Editing Windmill (section)

=== Wind turbines ===
{{main|Wind power|High-altitude wind power}}

[[File:西甸子梁风车 2.jpg|thumb|upright|A group of wind turbines in [[Zhangjiakou]], [[Hebei]], China]]

[[File:Huikku Hailuoto 20160803.jpg|thumb|upright|A wind turbine in Huikku, [[Hailuoto]], Finland]]

A [[wind turbine]] is a windmill-like structure specifically developed to generate electricity. They can be seen as the next step in the development of the windmill. The first wind turbines were built by the end of the nineteenth century by [[Prof James Blyth|James Blyth]] in [[Scotland]] (1887),<ref name="Shackleton">{{cite web|url=http://www.rgu.ac.uk/pressrel/BlythProject.doc|title=World First for Scotland Gives Engineering Student a History Lesson|last=Shackleton|first=Jonathan|publisher=The Robert Gordon University|access-date=20 November 2008|url-status=dead|archive-url=https://web.archive.org/web/20081217063550/http://www.rgu.ac.uk/pressrel/BlythProject.doc|archive-date=17 December 2008}}</ref> [[Charles F. Brush]] in [[Cleveland, Ohio]] (1887–1888)<ref>[Anon, 1890, 'Mr. Brush's Windmill Dynamo', Scientific American, vol 63 no. 25, 20 Dec, p. 54]</ref><ref>''History of Wind Energy'' in Cutler J. Cleveland,(ed) ''Encyclopedia of Energy Vol.6'', Elsevier, {{ISBN|978-1-60119-433-6}}, 2007, pp. 421–422</ref> and [[Poul la Cour]] in Denmark (1890s). La Cour's mill from 1896 later became the local power of the village of Askov. By 1908, there were 72 wind-driven electric generators in Denmark, ranging from 5 to 25&nbsp;kW. By the 1930s, windmills were widely used to generate electricity on farms in the United States where distribution systems had not yet been installed, built by companies such as [[Jacobs Wind]], Wincharger, Miller Airlite, Universal Aeroelectric, Paris-Dunn, Airline, and Winpower. The Dunlite Corporation produced turbines for similar locations in Australia.{{citation needed|date = February 2016}}

Forerunners of modern horizontal-axis utility-scale wind generators were the WIME-3D in service in [[Balaklava]], [[USSR]], from 1931 until 1942, a 100&nbsp;kW generator on a {{Convert|30|m|ft|adj=on}} tower,<ref>Erich Hau, ''Wind turbines: fundamentals, technologies, application, economics'', Birkhäuser, 2006 {{ISBN|3-540-24240-6}}, page 32, with a photo</ref> the [[Smith–Putnam wind turbine]] built in 1941 on the mountain known as Grandpa's Knob in [[Castleton, Vermont]], United States, of 1.25 MW,<ref name=NP>[http://www.noblepower.com/our-windparks/GrandpasKnob/documents/07.09.12-NEP-GPKHistoryHandout-G.pdf The Return of Windpower to Grandpa's Knob and Rutland County] {{webarchive|url=https://web.archive.org/web/20080828170455/http://www.noblepower.com/our-windparks/GrandpasKnob/documents/07.09.12-NEP-GPKHistoryHandout-G.pdf |date=28 August 2008 }}, Noble Environmental Power, LLC, 12 November 2007. Retrieved from Noblepower.com website 10 January 2010. Comment: this is the real name [http://www.mountainzone.com/mountains/detail.asp?fid=3618456 for the mountain] the turbine was built, in case you wondered.</ref> and the [[NASA wind turbines]] developed from 1974 through the mid-1980s. The development of these 13 experimental wind turbines pioneered many of the [[wind turbine design]] technologies in use today, including steel tube towers, variable-speed generators, composite blade materials, and partial-span pitch control, as well as aerodynamic, structural, and acoustic engineering design capabilities.  The modern [[wind power industry]] began in 1979 with the serial production of wind turbines by Danish manufacturers Kuriant, [[Vestas]], [[NEG Micon|Nordtank]], and [[Siemens|Bonus]]. These early turbines were small by today's standards, with capacities of 20–30&nbsp;kW each. Since then, commercial turbines have increased greatly in size, with the [[Enercon E-126]] capable of delivering up to 7 MW, while wind turbine production has expanded to many countries.{{citation needed|date = February 2016}}

As the 21st century began, rising concerns over [[energy security]], [[global warming]], and eventual [[peak oil|fossil fuel depletion]] led to an expansion of interest in all available forms of [[renewable energy]]. Worldwide, many thousands of wind turbines are now operating, with a total [[nameplate capacity]] of 591&nbsp;GW as of 2018.<ref>{{cite web | url=https://gwec.net/51-3-gw-of-global-wind-capacity-installed-in-2018/ | title=Global Installed Capacity in 2018 | publisher=GWEC | access-date=22 March 2019 | archive-date=27 July 2019 | archive-url=https://web.archive.org/web/20190727145745/https://gwec.net/51-3-gw-of-global-wind-capacity-installed-in-2018/ | url-status=dead }}</ref>

==== Materials ====
{{Main|Wind turbine design}}

In an attempt to make wind turbines more efficient and increase their energy output, they are being built bigger, with taller towers and longer blades, and being increasingly deployed in offshore locations.<ref>Ng C., Ran L. "Offshore Wind Farms: Technologies, Design and Operation" Woodhead Publishing (2016)</ref><ref>Paul Breeze, Chapter 11 - Wind Power,"Power Generation Technologies (Second Edition)", Newnes,2014, Pages 223-242,{{ISBN|9780080983301}}, https://doi.org/10.1016B978-0-08-098330-1.00011-9.</ref> While such changes increase their power output, they subject the components of the windmills to stronger forces and consequently put them at a greater risk of failure. Taller towers and longer blades suffer from higher fatigue, and offshore windfarms are subject to greater forces due to higher wind speeds and accelerated corrosion due to the proximity to seawater.
To ensure a long enough lifetime to make the return on the investment viable, the materials for the components must be chosen appropriately.

The blade of a wind turbine consists of 4 main elements: the root, spar, aerodynamic fairing, and surfacing. The fairing is composed of two shells (one on the pressure side, and one on the suction side), connected by one or more webs linking the upper and lower shells. The webs connect to the spar laminates, which are enclosed within the skins (surfacing) of the blade, and together, the system of the webs and spars resist the flapwise loading. Flapwise loading, one of the two different types of loading that blades are subject to, is caused by the wind pressure, and edgewise loading (the second type of loading) is caused by the gravitational force and torque load. The former loading subjects the spar laminate on the pressure (upwind) side of the blade to cyclic tension-tension loading, while the suction (downwind) side of the blade is subject to cyclic compression-compression loading. Edgewise bending subjects the leading edge to a tensile load, and the trailing edge to a compressive load. The remainder of the shell, not supported by the spars or laminated at the leading and trailing edges, is designed as a sandwiched structure, consisting of multiple layers to prevent elastic buckling.<ref>Mishnaevsky, Leon et al. “Materials for Wind Turbine Blades: An Overview.” Materials vol. 10,11 1285. 9 November 2017, doi:10.3390/ma10111285</ref>

In addition to meeting the stiffness, strength, and toughness requirements determined by the loading, the blade needs to be lightweight, and the weight of the blade scales with the cube of its radius. To determine which materials fit the criteria described above, a parameter known as the beam merit index is defined: Mb = E^1/2 / rho,<ref>H. R. Shercliff, M. F. Ashby,"Elastic Structures in Design", Reference Module in Materials Science and Materials Engineering, Elsevier,2016,{{ISBN|9780128035818}},
https://doi.org/10.1016/B978-0-12-803581-8.02944-1.</ref> where E is [[Young's modulus]] and rho is the density. The best blade materials are [[carbon fiber]] and [[glass fiber]] reinforced [[polymer]]s ([[Cfrp|CFRP]] and [[GFRP]]). Currently, GFRP materials are chosen for their lower cost, despite the much greater figure of merit of CFRP.<ref>Ennis, Kelley, et al. "Optimized Carbon Fiber Composites in Wind Turbine Blade Design" US Department of Energy (2019), https://www.energy.gov/eere/wind/downloads/optimized-carbon-fiber-composites-wind-turbine-blade-design</ref>

==== Recycling and waste problems with polymers blades ====
When the [[Vindeby Offshore Wind Farm]] was taken down in [[Denmark]] in 2017, 99% of the not-[[Biodegradable waste|degradable]] [[fiberglass]] from 33 wind turbine blades ended as cut up at the Rærup Controlled [[Landfill]] near [[Aalborg]] and in 2020, with considerably larger fiberglass quantities, even though it is the least [[Natural environment|environmentally]] friendly way of [[Waste management|handling]] [[waste]].{{Citation needed|date=January 2023}} Scrapped wind turbine blades are set to become a huge waste problem in Denmark and countries Denmark, to a greater and greater extent, [[export]] its many produced wind turbines.<ref name=":2" /><ref>{{Cite web |title=Tal og viden om eksport {{!}} Wind Denmark |url=https://winddenmark.dk/styrk-din-eksport-med-wind-denmark-danish-export-association/tal-viden-om-eksport |access-date=2022-09-15 |website=winddenmark.dk |language=da |archive-date=2022-09-15 |archive-url=https://web.archive.org/web/20220915122637/https://winddenmark.dk/styrk-din-eksport-med-wind-denmark-danish-export-association/tal-viden-om-eksport |url-status=dead }}</ref><ref>{{Cite web |title=Arbejdspladser og eksport {{!}} Wind Denmark |url=https://winddenmark.dk/tal-fakta/arbejdspladser-eksport |access-date=2022-09-15 |website=winddenmark.dk |language=da |archive-date=2022-09-15 |archive-url=https://web.archive.org/web/20220915122632/https://winddenmark.dk/tal-fakta/arbejdspladser-eksport |url-status=dead }}</ref>

"The reason why many wings end up in landfill is that they are incredibly difficult to separate from each other, which you will have to do if you hope to be able to [[Recycling|recycle]] the fiberglass", says Lykke Margot Ricard, [[Associate professor|Associate Professor]] in Innovation and Technological Foresight and education leader for civil engineering in Product Development and Innovation at the [[University of Southern Denmark]] (SDU). According to Dakofa, the Danish Competence Center for Waste and Resources, there is nothing specific in the Danish waste order about how to handle discarded fiberglass.<ref name=":2">{{Cite web |title=Verdens første havmøllepark er deponeret på en losseplads i Aalborg |url=https://plast.dk/plast-i-medierne/verdens-foerste-havmoellepark-er-deponeret-paa-en-losseplads-i-aalborg/ |access-date=2022-09-12 |website=plast.dk |date=25 October 2021 |language=da-DK |archive-date=2022-09-12 |archive-url=https://web.archive.org/web/20220912115816/https://plast.dk/plast-i-medierne/verdens-foerste-havmoellepark-er-deponeret-paa-en-losseplads-i-aalborg/ |url-status=dead }}</ref><ref>{{Cite web |last1=Olifent |first1=Af Louise |last2=Fredsted |first2=Rasmus |last3=Møgelbjerg 5 |first3=Sebastian Himmelstrup og Thomas |date=2020-04-17 |title=Glasfiber fra Vindeby Havmøllepark endte på losseplads i Aalborg |url=https://ing.dk/artikel/naceller-vindeby-endte-pa-losseplads-234245 |access-date=2022-09-12 |website=Ingeniøren |language=da}}</ref>

Several [[scrap dealer]]s tell [[Ingeniøren]] that they have handled wind turbine blades (wings) that have been [[Powder|pulverized]] after being taken to a recycling station.<ref name=":1">{{Cite web |last=Tiirikainen |first=Morten |title=Politikere kræver handling: Rester fra vindmøller dumpes i jorden |url=https://www.tv2east.dk/sjaelland-og-oeerne/politikere-kraever-handling-rester-fra-vindmoeller-dumpes-i-jorden |access-date=2022-09-15 |website=TV2 ØST |date=19 October 2020 |language=da}}</ref> One of them is the [[recycling company]] H.J. Hansen, where the [[product manager]] informed, that they have [[transport]]ed approximately half of the wings they have received since 2012 to Reno Nord's landfill in Aalborg. A total of around 1,000 wings have ended up there, he estimates - and today up to 99 percent of the wings the company receives end up in a landfill.<ref name=":0">{{Cite news |title=Vindmøllevinger ender i deponi |work=Energy Supply DK |url=https://www.energy-supply.dk/article/view/714000/vindmollevinger_ender_i_deponi |access-date=2022-09-12}}</ref>

Since 1996, according to an estimate made by Lykke Margot Ricard ([[University of Southern Denmark|SDU]]) in 2020, at least 8,810 [[tonne]]s of the wing [[scrap]] have been disposed of in Denmark, and the waste problem will grow significantly in the coming years when more and more wind turbines have reached their end of life. According to the SDU lecturer's calculations, the waste sector in Denmark will have to receive 46,400 tonnes of fiberglass from wind turbine blades over the next 20–25 years.<ref name=":0" />

As so, at the [[island]], [[Lolland]], in Denmark, 250 tonnes of fiberglass from wind turbine waste also pours up on a landfill at Gerringe in the middle of Lolland in 2020.<ref name=":1" /><ref>{{Cite web |last=Østergaard |first=Kasper Larsen Jens |title=Bagsiden af den grønne strøm - vindmøllerester graves ned i jorden |url=https://www.tv2east.dk/sjaelland-og-oeerne/bagsiden-af-den-groenne-stroem-vindmoellerester-graves-ned-i-jorden |access-date=2022-09-15 |website=TV2 ØST |date=19 October 2020 |language=da}}</ref>

In the [[United States]], worn-out wind turbine blades made of fiberglass go to the handful of landfills that accept them (e.g., in [[Lake Mills, Iowa|Lake Mills]], Iowa; [[Sioux Falls, South Dakota|Sioux Falls]], South Dakota; [[Casper, Wyoming|Casper]]).<ref>{{Cite news |last=Chris |first=Martin |date=2020 |title=Wind Turbine Blades Can't Be Recycled, So They're Piling Up in Landfills |work=Bloomberg |url=https://www.bloomberg.com/news/features/2020-02-05/wind-turbine-blades-can-t-be-recycled-so-they-re-piling-up-in-landfills}}</ref>