Wind turbine

A wind turbine is a device that converts the kinetic energy of wind into electrical energy. As of 2020^[update], hundreds of thousands of large turbines, in installations known as wind farms, were generating over 650 gigawatts of power, with 60 GW added each year.<ref>"World wind capacity at 650,8 GW, Corona crisis will slow down markets in 2020, renewables to be core of economic stimulus programmes" (Press release). WWEA. 16 April 2020. Retrieved 1 September 2021. Wind power capacity worldwide reaches 650,8 GW, 59,7 GW added in 2019</ref> Wind turbines are an increasingly important source of intermittent renewable energy, and are used in many countries to lower energy costs and reduce reliance on fossil fuels. One study claimed that, as of 2009,^[update] wind had the "lowest relative greenhouse gas emissions, the least water consumption demands and the most favorable social impacts" compared to photovoltaic, hydro, geothermal, coal and gas energy sources.<ref name="evans2009">Evans, Annette; Strezov, Vladimir; Evans, Tim (June 2009). "Assessment of sustainability indicators for renewable energy technologies". Renewable and Sustainable Energy Reviews. 13 (5): 1082–1088. doi:10.1016/j.rser.2008.03.008.</ref>

Smaller wind turbines are used for applications such as battery charging and remote devices such as traffic warning signs. Larger turbines can contribute to a domestic power supply while selling unused power back to the utility supplier via the electrical grid.<ref>"Installing and Maintaining a Small Wind Electric System". Energy.gov. Retrieved 22 May 2023.</ref>

Wind turbines are manufactured in a wide range of sizes, with either horizontal or vertical axes, though horizontal is most common.<ref name=":3">Righter, Robert W. (2011). Windfall: wind energy in America today. Norman: University of Oklahoma Press. ISBN 978-0-8061-4192-3.</ref>

History

The windwheel of Hero of Alexandria (10–70 CE) marks one of the first recorded instances of wind powering a machine.<ref>"Heron's Inventions includes Holy Water Dispenser and the Aeolipile". explorable.com. Retrieved 19 May 2023.</ref> However, the first known practical wind power plants were built in Sistan, an Eastern province of Persia (now Iran), from the 7th century. These "Panemone" were vertical axle windmills, which had long vertical drive shafts with rectangular blades.<ref>al-Hassan, Ahmad Y.; Hill, Donald R. (1992). Islamic Technology: An Illustrated History. Cambridge University Press. p. 54. ISBN 978-0-521-42239-0.</ref> Made of six to twelve sails covered in reed matting or cloth material, these windmills were used to grind grain or draw up water, and were used in the gristmilling and sugarcane industries.<ref>Hill, Donald, "Mechanical Engineering in the Medieval Near East", Scientific American, May 1991, pp. 64–69. (cf. Hill, Donald, Mechanical Engineering Archived 25 December 2007 at the Wayback Machine)</ref>

Wind power first appeared in Europe during the Middle Ages. The first historical records of their use in England date to the 11th and 12th centuries; there are reports of German crusaders taking their windmill-making skills to Syria around 1190.<ref name="Morthorst">Morthorst, Poul Erik; Redlinger, Robert Y.; Andersen, Per (2002). Wind energy in the 21st century: economics, policy, technology and the changing electricity industry. Houndmills, Basingstoke, Hampshire: Palgrave/UNEP. ISBN 978-0-333-79248-3.</ref> By the 14th century, Dutch windmills were in use to drain areas of the Rhine delta. Advanced wind turbines were described by Croatian inventor Fausto Veranzio in his book "Machinae Novae" (1595), he described vertical axis wind turbines with curved or V-shaped blades.

The first electricity-generating wind turbine was installed by the Austrian Josef Friedländer at the Vienna International Electrical Exhibition in 1883. It was a Halladay windmill for driving a dynamo. Friedländer’s 22-foot (6.6-meters) diameter Halladay “wind motor” was supplied by U.S. Wind Engine & Pump Co. of Batavia, Illinois. The five horsepower windmill drove a dynamo at ground level that fed electricity into a series of batteries. The batteries powered various electrical tools and lamps, as well as a threshing machine. Friedländer’s windmill and its accessories were prominently installed at the north entrance to the main exhibition hall ("Rotunde") in the Vienna Prater.<ref>"Austrian was First with Wind-Electric Turbine Not Byth or de Goyon". WIND WORKS. 25 July 2023. Retrieved 26 August 2023.</ref><ref>Windkraft, I. G. (2 August 2023). "Sensation: Österreicher baute bereits vor 140 Jahren das erste Windrad". www.igwindkraft.at (in Deutsch). Retrieved 26 August 2023.</ref><ref>"Die internationale elektrische Ausstellung Wien 1883 : unter besonderer Berücksichtigung der Organisation, sowie der baulichen und maschinellen Anlagen / von E. R. Leonhardt". www.e-rara.ch. 1884. Retrieved 26 August 2023.</ref>

In July 1887 Scottish academic James Blyth installed a battery-charging machine to light his holiday home in Marykirk, Scotland.<ref>"This Month in Physics History". www.aps.org. 4 June 2023. Retrieved 4 June 2023.</ref> Some months later, American inventor Charles F. Brush was able to build the first automatically operated wind turbine after consulting local University professors and his colleagues Jacob S. Gibbs and Brinsley Coleberd and successfully getting the blueprints peer-reviewed for electricity production.<ref name="ODNB">Price, Trevor J. (2004). "Blyth, James (1839–1906)". Oxford Dictionary of National Biography (online ed.). Oxford University Press. doi:10.1093/ref:odnb/100957. (Subscription or UK public library membership required.)</ref> Although Blyth's turbine was considered uneconomical in the United Kingdom,<ref name="ODNB" /> electricity generation by wind turbines was more cost effective in countries with widely scattered populations.<ref name="Morthorst" />

In Denmark by 1900, there were about 2500 windmills for mechanical loads such as pumps and mills, producing an estimated combined peak power of about 30 megawatts (MW). The largest machines were on 24-meter (79 ft) towers with four-bladed 23-meter (75 ft) diameter rotors. By 1908, there were 72 wind-driven electric generators operating in the United States from 5 kilowatts (kW) to 25 kW. Around the time of World War I, American windmill makers were producing 100,000 farm windmills each year, mostly for water-pumping.<ref name="Aermotor">"Quirky old-style contraptions make water from wind on the mesas of West Texas". Archived from the original on 3 February 2008.</ref>

By the 1930s, use of wind turbines in rural areas was declining as the distribution system extended to those areas.<ref>"History of wind power". U.S. Energy Information Administration (EIA). Retrieved 21 May 2023.</ref>

A forerunner of modern horizontal-axis wind generators was in service at Yalta, USSR in 1931. This was a 100 kW generator on a 30-meter (98 ft) tower, connected to the local 6.3 kV distribution system. It was reported to have an annual capacity factor of 32 percent, not much different from current wind machines.^{[citation needed]}

In the autumn of 1941, the first megawatt-class wind turbine was synchronized to a utility grid in Vermont. The Smith–Putnam wind turbine only ran for about five years before one of the blades snapped off.<ref>"The Unlikely Birth of Modern Renewable Energy On A Mountain Top in Vermont – 75 Years Ago Today". Stanford Law School. 19 October 2016. Retrieved 21 May 2023.</ref> The unit was not repaired, because of a shortage of materials during the war.<ref>Reicher, Dan (19 October 2016). "Reicher: Grampa's Knob 75th Anniversary". Vermont Public. Retrieved 6 June 2023.</ref>

The first utility grid-connected wind turbine to operate in the UK was built by John Brown & Company in 1951 in the Orkney Islands.<ref name="ODNB" /><ref>"Tiny Islands, Big Energy: How Orkney, Scotland Is Fighting Climate Change". Pulitzer Center. Retrieved 19 May 2023.</ref>

In the early 1970s, however, anti-nuclear protests in Denmark spurred artisan mechanics to develop microturbines of 22 kW despite declines in the industry.<ref>"Marching Activists: Transnational Lessons for Danish Anti-Nuclear Protest". Environment & Society Portal. 21 June 2017. Retrieved 20 May 2023.</ref> Organizing owners into associations and co-operatives led to the lobbying of the government and utilities and provided incentives for larger turbines throughout the 1980s and later. Local activists in Germany, nascent turbine manufacturers in Spain, and large investors in the United States in the early 1990s then lobbied for policies that stimulated the industry in those countries.<ref>"WindExchange: Wind Energy Policies and Incentives". windexchange.energy.gov. Retrieved 20 May 2023.</ref><ref>Hesse, Nicole (November 2021). "Visible winds: The production of new visibilities of wind energy in West Germany , 1973–1991". Centaurus. 63 (4): 695–713. doi:10.1111/1600-0498.12420. ISSN 0008-8994. S2CID 245544055.</ref><ref>Owens, Brandon N. (2019), "Spain's Wind Power Miracle", The Wind Power Story: A Century of Innovation that Reshaped the Global Energy Landscape, IEEE, pp. 223–235, doi:10.1002/9781118794289.ch15, ISBN 978-1-118-79430-2, S2CID 240648577, retrieved 20 May 2023</ref>

It has been argued that expanding the use of wind power will lead to increasing geopolitical competition over critical materials for wind turbines, such as rare earth elements neodymium, praseodymium, and dysprosium. However, this perspective has been critically dismissed for failing to relay how most wind turbines do not use permanent magnets and for underestimating the power of economic incentives for the expanded production of these minerals.<ref>Overland, Indra (1 March 2019). "The geopolitics of renewable energy: Debunking four emerging myths". Energy Research & Social Science. 49: 36–40. doi:10.1016/j.erss.2018.10.018. ISSN 2214-6296.</ref>

Wind power density

Wind Power Density (WPD) is a quantitative measure of wind energy available at any location. It is the mean annual power available per square meter of swept area of a turbine, and is calculated for different heights above ground. Calculation of wind power density includes the effect of wind velocity and air density.<ref>"NREL: Dynamic Maps, GIS Data, and Analysis Tools – Wind Maps". Nrel.gov. 3 September 2013. Retrieved 6 November 2013.</ref>

Wind turbines are classified by the wind speed they are designed for, from class I to class III, with A to C referring to the turbulence intensity of the wind.<ref>Appendix II IEC Classification of Wind Turbines. Wind Resource Assessment and Micro-siting, Science and Engineering. 2015. pp. 269–270. doi:10.1002/9781118900116.app2. ISBN 978-1-1189-0011-6.</ref>

Class	Avg Wind Speed (m/s)	Turbulence
IA	10	16%
IB	10	14%
IC	10	12%
IIA	8.5	16%
IIB	8.5	14%
IIC	8.5	12%
IIIA	7.5	16%
IIIB	7.5	14%
IIIC	7.5	12%

Efficiency

Conservation of mass requires that the amount of air entering and exiting a turbine must be equal. Accordingly, Betz's law gives the maximal achievable extraction of wind power by a wind turbine as 16⁄27 (59.3%) of the rate at which the kinetic energy of the air arrives at the turbine.<ref>"The Physics of Wind Turbines Kira Grogg Carleton College, 2005, p. 8" (PDF). Retrieved 6 November 2013.</ref>

The maximum theoretical power output of a wind machine is thus 16⁄27 times the rate at which kinetic energy of the air arrives at the effective disk area of the machine. If the effective area of the disk is A, and the wind velocity v, the maximum theoretical power output P is:

<math>

P=\frac{16}{27}\frac{1}{2}\rho v^3 A = \frac{8}{27}\rho v^3 A </math>,

where ρ is the air density.

Wind-to-rotor efficiency (including rotor blade friction and drag) are among the factors affecting the final price of wind power.<ref>"Wind Energy Basics". Bureau of Land Management. Archived from the original on 9 May 2019. Retrieved 23 April 2016.</ref> Further inefficiencies, such as gearbox losses, generator and converter losses, reduce the power delivered by a wind turbine. To protect components from undue wear, extracted power is held constant above the rated operating speed as theoretical power increases as the cube of wind speed, further reducing theoretical efficiency. In 2001, commercial utility-connected turbines delivered 75% to 80% of the Betz limit of power extractable from the wind, at rated operating speed.<ref name=Enercon>"Enercon E-family, 330 kW to 7.5 MW, Wind Turbine Specification" (PDF). Archived from the original (PDF) on 16 May 2011.</ref><ref>Burton, Tony; Sharpe; Jenkins; Bossanyi (12 December 2001). Wind Energy Handbook. John Wiley & Sons. p. 65. ISBN 978-0-471-48997-9.</ref>

Efficiency can decrease slightly over time, one of the main reasons being dust and insect carcasses on the blades, which alter the aerodynamic profile and essentially reduce the lift to drag ratio of the airfoil. Analysis of 3128 wind turbines older than 10 years in Denmark showed that half of the turbines had no decrease, while the other half saw a production decrease of 1.2% per year.<ref>Wittrup, Sanne (1 November 2013). "11 års vinddata afslørede overraskende produktionsnedgang" [11 years of wind data shows surprising production decrease]. Ingeniøren (in dansk). Archived from the original on 25 October 2018.</ref>

In general, more stable and constant weather conditions (most notably wind speed) result in an average of 15% greater efficiency than that of a wind turbine in unstable weather conditions, thus allowing up to a 7% increase in wind speed under stable conditions. This is due to a faster recovery wake and greater flow entrainment that occur in conditions of higher atmospheric stability. However, wind turbine wakes have been found to recover faster under unstable atmospheric conditions as opposed to a stable environment.<ref>Han, Xingxing; Liu, Deyou; Xu, Chang; Shen, Wen Zhong (2018). "Atmospheric stability and topography effects on wind turbine performance and wake properties in complex terrain". Renewable Energy. Elsevier BV. 126: 640–651. doi:10.1016/j.renene.2018.03.048. ISSN 0960-1481. S2CID 115433440.</ref>

Different materials have varying effects on the efficiency of wind turbines. In an Ege University experiment, three wind turbines, each with three blades with a diameter of one meter, were constructed with blades made of different materials: A glass and glass/carbon epoxy, glass/carbon, and glass/polyester. When tested, the results showed that the materials with higher overall masses had a greater friction moment and thus a lower power coefficient.<ref>Ozdamar, G. (2018). "Numerical Comparison of the Effect of Blade Material on Wind Turbine Efficiency". Acta Physica Polonica A. 134 (1): 156–158. Bibcode:2018AcPPA.134..156O. doi:10.12693/APhysPolA.134.156.</ref>

The air velocity is the major contributor to the turbine efficiency. This is the reason for the importance of choosing the right location. The wind velocity will be high near the shore because of the temperature difference between the land and the ocean. Another option is to place turbines on mountain ridges. The higher the wind turbine will be, the higher the wind velocity on average. A windbreak can also increase the wind velocity near the turbine.<ref>Garisto, Dan (30 July 2021). "Windbreaks May Improve Wind Farm Power". Physics. Vol. 14. p. 112.</ref>

Types

Wind turbines can rotate about either a horizontal or a vertical axis, the former being both older and more common.<ref>"Wind Energy Basics". American Wind Energy Association. Archived from the original on 23 September 2010. Retrieved 24 September 2009.</ref> They can also include blades or be bladeless.<ref>Stinson, Elizabeth (15 May 2015). "The Future of Wind Turbines? No Blades". Wired.</ref> Household-size vertical designs produce less power and are less common.<ref name="wind-works.org">Paul Gipe (7 May 2014). "News & Articles on Household-Size (Small) Wind Turbines". Wind-works.org. Archived from the original on 28 August 2022. Retrieved 29 September 2016.</ref>

Horizontal axis

Onshore Horizontal Axis Wind Turbines in Zhangjiakou, Hebei, China

Large three-bladed horizontal-axis wind turbines (HAWT) with the blades upwind of the tower produce the overwhelming majority of wind power in the world today.<ref name=":3" /> These turbines have the main rotor shaft and electrical generator at the top of a tower, and must be pointed into the wind. Small turbines are pointed by a simple wind vane, while large turbines generally use a wind sensor coupled with a yaw system. Most have a gearbox, which turns the slow rotation of the blades into a quicker rotation that is more suitable to drive an electrical generator.<ref>"How a Wind Turbine Works - Text Version". Energy.gov. Retrieved 26 May 2023.</ref> Some turbines use a different type of generator suited to slower rotational speed input. These don't need a gearbox and are called direct-drive, meaning they couple the rotor directly to the generator with no gearbox in between. While permanent magnet direct-drive generators can be more costly due to the rare earth materials required, these gearless turbines are sometimes preferred over gearbox generators because they "eliminate the gear-speed increaser, which is susceptible to significant accumulated fatigue torque loading, related reliability issues, and maintenance costs."<ref>Bywaters, G.; Mattila; Costin; Stowell; John; Hoskins; Lynch; Cole; Cate; C. Badger; B. Freeman (October 2007). "Northern Power NW 1500 Direct-Drive Generator" (PDF). National Renewable Energy Laboratory. p. iii.</ref> There is also the pseudo direct drive mechanism, which has some advantages over the permanent magnet direct drive mechanism.<ref>Neves, C. G. C.; Flores Filho, A. F.; Dorrel, D. G. (2016). "Design of a Pseudo Direct Drive for Wind Power Applications". 2016 International Conference of Asian Union of Magnetics Societies (ICAUMS). pp. 1–5. doi:10.1109/ICAUMS.2016.8479825. ISBN 978-1-5090-4383-5. S2CID 52934155.</ref>

Most horizontal axis turbines have their rotors upwind of the supporting tower.<ref>"Horizontal Axis Wind Turbine - an overview | ScienceDirect Topics". www.sciencedirect.com. Retrieved 21 May 2023.</ref> Downwind machines have been built, because they don't need an additional mechanism for keeping them in line with the wind. In high winds, downwind blades can also be designed to bend more than upwind ones, which reduces their swept area and thus their wind resistance, mitigating risk during gales. Despite these advantages, upwind designs are preferred, because the pulsing change in loading from the wind as each blade passes behind the supporting tower can cause damage to the turbine.<ref>Bortolotti, Pietro; Kapila, Abhinav; Bottasso, Carlo L. (31 January 2019). "Comparison between upwind and downwind designs of a 10 MW wind turbine rotor". Wind Energy Science. 4 (1): 115–125. Bibcode:2019WiEnS...4..115B. doi:10.5194/wes-4-115-2019. ISSN 2366-7443. S2CID 197548612.</ref>

Turbines used in wind farms for commercial production of electric power are usually three-bladed. These have low torque ripple, which contributes to good reliability. The blades are usually colored white for daytime visibility by aircraft and range in length from 20 to 80 meters (66 to 262 ft). The size and height of turbines increase year by year. Offshore wind turbines are built up to 8 MW today and have a blade length up to 80 meters (260 ft). Designs with 10 to 12 MW were in preparation in 2018,<ref>"MHI Vestas Launches World's First* 10 Megawatt Wind Turbine". CleanTechnica. 26 September 2018.</ref> and a "15 MW+" prototype with three 118 meters (387 ft) blades is planned to be constructed in 2022.<ref>"World's biggest wind turbine shows the disproportionate power of scale". 22 August 2021.</ref> The average hub height of horizontal axis wind turbines is 90 meters.<ref>"Wind Energy Factsheet". Center for Sustainable Systems. Retrieved 21 May 2023.</ref>

Vertical axis

Vertical-axis wind turbines (or VAWTs) have the main rotor shaft arranged vertically. One advantage of this arrangement is that the turbine does not need to be pointed into the wind to be effective,<ref>"Vertical Axis Wind Turbine - an overview | ScienceDirect Topics". www.sciencedirect.com. Retrieved 22 May 2023.</ref> which is an advantage on a site where the wind direction is highly variable. It is also an advantage when the turbine is integrated into a building because it is inherently less steerable. Also, the generator and gearbox can be placed near the ground, using a direct drive from the rotor assembly to the ground-based gearbox, improving accessibility for maintenance. However, these designs produce much less energy averaged over time, which is a major drawback.<ref name="wind-works.org"/><ref>Michael Barnard (7 April 2014). "Vertical Axis Wind Turbines: Great In 1890, Also-rans In 2014". CleanTechnica.</ref>

Vertical turbine designs have much lower efficiency than standard horizontal designs.<ref>Hau, E., Wind Turbines: Fundamentals, Technologies, Application, Economics. Springer. Germany. 2006</ref> The key disadvantages include the relatively low rotational speed with the consequential higher torque and hence higher cost of the drive train, the inherently lower power coefficient, the 360-degree rotation of the aerofoil within the wind flow during each cycle and hence the highly dynamic loading on the blade, the pulsating torque generated by some rotor designs on the drive train, and the difficulty of modelling the wind flow accurately and hence the challenges of analysing and designing the rotor prior to fabricating a prototype.<ref>Michael C Brower; Nicholas M Robinson; Erik Hale (May 2010). "Wind Flow Modeling Uncertainty" (PDF). AWS Truepower. Archived from the original on 2 May 2013.{{cite web}}: CS1 maint: unfit URL (link)</ref>

When a turbine is mounted on a rooftop the building generally redirects wind over the roof and this can double the wind speed at the turbine. If the height of a rooftop mounted turbine tower is approximately 50% of the building height it is near the optimum for maximum wind energy and minimum wind turbulence. While wind speeds within the built environment are generally much lower than at exposed rural sites,<ref>Piggott, Hugh (6 January 2007). "Windspeed in the city – reality versus the DTI database". Scoraigwind.com. Retrieved 6 November 2013.</ref><ref>"Urban Wind Turbines" (PDF).</ref> noise may be a concern and an existing structure may not adequately resist the additional stress.

Subtypes of the vertical axis design include:

Darrieus wind turbine

"Eggbeater" turbines, or Darrieus turbines, were named after the French inventor, Georges Darrieus.<ref>Möllerström, Erik; Gipe, Paul; Beurskens, Jos; Ottermo, Fredric (1 May 2019). "A historical review of vertical axis wind turbines rated 100 kW and above". Renewable and Sustainable Energy Reviews. 105: 1–13. doi:10.1016/j.rser.2018.12.022. ISSN 1364-0321. S2CID 117471815.</ref> They have good efficiency, but produce large torque ripple and cyclical stress on the tower, which contributes to poor reliability. They also generally require some external power source, or an additional Savonius rotor to start turning, because the starting torque is very low. The torque ripple is reduced by using three or more blades, which results in greater solidity of the rotor. Solidity is measured by blade area divided by the rotor area.

Giromill

A subtype of Darrieus turbine with straight, as opposed to curved, blades. The cycloturbine variety has variable pitch to reduce the torque pulsation and is self-starting.<ref>Eric Eggleston & AWEA Staff. "What Are Vertical-Axis Wind Turbines (VAWTs)?". American Wind Energy Association. Archived from the original on 3 April 2005.</ref> The advantages of variable pitch are: high starting torque; a wide, relatively flat torque curve; a higher coefficient of performance; more efficient operation in turbulent winds; and a lower blade speed ratio which lowers blade bending stresses. Straight, V, or curved blades may be used.<ref>Marloff, Richard H. (1 January 1978). "Stresses in turbine-blade tenons subjected to bending". Experimental Mechanics. 18 (1): 19–24. doi:10.1007/BF02326553. ISSN 1741-2765. S2CID 135685029.</ref>

Savonius wind turbine

These are drag-type devices with two (or more) scoops that are used in anemometers, Flettner vents (commonly seen on bus and van roofs), and in some high-reliability low-efficiency power turbines. They are always self-starting if there are at least three scoops.<ref>"Savonius Wind Turbine - an overview | ScienceDirect Topics". www.sciencedirect.com. Retrieved 23 May 2023.</ref>

Twisted Savonius is a modified savonius, with long helical scoops to provide smooth torque. This is often used as a rooftop wind turbine and has even been adapted for ships.<ref>Rob Varnon (2 December 2010). "Derecktor converting boat into hybrid passenger ferry". Connecticut Post. Retrieved 25 April 2012.</ref>

Airborne wind turbine

Airborne wind turbines consist of wings or a small aircraft tethered to the ground.<ref>Cherubini, Antonello; Papini, Andrea; Vertechy, Rocco; Fontana, Marco (1 November 2015). "Airborne Wind Energy Systems: A review of the technologies". Renewable and Sustainable Energy Reviews. 51: 1461–1476. doi:10.1016/j.rser.2015.07.053. hdl:11382/503316. ISSN 1364-0321.</ref> They are useful for reaching faster winds above which traditional turbines can operate. There are prototypes in operation in east Africa.<ref>"After a Shaky Start, Airborne Wind Energy Is Slowly Taking Off". Yale E360. Retrieved 2 June 2023.</ref>

Floating wind turbine

These are offshore wind turbines that are supported by a floating platform.<ref>"So, What Exactly Is Floating Offshore Wind?". www.greentechmedia.com. Retrieved 2 June 2023.</ref> By having them float, they are able to be installed in deeper water allowing more of them. This also allows them to be further out of sight from land and therefore less public concern about the visual appeal.<ref>"The US has just started building floating wind turbines – how do they work?". World Economic Forum. 16 December 2022. Retrieved 2 June 2023.</ref>

Unconventional types

Counter-rotating wind turbine
Vertical Axis Wind Turbine offshore
Light pole wind turbine

Design and construction

Wind turbine design is a careful balance of cost, energy output, and fatigue life.

Components

Wind turbines convert wind energy to electrical energy for distribution. Conventional horizontal axis turbines can be divided into three components:

The rotor, which is approximately 20% of the wind turbine cost, includes the blades for converting wind energy to low speed rotational energy.<ref name=":4" />
The generator, which is approximately 34% of the wind turbine cost, includes the electrical generator,<ref>Navid Goudarzi (June 2013). "A Review on the Development of the Wind Turbine Generators across the World". International Journal of Dynamics and Control. 1 (2): 192–202. doi:10.1007/s40435-013-0016-y.</ref><ref>Navid Goudarzi; Weidong Zhu (November 2012). "A Review of the Development of Wind Turbine Generators Across the World". ASME 2012 International Mechanical Engineering Congress and Exposition. 4 – Paper No: IMECE2012-88615: 1257–1265.</ref> the control electronics, and most likely a gearbox (e.g., planetary gear box),<ref>"Hansen W4 series". Hansentransmissions.com. Archived from the original on 15 March 2012. Retrieved 6 November 2013.</ref> adjustable-speed drive, or continuously variable transmission<ref>Gardner, John; Haro, Nathaniel & Haynes, Todd (October 2011). "Active Drivetrain Control to Improve Energy Capture of Wind Turbines" (PDF). Boise State University. Archived from the original (PDF) on 7 March 2012. Retrieved 28 February 2012.</ref> component for converting the low-speed incoming rotation to high-speed rotation suitable for generating electricity.
The surrounding structure, which is approximately 15% of the wind turbine cost, includes the tower and rotor yaw mechanism.<ref name=":4">""Wind Turbine Design Cost and Scaling Model", Technical Report NREL/TP-500-40566, December, 2006, page 35, 36" (PDF). National Renewable Energy Laboratory. Retrieved 6 November 2013.</ref>

A 1.5 (MW) wind turbine of a type frequently seen in the United States has a tower 80 meters (260 ft) high. The rotor assembly (blades and hub) measures about 80 meters (260 ft) in diameter.<ref>Bauer, Lucas. "GE General Electric GE 1.5s - 1,50 MW - Wind turbine". en.wind-turbine-models.com. Retrieved 23 May 2023.</ref> The nacelle, which contains the generator is 15.24 meters (50.0 ft) and weigh around 300 tons.<ref>"Nacelles | How are they manufactured?". Windpower Engineering & Development. Retrieved 23 May 2023.</ref>

Turbine monitoring and diagnostics

Due to data transmission problems, structural health monitoring of wind turbines is usually performed using several accelerometers and strain gages attached to the nacelle to monitor the gearbox and equipment. Currently, digital image correlation and stereophotogrammetry are used to measure dynamics of wind turbine blades. These methods usually measure displacement and strain to identify location of defects. Dynamic characteristics of non-rotating wind turbines have been measured using digital image correlation and photogrammetry.<ref>Baqersad, Javad; Niezrecki, Christopher; Avitabile, Peter (2015). "Full-field dynamic strain prediction on a wind turbine using displacements of optical targets measured by stereophotogrammetry". Mechanical Systems and Signal Processing. 62–63: 284–295. Bibcode:2015MSSP...62..284B. doi:10.1016/j.ymssp.2015.03.021.</ref> Three dimensional point tracking has also been used to measure rotating dynamics of wind turbines.<ref>Lundstrom, Troy; Baqersad, Javad; Niezrecki, Christopher; Avitabile, Peter (4 November 2012). "Using High-Speed Stereophotogrammetry Techniques to Extract Shape Information from Wind Turbine/Rotor Operating Data". In Allemang, R.; De Clerck, J.; Niezrecki, C.; Blough, J.R. (eds.). Topics in Modal Analysis II, Volume 6. Conference Proceedings of the Society for Experimental Mechanics Series. Springer New York. pp. 269–275. doi:10.1007/978-1-4614-2419-2_26. ISBN 978-1-4614-2418-5.</ref>

Technology

Generally, efficiency increases along with turbine blade lengths. The blades must be stiff, strong, durable, light and resistant to fatigue.<ref name="citeseerx.ist.psu.edu">Ancona, Dan; Jim, McVeigh (2001), Wind Turbine – Materials and Manufacturing Fact Sheet, CiteSeerX 10.1.1.464.5842</ref> Materials with these properties include composites such as polyester and epoxy, while glass fiber and carbon fiber have been used for the reinforcing.<ref name=WS2010>Watson, James; Serrano, Juan (September 2010). "Composite Materials for Wind Blades". Wind Systems. Archived from the original on 11 November 2017. Retrieved 6 November 2016.</ref> Construction may involve manual layup or injection molding. Retrofitting existing turbines with larger blades reduces the task and risks of redesign.<ref>Jossi, Frank (4 February 2021). "Wind developers are retrofitting newer projects with bigger, better blades". Energy News Network. Retrieved 2 June 2023.</ref>

As of 2021, the longest blade was 115.5 m (379 ft), producing 15 MW.<ref name=":5">Venditti, Bruno (3 June 2022). "Animation: The World's Biggest Wind Turbines". Visual Capitalist. Retrieved 20 May 2023.</ref>

Blades usually last around 20 years, the typical lifespan of a wind turbine.<ref>"What happens to end-of-life wind turbine blades?". www.ny1.com. 19 August 2022. Retrieved 4 June 2023.</ref>

Blade materials

Materials commonly used in wind turbine blades are described below.

Glass and carbon fibers

The stiffness of composites is determined by the stiffness of fibers and their volume content. Typically, E-glass fibers are used as main reinforcement in the composites. Typically, the glass/epoxy composites for wind turbine blades contain up to 75% glass by weight. This increases the stiffness, tensile and compression strength. A promising composite material is glass fiber with modified compositions like S-glass, R-glass etc. Other glass fibers developed by Owens Corning are ECRGLAS, Advantex and WindStrand.<ref>"Materials and Innovations for Large Blade Structures: Research Opportunities in Wind Energy Technology" (PDF). windpower.sandia.gov. Archived from the original (PDF) on 13 August 2017. Retrieved 27 February 2018.</ref>

Carbon fiber has more tensile strength, higher stiffness and lower density than glass fiber. An ideal candidate for these properties is the spar cap, a structural element of a blade which experiences high tensile loading.<ref name=WS2010/> A 100-metre (330 ft) glass fiber blade could weigh up to 50 tonnes (110,000 lb), while using carbon fiber in the spar saves 20% to 30% weight, about 15 tonnes (33,000 lb).<ref>"Wind turbine blades: Glass vs. carbon fiber". www.compositesworld.com. Retrieved 12 November 2016.</ref>

Hybrid reinforcements

Instead of making wind turbine blade reinforcements from pure glass or pure carbon, hybrid designs trade weight for cost. For example, for an 8-metre (26 ft) blade, a full replacement by carbon fiber would save 80% of weight but increase costs by 150%, while a 30% replacement would save 50% of weight and increase costs by 90%. Hybrid reinforcement materials include E-glass/carbon, E-glass/aramid. The current longest blade by LM Wind Power is made of carbon/glass hybrid composites. More research is needed about the optimal composition of materials <ref>Vries, Eize de. "Turbines of the year: Rotor blades". www.windpowermonthly.com.</ref>

Nano-engineered polymers and composites

Additions of small amount (0.5 weight %) of nanoreinforcement (carbon nanotubes or nanoclay) in the polymer matrix of composites, fiber sizing or inter-laminar layers can improve fatigue resistance, shear or compressive strength, and fracture toughness of the composites by 30% to 80%. Research has also shown that incorporating small amounts of carbon nanotubes (CNT) can increase the lifetime up to 1500%.<ref>Panduranga, Raghu; Alamoudi, Yasser; Ferrah, Azzeddine (2019). "Nanoengineered Composite Materials for Wind Turbine Blades". 2019 Advances in Science and Engineering Technology International Conferences (ASET). pp. 1–7. doi:10.1109/ICASET.2019.8714217. ISBN 978-1-5386-8271-5. S2CID 155109369.</ref>

Costs

As of 2019^[update], the capital cost of a wind turbine was around $1 million per megawatt of nameplate capacity, though this figure varies by location; for example, such numbers ranged from a half million in South America to $1.7 million in Asia.<ref>"IntelStor expects wind turbine prices to recover 5% in next two years". Windpower Engineering & Development. 22 October 2019.</ref>

For the wind turbine blades, while the material cost is much higher for hybrid glass/carbon fiber blades than all-glass fiber blades, labor costs can be lower. Using carbon fiber allows simpler designs that use less raw material. The chief manufacturing process in blade fabrication is the layering of plies. Thinner blades allow reducing the number of layers and so the labor, and in some cases, equate to the cost of labor for glass fiber blades.<ref>Ong, Cheng-Huat & Tsai, Stephen W. (1 March 2000). "The Use of Carbon Fibers in Wind Turbine Blade Design" (PDF). energy.sandia.gov.</ref>

Offshore has significantly higher installation costs.<ref>"Onshore vs offshore wind energy: what's the difference?". National Grid Group. Retrieved 23 May 2023.</ref>

Non-blade materials

Wind turbine parts other than the rotor blades (including the rotor hub, gearbox, frame, and tower) are largely made of steel. Smaller turbines (as well as megawatt-scale Enercon turbines) have begun using aluminum alloys for these components to make turbines lighter and more efficient. This trend may grow if fatigue and strength properties can be improved. Pre-stressed concrete has been increasingly used for the material of the tower, but still requires much reinforcing steel to meet the strength requirement of the turbine. Additionally, step-up gearboxes are being increasingly replaced with variable speed generators, which requires magnetic materials.<ref name="citeseerx.ist.psu.edu" />

Modern turbines use a couple of tons of copper for generators, cables and such.<ref>Frost and Sullivan, 2009, cited in Wind Generator Technology, by Eclareon S.L., Madrid, May 2012; www.eclareon.com; Available at Leonardo Energy – Ask an Expert; "Ask an expert | Leonardo ENERGY". Archived from the original on 26 November 2012. Retrieved 12 December 2012.</ref> As of 2018^[update], global production of wind turbines use 450,000 tonnes (990 million pounds) of copper per year.<ref>"Fast pace of growth in wind energy driving demand for copper". Riviera Maritime Media.</ref>

Material supply

A 2015 study of the material consumption trends and requirements for wind energy in Europe found that bigger turbines have a higher consumption of precious metals but lower material input per kW generated. The material consumption and stock at that time was compared to input materials for various onshore system sizes. In all EU countries, the estimates for 2020 doubled the values consumed in 2009. These countries would need to expand their resources to meet the estimated demand for 2020. For example, the EU had 3% of world supply of fluorspar, and it would require 14% by 2020. Globally, the main exporting countries are South Africa, Mexico, and China. This is similar with other critical and valuable materials required for energy systems such as magnesium, silver and indium. The levels of recycling of these materials are very low, and focusing on that could alleviate supply. Because most of these valuable materials are also used in other emerging technologies, like light emitting diodes (LEDs), photo voltaics (PVs) and liquid crystal displays (LCDs), their demand is expected to grow.<ref>Kim, Junbeum; Guillaume, Bertrand; Chung, Jinwook; Hwang, Yongwoo (1 February 2015). "Critical and precious materials consumption and requirement in wind energy system in the EU 27". Applied Energy. 139: 327–334. Bibcode:2015ApEn..139..327K. doi:10.1016/j.apenergy.2014.11.003. ISSN 0306-2619.</ref>

A 2011 study by the United States Geological Survey estimated resources required to fulfill the US commitment to supplying 20% of its electricity from wind power by 2030. It did not consider requirements for small turbines or offshore turbines because those were not common in 2008 when the study was done. Common materials such as cast iron, steel and concrete would increase by 2%–3% compared to 2008. Between 110,000 and 115,000 metric tons of fiber glass would be required per year, a 14% increase. Rare-earth metal use would not increase much compared to available supply, however rare-earth metals that are also used for other technologies such as batteries which are increasing its global demand need to be taken into account. Land required would be 50,000 square kilometers onshore and 11,000 offshore. This would not be a problem in the US due to its vast area and because the same land can be used for farming. A greater challenge would be the variability and transmission to areas of high demand.<ref name=wilburn>Wilburn, David R. (2011). Wind Energy in the United States and Materials Required for the Land-Based Wind Turbine Industry from 2010 through 2030 (Scientific Investigations Report 2011-5036) (PDF). USGS. Retrieved 15 January 2023.</ref>

Permanent magnets for wind turbine generators contain rare-earth metals such as neodymium (Nd), praseodymium (Pr), terbium (Tb), and dysprosium (Dy). Systems that use magnetic direct drive turbines require greater amounts of rare-earth metals. Therefore, an increase in wind turbine manufacture would increase the demand for these resources. By 2035, the demand for Nd is estimated to increase by 4,000 to 18,000 tons and for Dy by 200 to 1200 tons. These values are a quarter to half of current production. However, these estimates are very uncertain because technologies are developing rapidly.<ref>Buchholz, Peter; Brandenburg, Torsten (1 January 2018). "Demand, Supply, and Price Trends for Mineral Raw Materials Relevant to the Renewable Energy Transition Wind Energy, Solar Photovoltaic Energy, and Energy Storage". Chemie Ingenieur Technik. 90 (1–2): 141–153. doi:10.1002/cite.201700098. ISSN 1522-2640.</ref>

Reliance on rare earth minerals for components has risked expense and price volatility as China has been main producer of rare earth minerals (96% in 2009) and was reducing its export quotas.<ref name=wilburn /> However, in recent years other producers have increased production and China has increased export quotas, leading to a higher supply and lower cost, and a greater viability of large scale use of variable-speed generators.<ref>Yap, Chui-Wei (5 January 2015). "China Ends Rare-Earth Minerals Export Quotas". Wall Street Journal.</ref>

Glass fiber is the most common material for reinforcement. Its demand has grown due to growth in construction, transportation and wind turbines. Its global market might reach US$17.4 billion by 2024, compared to US$8.5 billion in 2014. In 2014, Asia Pacific produced more than 45% of the market; now China is the largest producer. The industry receives subsidies from the Chinese government allowing it to export cheaper to the US and Europe. However, price wars have led to anti-dumping measures such as tariffs on Chinese glass fiber.<ref>"Glass fiber market to reach to US$17 billion by 2024". Reinforced Plastics. 60 (4): 188–189. 1 July 2016. doi:10.1016/j.repl.2016.07.006. ISSN 0034-3617.</ref>

Wind turbines on public display

A few localities have exploited the attention-getting nature of wind turbines by placing them on public display, either with visitor centers around their bases, or with viewing areas farther away.<ref name="wind_farm_tourism">Young, Kathryn (3 August 2007). "Canada wind farms blow away turbine tourists". Edmonton Journal. Archived from the original on 25 April 2009. Retrieved 6 September 2008.</ref> The wind turbines are generally of conventional horizontal-axis, three-bladed design, and generate power to feed electrical grids, but they also serve the unconventional roles of technology demonstration, public relations, and education.<ref>Rudgard, Olivia (20 February 2023). "Despite perception as eyesore, wind turbine tourism takes off". The Japan Times. Retrieved 2 June 2023.</ref>

Small wind turbines

Small wind turbines may be used for a variety of applications including on- or off-grid residences, telecom towers, offshore platforms, rural schools and clinics, remote monitoring and other purposes that require energy where there is no electric grid, or where the grid is unstable. Small wind turbines may be as small as a fifty-watt generator for boat or caravan use. Hybrid solar and wind powered units are increasingly being used for traffic signage, particularly in rural locations, as they avoid the need to lay long cables from the nearest mains connection point.<ref>Anon. "Solar & Wind Powered Sign Lighting". Energy Development Cooperative Ltd. Retrieved 19 October 2013.</ref> The U.S. Department of Energy's National Renewable Energy Laboratory (NREL) defines small wind turbines as those smaller than or equal to 100 kilowatts.<ref>Small Wind Archived 15 November 2011 at the Wayback Machine, U.S. Department of Energy National Renewable Energy Laboratory website</ref> Small units often have direct drive generators, direct current output, aeroelastic blades, lifetime bearings and use a vane to point into the wind.<ref>Castellano, Robert (2012). Alternative Energy Technologies: Opportunities and Markets. Archives contemporaines. ISBN 978-2-8130-0076-7.</ref>

Wind turbine spacing

On most horizontal wind turbine farms, a spacing of about 6–10 times the rotor diameter is often upheld. However, for large wind farms distances of about 15 rotor diameters should be more economical, taking into account typical wind turbine and land costs. This conclusion has been reached by research<ref>Meyers, Johan (2011). "Optimal turbine spacing in fully developed wind farm boundary layers". Wind Energy. 15 (2): 305–317. Bibcode:2012WiEn...15..305M. doi:10.1002/we.469.</ref> conducted by Charles Meneveau of Johns Hopkins University<ref>"New study yields better turbine spacing for large wind farms". Johns Hopkins University. 18 January 2011. Retrieved 6 November 2013.</ref> and Johan Meyers of Leuven University in Belgium, based on computer simulations<ref>M. Calaf; C. Meneveau; J. Meyers (2010). "Large eddy simulation study of fully developed wind-turbine array boundary layers". Phys. Fluids. 22 (1): 015110–015110–16. Bibcode:2010PhFl...22a5110C. doi:10.1063/1.3291077.</ref> that take into account the detailed interactions among wind turbines (wakes) as well as with the entire turbulent atmospheric boundary layer.

Recent research by John Dabiri of Caltech suggests that vertical wind turbines may be placed much more closely together so long as an alternating pattern of rotation is created allowing blades of neighbouring turbines to move in the same direction as they approach one another.<ref>Dabiri, John O. (1 July 2011). "Potential order-of-magnitude enhancement of wind farm power density via counter-rotating vertical-axis wind turbine arrays". Journal of Renewable and Sustainable Energy. 3 (4): 043104. arXiv:1010.3656. doi:10.1063/1.3608170. S2CID 10516774.</ref>

Operability

Maintenance

Wind turbines need regular maintenance to stay reliable and available. In the best case turbines are available to generate energy 98% of the time.<ref>van Bussel, G.J.W.; Zaaijer, M.B. (2001). "Reliability, Availability and Maintenance aspects of large-scale offshore wind farms" (PDF). Delft University of Technology. p. 2. Archived from the original (PDF) on 12 April 2016. Retrieved 30 May 2016.</ref><ref>"Iberwind builds on 98% availability with fresh yaw, blade gains". 15 February 2016. Retrieved 30 May 2016.</ref> Ice accretion on turbine blades has also been found to greatly reduce the efficiency of wind turbines, which is a common challenge in cold climates where in-cloud icing and freezing rain events occur.<ref>Barber, S.; Wang, Y.; Jafari, S.; Chokani, N.; Abhari, R. S. (28 January 2011). "The Impact of Ice Formation on Wind Turbine Performance and Aerodynamics". Journal of Solar Energy Engineering. 133 (1): 011007–011007–9. doi:10.1115/1.4003187. ISSN 0199-6231.</ref> De-icing is mainly performed by internal heating, or in some cases by helicopters spraying clean warm water on the blades.<ref>Nilsen, Jannicke (1 February 2015). "Her spyler helikopteret bort et tykt lag med is". Tu.no (in norsk). Teknisk Ukeblad. Archived from the original on 20 January 2021. These work .. by blowing hot air into the rotor blades so that the ice melts, or by using heating cables on the front edge of the rotor blades where the ice sticks. No chemicals are added to the water, in contrast to aircraft de-icing, which often involves extensive use of chemicals. The price tag for de-icing a wind turbine is equivalent to the value of two days' turbine production.</ref>

Modern turbines usually have a small onboard crane for hoisting maintenance tools and minor components. However, large, heavy components like generator, gearbox, blades, and so on are rarely replaced, and a heavy lift external crane is needed in those cases. If the turbine has a difficult access road, a containerized crane can be lifted up by the internal crane to provide heavier lifting.<ref>Morten Lund (30 May 2016). "Dansk firma sætter prisbelønnet selvhejsende kran i serieproduktion". Ingeniøren. Archived from the original on 31 May 2016. Retrieved 30 May 2016.</ref>

Repowering

Installation of new wind turbines can be controversial. An alternative is repowering, where existing wind turbines are replaced with bigger, more powerful ones, sometimes in smaller numbers while keeping or increasing capacity.<ref>"Wind Repowering Helps Set the Stage for Energy Transition". Energy.gov. Retrieved 23 May 2023.</ref>

Demolition and recycling

Some wind turbines which are out of use are recycled or repowered.<ref>Jeremy Fugleberg (8 May 2014). "Abandoned Dreams of Wind and Light". Atlas Obscura. Retrieved 30 May 2016.</ref><ref>Tom Gray (11 March 2013). "Fact check: About those 'abandoned' turbines …". American Wind Energy Association. Archived from the original on 8 June 2016. Retrieved 30 May 2016.</ref> 85% of turbine materials are easily reused or recycled, but the blades, made of a composite material, are more difficult to process.<ref name=":2"/>

Interest in recycling blades varies in different markets and depends on the waste legislation and local economics. A challenge in recycling blades is related to the composite material, which is made of fiberglass with carbon fibers in epoxy resin, which cannot be remolded to form new composites.<ref>"Wind Turbine Blades Can't Be Recycled, So They're Piling Up in Landfills". Bloomberg.com. 5 February 2020. Retrieved 7 June 2023.</ref>

Wind farm waste is less toxic than other garbage. Wind turbine blades represent only a fraction of overall waste in the US, according to the Wind-industry trade association, American Wind Energy Association.<ref>"Turbines Tossed Into Dump Stirs Debate on Wind's Dirty Downside". Bloomberg. 31 July 2019. Retrieved 6 December 2019.</ref>

Several utilities, start-up companies, and researchers are developing methods for reusing or recycling blades.<ref name=":2">"Wind Turbine Blades Don't Have To End Up In Landfills". The Equation. 30 October 2020. Retrieved 23 January 2022.</ref> Manufacturer Vestas has developed technology that can separate the fibers from the resin, allowing for reuse.<ref>Barsoe, Tim (17 May 2021). "End of wind power waste? Vestas unveils blade recycling technology". Reuters. Retrieved 23 January 2022.</ref> In Germany, wind turbine blades are commercially recycled as part of an alternative fuel mix for a cement factory.<ref name=":2"/> In the United Kingdom, a project will trial cutting blades into strips for use as rebar in concrete, with the aim of reducing emissions in the construction of High Speed 2.<ref>"New HS2 pilot project swaps steel for retired wind turbine blades to reinforce concrete". High Speed 2. Retrieved 12 March 2021.</ref> Used wind turbine blades have been recycled by incorporating them as part of the support structures within pedestrian bridges in Poland<ref>Mason, Hannah (21 October 2021). "Anmet installs first recycled wind turbine blade-based pedestrian bridge". CompositesWorld.</ref> and Ireland.<ref>Stone, Maddie (11 February 2022). "Engineers are building bridges with recycled wind turbine blades". The Verge.</ref>

Comparison with other power sources

Advantages

Wind turbines is one of the lowest-cost sources of renewable energy along with solar panels.<ref>"Renewable Power Remains Cost-Competitive amid Fossil Fuel Crisis". www.irena.org. 13 July 2022. Retrieved 19 May 2023.</ref> As technology needed for wind turbines continued to improve, the prices decreased as well. In addition, there is currently no competitive market for wind energy (though there may be in the future), because wind is a freely available natural resource, most of which is untapped.<ref name=":0">"Advantages and Disadvantages of Wind Energy – Clean Energy Ideas". Clean Energy Ideas. 19 June 2013. Retrieved 10 May 2017.</ref> The main cost of small wind turbines is the purchase and installation process, which averages between $48,000 and $65,000 per installation. Usually, the total amount of energy harvested amount to more than the cost of the turbines.<ref>"WINDExchange: Economics and Incentives for Wind". windexchange.energy.gov. Retrieved 19 May 2023.</ref>

Wind turbines provide a clean energy source,<ref name="rue21" /> use little water,<ref name=evans2009/> emitting no greenhouse gases and no waste products during operation. Over 1,400 tonnes (1,500 short tons) of carbon dioxide per year can be eliminated by using a one-megawatt turbine instead of one megawatt of energy from a fossil fuel.<ref name=":1">"About Wind Energy: Factsheets and Statistics". www.pawindenergynow.org. Retrieved 10 May 2017.</ref>

Disadvantages

Wind turbines can be very large, reaching over 140 m (460 ft) tall and with blades 55 m (180 ft) long,<ref>"Turbine Size". Fraunhofer Wind Monitor. Archived from the original on 5 October 2017. Retrieved 14 October 2017.</ref> and people have often complained about their visual impact.

Environmental impact of wind power includes effect on wildlife, but can be mitigated if proper strategies are implemented.<ref>Parisé, J.; Walker, T. R. (2017). "Industrial wind turbine post-construction bird and bat monitoring: A policy framework for Canada". Journal of Environmental Management. 201: 252–259. doi:10.1016/j.jenvman.2017.06.052. PMID 28672197.</ref> Thousands of birds, including rare species, have been killed by the blades of wind turbines,<ref>Hosansky, David (1 April 2011). "Wind Power: Is wind energy good for the environment?". CQ Researcher.</ref> though wind turbines contribute relatively insignificantly to anthropogenic avian mortality. Wind farms and nuclear power plants are responsible for between 0.3 and 0.4 bird deaths per gigawatt-hour (GWh) of electricity while fossil fuel power stations are responsible for about 5.2 fatalities per GWh. In comparison, conventional coal fired generators contribute significantly more to bird mortality.<ref>"How Harmful is Renewable Energy to Birds? | Article | EESI". www.eesi.org. Retrieved 2 June 2023.</ref> A study on recorded bird populations in the United States from 2000 to 2020 found the presence of wind turbines had no significant effect on bird population numbers.<ref>Katovich, Erik (28 December 2023). "Quantifying the Effects of Energy Infrastructure on Bird Populations and Biodiversity". Environmental Science & Technology. 58 (1): 323–332. doi:10.1021/acs.est.3c03899. PMID 38153963. S2CID 266596763.</ref>

Energy harnessed by wind turbines is variable, and is not a "dispatchable" source of power; its availability is based on whether the wind is blowing, not whether electricity is needed. Turbines can be placed on ridges or bluffs to maximize the access of wind they have, but this also limits the locations where they can be placed.<ref name=":0" /> In this way, wind energy is not a particularly reliable source of energy. However, it can form part of the energy mix, which also includes power from other sources. Technology is also being developed to store excess energy, which can then make up for any deficits in supplies.<ref>"Grid-Scale Storage – Analysis". IEA. Retrieved 2 June 2023.</ref>

Wind turbines have blinking lights that warn aircraft, to avoid collisions.<ref name=Electrek_20230929/> Residents living near windfarms, especially those in rural areas, have complained that the blinking lights are a bothersome form of light pollution.<ref name=Electrek_20230929/> A light mitigation approach involves Aircraft Detection Lighting Systems (ADLSs) by which the lights are turned on, only when the ADLS's radar detects aircraft within thresholds of altitude and distance.<ref name=Electrek_20230929>Lewis, Michelle (29 September 2023). "A new wind farm in Kansas trailblazes with light-mitigating technology". Electrek. Archived from the original on 29 September 2023.</ref>

Records

Éole, the largest vertical axis wind turbine, in Cap-Chat, Quebec, Canada


Record	Model/Name	Location	Constructor/Manufacturer
Largest and most powerful	V236-15<ref>Reiser, Anya (23 January 2023). "World's Most Powerful Wind Turbine Successfully Produces Power". TOMORROW’S WORLD TODAY®. Retrieved 20 May 2023.</ref>	Østerild Wind Turbine Test Field	Vestas
Largest vertical-axis	Éole<ref name="canada_wind2">"Wind Energy Power Plants in Canada – other provinces". 5 June 2010. Archived from the original on 4 September 2012. Retrieved 24 August 2010.</ref>	Cap-Chat, Québec, Canada	NRC, Hydro-Québec
Largest 1-blade turbine	Monopteros M50<ref>"MBB Messerschmitt Monopteros M50 - 640,00 kW - Wind turbine". en.wind-turbine-models.com.</ref>	Jade Wind Park	MBB Messerschmitt
Largest 2-blade turbine	SCD6.5<ref>"Ming Yang completes 6.5MW offshore turbine". www.windpowermonthly.com. 1 July 2013. Retrieved 6 June 2023.</ref>	Longyuan Wind Farm	Mingyang Wind Power
Most rotors	Four-in-One<ref>"When More is More: Multi-Rotor Turbines". www.utmconsultants.com. Retrieved 31 May 2023.</ref>	Maasvlakte	Lagerwey
Highest-situated	2.5<ref>"Highest altitude wind generator". Guinness World Records. 19 June 2013. Retrieved 6 June 2023.</ref>	Pastoruri Glaicer	WindAid
Largest offshore	Haliade-X<ref name=":5" />	Netherlands	GE Wind Energy

References

<references group="" responsive="0"><ref name="rue21">Rueter, Gero (27 December 2021). "How sustainable is wind power?". Deutsche Welle. Retrieved 28 December 2021. An onshore wind turbine that is newly built today produces around nine grams of CO2 for every kilowatt hour (kWh) it generates ... a new offshore plant in the sea emits seven grams of CO2 per kWh ... solar power plants emit 33 grams CO2 for every kWh generated ... natural gas produces 442 grams CO2 per kWh, power from hard coal 864 grams, and power from lignite, or brown coal, 1034 grams ... nuclear energy accounts for about 117 grams of CO2 per kWh, considering the emissions caused by uranium mining and the construction and operation of nuclear reactors.</ref></references>

External links

Media related to Lua error in Module:Commons_link at line 63: attempt to index field 'wikibase' (a nil value). at Wikimedia Commons
Global Wind Energy Council
World's Largest Wind Turbine
Harvesting the Wind (45 lectures about wind turbines by professor Magdi Ragheb

Lua error in Module:Authority_control at line 181: attempt to index field 'wikibase' (a nil value).

v t e Wind power
Wind power	High-altitude History By country Land vehicles Offshore Turbines on public display Windmill Panemone
Wind farms	Community-owned Farms by country Offshore farms by country Onshore farms
Wind turbines	Aerodynamics Airborne Crosswind kite Design Floating Nacelle Pitch bearing QBlade Small Unconventional Vertical-axis Savonius Darrieus Yaw system Yaw bearing Yaw drive
Wind power industry	Consulting companies Manufacturers Software
Manufacturers	Enercon GE Wind Energy including GE Offshore Wind Goldwind Nordex Senvion Siemens Gamesa Suzlon Vestas
Concepts	2020s in wind power research Betz's law Blade element momentum theory Capacity factor Energy return on investment Wind power forecasting Grid energy storage HVDC Intermittency Variability Laddermill Net energy gain Resource assessment Storage Subsidies Tip-speed ratio Virtual power plant Wind hybrid power systems Wind profile power law
Lua error in mw.title.lua at line 318: bad argument #2 to 'title.new' (unrecognized namespace name 'Portal'). Category Commons Additional portals: Renewable energy Energy

Anonymous

Search