How windmills generate electricity / energy

In those areas where good wind speed is common the windmills are a common sight now a days.
This is a very good source of converting the wind energy to electrical energy. Wind is a perpetual source on the Earth and it makes sense to convert it to the electricity. We use wind energy in many ways like sailing the yacht boat or flying a kite. A windmill can be understood in a layman term as opposite to an electrical fan where electricity drives the fan and its blades move to create wind in the room. So in a fan what we are doing is converting electrical energy to mechanical one. In a windmill the opposite happens. The blades of the windmill are rotated by the wind speed and that is connected to a generator where this mechanical energy is converted to electrical energy. The blades are designed in such a way that they use the wind flow optimally and efficiently in converting it to their rotation. For understanding it better just compare it with the electricity generation in dams where the water falling from a height moves the blades in the turbines creating electricity.

The blade assembly and associated gear mechanism are fixed on the top of a tower for easy accessibility to wind and this top part is commonly known as a wind turbine. There are two types of wind turbines - Horizontal-axis wind turbines and Vertical-axis wind turbines. In the former design the turbine will align in the direction of the wind for optimisation while in the later design it can take advantage of the wind due to its multidimensional design. In our country what we observe are mostly horizontal-axis wind turbines. The size of the wind turbine varies as per the capacity and designs are available starting from 100 kilowatts to several mega watts. There are smaller turbines also below 100 kilowatt used for residential or agricultural purposes.

The cost for a windmill producing 250 kilowatt comes to about Rs 1 crore. Banks give 70% loans for this on reasonable interest rates. So, one has to put about 30-35 lakhs from personal fund. One has to take NOC from the State Electricity Boards (SEBs) and State Nodal Agencies (SNAs) that are responsible for clearance of wind power projects. There are some other associated paper and document formalities which are also to be completed.

The wind is a natural resource available to us. We require this for our living. We can convert this wind energy to electrical energy in our windmills. Electricity is a very important commodity and we require this day in and day out. So using wind producing electricity is a very important concept. If you imagine a fan without a power connection, you can move the wings of the fan manually or can be produced by moving the wings of the fan with the wind. The mechanical energy that is coming to the fan from the wind will make the fan wings to move. This energy will be converted into electrical energy by connecting it to a generator.

The design of the windmill, the location of the windmill will have a lot of say in the efficiency of the wind power generation through a mechanical moment of the wind. The wind turbine will be at the top of the tower of the windmill. The mechanism which will make the blades to move as per the wind available will be also at the top of the windmill.

There are two types of windmills.
1. Horizontal-axis wind turbines.
2. Vertical-axis wind turbines.

The cost will depend on the size of the windmill you are planning and the expected generation of power. if you propose to have 100 Kilowatt energy the expenditure may come around 42 lakhs. You will get a subsidy from the state or central government.

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.

Wind - power converts the kinetic energy in wind to generate electricity or mechanical power. This is achieved by using large wind turbine consisting of propellers. The turbine is connected to a generator in order to generate electricity. As the wind passes through the turbine, it moves the blade which spins the shaft. There are currently two types of turbines in the propellor or fans suiting to different type of turbines in the propeller.
Conversion of Wind to Mechanical Energy- Wind is converted by the blades to wind turbines. The blades of wind turbines are designed in two different ways -
1) Drag Type - The blade design uses the force of the wind to push the blade around. The blades have higher torques than the left design with the charecterestics of slower rotating speed. As the rotating speed of the blades are much slower than the left type, this type of design is rarely used for generating large scale of energy.
2) Left - type - Most modern HAW adopts the design. Both sides of the blades have air blown across it resulting in air taking longer to travel across the edge. In this way, lower air pressure is created on the tail end. Because of this pressure difference, the blade is pushed and pulled around, creating a higher rotational speed needed for the generation of electricity.
Creating Electricity from the wind - To generate electricity from the wind, the shaft of the turbine must be connected to the generation unit. The generator uses the turning motion of the shaft to rotate a rotor having oppositely charged magnates and is surmounted with the copper wire loops.Electromagnetic Induction is created by rotor spinning inside the core which generate electricity.
Distribution of Electricity- The generated electricity must go through a transformer so as to step up voltage and is ensured that the electricity is distributed conveniently at a long distance. Power stations and fuse boxes receive the current and then transform to a lower voltage so as to be utilised by the consumers.

Windmill generates electrical energy by converting the mechanical energy in the blowing wind to electrical energy by using a turbine mounted on a tower. The blades of the tubing are designed in a way as to rotate by the naturally blowing wind in the area and depending upon the size of the blades and capacity of the turbine the electrical energy would be produced. Small wind turbines are capable of producing in kilowatt ranges while big and high power turbines are able to give output in megawatts of electrical energy.

The interesting thing about the wind energy is that it is always available as wind blows perpetually. So people have understood its potential in long run and many Govt including India are giving good subsidy on it. Presently the Govt has given a thrust on development of non-conventional energy sources like solar and wind energy and there are many entrepreneurs coming in this area for installation of windmills especially in the areas where wind blows in plenty.