Misplaced Pages

Wind turbine: Difference between revisions

Article snapshot taken from Wikipedia with creative commons attribution-sharealike license. Give it a read and then ask your questions in the chat. We can research this topic together.
Browse history interactively← Previous editNext edit →Content deleted Content addedVisualWikitext
Revision as of 09:27, 28 January 2011 view sourceClueBot NG (talk | contribs)Bots, Pending changes reviewers, Rollbackers6,439,128 editsm Reverting possible vandalism by JoeBaldwinTheGreat to version by Zonk43. False positive? Report it. Thanks, ClueBot NG. (234048) (Bot)← Previous edit Revision as of 09:28, 28 January 2011 view source JoeBaldwinTheGreat (talk | contribs)2 edits ←Replaced content with 'lol'Next edit →
Line 1: Line 1:
lol
] off ]]]
:''This article discusses wind-powered electrical generators. See ] for wind-powered machinery used to grind grain or pump water.''

A '''wind turbine''' is a device that converts ] from the wind into ]. If the mechanical energy is used to produce electricity, the device may be called a '''wind generator''' or '''wind charger'''. If the mechanical energy is used to drive machinery, such as for grinding grain or pumping water, the device is called a ] or ].

== History ==
{{Main|History of wind power}}
]
Windmills were used in Persia (present-day Iran) as early as 200 B.C.<ref>
{{cite web
|url=http://www.telosnet.com/wind/early.html
|title=Part 1&nbsp;— Early History Through 1875
|accessdate=2008-07-31}}
</ref> The windwheel of ] marks one of the first known instances of wind powering a machine in history.<ref name="Drachmann">A.G. Drachmann, "Heron's Windmill", ''Centaurus'', 7 (1961), pp. 145–151</ref><ref name="Lohrmann 10f.">Dietrich Lohrmann, "Von der östlichen zur westlichen Windmühle", ''Archiv für Kulturgeschichte'', Vol. 77, Issue 1 (1995), pp. 1–30 (10f.)</ref> However, the first practical windmills were built in ], a region between Afghanistan and Iran, from the 7th century. These "]" were vertical axle windmills, which had long vertical ]s with rectangular blades.<ref>], ] (1986). ''Islamic Technology: An illustrated history'', p. 54. ]. ISBN 0-521-42239-6.</ref> Made of six to twelve ]s covered in reed matting or cloth material, these windmills were used to grind ] or draw up water, and were used in the ]ing and sugarcane industries.<ref>], "Mechanical Engineering in the Medieval Near East", ''Scientific American'', May 1991, p. 64-69. (] ], )</ref>

Windmills first appeared in Europe during the ] The first historical records for their use in England date to the 11th or 12th centuries and there are reports of German ] taking their windmill-making skills to Syria around 1190. <ref name="Morthorst">{{cite book |author=Morthorst, Poul Erik; Redlinger, Robert Y.; Andersen, Per |title=Wind energy in the 21st century: economics, policy, technology and the changing electricity industry |publisher=Palgrave/UNEP |location=Houndmills, Basingstoke, Hampshire |year=2002 |pages= |isbn=0-333-79248-3 |oclc= |doi= |accessdate=18 December 2010}}</ref> By the 14th century, Dutch windmills were in use to drain areas of the ] delta.

]

The first electricity generating wind turbine, was a battery charging machine installed in July 1887 by Scottish academic, ] to light his holiday home in ], Scotland.<ref name="ODNB">{{cite web|url=http://www.oxforddnb.com/public/dnb/100957.html|title=James Blyth|work=Oxford Dictionary of National Biography|publisher=Oxford University Press|accessdate=2009-10-09}}</ref> Some months later American inventor ] built the first automatically operated wind turbine for electricity production in ].<ref name="ODNB"/> 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 MW. The largest machines were on {{convert|24|m|ft|adj=on}} towers with four-bladed {{convert|23|m|ft|adj=on}} diameter rotors. By 1908 there were 72 wind-driven electric generators operating in the US from 5&nbsp;kW to 25&nbsp;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"></ref>
By the 1930s, windmills for electricity were common on farms, mostly in the United States where distribution systems had not yet been installed. In this period, high-tensile steel was cheap, and windmills were placed atop prefabricated open steel lattice towers.

A forerunner of modern horizontal-axis wind generators was in service at ], USSR in 1931. This was a 100&nbsp;kW generator on a {{convert|30|m|ft|adj=on}} tower, connected to the local 6.3 kV distribution system. It was reported to have an annual ] of 32 per cent, not much different from current wind machines.<ref>Alan Wyatt: ''Electric Power: Challenges and Choices''. Book Press Ltd., Toronto 1986, ISBN 0-920650-00-7</ref>
In the fall of 1941, the first megawatt-class wind turbine was synchronized to a utility grid in ]. The ] only ran for 1,100 hours before suffering a critical failure. The unit was not repaired because of shortage of materials during the war.

The first utility grid-connected wind turbine to operate in the U.K. was built by ] in 1951 in the ].<ref name="ODNB"/><ref>{{cite web|url=http://www.orkneywind.co.uk/costa.html|title=Costa Head Experimental Wind Turbine|last=Anon|work=orkney Sustainable Energy Website|publisher=Orkney Sustainable Energy Ltd|accessdate=19 December 2010}}</ref> It had an {{convert|18|m|ft|adj=on}} diameter, three-bladed rotor and a rated output of 100&nbsp;kW.{{Citation needed|date=September 2010}}

== Resources ==
{{Main|Wind power}}
A quantitative measure of the wind energy available at any location is called the ] (WPD) It is a calculation of the mean annual power available per square meter of swept area of a turbine, and is tabulated for different heights above ground. ] includes the effect of wind velocity and air density. Color-coded maps are prepared for a particular area described, for example, as "Mean Annual Power Density at 50 Meters." In the United States, the results of the above calculation are included in an index developed by the ] ] and referred to as "NREL CLASS." The larger the WPD calculation, the higher it is rated by class. Classes range from Class 1 (200 watts/square meter or less at 50 meters altitude) to Class 7 (800 to 2000 watts/square meter). Commercial wind farms generally are sited in Class 3 or higher areas, although isolated points in an otherwise Class 1 area may be practical to exploit.<ref>http://www.nrel.gov/gis/wind.html Dynamic Maps, GIS Data and Tools</ref>

== Types ==
]
Wind turbines can rotate about either a horizontal or a vertical axis, the former being both older and more common.<ref>
{{cite web
|url=http://www.awea.org/faq/wwt_basics.html
|title=Wind Energy Basics
|publisher=American Wind Energy Association
|accessdate=2009-09-24}} {{Dead link|date=November 2010|bot=H3llBot}}</ref>
=== Horizontal axis ===
]
Horizontal-axis wind turbines (HAWT) have the main ] shaft and ] at the top of a tower, and must be pointed into the wind. Small turbines are pointed by a simple ], while large turbines generally use a wind sensor coupled with a ]. 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>http://www.windpower.org/en/tour/wtrb/comp/index.htm Wind turbine components retrieved November 8, 2008</ref>

Since a tower produces ] behind it, the turbine is usually positioned upwind of its supporting tower. Turbine blades are made stiff to prevent the blades from being pushed into the tower by high winds. Additionally, the blades are placed a considerable distance in front of the tower and are sometimes tilted forward into the wind a small amount.

Downwind machines have been built, despite the problem of turbulence (mast wake), because they don't need an additional mechanism for keeping them in line with the wind, and because in high winds the blades can be allowed to bend which reduces their swept area and thus their wind resistance. Since cyclical (that is repetitive) turbulence may lead to ] failures, most HAWTs are of upwind design.
{{wide image|windpark Estinnes 20juli2010 kort voor voltooiing.jpg|800px|11x 7,5 MW E126 Estinnes windfarm Belgium July 2010, one month before completion, see unique 2 part blades}}
; Modern wind turbines
] in the ]]]

Turbines used in ]s for commercial production of electric power are usually three-bladed and pointed into the wind by computer-controlled motors. These have high tip speeds of over {{convert|320|km/h|mph}}, high efficiency, and low torque ripple, which contribute to good reliability. The blades are usually colored light gray to blend in with the clouds and range in length from {{convert|20|to|40|m|ft}} or more. The tubular steel towers range from {{convert|60|to|90|m|ft}} tall. The blades rotate at 10-22 revolutions per minute. At 22 rotations per minute the tip speed exceeds {{convert|300|ft/s|m/s}}.<ref></ref><ref></ref> A gear box is commonly used for stepping up the speed of the generator, although designs may also use direct drive of an annular generator. Some models operate at constant speed, but more energy can be collected by variable-speed turbines which use a solid-state power converter to interface to the transmission system. All turbines are equipped with protective features to avoid damage at high wind speeds, by ] the blades into the wind which ceases their rotation, supplemented by ]s.

=== Vertical axis design ===
{{Unreferenced section|date=September 2009}}

''']s''' (or VAWTs) have the main rotor shaft arranged vertically. Key advantages of this arrangement are that the turbine does not need to be pointed into the wind to be effective. This is an advantage on sites where the wind direction is highly variable, for example when integrated into buildings. The key disadvantages include the low rotational speed with the consequential higher ] and hence higher cost of the drive train, the inherently lower ], 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 to model the wind flow accurately and hence the challenges of analysing and designing the rotor prior to fabricating a prototype.

With a vertical axis, the generator and gearbox can be placed near the ground, hence avoiding the need of a tower and improving accessibilty for maintenance. Drawbacks for this configuration include that wind speeds are lower close to the ground, so less wind energy is available for a given size turbine, and wind shear more severe close to the ground, so the rotor experiences higher loads. Air flow near the ground and other objects can create turbulent flow, which can introduce issues of vibration, including noise and bearing wear which may increase the maintenance or shorten the service life. However, 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 the rooftop mounted turbine tower is approximately 50% of the building height, this is near the optimum for maximum wind energy and minimum wind turbulence. It should be borne in mind that wind speeds within the built environment are generally much lower than at exposed rural sites.

==== Subtypes ====
] of 30&nbsp;m in the ]]]
; ] : "Eggbeater" turbines, or Darrieus turbines, were named after the French inventor, Georges Darrieus.<ref>http://www.symscape.com/blog/vertical_axis_wind_turbine</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 a higher solidity for the rotor. Solidity is measured by blade area divided by the rotor area. Newer Darrieus type turbines are not held up by ]s but have an external superstructure connected to the top bearing.

; ]: 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>http://www.awea.org/faq/vawt.html</ref> The advantages of variable pitch are: high starting torque; a wide, relatively flat torque curve; a lower blade speed ratio; 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.

; ] : 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. They sometimes have long helical scoops to give a smooth torque.

== Turbine design and construction ==
]
{{Main|Wind turbine design}}
Wind turbines are designed to exploit the wind energy that exists at a location. ] is used to determine the optimum tower height, control systems, number of blades and blade shape.

Wind turbines convert wind energy to electricity for distribution. Conventional horizontal axis turbines can be divided into three components.
*The rotor component, which is approximately 20% of the wind turbine cost, includes the blades for converting wind energy to low speed rotational energy.
*The generator component, which is approximately 34% of the wind turbine cost, includes the ], the control electronics, and most likely a ] (e.g. ]<ref></ref>, ] <ref></ref> or ]<ref></ref>) component for converting the low speed incoming rotation to high speed rotation suitable for generating electricity.
*The structural support component, which is approximately 15% of the wind turbine cost, includes the tower and rotor yaw mechanism.<ref>"Wind Turbine Design Cost and Scaling Model," Technical Report NREL/TP-500-40566, December, 2006, page 35,36. http://www.nrel.gov/docs/fy07osti/40566.pdf</ref>

A 1.5 MW wind turbine of a type frequently seen in the United States has a tower 80 meters high. The rotor assembly (blades and hub) weighs {{convert|48,000|lbs}}. The nacelle, which contains the generator component, weighs {{convert|115,000|lbs}}. The concrete base for the tower is constructed using {{convert|58,000|lbs}} of reinforcing steel and contains 250 cubic yards of concrete. The base is {{convert|50|ft}} in diameter and {{convert|8|ft}} thick near the center.<ref></ref>

== Unconventional wind turbines ==
{{Main|Unconventional wind turbines}}

One E-66 wind turbine at ], Germany, carries an observation deck, open for visitors. Another turbine of the same type, with an observation deck, is located in ], England. ]s have been investigated many times but have yet to produce significant energy. Conceptually, wind turbines may also be used in conjunction with a large vertical ] to extract the energy due to air heated by the sun.

Wind turbines which utilise the ] have been developed.

== Small wind turbines ==
]]]
{{Main|Small wind turbine}}
Small wind turbines may be as small as a fifty-watt generator for boat or caravan use. Small units often have direct drive generators, ] output, aeroelastic blades, lifetime bearings and use a vane to point into the wind.

Larger, more costly turbines generally have geared power trains, alternating current output, flaps and are actively pointed into the wind. Direct drive generators and aeroelastic blades for large wind turbines are being researched.

== Record-holding turbines ==
=== Largest capacity ===
The ] has a rated capacity of 7.58&nbsp;MW
<ref>http://www.enercon.de/p/downloads/EN_Produktuebersicht_0710.pdf</ref>
, has an overall height of 198&nbsp;m (650&nbsp;ft), a diameter of 126&nbsp;m (413&nbsp;ft), and is the world's largest-capacity wind turbine since its introduction in 2007.
<ref name="worlds_largest_wind_turbine">{{Cite web
|url=http://www.metaefficient.com/news/new-record-worlds-largest-wind-turbine-7-megawatts.html
|title=New Record: World’s Largest Wind Turbine (7+ Megawatts) — MetaEfficient Reviews
|publisher=MetaEfficient.com
|accessdate=2010-04-17
|date=2008-02-03
}}</ref>

At least four companies are working on the development of a 10MW turbine:
* ]<ref name="eetweb0901">{{cite web
|url=http://eetweb.com/wind/wind-turbines-go-supersized-20091001/
|title=Wind Turbines go Super-Sized
|accessdate=2010-07-26
|date=2009-09-01
|publisher=Energy Efficiency & Technology
}}</ref>
* ] are developing a 10&nbsp;MW VAWT, the Aerogenerator X<ref name="guardian20100726">{{cite news
|url=http://www.guardian.co.uk/environment/2010/jul/26/offshore-turbine-britain
|title=Engineers race to design world's biggest offshore wind turbines
|newspaper=The Guardian
|date=2010-07-26
|accessdate=2010-07-26
|first=John |last=Vidal
}}</ref>
* ] are developing the Britannia 10&nbsp;MW HAWT<ref name="eetweb0901"/><ref name="guardian20100726"/><ref name="reuters0329">
{{cite news
|url=http://www.reuters.com/article/idUSTRE62S2ZP20100329
|title=Offshore wind turbines may be 10 MW giants: Veritas
|newspaper=Reuters
|accessdate=2010-07-26
|date=2010-03-29
}}</ref>
* ] announced the proposed development of a prototype 10&nbsp;MW wind turbine with a height of 162.5&nbsp;m (533&nbsp;ft) and a rotor diameter of 145&nbsp;m (475&nbsp;ft).<ref name="guardian20100726"/><ref name="reuters0329"/><ref>http://www.google.com/hostednews/afp/article/ALeqM5j-BZEK4lR-_hxsz2hQ-92_c0oSHQ Retrieved 2010-02-13</ref>
<!--ref>http://www.norwaypost.no/content/view/23186/48/ Retrieved 2010-02-13{{dead link}}</ref>
<ref>http://www.grist.org/article/2010-02-12-norway-plans-the-worlds-most-powerful-wind-turbine/ Retrieved 2010-02-16 {{dead link}}</ref-->

=== Largest swept area===
The turbine with the largest swept area is a prototype installed by ] at ], ], Spain in 2009. The G10X – 4.5 MW has a rotor diameter of 128m.
<ref>{{cite web
|url=http://www.renewable-energy-sources.com/2009/06/29/gamesa-presents-g10x-4-5-mw-wind-turbine-prototype/
|title=Gamesa Presents G10X-4.5 MW Wind Turbine Prototype
|accessdate=2010-07-26
}}</ref>

=== Tallest ===
The tallest wind turbine is ]. Its axis is 160 meters above ground and its rotor tips can reach a height of 205 meters. It is the only wind turbine taller than 200 meters in the world.<ref name="tallest">{{cite web | url=http://fuhrlaender.de/produkte/index_de.php?produkt_gesucht=1&produkt_name=FL+2500 | title=FL 2500 Noch mehr Wirtschaftlichkeit | language=German |publisher=Fuhrlaender AG | accessdate=2009-11-05 }}</ref>

=== Largest vertical-axis ===
Le Nordais wind farm in ] has a ] (VAWT) named Éole, which is the world's largest at 110 m.<ref name="">{{Cite web
|url=http://www.eolecapchat.com/e_1b-grande.html
|title=Visits > Big wind turbine
|accessdate=2010-04-17
}}</ref> It has a ] of 3.8MW.<ref name="canada_wind">{{Cite web
|url=http://www.industcards.com/wind-canada.htm
|title=Wind Energy Power Plants in Canada - other provinces
|accessdate=2010-08-24
|date=2010-06-05
}}</ref>

=== Most southerly ===
The turbines currently operating closest to the ] are three ''Enercon E-33'' in ], powering New Zealand's ] and the United States' ] since December 2009<ref></ref><ref></ref> although a modified HR3 turbine from Northern Power Systems operated at the ] in 1997 and 1998.<ref>Bill Spindler, .</ref> In March 2010 ] designed, built and installed a wind turbine in Argentine ].<ref></ref>

=== Most productive ===
Four turbines at Rønland ] in Denmark share the record for the most productive wind turbines, with each having generated 63.2&nbsp;GWh by June 2010<ref>{{cite web
|url=http://www.energynumbers.info/surpassing-matilda-record-breaking-danish-wind-turbines
|accessdate=2010-07-26
|title=Surpassing Matilda: record-breaking Danish wind turbines
}}</ref>

=== Highest-situated ===
The world's highest-situated wind turbine is made by ] and located in the Andes, Argentina around {{convert|4100|m}} above sea level. The site uses a type D8.2&nbsp;- 2000&nbsp;kW&nbsp;/ 50&nbsp;Hz turbine. This turbine has a new drive train concept with a special torque converter (WinDrive) made by ] and a synchronous generator. The WKA was put into operation in December 2007 and has supplied the Veladero mine of ] with electricity since then.<ref>http://www.voithturbo.com/vt_en_pua_windrive_project-report_2008.htm</ref>

=== Gallery of record-holders ===
<gallery caption="" widths="150px" heights="150px" perrow="6">
Image:E 126 Georgsfeld.JPG|Enercon E-126, highest rated capacity
Image:Windkraftanlage Laasow.jpg|Fuhrländer Wind Turbine Laasow, world's tallest
File:Quebecturbine.JPG|Éole, the largest ], in ]
File:Veladero 01.png|Highest-situated wind turbine, at the Veladero mine in ], ]
File:Rønland Windpark.jpg|Rønland, most productive turbines, in ]
</gallery>

== See also ==
{{portal box|Renewable energy|Sustainable development}}

{{div col|cols=2}}
* ]
* ]
* ]
* ]
* ]
* ]
* ]
* ]
* ]
* ]
* ]
* ]
* ]
* ]
* ]
* ]
* ]
* ]
* ]
* ]
* ]
* ]
* ]
* ]
{{div col end}}

== References ==

{{Reflist|2}}

== Further reading ==

* Tony Burton, David Sharpe, Nick Jenkins, Ervin Bossanyi: ''Wind Energy Handbook'', John Wiley & Sons, 1st edition (2001), ISBN 0-471-48997-2
* Darrell, Dodge, , TeloNet Web Development, Copyright 1996–2001
* David, Macaulay, New Way Things Work, Houghton Mifflin Company, Boston, Copyright 1994–1999, pg.41-42
* Erich Hau ''Wind turbines: fundamentals, technologies, application, economics '' Birkhäuser, 2006 ISBN 3540242406 (preview on Google Books)
* David Spera (ed,) Wind Turbine Technology: Fundamental Concepts in Wind Turbine Engineering, Second Edition (2009), ASME Press, ISBN #: 9780791802601

==External links==
<!-- === ({{NoMoreLinks}}) === -->

{{Commons|Wind turbine}}
*
*
*
*
*
*
*
* Movie and information on wind turbine engineering
*


{{Wind power}}

{{DEFAULTSORT:Wind Turbine}}

]
]
]
]
]
]

{{Link FA|de}}

]
]
]
]
]
]
]
]
]
]
]
]
]
]
]
]
]
]
]
]
]
]
]
]
]
]
]
]
]
]
]
]
]
]
]
]
]
]
]
]
]
]

Revision as of 09:28, 28 January 2011

lol