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Windmill

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A windmill is a machine which converts the energy of wind into rotational energy by means of vanes called sails
Windmill sail
Windmills are powered by their sails. Sails are found in different designs, from primitive common sails to the advanced patent sails.-Jib sails:...

 or blades. Originally windmills were developed for milling grain for food production. In the course of history the windmill was adapted to many other industrial uses. An important application was to pump water. Windmills used for generating electricity are commonly known as wind turbines.

Windmills in antiquity


The windwheel of the Greek engineer Heron of Alexandria in the 1st century AD is the earliest known instance of using a wind-driven wheel to power a machine. Another early example of a wind-driven wheel was the prayer wheel
Prayer wheel
A prayer wheel is a cylindrical "wheel" on a spindle made from metal, wood, stone, leather or coarse cotton. Traditionally, the mantra Om Mani Padme Hum is written in Sanskrit on the outside of the wheel. Also sometimes depicted are Dakinis, Protectors and very often the 8 auspicious symbols...

, which was used in ancient Tibet
Tibet
Tibet is a plateau region in Asia, north-east of the Himalayas. It is the traditional homeland of the Tibetan people as well as some other ethnic groups such as Monpas, Qiang, and Lhobas, and is now also inhabited by considerable numbers of Han and Hui people...

 and China
China
Chinese civilization may refer to:* China for more general discussion of the country.* Chinese culture* Greater China, the transnational community of ethnic Chinese.* History of China* Sinosphere, the area historically affected by Chinese culture...

 since the 4th century.
It has been claimed that the Babylonia
Babylonia
Babylonia was an ancient cultural region in central-southern Mesopotamia , with Babylon as its capital. Babylonia emerged as a major power when Hammurabi Babylonia was an ancient cultural region in central-southern Mesopotamia (present-day Iraq), with Babylon as its capital. Babylonia emerged as...

n emperor Hammurabi
Hammurabi
Hammurabi Hammurabi Hammurabi (Akkadian from Amorite ʻAmmurāpi, "the kinsman is a healer", from ʻAmmu, "paternal kinsman", and Rāpi, "healer"; (died c...

 planned to use wind power for his ambitious irrigation project in the 17th century BC.

Horizontal windmills


The first practical windmills had sails that rotated in a horizontal plane, around a vertical axis. They were invented in eastern Persia
Greater Iran
Greater Iran refers to the regions that have significant Iranian cultural influence. It roughly corresponds to the territory on the Iranian plateau and its bordering plains, stretching from Iraq, the Caucasus, and Turkey in the west to the Indus River in the east...

 as recorded by the Persian geographer Estakhri
Estakhri
Abu Ishaq Ibrahim ibn Muhammad al-Farisi al Istakhri was a medieval Persian geographer in the 10th century.-Career:...

 in the 9th century. The authenticity of an earlier anecdote of a windmill involving the second caliph
Caliph
The Caliph is the head of state in a Caliphate, and the title for the ruler of the Islamic Ummah, an Islamic community ruled by the Shari'ah. It is a transcribed version of the Arabic word   which means "successor" or "representative"...

 Umar
Umar
`Umar ibn al-Khattāb c. 2 November , was a leading companion and adviser to the Islamic prophet Muhammad who later became the second Muslim Caliph after Muhammad's death....

 (AD 634–644) is questioned on the grounds that it appears in a 10th-century document. 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 quite different from the later European vertical windmills. Windmills were in widespread use across the Middle East
Middle East
The Middle East is a region that encompasses Western Asia and Northern Africa. It is often used as a synonym for Near East, in opposition to Far East...

 and Central Asia
Central Asia
Central Asia is a core region of the Asian continent from the Caspian Sea in the west, China in the east, Afghanistan in the south, and Russia in the north...

, and later spread to China and India
Indian subcontinent
The Indian subcontinent, also Indian Subcontinent, Indo-Pak Subcontinent or South Asian Subcontinent is a region of the Asian continent on the Indian tectonic plate from the Hindu Kush or Hindu Koh, Himalayas and including the Kuen Lun and Karakoram ranges, forming a land mass which extends...

 from there.

A similar type of horizontal windmill with rectangular blades, used for irrigation, can also be found in 13th-century China (during the Jurchen Jin Dynasty in the north), introduced by the travels of Yelü Chucai to Turkestan
Turkestan
Turkestan, spelled also as Turkistan, literally means "Land of the Turks".The term Turkestan is of Persian origin and has never been in use to denote a single nation. It was first used by Persian geographers to describe the place of Turkish peoples...

 in 1219.
Horizontal windmills were built, in small numbers, in Europe during the eighteenth and nineteenth centuries, for example Fowler's Mill at Battersea
Battersea
Battersea is an area of the London Borough of Wandsworth, England. It is an inner-city district of South London, situated on the south side of the River Thames, 2.9 miles south-west of Charing Cross. Battersea spans from Fairfield in the west to Queenstown in the east...

 in London, and Hooper's Mill at Margate in Kent. These early modern examples seem not to have been directly influenced by the horizontal windmills of the Middle and Far East, but to have been independent inventions by engineers influenced by the Industrial Revolution.

Vertical windmills


There is an ongoing debate among historians on whether and how the windmill from the middle East influenced the development of the early European windmill. In northwestern Europe
Europe
Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...

, the horizontal-axis or vertical windmill (so called due to the plane of the movement of its sails) is believed to date from the last quarter of the 12th century in the triangle of northern France, eastern England and Flanders
Flanders
Flanders is the community of the Flemings but also one of the institutions in Belgium, and a geographical region located in parts of present-day Belgium, France and the Netherlands. "Flanders" can also refer to the northern part of Belgium that contains Brussels, Bruges, Ghent and Antwerp...

.
The earliest certain reference to a windmill in Europe (assumed to have been of the vertical type) dates from 1185, in Weedley, Yorkshire, although a number of earlier but less certainly dated twelfth century European sources referring to windmills have also been found.
These earliest mills were used to grind cereals
Gristmill
The terms gristmill or grist mill can refer either to a building in which grain is ground into flour, or to the grinding mechanism itself.- Early history :...

.

Post mill




The evidence at present is that the earliest type of European windmill was the post mill, so named because of the large upright post on which the mill's main structure (the "body" or "buck") is balanced. By mounting the body this way, the mill is able to rotate to face the wind direction; an essential requirement for windmills to operate economically in North-Western Europe, where wind directions are variable. The body contains all the milling machinery. The first post mills were of the sunken type where the post was buried in an earth mound to support it. Later a wooden support was developed called the trestle
Trestle (mill)
The Trestle of a Post mill is the arrangement of the Main post, crosstrees and quarterbars that form the substructure of this type of windmill. It may or may not be surrounded by a roundhouse...

. This was often covered over or surrounded by a roundhouse to protect the trestle from the weather and to provide storage space. This type of windmill was the most common in Europe until the 19th century when more powerful tower and smock mills replaced them.

Hollow-post mill


In a hollow-post mill the post on which the body is mounted is hollowed out, to accommodate the drive shaft.
In this way it is possible to drive machinery below or outside the body while still being able to rotate the body into the wind. Hollow-post mills driving scoop wheels were used in the Netherlands to drain wetlands from the 14th century onwards.

Tower mill


By the end of the thirteenth century the masonry tower mill
Tower mill
A tower mill is a type of windmill which consists of a brick or stone tower, on top of which sits a roof or cap which can be turned to bring the sails into the wind....

, on which only the cap is rotated rather than the whole body of the mill, had been introduced. The spread of tower mills came with a growing economy that called for larger and more stable sources of power though they were more expensive to build. In contrast to the post mill, only the cap of the tower mill needs to be turned into the wind, so the main structure can be made much taller, allowing the sails to be made longer, which enables them to provide useful work even in low winds. The cap can be turned into the wind either by winches or gearing inside the cap or from a winch on the tail pole outside the mill. A method of keeping the cap and sails into the wind automatically is by using a fantail
Windmill fantail
A Fantail is a small windmill mounted at right angles to the sails, at the rear of the windmill, and which turns the cap automatically to bring it into the wind. The fantail was patented in 1745 by Edmund Lee, a blacksmith working at Brockmill Forge near Wigan, England, and perfected on mills...

, a small windmill mounted at right angles to the sails, at the rear of the windmill. These are also fitted to tail poles of post mills and are common in Great Britain and English-speaking countries of the former British Empire, Denmark and Germany but rare in other places. Tower mills with a fixed cap are found around the Mediterranean Sea. They are built with the sails facing the prevailing wind direction.

Smock mill


The smock mill is a later development of the tower mill where the tower is replaced by a wooden framework, called the "smock." The smock is commonly of octagonal plan, though examples with more, or fewer, sides exist. The smock is thatched, boarded or covered by other materials like slate, sheet metal
Sheet metal
Sheet metal is simply metal formed into thin and flat pieces. It is one of the fundamental forms used in metalworking, and can be cut and bent into a variety of different shapes. Countless everyday objects are constructed of the material...

 or tar paper
Tar paper
Tar paper is a heavy-duty paper used in construction. Tar paper is made by impregnating paper with tar, producing a waterproof material useful for roof construction. It can be distinguished from Roofing felt:Asphalt-saturated felt. Roofing felt has been in use for over a hundred years...

. The lighter construction in comparison to tower mills make smock mills practical as drainage mills as these often had to be built in areas with unstable subsoil. Having originated as a drainage mill, smock mills are also used for a variety of purposes. When used in a built-up area it is often placed on a masonry base to raise it above the surrounding buildings.

Sails


Common sails consist of a lattice framework on which a sailcloth is spread. The miller can adjust the amount of cloth spread according to the amount of wind available and power needed. In medieval mills the sailcloth was wound in and out of a ladder type arrangement of sails. Post-medieval mill sails had a lattice framework over which the sailcloth was spread, while in colder climates the cloth was replaced by wooden slats, which were easier to handle in freezing conditions. The jib sail is commonly found in Mediterranean countries, and consists of a simple triangle of cloth wound round a spar.
In all cases the mill needs to be stopped to adjust the sails. Inventions in Great Britain in the late 18th and 19th century led to sails that automatically adjust to the wind speed without the need for the miller to intervene, culminating in Patent sails invented by William Cubitt
William Cubitt
Sir William Cubitt was an eminent English civil engineer and millwright. Born in Norfolk, England, he was employed in many of the great engineering undertakings of his time. He invented a type of windmill sail and the prison treadwheel, and was employed as chief engineer, at Ransomes of Ipswich,...

 in 1813. In these sails the cloth is replaced by a mechanism of connected shutters. In France, Berton invented a system consisting of longitudinal wooden slats connected by a mechanism that lets the miller open them while the mill is turning. In the 20th century increased knowledge of aerodynamics from the development of the airplane led to further improvements in efficiency by German engineer Bilau and several Dutch millwrights.
The majority of windmills have four sails. Multi-sailed mills, with five, six or eight sails, were built in Great Britain (especially in and around the counties of Lincolnshire
Lincolnshire
Lincolnshire is a county in the east of England. It borders Norfolk to the south east, Cambridgeshire to the south, Rutland to the south west, Leicestershire and Nottinghamshire to the west, South Yorkshire to the north west, and the East Riding of Yorkshire to the north. It also borders...

 and Yorkshire
Yorkshire
Yorkshire is a historic county of northern England and the largest in the United Kingdom. Because of its great size in comparison to other English counties, functions have been increasingly undertaken over time by its subdivisions, which have also been subject to periodic reform...

), Germany and less commonly elsewhere. Earlier multi-sailed mills are found in Spain, Portugal, Greece, parts of Romania, Bulgaria and Russia A mill with an even number of sails has the advantage of being able to run with a damaged sail and the one opposite removed without resulting in an unbalanced mill.

Machinery


Gears inside a windmill convey power from the rotary motion of the sails to a mechanical device. The sails are carried on the horizontal windshaft. Windshafts can be wholly made of wood, or wood with a cast iron poll end (where the sails are mounted) or entirely of cast iron. The brake wheel is fitted onto the windshaft between the front and rear bearing. It has the brake around the outside of the rim and teeth in the side of the rim which drive the horizontal gearwheel called wallower on the top end of the vertical upright shaft. In grist mills the great spur wheel, lower down the upright shaft, drives one or more stone nuts on the shafts driving each millstone. Post mills sometimes have a head and/or tail wheel driving the stone nuts directly, instead of the spur gear arrangement. Additional gear wheels drive a sack hoist or other machinery.
The machinery differs if the windmill is used for other applications than milling grain. A drainage mill uses another set of gear wheels on the bottom end of the upright shaft to drive a scoop wheel or Archimedes' screw
Archimedes' screw
The Archimedes' screw, also called the Archimedean screw or screwpump, is a machine historically used for transferring water from a low-lying body of water into irrigation ditches...

. Sawmill
Sawmill
A sawmill is a facility where logs are cut into boards.-Sawmill process:A sawmill's basic operation is much like those of hundreds of years ago; a log enters on one end and dimensional lumber exits on the other end....

s use a crankshaft with to provide a reciprocating motion to the saws. Windmills have been used to power many other industrial processes, including papermills, threshing
Threshing
Threshing is the process of loosening the edible part of cereal grain from the scaly, inedible chaff that surrounds it. It is the step in grain preparation after harvesting and before winnowing, which separates the loosened chaff from the grain...

 mills, and for example to process oil seeds, wool, paints and stone products

Spread and decline


The total number of wind powered mills in Europe is estimated to have been around 200,000 at its peak, compared to some 500,000 waterwheels. With the coming of the industrial revolution
Industrial Revolution
The Industrial Revolution was a period from the 18th to the 19th century where major changes in agriculture, manufacturing, mining, transportation, and technology had a profound effect on the social, economic and cultural conditions of the times...

, the importance of wind (and water) as primary industrial energy source declined and was eventually replaced by steam (in steam mill
Steam mill
A steam mill is a type of grinding mill using a stationary steam engine to power its mechanism.-Reference to Marx:For Karl Marx, what defined feudalism was that the power of the ruling class rested on their control of arable land, leading to a class society based upon the exploitation of the...

s) and internal combustion engines, although windmills continued to be built in large numbers until late in the 19th Century.
More recently windmills have been preserved for their historic value, in some cases as static exhibits when the antique machinery is too fragile to put in motion, and in other cases as fully working mills. There are around 50 working mills in operation in Britain as of 2009.

Of the 10,000 windmills in use in the Netherlands around 1850, about 1000 are still standing. Most of these are being run by volunteers though there are some grist mills still operating commercially. Many of the drainage mills have been appointed as backup to the modern pumping stations. The Zaan district
Zaanse Schans
Zaanse Schans is a neighbourhood of Zaandam, near Zaandijk in the municipality ofZaanstad in the Netherlands, in the province of North Holland. It has a collection...

 has been said to have been the first industrialized region of the world with around 600 operating wind powered industries by the end of the 18th century. Economic fluctuations and the industrial revolution had a much greater impact on these industries than on grain and drainage mills so only very few are left.

Construction of mills spread to the Cape Colony
Cape Colony
The Cape Colony, part of modern South Africa, was established by the Dutch East India Company in 1652, with the founding of Cape Town. It was subsequently occupied by the British in 1795 when the Netherlands were occupied by revolutionary France, so that the French revolutionaries could not take...

 in the 17th century. The early tower-mills did not survive the gales of the Cape Peninsula
Cape Peninsula
The Cape Peninsula is a generally rocky peninsula that juts out for 75 km into the Atlantic Ocean at the south-western extremity of the African continent. At the southern end of the peninsula are Cape Point and the Cape of Good Hope...

, so that in 1717 the Heeren XVII sent carpenters, masons and materials to construct a durable mill. The mill was completed in 1718 and became known as the Oude Molen and was located between Pinelands Station and the Black River. Long since demolished, its name lives on as that of a Technical school in Pinelands
Pinelands, Cape Town
The "garden city" suburb of Pinelands is located on the edge of the southern suburbs of Cape Town in South Africa and is known for its large thatched houses. The suburb is primarily residential and is often praised for its peacefulness and abundance of trees...

. By 1863 Cape Town could boast eleven mills stretching from Paarden Eiland to Mowbray
Mowbray, Cape Town
Mowbray is one of the Southern Suburbs of Cape Town, South Africa. Its original name was Driekoppen .-Geography:Mowbray is bounded on the west by the M3 freeway, beyond which lies Devil's Peak, and on the north by the N2 freeway, beyond which lies the suburb of Observatory...

.

Windpumps


Windpumps are used extensively on farms and ranches in the central plains and South West of the United States and in Southern Africa
Southern Africa
Southern Africa is the southernmost region of the African continent, variably defined by geography or geopolitics. Within the region are numerous territories, including the Republic of South Africa ; nowadays, the simpler term South Africa is generally reserved for the country in English.-UN...

 and Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...

. These mills feature a large number of blades so that they turn slowly with considerable torque
Torque
Torque, moment or moment of force , is the tendency of a force to rotate an object about an axis, fulcrum, or pivot. Just as a force is a push or a pull, a torque can be thought of as a twist....

 in low winds and be self regulating in high winds. A tower-top gearbox
Transmission (mechanics)
A machine consists of a power source and a power transmission system, which provides controlled application of the power. Merriam-Webster defines transmission as: an assembly of parts including the speed-changing gears and the propeller shaft by which the power is transmitted from an engine to a...

 and crankshaft
Crankshaft
The crankshaft, sometimes casually abbreviated to crank, is the part of an engine which translates reciprocating linear piston motion into rotation...

 convert the rotary motion into reciprocating strokes carried downward through a rod to the pump cylinder below.
The farm wind pump was invented by Daniel Halladay
Daniel Halladay
Daniel Halladay was an American engineer, inventor and businessman, best known for his innovative 1854 self-regulating farm wind pump...

 in 1854. Eventually steel blades and steel towers replaced wooden construction, and at their peak in 1930, an estimated 600,000 units were in use. The multi-bladed wind turbine
Turbine
A turbine is a rotary engine that extracts energy from a fluid flow and converts it into useful work.The simplest turbines have one moving part, a rotor assembly, which is a shaft or drum with blades attached. Moving fluid acts on the blades, or the blades react to the flow, so that they move and...

 atop a lattice tower made of wood or steel hence became, for many years, a fixture of the landscape throughout rural America. Firms such as Star, Eclipse, Fairbanks-Morse
Fairbanks-Morse
Fairbanks Morse and Company was a manufacturing company in the late 19th and early 20th century. Originally a weighing scale manufacturer, it later diversified into pumps, engines, windmills, locomotives and industrial supplies until it was merged in 1958...

 and Aermotor
Aermotor Windmill Company
Aermotor Windmill Company is the only windmill manufacturer in the United States. The company was established in 1888.-History:La Verne Noyes, founder of Aermotor Windmill Company, had hired engineer Thomas_O._Perry for a different job but saw the potential of the all-metal windpump developed by...

 became famed suppliers in North and South America.

Wind turbine


A windmill used to generate electricity is commonly called a wind turbine
Wind turbine
A wind turbine is a device that converts kinetic energy from the wind into mechanical energy. 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...

. The first windmills for electricity production were built by the end of the 19th century by Prof James Blyth in Scotland
Scotland
Scotland is a country that is part of the United Kingdom. Occupying the northern third of the island of Great Britain, it shares a border with England to the south and is bounded by the North Sea to the east, the Atlantic Ocean to the north and west, and the North Channel and Irish Sea to the...

 (1887), Charles F. Brush
Charles F. Brush
Charles Francis Brush was a U.S. inventor, entrepreneur and philanthropist.-Biography:Born in Euclid Township, Ohio, Brush was raised on a farm about 10 miles from downtown Cleveland...

 in Cleveland, Ohio
Cleveland, Ohio
Cleveland is a city in the U.S. state of Ohio and is the county seat of Cuyahoga County, the most populous county in the state. The city is located in northeastern Ohio on the southern shore of Lake Erie, approximately west of the Pennsylvania border...

 (1887–1888) and Poul la Cour
Poul la Cour
Poul la Cour was a Danish scientist, inventor and educationalist. Today la Cour is especially recognized for his early work on wind power, both experimental work on aerodynamics and practical implementation of wind power plants. He worked most of his life at Askov Folk High School where he...

 in Denmark (1890s). La Cour's mill from 1896 later became the local powerplant of the village Askov. By 1908 there were 72 wind-driven electric generators in Denmark from 5 kW to 25 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 like Jacobs Wind
Jacobs Wind
Jacobs Wind Electric Co. Inc. is the oldest small wind turbine company in the United States. It has been designing consumer wind systems sized to the changing distributed electric loads of their periods since the mid 1920s....

, Wincharger, Miller Airlite, Universal Aeroelectric, Paris-Dunn, Airline and Winpower and by the Dunlite Corporation for similar locations in Australia.
Forerunners of modern horizontal-axis utility-scale wind generators were the WIME-3D in service in Balaklava
Balaklava
Balaklava is a former city on the Crimean peninsula and part of the city of Sevastopol which carries a special administrative status in Ukraine. It was a city in its own right until 1957 when it was formally incorporated into the municipal borders of Sevastopol by the Soviet government...

 USSR from 1931 until 1942, a 100 kW generator on a 30 m (100 ft) tower, the Smith-Putnam wind turbine
Smith-Putnam wind turbine
In 1941 the Smith-Putnam wind turbine, the world's first megawatt-size wind turbine, was connected to the local electrical distribution system on Grandpa's Knob in Castleton, Vermont, USA. It was designed by Palmer Cosslett Putnam and manufactured by the S. Morgan Smith Company...

 built in 1941 on the mountain known as Grandpa's Knob in Castleton, Vermont
Castleton, Vermont
Castleton is a town in Rutland County, Vermont, United States. Castleton is about to the west of Rutland, and about east of the New York/Vermont state border. The town had a population of 4,717 at the 2010 census. Castleton State College is located there, with roots dating to 1787...

, USA of 1.25 MW and the NASA wind turbines
NASA wind turbines
Starting in 1975, NASA developed technologies and was the technical manager for the United States Department of Energy and the United States Department of Interior on a program to develop utility-scale wind turbines for the production of electric power, in response to the increase in oil prices.A...

 developed from 1974 through the mid 1980's. The development of these 13 experimental wind turbines pioneered many of the wind turbine design
Wind turbine design
Wind turbine design is the process of defining the form and specifications of a wind turbine to extract energy from the wind. A wind turbine installation consists of the necessary systems needed to capture the wind's energy, point the turbine into the wind, convert mechanical rotation into...

 technologies in use today, including: steel tube towers, variable-speed generators, composite blade materials, partial-span pitch control, as well as aerodynamic, structural, and acoustic engineering design capabilities. The modern wind power industry
Wind power industry
The wind power industry is involved with the design, manufacture, construction, and maintenance of wind turbines. The modern wind power industry began in 1979 with the serial production of wind turbines by Danish manufacturers...

 began in 1979 with the serial production of wind turbines by Danish manufacturers Kuriant, Vestas
Vestas
Vestas Wind Systems A/S is a Danish manufacturer, seller, installer, and servicer of wind turbines. It is the largest in the world, but due to very rapid growth of its competitors, its market share decreased from 28% in 2007 to 12.5% in 2009...

, Nordtank
NEG Micon
NEG Micon is a former Danish wind turbine manufacturer. It was formed in 1997 as a result of a merger between Nordtank Energy Group and Micon....

, and Bonus
Siemens
Siemens may refer toSiemens, a German family name carried by generations of telecommunications industrialists, including:* Werner von Siemens , inventor, founder of Siemens AG...

. These early turbines were small by today's standards, with capacities of 20–30 kW each. Since then, they 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.

As the 21st century began, rising concerns over energy security
Energy security
Energy security is a term for an association between national security and the availability of natural resources for energy consumption. Access to cheap energy has become essential to the functioning of modern economies. However, the uneven distribution of energy supplies among countries has led...

, global warming
Global warming
Global warming refers to the rising average temperature of Earth's atmosphere and oceans and its projected continuation. In the last 100 years, Earth's average surface temperature increased by about with about two thirds of the increase occurring over just the last three decades...

, and eventual fossil fuel depletion
Peak oil
Peak oil is the point in time when the maximum rate of global petroleum extraction is reached, after which the rate of production enters terminal decline. This concept is based on the observed production rates of individual oil wells, projected reserves and the combined production rate of a field...

 led to an expansion of interest in all available forms of renewable energy
Renewable energy
Renewable energy is energy which comes from natural resources such as sunlight, wind, rain, tides, and geothermal heat, which are renewable . About 16% of global final energy consumption comes from renewables, with 10% coming from traditional biomass, which is mainly used for heating, and 3.4% from...

. Worldwide there are now many thousands of wind turbines operating, with a total nameplate capacity
Nameplate capacity
Nameplate capacity, also known as the rated capacity, nominal capacity, installed capacity or maximum effect, refers to the intended technical full–load sustained output of a facility such as a power plant, a chemical plant, fuel plant, metal refinery, mine, and many others.For dispatchable power,...

 of 194,400 MW. Europe accounted for 48% of the total in 2009.

A wind turbine looking like a windmill is De Nolet
De Nolet
De Nolet is a wind turbine in Schiedam, The Netherlands which resembles a traditional Schiedam windmill...

 in Rotterdam.

See also


  • List of windmills
  • Mill machinery
    Mill machinery
    This article covers the various major pieces of mill machinery to be found in windmills, watermills and horse mills. It does not cover machinery found in modern factories.-Watermill machinery:Axle...

  • Millstone
    Millstone
    Millstones or mill stones are used in windmills and watermills, including tide mills, for grinding wheat or other grains.The type of stone most suitable for making millstones is a siliceous rock called burrstone , an open-textured, porous but tough, fine-grained sandstone, or a silicified,...

  • Molinology
    Molinology
    Molinology is the study of mills or other mechanical devices which use the kinetic energy of moving water or wind to power machines for such purposes as hammering, grinding, pumping, sawing, pressing or fulling. Muscle-powered mills are also considered to be part of the field...

  • Éolienne Bollée
    Éolienne Bollée
    The Éolienne Bollée is an unusual wind turbine, unique for having a stator and a rotor, as a water turbine has. The eponymous invention was first patented in 1868 by Ernest Sylvain Bollée in France...

  • Renewable energy
    Renewable energy
    Renewable energy is energy which comes from natural resources such as sunlight, wind, rain, tides, and geothermal heat, which are renewable . About 16% of global final energy consumption comes from renewables, with 10% coming from traditional biomass, which is mainly used for heating, and 3.4% from...

  • Watermill
    Watermill
    A watermill is a structure that uses a water wheel or turbine to drive a mechanical process such as flour, lumber or textile production, or metal shaping .- History :...


Further reading

  • Ahmad Y Hassan, Donald Routledge Hill (1986). Islamic Technology: An illustrated history. Cambridge University Press. ISBN 0-521-42239-6.
  • Chartrand, French Fortresses in North America 1535–1763: Quebec, Montreal, Louisbourg and New Orleans.
  • Dietrich Lohrmann, "Von der östlichen zur westlichen Windmühle", Archiv für Kulturgeschichte, Vol. 77, Issue 1 (1995)
  • A.G. Drachmann, "Heron's Windmill", Centaurus, 7 (1961).
  • Needham, Joseph (1986). Science and Civilization in China: Volume 4, Physics and Physical Technology, Part 2, Mechanical Engineering. Taipei: Caves Books Ltd.
  • Hugh Pembroke Vowles
    Hugh Pembroke Vowles
    Hugh Pembroke Vowles was a British engineer, socialist and author.- Early life and education :...

    : "An Enquiry into Origins of the Windmill", Journal of the Newcomen Society, Vol. 11 (1930–31)
  • Roy Gregory and Laurence Turner (2009) Windmills of Yorkshire ISBN 978-1-84033-475-3
  • Edwin Tunis (1999), Colonial living, The Johns Hopkins University Press ", ISBN 0-8018-6227-2, pp. 72 and 73

External links