Airborne wind generator of Savonius style

An airborne wind turbine is a design concept for a wind turbine that is supported in the air without a tower.^[1] Airborne wind turbines may operate in low or high altitudes; they are part of a wider class of airborne wind energy systems (AWE) addressed by high-altitude wind power. When the generator is on the ground,^[2] then the tethered aircraft need not carry the generator mass or have a conductive tether. When the generator is aloft, then a conductive tether would be used to transmit energy to the ground or used aloft or beamed to receivers using microwave or laser. Airborne turbine systems would have the advantage of tapping an almost constant wind, without requirements for slip rings or yaw mechanism, and without the expense of tower construction. Kites and 'helicopters' come down when there is insufficient wind; kytoons and blimps resolve the matter. Also, bad weather such as lightning or thunderstorms, could temporarily suspend use of the machines, probably requiring them to be brought back down to the ground and covered. Some schemes require a long power cable and, if the turbine is high enough, an aircraft exclusion zone. As of 2011, no commercial airborne wind turbines are in regular operation.^[3]

Aerodynamic variety[link]

An aerodynamic airborne wind power system relies on the wind for support.

Bryan Roberts, a professor of engineering at the University of Technology, in Sydney, Australia, has proposed a helicopter-like craft which flies to 15,000 feet (4,600 m) altitude and stays there, held aloft by wings that generate lift from the wind, and held in place by a cable to a ground anchor. According to its designers, while some of the energy in the wind would be 'lost' on lift, the constant and potent winds would allow it to generate constant electricity. Since the winds usually blow horizontally, the turbines would be at an angle from the horizontal, catching winds while still generating lift. Deployment could be done by feeding electricity to the turbines, which would turn them into electric motors, lifting the structure into the sky.

The Dutch ex-astronaut and physicist Wubbo Ockels, working with the Delft University of Technology in the Netherlands, has designed and demonstrated ^[4] an airborne wind turbine he calls a "Laddermill". It consists of an endless loop of kites. The kites lift one end of the endless loop, (the "ladder") up, and the released energy is used to drive an electric generator.

A Sept'09 paper^[5] from Carbon Tracking Ltd., Ireland has shown the capacity factor of a kite using ground-based generation to be 52.2%, which compares favorably with terrestrial wind-farm capacity factors of 30%.

A team from Worcester Polytechnic Institute in the United States has developed a smaller-scale ^[6] with an estimated output of about 1 kW. It uses a kiteboarding kite to induce a rocking motion in a pivoting beam.

The Kitegen uses a prototype vertical-axis wind turbine. It is an innovative plan (still in the construction phase) that consists of one wind farm with a vertical spin axis, and employs kites to exploit high-altitude winds. The Kite Wind Generator (KWG) or Kitegen is claimed to eliminate all the static and dynamic problems that prevent the increase of the power (in terms of dimensions) obtainable from the traditional horizontal-axis wind turbine generators. Generating equipment would remain on the ground, and only the airfoils are supported by the wind. Such a wind power plant would be capable of producing the energy equivalent to a nuclear plant, while using an area of few square kilometres, without occupying it exclusively. (The majority of this area can still be used for agriculture, or navigation in the case of an offshore installation.)

Dave Santos, of KiteLab in Ilwaco, Washington, has been advancing single-surface wingmills to generate useful electricity with a ground-based generator.^[7]

The Rotokite ^[8] is developed from Gianni Vergnano's idea. It uses aerodynamic profiles similar to kites that have been rotated on their own axis, emulating the performance of a propeller. The use of the rotation principle simplifies the problem of checking the flight of the kites and eliminates the difficulties due to the lengths of cables, enabling the production of wind energy at low cost. The Heli Wind Power is a project of Gianni Vergnano that uses a tethered kite.

In August 2011 the German company SkySails, producer of kites for ship propulsion, announced a kite-based wind power system for on- and offshore applications that is supposed to be "30% cheaper than current offshore solutions".^[9]

Aerostat variety[link]

An aerostat-type wind power system relies at least in part on buoyancy to support the wind-collecting elements. Aerostats vary in their designs and resulting lift-over-drag aerodynamic characteristic; the kiting effect of higher lift-over-drag shapes for the aerostat can effectively keep an airborne turbine aloft; a variety of such kiting balloons were made famous in the kytoon by Domina C. Jalbert.

Balloons can be added to the mix to keep systems up without wind, but balloons leak slowly and have to be resupplied with lifting gas, possibly patched as well. Very large, sun heated balloons may solve the helium or hydrogen leakage problems.

An Ontario based company called Magenn ^[10] is developing a turbine called the Magenn Air Rotor System (MARS). The 1,000-foot (300 m)-wide MARS system uses a horizontal rotor in a helium suspended apparatus which is tethered to a transformer on the ground. Magenn claims that their technology provides high torque, low starting speeds, and superior overall efficiency thanks to its ability to deploy higher in comparison to non-aerial solutions.^[11] The first prototypes were built by TCOM in April 2008.No production units have been delivered. ^[12]

Concept drawing of the Twind technology.

The Twind Technology concept uses a pair of captive balloons at an altitude of 800 meters. The tether cables transmit force to a rotating platform on the ground. Each balloon has a sail connected to it. The two balloons move alternately, the balloon with the sail open moves downwind and draws the other balloon upwind, and then the motion reverses. The tether cable can be used to turn the shaft of a generator to produce electrical energy or perform other works (grinding, sawing, pumping).

Estimated costs[link]

Sky Windpower estimates that its technology will be capable of producing electricity for $0.02 per KWh, while a system of raising a kite to a high altitude while turning a generator on the ground, and then changing its shape so that it can be drawn back down with less energy than it produced on the way up, has been estimated to be capable of producing electricity for $0.01 per KWh^[13] - both numbers being significantly lower than the current price of non-subsidized electricity.

See also[link]

	Sustainable development portal
	Energy portal

• Kite
• Kite mooring
• Kite types
• Kite applications

References[link]

External links[link]

• Airborne Wind Energy Association
• Ampyx Power
• Joby Energy
• Xercesblue: a summing up of the projects and the problems concerning the upper level generation
• Wired Magazine
• Kite Generator home page
• WPI Kite Power Team
• Sky Windpower
• Makani Power
• SkyMill Energy with autogyro reel-in-out system
• TWIND Technology
• Wind Power: High hopes Nature Article
• Electricity-Generating Kite Systems EGKS
• Included in Time´s 2008 Best Inventions
• Magenn Power Inc. - air rotor products
• High-altitude winds: The greatest source of concentrated energy on Earth (Stanford Report, June 2009)
• SEQUOIA IT s.r.l. Rotokite
• German Airborne Wind Turbine
• Airborne wind turbines

v t e Wind power Wind power Environmental effects History Vehicles Offshore wind power Wind turbine Windmill Kitegen Wind power by country Asia Australia Austria Belgium Canada China Croatia Denmark Estonia European Union Finland France Germany Greece Hungary India Iran Ireland Italy Japan Malta Netherlands New Zealand Pakistan Portugal Romania Russia Scotland Serbia Spain Sweden Turkey UK US Wind turbines Aerodynamics Airborne Darrieus Design Floating Savonius Quietrevolution Small Unconventional Vertical axis Devices in use Wind power industry Consultants Manufacturers Software Wind farm management Wind farms Community-owned List of offshore wind farms List of onshore wind farms Concepts Betz' law Capacity factor EROEI Grid energy storage HVDC Intermittency Net energy gain Storage Subsidies Wind power forecasting Wind profile power law Wind resource assessment

Offshore wind farm using 5MW turbines REpower 5M in the North Sea off Belgium

A wind turbine is a device that converts kinetic energy from the wind, also called wind energy, into mechanical energy; a process known as wind power. If the mechanical energy is used to produce electricity, the device may be called wind turbine or wind power plant. If the mechanical energy is used to drive machinery, such as for grinding grain or pumping water, the device is called a windmill or wind pump. Similarly, it may be called wind charger when it is used to charge batteries.

The result of over a millennium of windmill development and modern engineering, today's wind turbines are manufactured in a wide range of vertical and horizontal axis types. The smallest turbines are used for applications such as battery charging or auxiliary power on boats; while large grid-connected arrays of turbines are becoming an increasingly important source of wind power-produced commercial electricity.

History[link]

James Blyth's electricity generating wind turbine photographed in 1891

Windmills were used in Persia (present-day Iran) as early as 200 B.C.^[1] The windwheel of Heron of Alexandria marks one of the first known instances of wind powering a machine in history.^[2][3] However, the first known practical windmills were built in Sistan, a region between Afghanistan and Iran, from the 7th century. These "Panemone" were vertical axle windmills, which had long vertical driveshafts with rectangular blades.^[4] 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.^[5]

Windmills first appeared in Europe during the middle ages. The first historical records of their use in England date to the 11th or 12th centuries and there are reports of German crusaders taking their windmill-making skills to Syria around 1190.^[6] By the 14th century, Dutch windmills were in use to drain areas of the Rhine delta.

The first electricity generating wind turbine, was a battery charging machine installed in July 1887 by Scottish academic James Blyth to light his holiday home in Marykirk, Scotland.^[7] Some months later American inventor Charles F Brush built the first automatically operated wind turbine for electricity production in Cleveland, Ohio.^[7] Although Blyth's turbine was considered uneconomical in the United Kingdom^[7] electricity generation by wind turbines was more cost effective in countries with widely scattered populations.^[6]

The first automatically operated wind turbine, built in Cleveland in 1887 by Charles F. Brush. It was 60 feet (18 m) tall, weighed 4 tons (3.6 metric tonnes) and powered a 12kW generator.^[8]

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 24-metre (79 ft) towers with four-bladed 23-metre (75 ft) diameter rotors. By 1908 there were 72 wind-driven electric generators operating in the US from 5 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.^[9] By the 1930s, wind generators 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 the generators were placed atop prefabricated open steel lattice towers.

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-metre (98 ft) tower, connected to the local 6.3 kV distribution system. It was reported to have an annual capacity factor of 32 per cent, not much different from current wind machines.^[10] In the fall of 1941, the first megawatt-class wind turbine was synchronized to a utility grid in Vermont. The Smith-Putnam wind turbine 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 UK was built by John Brown & Company in 1951 in the Orkney Islands.^[7][11]

Resources[link]

A quantitative measure of the wind energy available at any location is called the Wind Power Density (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. Calculation of wind power density 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 National Renewable Energy Laboratory 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 per square meter or less at 50 meters altitude) to Class 7 (800 to 2000 watts per 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.^[12]

Efficiency[link]

Theoretical power captured by a wind turbine[link]

Total wind power could be captured only if the wind velocity is reduced to zero. In a realistic wind turbine this is impossible, as the captured air must also leave the turbine. A relation between the input and output wind velocity must be considered. Using the concept of stream tube, the maximal achievable extraction of wind power by a wind turbine is 59% of the total theoretical wind power^[13] (see: Betz' law).

Practical wind turbine power[link]

Further insufficiencies, such as rotor blade friction and drag, gearbox losses, generator and converter losses, reduce the power delivered by a wind turbine. The basic relation that the turbine power is (approximately) proportional to the third power of velocity remains.

Example of a horizontal axis machine Wind Turbine

Types[link]

The three primary types:VAWT Savonius, HAWT towered; VAWT Darrieus as they appear in operation

Wind turbines can rotate about either a horizontal or a vertical axis, the former being both older and more common.^[14]

Horizontal axis[link]

Components of a horizontal axis wind turbine (gearbox, rotor shaft and brake assembly) being lifted into position

A turbine blade convoy passing through Edenfield, UK

Horizontal-axis wind turbines (HAWT) 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 servo motor. 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.^[15]

Since a tower produces turbulence 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 fatigue failures, most HAWTs are of upwind design.

Turbines used in wind farms 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 320 km/h (200 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 20 to 40 metres (66 to 130 ft) or more. The tubular steel towers range from 60 to 90 metres (200 to 300 ft) tall. The blades rotate at 10 to 22 revolutions per minute. At 22 rotations per minute the tip speed exceeds 90 metres per second (300 ft/s).^[16][17] 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 feathering the blades into the wind which ceases their rotation, supplemented by brakes.

Vertical axis design[link]

A vertical axis Twisted Savonius type turbine.

Vertical-axis wind turbines (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 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.^[18]

With a vertical axis, the generator and gearbox can be placed near the ground, using a direct drive from the rotor assembly to the ground-based gearbox, hence improving accessibility for maintenance.

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.^[19][20]

Another type of vertical axis is the Parallel turbine similar to the crossflow fan or centrifugal fan it uses the ground effect. Vertical axis turbines of this type have been tried for many years: a large unit producing up to 10 kW was built by Israeli wind pioneer Bruce Brill in 1980s:^[21] the device is mentioned in Dr. Moshe Dan Hirsch's 1990 report, which decided the Israeli energy department investments and support in the next 20 years.^{[citation needed]} The Magenn WindKite blimp uses this configuration as well, chosen because of the ease of running.^[22]

Subtypes of the vertical axis design include:

Darrieus wind turbine

"Eggbeater" turbines, or Darrieus turbines, were named after the French inventor, Georges Darrieus.^[23] 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. Newer Darrieus type turbines are not held up by guy-wires but have an external superstructure connected to the top bearing.^[24]

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.^[25] 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.^[26]

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.

Twisted Savonius

Twisted Savonius is a modified savonius, with long helical scoops to provide smooth torque. This is often used as a rooftop windturbine and has even been adapted for ships.^[27]

Design and construction[link]

Components of a horizontal-axis wind turbine

Size comparison of a five year old child with an Enercon E-70 wind turbine rotor hub.

Wind turbines are designed to exploit the wind energy that exists at a location. Aerodynamic modelling 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 electrical generator, the control electronics, and most likely a gearbox (e.g. planetary gearbox,^[28] adjustable-speed drive^[29] or continuously variable transmission^[30]) 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.^[31]

A 1.5 MW wind turbine of a type frequently seen in the United States has a tower 80 metres (260 ft) high. The rotor assembly (blades and hub) weighs 48,000 pounds (22,000 kg). The nacelle, which contains the generator component, weighs 115,000 pounds (52,000 kg). The concrete base for the tower is constructed using 58,000 pounds (26,000 kg) of reinforcing steel and contains 250 cubic yards (190 m³) of concrete. The base is 50 ft (15 m) in diameter and 8 ft (2.4 m) thick near the center.^[32]

Unconventional designs[link]

One E-66 wind turbine at Windpark Holtriem, Germany, carries an observation deck, open for visitors. Another turbine of the same type, with an observation deck, is located in Swaffham, England. Airborne wind turbines 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 solar updraft tower to extract the energy due to air heated by the sun.

Wind turbines which utilise the Magnus effect have been developed.^[33]

The ram air turbine is a specialist form of small turbine that is fitted to some aircraft. When deployed, the RAT is spun by the airstream going past the aircraft and can provide power for the most essential systems if there is a loss of all on–board electrical power.^{[citation needed]}

Small wind turbines[link]

A small Quietrevolution QR5 Gorlov type vertical axis wind turbine in Bristol, England. Measuring 3m in diameter and 5m high, it has a nameplate rating of 6.5kW to the grid.

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. 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.^[34] Small units often have direct drive generators, direct current 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.

Wind turbine spacing[link]

On most horizontal windturbine 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 economically optimal, taking into account typical wind turbine and land costs. This conclusion has been reached by research^[35] conducted by Charles Meneveau of the Johns Hopkins University,^[36] and Johan Meyers of Leuven University in Belgium, based on computer simulations^[37] that take into account the detailed interactions among wind turbines (wakes) as well as with the entire turbulent atmospheric boundary layer. Moreover, 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 neighboring turbines to move in the same direction as they approach one another.^[38]

Accidents[link]

Several cases occurred where the housings of wind turbines caught fire. As housings are normally out of the range of standard fire extinguishing equipment, it is nearly impossible to extinguish such fires on older turbine units which lack fire suppression systems. In several cases one or more blades were damaged or torn away.^[39] In 2010 70 mph (110 km/h; 61 kn) storm winds damaged some blades, prompting blade removal and inspection of all 25 wind turbines in Campo Indian Reservation in the US State of California.^[40] Several wind turbines also collapsed.

Severe wind turbine accidents have had relatively low impacts on the communities where the accidents occurred, compared with the widespread effects of accidents at nuclear and hydroelectric power plants.

Records[link]

Fuhrländer Wind Turbine Laasow, the world's tallest wind turbine

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

Largest capacity

The Enercon E-126 has a rated capacity of 7.58 MW,^[50] has an overall height of 198 m (650 ft), a diameter of 126 m (413 ft), and is the world's largest-capacity wind turbine since its introduction in 2007.^[51] At least five companies are working on the development of a 10MW turbine.

Largest swept area

The turbine with the largest swept area is a prototype installed by Gamesa at Jaulín, Zaragoza, Spain in 2009. The G10X – 4.5 MW has a rotor diameter of 128m.

^[52]

Tallest

The tallest wind turbine is Fuhrländer Wind Turbine Laasow. Its axis is 160 meters above ground and its rotor tips can reach a height of 205 meters. It is the only wind turbine in the world taller than 200 meters.^[53]

Largest vertical-axis

Le Nordais wind farm in Cap-Chat, Quebec has a vertical axis wind turbine (VAWT) named Éole, which is the world's largest at 110 m.^[54] It has a nameplate capacity of 3.8MW.^[55]

Most southerly

The turbines currently operating closest to the South Pole are three Enercon E-33 in Antarctica, powering New Zealand's Scott Base and the United States' McMurdo Station since December 2009^[56][57] although a modified HR3 turbine from Northern Power Systems operated at the Amundsen-Scott South Pole Station in 1997 and 1998.^[58] In March 2010 CITEDEF designed, built and installed a wind turbine in Argentine Marambio Base.^[59]

Most productive

Four turbines at Rønland wind farm in Denmark share the record for the most productive wind turbines, with each having generated 63.2 GWh by June 2010^[60]

Highest-situated

The world's highest-situated wind turbine is made by DeWind installed by the Seawind Group and located in the Andes, Argentina around 4,100 metres (13,500 ft) above sea level. The site uses a type D8.2 - 2000 kW / 50 Hz turbine. This turbine has a new drive train concept with a special torque converter (WinDrive) made by Voith and a synchronous generator. The WKA was put into operation in December 2007 and has supplied the Veladero mine of Barrick Gold with electricity since then.^[61]

Largest floating wind turbine

The world's largest—and also the first operational deep-water large-capacity—floating wind turbine is the 2.3 MW Hywind currently operating 10 kilometres (6.2 mi) offshore in 220-meter-deep water, southwest of Karmøy, Norway. The turbine began operating in September 2009 and utilizes a Siemens 2.3 MW turbine^[62][63]

See also[link]

	Renewable energy portal
	Sustainable development portal

• Small wind turbine
• Compact wind acceleration turbine
• Environmental effects of wind power
• Éolienne Bollée
• GE 1.5 MW wind turbine
• List of wind turbine manufacturers
• List of wind turbines
• Wind farm
• Wind turbines on public display
• Windpump
• Windbelt

References[link]

Further reading[link]

• Tony Burton, David Sharpe, Nick Jenkins, Ervin Bossanyi: Wind Energy Handbook, John Wiley & Sons, 1st edition (2001), ISBN 0-471-48997-2
• Darrell, Dodge, Early History Through 1875, 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 3-540-24240-6 (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[link]

Wikimedia Commons has media related to: Wind turbine

• Harvesting the Wind (45 lectures about wind turbines by professor Magdi Ragheb
• Time-lapse video of wind turbine installation at the WMRA Deer Island Wastewater Treatment Plant
• Wind Projects
• Guided tour on wind energy
• Wind Energy Technology World Wind Energy Association
• Wind turbine simulation, National Geographic
• Airborne Wind Industry Association international

v t e Wind power Wind power Environmental effects History Vehicles Offshore wind power Wind turbine Windmill Kitegen Wind power by country Asia Australia Austria Belgium Canada China Croatia Denmark Estonia European Union Finland France Germany Greece Hungary India Iran Ireland Italy Japan Malta Netherlands New Zealand Pakistan Portugal Romania Russia Scotland Serbia Spain Sweden Turkey UK US Wind turbines Aerodynamics Airborne Darrieus Design Floating Savonius Quietrevolution Small Unconventional Vertical axis Devices in use Wind power industry Consultants Manufacturers Software Wind farm management Wind farms Community-owned List of offshore wind farms List of onshore wind farms Concepts Betz' law Capacity factor EROEI Grid energy storage HVDC Intermittency Net energy gain Storage Subsidies Wind power forecasting Wind profile power law Wind resource assessment