What is a Wind Turbine? | How does a Wind Turbine Work?

The turbines are the most widely used machine all over the world for the production of electricity. The turbines have multiple types that are designed according to the different application requirements. The main objective of a turbine is to produce electricity by using the energy of water, steam, gas, or wind. The turbines have multiple types, and wind turbine is one of them. A wind turbine uses to produce electricity by using wind power.  According to the working fluid, the turbines have four major types:

1) Steam turbine

2) Wind turbine

3) Gas Turbine

4) Water Turbine

In the previous articles, we discussed steam turbines and gas turbines. This article only explains the working of wind turbines and its components. 

What is a Wind Turbine?

The air motion is called wind. This movement is mostly in a horizontal direction because the vertical components are small as compared to the horizontal components.

A wind turbine is a mechanical machine that converts wind energy (wind kinetic energy) into mechanical power (rotational energy). These turbines have become the cheapest source of energy. The wind turbines have a very design and very high efficiency. Professor James Blyth invented the first wind turbine in the 1887s

Wind energy is a significant source of energy through that we produce the cheapest electricity by using its power.  A wind turbine generator is a mechanical machine that transforms the mechanical energy of the turbine into electricity

Wind turbines, also known as wind power converters. These turbines manufacture into two designs as horizontal and vertical axis wind turbines. The small wind turbines use for purposes like charging batteries that supply caravans and boats with extra energy. These small wind turbines also use to supply energy to traffic warning signs. While a large wind turbine uses to add energy to the home, while unused energy sells through the grid to utility companies.

The electricity that we produce through wind turbine generators is the cheapest form of electricity than other types of electricity that we produce through gas, geothermal, coal, steam, photovoltaic, and hydro processes. The wind turbine has the minimum emission of greenhouse gases. 

How does a Wind Turbine work? 

The working principle of the wind turbine is very simple.

wind turbine working
                        Fig: Wind Turbine Working Principle

As the wind turbine starts working, the wind firstly hits the blades of the rotor with high velocity. After that, the rotor blades start moving in rotary motion. The rotor also rotates with the movement of the blades. This rotor connects with a gearbox. The gearbox converts the rotary motion of the rotor from minimum to maximum speed.

The gearbox couples to an electric generator’s rotor through a shaft. This shaft is connected with the generator’s coil.  This coil moves according to the movement of the gearbox shaft. An exciter is required to provide the obligatory excitation for the generator electromagnetic coil system so that the wind power generator can produce electricity according to requirements.

The voltage produced at the generator’s output terminal is proportional to the magnetic flux and the speed of the generator. The speed is controlled with the help of uncontrolled wind energy. Therefore, to sustain the consistency of the generator output, it is necessary to control the excitation according to natural wind energy availability.

The current of the exciter controls through a controller of the turbine that records the speed of the wind. After this, the generator output voltage sends to the rectifier. This rectifier converts the generator output voltage to direct current.

Next, the rectified direct current (DC) is transferred to the line converter unit to convert it into a stable alternating current (AC) output. And finally, via a step-up transformer, this AC output transfers to different hoses, buildings and industries. Some additional devices use to send the wind power to the wind turbine’s internal auxiliary devices such as battery and electric motors.  

Types of Wind Turbine

Wind turbines have two major types:

  1. Horizontal Wind turbines
  2. Vertical Wind Turbines

types of wind turbines

1) Vertical Axis Wind Turbine

Main article: Vertical Axis Wind Turbine 

The blades of the VAWT are perpendicular to the airflow line and perpendicular to the ground. And drag is the leading force in the working of this wind turbine.  And also, the Yaw mechanism does not require in these wind turbine working. VAWTs further divides into the following types.

vertical axis wind turbine

The vertical axis wind turbines have the following types:

1)  Darrieus wind turbine

Darrieus wind turbine is a famous VAWT. It has many curved aerodynamic blades that are located on the rotating axis or frames. These blades can bear the tension only at a high rotational speed.  The market has many closely related wind turbines that have straight rotor blades.

The blades of the Darrieus turbine rotate with the rotation of the rotor. The aerodynamic principle of the rotating rotor corresponds to the aerodynamic principle of an autogiro or a normal helicopter that rotates automatically. When the airfoil moves behind the device, the angle of attack changes to the reverse sign, but the force generated is tilted in the rotation direction as if the airfoil was in front. The rotor rotates at a speed that is independent of the wind speed and is usually many times higher.

One main issue with the classic design of the blades is that the angle of attack varies according to the turbine rotation, and each blade only produces extreme torque in front of and behind the turbine. This process leads to pulsating energy cycles that complicate the turbine design. Furthermore, if this pulsation generates at the blade’s natural frequency, the resulting resonance will damage the turbine.

Darrieus wind turbine

In a Darrieus wind turbine configuration, maximum tension is in the blade area, creating torque opposite to the generator at the turbine bottom. Thus, the only forces that need to be balanced perpendicularly are the wind force trying to blow over the turbine and the compressive loads produced due to the outward bending of the rotor blades (i.e., trying to “squeeze” the tower).

These types of wind turbines use to generate electricity, heating, cooling, and water pumping.

Darrieus Wind Turbine Design

Darrieus wind turbine designs can manufacture by using multiple curved aerodynamic rotor blades mounted on a rotating axis. These are vertical axis wind turbines that utilize to generate electricity from wind energy. However, the curvature blades of these turbines can only tolerate tension force only at high speed.

Many closely related wind turbines use straight rotor blades. The French aeronautical engineer Georges Jean Marie Darius was patented the first design of this turbine and registered it as intellectual property on October 1, 1926.

Darrieus Wind Turbine Efficiency

Darrieus wind turbines are less efficient than horizontal axis wind turbines because of their designs and operational features.

In general, the HAWT has an efficiency between 40% and 50%. It means these wind turbines can convert 40% to 50% of the recorded KE into actual electrical energy. Alternatively, the Savonius vertical axis wind turbine has an efficiency range of 10% to 17%. It means this turbine can convert 10% to 17% of the recorded KE into actual electrical energy.

The Darrieus turbine has an efficiency range of 30% to 40%. It means it can transform 30% to 40% of the recorded kinetic energy into actual electrical power. Thus, savonius wind turbines can produce enough electricity to cover the annual consumption of a typical two-person household.

Advantages and Disadvantages of the Darrieus Wind Turbine

                Advantages

             Disadvantages

This type of wind turbine is portable.

It has low efficiency than HAWT.

It can easily arrange in a building.

It can’t produce more electricity than HAWT.

Scalability

It has low rotational efficiency.

It has a quiet operation.

Its initial start is difficult than a Savonius wind turbine.

Darrieus turbine has a small size than HAWT.

The components of this turbine wear down in a very short time.

Safe to use.

Self-starting mechanism

It has the capability to receive wind energy from all directions.

Less availability of wind speed

Its blades rotate slowly that reduces the risk for birds and humans.

It generates high torque ripples and cyclic stress on the turbine tower, which causes poor reliability.

ii) Savonius Turbine

It is VAWT. A Finnish Engineer, Sigurd Johannes Savonius was invented the Savonius wind turbine in 1922.  It is one of the simplest designs of wind turbines. It has more than one “scoop” that uses resistance to change wind energy into torque to run the turbine. A Savonius turbine having two blades looks like S-shaped when viewed from above in cross-section: Because of the blade’s curvature, the turbine has less drag against the wind.

Savonius vertical-axis wind turbine

Savonius turbine is a drag-type turbine and most widely used in many reliable applications like anemometers and ventilation. This type of turbine has low efficiency compared to a HAWT. These are best suitable in areas with turbulent winds and self-starting.

The Savonius wind turbine has an efficiency range of 10% to 17%. However, it can transform only 10% to 17% of the recorded kinetic energy into actual electrical energy.

Advantages and Disadvantages of Savonius wind turbine

                 Advantages

               Disadvantage

This vertical wind turbine works efficiently even with changing wind directions.

It produces low electricity than HAWT.

The Savonius design works well even at low wind speed, eliminating the necessity of towers and other costly parts and significantly reducing initial installation costs.

The blade used to extract wind energy is half as effective as a conventional turbine and reduces electricity generation.

 

It has a small size, quiet operation, and easy maintenance.

It is less efficient.

It has easy to design.

It produces less energy than the Darrieus wind turbine.

 iii) Giromill Wind Turbines

It is a type of Darrieus wind turbine. Its operation is the same as the Darrieus turbine. The main difference is that the Giromill turbine has an H-shaped rotor. This turbine utilizes lift force generated by the aerofoils to transform the kinetic energy of the wind to rotational energy.

Giromill turbines

2) HAWT (Horizontal Axis Wind Turbine)

Main article: Horizontal Axis Wind Turbine

Horizontal axis wind turbines have an axis in the horizontal direction to the ground. And also, the Yaw mechanism does not require in the working of these wind turbines. In these types of turbine, the lift is the main force. 95% of the present wind turbines are HAWT.

Horizontal wind turbines further divide into the following two types:

upwind and downwind turbines

i) Upwind Turbines

The upwind turbine rotor is at the front of the device, and its position is similar to that of a propeller-driven plane. It is the most common type of small wind turbine that most widely use in the United States of America. These turbines require a yaw mechanism for their proper operation.

Advantages and Disadvantages of Upwind Turbines

              Advantages

           Disadvantages

It stops the shade on the tower back.

It requires a yaw mechanism to maintain the turbine face toward the wind.

It has a small size.

There is shade on the tower’s front side.

ii) Downwind Turbine

The rotor of the Downwind turbine is on the leeward side of the tower. The most extensive advantage of this turbine is that it can design without a yaw mechanism. This is possible in a condition if the nacelle and rotor have an appropriate that allows the nacelle to follow the wind passively. However, this is a somewhat suspicious benefit for large HAWTs as cables are required to draw power from the generator.

The most important advantage is that the rotor of this turbine is very flexible.

Advantages and Disadvantages of Downwind Turbines

               Advantages

            Disadvantages

It can design without a yaw mechanism.

Wind power fluctuation due to the rotor passing shadow on the tower.

Its rotor can design more flexibly as you want.

Its tower gives more fatigue load on the turbine than an upward turbine.

Wind turbine Components

The wind turbine has the following major parts:

components of wind turbine

1) Brake

It is included in the basic components of the wind turbine. Disc brakes can be operated hydraulically, electrically, or mechanically. So, the turbine rotor can be stopped quickly by brake in emergency form.

2) Anemometer

This is the second part of the turbine. It measures the speed of the wind. Then sends this data to the controller.

3) Controller

This is also included in the most compulsory components of the wind turbine. This part of the turbine turns the machine on at a wind velocity from 8mph to 16mph. The turbine cannot run at wind speeds greater than 65 miles per hour because the wind turbine generator may overheat.

4) Blades or Axis

Maximum wind turbines have 2 or 3 blades. Without blades, the turbine can’t produce electricity. The wind that blows on the blade assists the blades to turn.

5) Nacelle

This is a fifth compulsory part of the turbine. The nacelle attaches to the turbine rotor. The nacelle is on top of the tower and contains brakes, controllers, generators, low-speed shafts, high-speed shafts, and gears. The cover protects the nacelle parts.

6) High-speed shaft

It is an essential part of the turbine. A high-speed shaft turns the coil of the generator so that electricity can be generated.

7) Tower

The tower includes in the most crucial components of the wind turbine. The tower makes a steel lattice or tubular steel. The higher towers of turbines generate high energy. Because with height, the wind velocity increases, and the turbine axis rotates faster.

8) Low-speed shaft

It is the most compulsory part of the turbine. The rotor of the turbine drives it at about 30 to 60 rotations per minute.

9) Rotor

The blade and hub are collectively referred to as the rotor. As shown in the above fig. The primary function of the turbine rotors is to increase the speed of the air. So that the turbine shaft can increase the speed of the connected generator coil.

Advantages & Disadvantages and applications of wind energy

There are multiple advantages and disadvantages of wind energy, but some of them are given below in detail.

Advantages of Wind Energy

Different advantages of wind energy are given below.

1) Wind produces job

A significant advantage of wind energy is that it creates jobs. Wind power generation is a most fast-growing industry. The wind power industry flourished when wind turbines became economically feasible. And this industry is creating maximum jobs every year. Employment opportunities are creating in the areas of wind turbine maintenance, installation, and wind turbine manufacture. And also, this department announces jobs for wind power consulting purposes.

According to an international statement, wind power has the capacity to produce jobs of more than 600000 for maintenance, installation, and manufacturing purposes of wind power plants.

2) Wind energy cost-effective

As technology advances, wind energy is getting inexpensive and cheaper. Prices have been falling over the past 40 years and may not have continued to the same extent, but this trend is on the decline for a predictable future. Almost all companies should install, maintain and buy their wind power convertor.

3) Supports to the country economy

Wind energy is the most profitable source of energy. It supports the country’s economy. It is almost free because there is no use of any fuel. There is just need air that rotates to the blades of the wind turbine. And electricity produces by this process is almost free in cost. And we can sell our extra electricity to other countries. In this way, wind energy supports the country’s economy. It is a significant advantage of wind energy.

4) Renewable

Wind causes by the unevenness of the earth’s surface and the rotation of the earth when the sun warms the atmosphere. Technology has improved, and current wind turbines could be replaced with more or better units, but the wind is always there. Wind energy is a renewable source of energy. We can produce electricity for a lifetime with this process. The wind is an unlimited source of energy.

5) Cost-effective

Another advantage of wind energy is that the energy produces through wind is almost without any cost. There is no market for supply and requirement for wind power, and anyone can use it. It is one of the cheapest renewable sources of energy that is accessible today, depending on wind energy funding and specific projects. With free electricity, onshore wind turbines can generate the cheapest electricity in the world.

Since the electricity generated in the wind turbine is selling at a fixed price over a long period, a sharp increase in price does not affect the electricity generated by fossil fuels. Electrical power generation is not cheap.

6) Wind energy is sustainable

A massive advantage of wind energy is that it is sustainable. Wind energy is a type of solar energy. Wind causes by the unevenness of the earth’s surface and the rotation of the earth when the sun warms the atmosphere. As long as the sun is shining and the wind is blowing, the energy generated can be used to transmit electricity in the grid.

7) Space efficient

Wind turbines are larger and more efficient while taking up similar space. That is another advantage of wind energy. With just one year of electricity, electricity generation can supply 600 typical American households with sufficient electricity. These larger turbines need further expansion, but the land between them can be used for other purposes, like food production. Therefore, wind power plants are more efficient than solar power plants.

Disadvantages of Wind Energy

In this section, I am going to explain the different disadvantages of wind energy.

1) Visual Pollution

A most important disadvantage of wind turbines is the visual pollution they cause. A lot of people like the look of a windmill; some don’t. Others do not and see them as a blot on the land. However, this tends to be summed up in a personal opinion. The more wind turbines built, the more popular it is among the public.

2) Noise pollution

Wind turbine causes noise pollution. And this is a significant disadvantage of the wind energy generator process. The sound of the windmill can be examined from a distance of several hundred meters even though measures are usually taken to keep the wind turbine away from the house.

3) Dangerous for Wildlife

A significant disadvantage of a wind turbine is that a lot of birds kill by it. Because when birds fly into the rotating blades of the wind turbine, then they kill. In maximum countries, this problem has been solved or significantly decreased by improving technology or the proper placement of wind power generators.

4) Land Cost

Wind energy resource development may not be the most beneficial land use. Suitable land for the installation of wind turbines must compare with alternative land uses and can be more valuable than making electricity.

5) Wind Turbine’s cost

Even though the cost is falling while the price of wind turbines is still too high, first of all, engineers must conduct a field study. This may include installing research turbines to compute wind speed overtime period. If you think this is enough, you need to buy, transport, and install a wind turbine. All of these steps result in high costs when purchasing and installing a wind turbine.

Applications of Wind Energy

  1. Wind turbines are the best source of renewable energy resources. These turbines use to produce cheap cost electricity.
  2. Wind power uses to facilitate the transport of boats on seas and rivers to move goods and people from one location to another location.
  3. These types of turbines use to power the pump and pull water from the ground through the windmill.
  4. This type of energy also operates a flour mill that grinds grains such as corn and wheat into the flour.
  5. Wind energy can be seen as the fastest-growing energy source in the world.
  6. Today, wind energy is used for generating electrical power.

What materials are used to make wind turbines?

According to the report by the National Renewable Energy Laboratory, a wind turbine mainly consists of aluminum (0% to 2%); copper (1%); cast iron or iron (5% to 17%); plastic, resin, or fiberglass (11% to 16%); and steel (71% to 79% of the total mass of the turbine).

Many turbine parts are locally purchased and manufactured in the US (Wind Technology Market Report). The domestically purchased parts are wind turbine hub and blades parts (40% to 70%), towers (65% to 85%), and more than 90% of the nacelle parts. In addition, many internal components such as controllers, bolts, bearings, yaw systems, and pitch are imported.

How much does a wind turbine cost?

The cost of a wind turbine varies according to country, city, and residence location. Because of economies of scale, the cost per kilowatt of installing a large turbine is lower than the cost of installing a small turbine, and the cost per kilowatt of a single turbine site is higher than the cost of installing multiple turbine sites.

The wind turbines having power up to 100 kW cost around $2900 to $8100. Therefore, the cost of installing a 10 KW turbine can range from $49,900 to $90,000. Most commercial turbines installed nowadays are 2 MW in size and cost from $3 to $4 million.

Maximum Power OutputTypical Turbine TypeProject Cost
3.5 MWEnercon E126 EP3 £3.13 million
3 MWEnercon E82£2.33 million
1 MWEWT DW61£1.25 million
800 kWEnercon E53£1.03 million
100 kWNorvento nED-100£345 k

FAQ Section

How tall is a wind turbine?

Most commercial wind turbine towers are from 200ft to 260ft tall. When calculating the overall height, blades that are typically over 100ft long. The rotor blades of the wind turbines of the Gamesa G87 model have a height of 120 meters.

How fast does a wind turbine rotate?

The speed of the wind turbine blade is between 120 to 180 miles/hour. However, this speed may vary according to the conditions.

Due to the massive size of the wind turbine (having blades over 100 feet), it appears to spin slowly, but the blade’s tip is very fast.

How many homes can one wind turbine power?

This number varies according to some factors such as blade length, maintenance, wind conditions, and size, but a typical wind turbine can supply electricity to 1,000 and 2,000 households per year. Therefore, 1MW of power generation capacity supplies around 1,000 households, and many onshore turbines have an output of 2MW to 3MW.

Why are wind turbines bad?

The wind turbines are bad due to the following reasons:

  • It kills birds
  • It causes visual pollution
  • It generates high noise
  • These turbines have high initial installation costs

Do windmills actually kill birds?

The windmills are a very high danger for the birds because these turbines kill the birds if the birds fly near the turbines during their operation. The US Fish and Wildlife Service guesses that birds from 140,000 to 500,000 birds die in wind farms each year.

How long does it take a wind turbine to pay for itself?

The latest wind turbine has a service life of approx. 20 years and the costs can be amortized in an average of 15 years, but this period can be shortened or lengthened depending on the environmental conditions.

How long does a wind turbine last?

A good and latest wind turbine has a service life of approximately 20 years. Still, this service life can be gone up to 25 years or more according to the environmental conditions and proper maintenance procedures.

What are the types of Wind Turbines?

The wind turbines have the following types:

  1. Horizontal wind turbine
  2. Vertical wind turbine
  3. Upwind turbine
  4. Darrieus wind turbine
  5. Savonius Turbine
  6. Downwind turbine

Conclusion:

In this article, we deeply discussed the wind turbine working principle and some other aspects. A wind turbine is the most common type of turbine. The popularity of these turbines is increasing day by day because wind energy is the cheapest form of energy worldwide. Actually, it is a process of using wind to produce electrical energy or mechanical energy. And also these turbines have the least requirement of water consumption.

One more reason for the popularity of these turbines is that these types of turbines don’t produce environmental pollution. They are very environment friendly. It creates thousands of jobs each year for different country people. So, we should mostly use wind energy. In this way, we can save our money and the other resources that we use for generating electricity.

We also have listed the various disadvantage and advantages of wind energy. Although there are a lot of disadvantages of wind energy to consider, the wind is still one of the least expensive and cleanest sources of energy. Using wind energy, you can reduce your reliance on traditional power plants that pollute the earth and burn fossil fuels.

If you have any questions regarding this article then you may let me know through the comment box. I will try my best to get you back soon.

See More:

1) Turbines and types of turbines.

2) How does an Impulse turbine work?

3) What is a Reaction turbine?

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