Wind is a type of solar energy and it’s caused by uneven atmosphere heating by the sun, the earth’s surface irregularities and the earth’s rotation. The pattern in which the wind flows is determined by water bodies, the earth’s terrain and vegetative cover. When this wind flow or motion energy is harvested using wind turbines, it may be used to produce electricity.
Wind power or wind energy refers to the process through which the wind is used to produce electricity or mechanical power.
The mechanical power is converted from kinetic energy using wind turbines and it may be used for tasks such as pumping water or grinding grain. A generator can also convert the mechanical power into electricity for powering homes, schools and businesses.
They act like plane propellers, turning the moving air and therefore powering an electric generator which then produces an electric current. As opposed to a fan (which uses electricity to produce wind) a wind turbine makes use of wind to produce electricity. Turning of the blades by the wind spins a shaft connected to a generator which makes the electricity.
There are two types of turbines:
1. Horizontal Axis
These have an electrical generator atop a tower and a main rotor shaft. They are similar to traditional windmills used in the farm for pumping water.
2. Vertical Axis
They have a vertical rotor shaft. This has the advantage of there being no need to point it towards the wind. This is particularly important on a site where there is a variable wind direction.
Most of the large wind turbines are of the horizontal axis type. Horizontal turbine parts include:
• A drive train which includes a generator and a gear box.
• A rotor or blade which converts the wind energy to rotational shaft energy.
• A tower that gives support to the drive train and rotor.
• Controls, ground support equipment, cables, electrical equipment and interconnection equipment.
Turbines are usually grouped into a wind power plant or wind farm to generate electrical power in bulk. Electricity from the turbines is directed into a utility grid and delivered to customers just as with any other plant.
Wind turbines are available in a range of sizes and power ratings. There are turbines with blades longer than a football field standing building 20 stories high producing electricity that can power 1400 homes. A home sized wind machine has rotors of a diameter between 8 and 25 feet standing more than 30 feet and supplying an all-electric house or small business. Utility scale turbines range between 50 and 750 kilowatts. The small ones below 50 kilowatts are used for pumping water, in homes and for communication dishes.
Advantages of wind energy
1. Wind energy is renewable and free.
It produces clean and non-polluting electricity.
Wind costs are lower compared to other technologies since there are no fuel costs and operating expenses are minimal.
3. Environmental benefits
Wind plants have no impact on the environment. As opposed to normal power plants, wind plants don’t release any green house gases or air pollutants.
4. Transport and supply issues
Wind plants may be located in land for farming or grazing.
Disadvantages of wind energy
1. Initial investment
Wind power needs a higher initial investment compared to fossil generators. There is the cost of machinery, site preparation and installation.
2. Environmental impact
The rotor blades on turbines produce noise. Bats and birds are killed when they fly into rotors. There is also a visual impact.
3. Transport and supply issues
Wind is not easy to store. Great wind sites are located in areas that are remote. Wind energy development also competes with other land uses which may be more valuable than power generation.