Wind energy or wind turbines are the way of making electricity using the wind or its flow on the earth which is a natural source in the atmosphere. These days, Modern wind turbines are applied to seize the kinetic energy from the wind and effectuate electricity.
Normally many people interchange the term "windmill" and "wind turbine" but there is a difference with both the terms. A windmill is used by people for centuries to grind grain, pump water and do other work i.e. it only generates mechanical energy whereas a wind turbine utilizes wind's kinetic energy and converts it into electricity.
There are three main types of wind turbines:
a) Wind turbines in the range from 100 kilowatts to several megawatts. In this type, the electricity is delivered to the power grid or company and they distributed it to the end-user or public by electric utilities or power system operators.
b) Small wind turbines: These turbines generate below 100 kilowatts of electricity and can provide power directly to a home, farm or small business without the power grid.
c) Offshore wind turbines: These are erected in large bodies of water and are larger than land-based turbines and can generate more power.
How wind turbines generate electricity or energy?
Let me put it in point to explain the procedure of generating electricity using winds kinetic energy.
- The flowing air or wing has kinetic energy which makes the blade of the rotor rotate when it blows.
- As the rotor rotates, it turns the central axel or the drive shaft that supports the rotor. The rotor blade turns fast but the central driveshaft turns slowly and depends upon the velocity of the wind.
- In modern times, the big turbines blade i.e the rotor blade are made to swivel on the hub to meet the wind flow angle or the pitch to generate energy and is referred to as pitch control mechanism. On Smaller turbine, the pitch control is often mechanical or have fixed rotors without pitch control. On big turbines, hydraulic ram or electric motors are used to swivel the rotor blades front or back to harvest the best generation of energy.
- Inside the main body, the gearbox turns the low-speed rotation of the drive shaft into high-speed rotation i.e. fast enough to drive the generator efficiently i.e. 10 revolutions per minute (rpm) to 1000 rpm).
- The generator behind the gearbox converts the kinetic energy from the rotating driveshaft into electrical energy. In its max. efficiency, a typical 2MW turbine generator can produce nearly 2 million watts of power at about 700 volts.
- The automatic speed measuring devices i.e. the anemometers at the back of the main body supply the measurement of the direction and speed of the wind.
- Using the reading from the anemometers, the rotors and the main body of the turbine is rotated by a yaw motor so as to face the direction of the wind and take the maximum amount of energy.
- During turbulence weather, sandstorm, windy climate or maintenance, brakes are applied to stop the motor from rotating fro safety purposes.
- The electricity produced by the generator runs through the cable through the inside of the tower. A step-up transformer is used to convert the electricity to about 50times higher voltage in order that it can be sent across efficiently to nearby locations or buildings. For higher voltage, a substation can be used which can get inputs from many turbines.
- We get clean electricity and enjoy the energy as no gas or pollution is formed in the production of electricity.
A small comparison between large and small wind turbine is:
i) A large turbine needs to be mounted at roughly 80–100m (260–344ft) high whereas a small turbine can be mounted on a rooftop typically within 10m (30ft) high.
ii) The diameter of the rotor or blade of the turbine of a large turbine is Up to 90m (300ft) whereas a small turbine is just 1–4m (3–12ft).
iii) The large turbine will operate at a wind speed of 10–55mph (16–90 km/h) whereas a small turbine may operate at 10–40mph (16–64 km/h).
iv) A large turbine produces 1–8 megawatts (1000–8000 kilowatts) energy while the small turbine produces 50–40,000 watts (0.05–40 kilowatts).
v) A large turbine of the given capacity can provide energy or electricity to 500–5500 homes whereas the small turbine can provide energy or electricity to a single unit or home.
vi) An average cost to the start-up of a large turbine is roughly 75–150 Million per MW whereas it ranges from 30L – 50Lac for setting up a small turbine unit.
If you are planning to set-up a small turbine for personal use, kindly bear in mind that the wind turbine rotates at high speed and has vibration and noise. It requires technical knowledge and skills thus consulting a professional is recommended. You may require your neighbors and local clearance to set-up in the city or village.
“The most important thing in life is to learn how to give out love, and to let it come in." — Morrie Schwartz