mechanical energy.

1. Methods of harnessing wind energy

1. Wind mill

It is a device used to convert wind energy into mechanical energy.

Sequence of energy conversion

Wind Energy → Kinetic Energy → Mechanical Energy → Electrical Energy

Construction and working of a wind mill

It consists of a wheel containing number of blades. The wheel rotates about an axle mounted on a pole (Fig. 7.11). The wind energy is used to rotate the wheel. One end of the axle is connected to the armature of a generator, which rotates between two poles (north and south poles) of a strong magnet.

Fig. 7.11 Wind Energy

Another end of the axle is connected to the shaft of the wind mill. When wind falls on the wheel of a wind mill, it rotates and electric current is produced. Thus, the kinetic energy of the wind is converted into electric energy.

2. Wind farm

The electricity produced by a single wind mill is very small, which cannot be used for commercial purpose. To produce electricity on a large scale, a large number of wind mills are connected.

Thus, the region where large number of wind mills are erected to produce electricity is called wind energy farm. The small amount of electricity produced by each generator connected to each wind mill is combined to get electricity on a large scale.

3. Other methods

Other methods adopted for harnessing wind energy are

(a) Sky sail.

(b) Ladder mill.

(c) Kite ship (Large free flying sails).

(d) Sky wind power (Flying electric generator).

(e) Briza technologies (Hovering wind turbine).

(f) Sequoia automation (The kite wind generator).

2. Advantages and Disadvantages of wind energy

Advantages (or) Merits

(i) It does not cause any pollution.

(ii) It is very cheap and economic.

(iii) It is renewable.

Disadvantages (or) Demerits

1. Public resists for locating the wind farms in populated areas due to noise generated by the machines and loss of aesthetic appearance.

2. Wind farms located on the migratory routes of birds will cause hazards.

3. Wind farms produce unwanted sound.

4. Wind turbines interfere with electromagnetic signals (TV, Radio signals).

5. Wind energy is not sufficient to operate very heavy machine.

3. Uses of wind energy

1. Wind energy is used to move the sail boats in lakes, rivers and seas.

2. It is used to operate water pumps.

3. It is used to run the flour mill to grind the grains.

4. It is also used to produce electricity.