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. A wind turbine is one of the most common types of turbines. This article explains the wind turbine working, types, and applications.
What is a Wind Turbine?
A wind turbine is a type of turbine that converts wind energy (wind kinetic energy) into mechanical power (rotational energy). These turbines have become the cheapest source of energy.
Wind turbines have a simple 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 wind turbine into electricity.
The turbine has a rotor, which is usually three-bladed. This rotor is installed on a tall tower. It is connected to a generator through a shaft. As the wind starts blowing, it rotates the rotor and the rotor further rotates the generator to produce electricity.
The small wind turbines are used for applications like charging batteries that supply caravans and boats with extra energy. These small wind turbines are also utilized to supply energy to traffic warning signs.
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 also has the minimum emission of greenhouse gases.
How does a Wind Turbine work?
The working principle of the wind turbine is very simple.
As the wind turbine starts working, the wind first hits the blades of the rotor with high velocity. After that, the rotor blades start moving in a rotary motion. The rotor also rotates with the movement of the blades. This rotor is attached to a gearbox.
The gearbox converts the rotary motion of the rotor from minimum to maximum speed. The gearbox is coupled to an electric generator’s rotor through a shaft. This shaft is connected to the generator’s coil.
The generator coil rotates according to the movement of the gearbox shaft. An exciter is required to provide the obligatory excitation for the generator’s 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 is controlled 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.
Types of Wind Turbines
Wind turbines have two major types:
- Horizontal Wind turbines
- Vertical Wind Turbines
1) 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 for these wind turbines to work.
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.
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).
Darrieus wind turbines are less efficient than horizontal axis wind turbines because of their designs and operational features.
Advantages and Disadvantages of the Darrieus Wind Turbine
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Advantages |
Disadvantages |
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This type of wind turbine is portable. |
It has low efficiency than HAWT. |
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It can easily arrange in a building. |
It can’t produce more electricity than HAWT. |
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Scalability |
It has low rotational efficiency. |
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It has a quiet operation. |
Its initial start is more difficult than a Savonius wind turbine. |
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Darrieus turbine has a small size than HAWT. |
The components of this turbine wear down in a very short time. |
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Safe to use. |
Self-starting mechanism |
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It has the capability to receive wind energy from all directions. |
Less availability of wind speed |
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Its blades rotate slowly which 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 one of the famous types of wind turbines. 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 turbine is a drag-type turbine and is 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
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Advantages |
Disadvantage |
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This vertical wind turbine works efficiently even with changing wind directions. |
It produces low electricity than HAWT. |
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The Savonius design works well even at low wind speeds, 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.
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It has a small size, quiet operation, and easy maintenance. |
It is less efficient. |
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It has easy to design. |
It produces less energy than the Darrieus wind turbine. |
iii) Giromill Wind Turbine
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 into rotational energy.
2) HAWT (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 turbines, the lift is the main force. 95% of the present wind turbines are HAWT.
Nowadays, the large 3-blade horizontal axis wind turbine generates most of the world’s wind energy when the blades surround the tower. These turbine towers have a generator and a rotor shaft that must be directed into the wind.
The horizontal axis wind turbines are available in numerous sizes from 100W to 100KW. These HAWTs are usually deployed in streamlined air conditions that allow constant airflow and direction to pick up maximum wind power.
Horizontal wind turbines further divide into the following two types:
i) Upwind Turbine
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 is most widely used in the United States of America. These turbines require a yaw mechanism for their proper operation.
Advantages and Disadvantages of Upwind Turbines
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Advantages |
Disadvantages |
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It stops the shade on the tower back. |
It requires a yaw mechanism to maintain the turbine face toward the wind. |
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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. In this configuration, the blades of the turbine are pushed by the wind and rotate in the same direction as the wind.
In a downwind turbine, the rotor is not supported by a front-facing bearing and the tower can be narrower since the rotor is located behind it. This design reduces the weight and cost of the turbine. Additionally, downwind turbines typically have a simpler design since they don’t require mechanisms to turn the rotor to face the wind.
Advantages and Disadvantages of Downwind Turbines
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Advantages |
Disadvantages |
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It can design without a yaw mechanism. |
Wind power fluctuation due to the rotor passing shadow on the tower. |
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Its rotor can design more flexibly as you want. |
Its tower gives more fatigue load on the turbine than an upward turbine. |
Components of Wind Turbine
The wind turbine has the following major components:
- Rotor
- Gearbox
- Controller
- Nacelle
- Tower
- Blades
- Yaw motor
- Yaw drive
- Brake
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
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 the 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.
10) Hub
A hub is one of the major components of the wind turbine. In the rigid hub, all blades bolt with the hub. This hub severely connects to the turbine shaft. The blades cantilevered from the turbine shaft and transfer their dynamic loads directly to the shaft.
Advantages of Wind Energy
- Wind produces jobs: A significant advantage of wind energy is that it creates jobs. Wind power generation is a fast-growing industry. The wind power industry flourished when wind turbines became economically feasible. And this industry is creating the maximum number of jobs every year.
- 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.
- Supports to the 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 a need for air that rotates to the blades of the wind turbine. And electricity produces by this process is almost free in cost.
- Renewable: Wind causes by the unevenness of the earth’s surface and the rotation of the earth when the sun warms the atmosphere. 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.
- Cost-effective: Another advantage of wind energy is that the energy produces through wind is almost without any cost. It is one of the cheapest renewable sources of energy that is accessible today, depending on wind energy funding and specific projects.
- 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.
- 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.
Disadvantages of Wind Energy
- Visual Pollution: The 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.
- Noise pollution: Wind turbine causes noise pollution. And this is a significant disadvantage of the wind energy generator process.
- 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.
- 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.
- Wind Turbine 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 over time the 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 Turbines
- Research and education: Wind turbines are sometimes installed at public demonstration sites, research facilities, or educational institutions to support renewable energy, train students, and gather data on wind energy production.
- Offshore wind farms: These wind turbines are mounted in bodies of water, usually in the ocean. These turbines take benefit from stronger and more consistent winds at sea and produce maximum energy.
- Distributed or small-scale wind power: Smaller wind turbines are most commonly used for small business, agricultural, and residential applications. These turbines may also be installed on private properties to offset energy costs or offer a backup power source.
- Utility-scale wind farms: Large-scale wind turbines are installed to produce electrical power for the grids. Large-scale wind farms can vary in size, consisting of tens to hundreds of wind turbines.
- Hybrid systems: They can be combined with other renewable energy sources, such as energy storage systems or solar panels, to produce a hybrid power system.
- Remote applications: They are used to deliver power to off-grid areas, islands, or remote areas.
- Telecommunication sites: They have the ability to supply power to telecommunication sites in remote areas.
- Water pumping: Wind turbines may also be utilized for pumping water for domestic, livestock watering, or agricultural irrigation applications. In these applications, the rotational energy produced by the turbine is used to run a water pump.
Wind Turbine Cost
The cost of a wind turbine varies according to country, city, and residence location.
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 Output | Typical Turbine Type | Project Cost |
|---|---|---|
| 3.5 MW | Enercon E126 EP3 | £3.13 million |
| 3 MW | Enercon E82 | £2.33 million |
| 1 MW | EWT DW61 | £1.25 million |
| 800 kW | Enercon E53 | £1.03 million |
| 100 kW | Norvento 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:
- Horizontal wind turbine
- Vertical wind turbine
- Upwind turbine
- Darrieus wind turbine
- Savonius Turbine
- Downwind turbine
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).