An example of a wind turbine. This 3 bladed turbine is the most common design of modern wind turbines.

Wind power is the conversion of wind energy into useful form, such as electricity, using wind turbines. At the end of 2006, worldwide capacity of wind-powered generators was 73.9 gigawatts; although it currently produces just over 1% of world-wide electricity use,^[1] it accounts for approximately 20% of electricity production in Denmark, 9% in Spain, and 7% in Germany.^[2] Globally, wind power generation more than quadrupled between 2000 and 2006.^[3] Image File history File links Download high-resolution version (1600x1043, 965 KB) Summary Licensing File links The following pages on the English Wikipedia link to this file (pages on other projects are not listed): Wind turbine ... Image File history File links Download high-resolution version (1600x1043, 965 KB) Summary Licensing File links The following pages on the English Wikipedia link to this file (pages on other projects are not listed): Wind turbine ... This article is about the machine for converting the kinetic energy in the wind into mechanical energy. ... Renewable energy effectively utilizes natural resources such as sunlight, wind, tides and geothermal heat, which are naturally replenished. ... For articles on specific fuels used in vehicles, see Biogas, Bioethanol, Biobutanol, Biodiesel, and Straight vegetable oil. ... For the use of the term in ecology, see Biomass (ecology). ... Krafla Geothermal Station in northeast Iceland Geothermal power is energy generated by heat stored beneath the Earths surface. ... Hydroelectricity is electricity produced by hydropower. ... Heat and light from the Sun fuel life on Earth. ... Tidal energy, sometimes called tidal power, is a form of hydropower that exploits the movement of water caused by tidal currents or the rise and fall in sea levels due to the tides. ... Wave power refers to the energy of ocean surface waves and the capture of that energy to do useful work - including electricity generation, desalination, and the pumping of water (into reservoirs). ... This article is about the machine for converting the kinetic energy in the wind into mechanical energy. ... The gigawatt (symbol: GW) is a unit for measuring power corresponding to one billion (109) watts. ...

Most modern wind power is generated in the form of electricity by converting the rotation of turbine blades into electrical current by means of an electrical generator. In windmills (a much older technology), wind energy is used to turn mechanical machinery to do physical work, such as crushing grain or pumping water. This article is about the machine for converting the kinetic energy in the wind into mechanical energy. ... This article is about machines that produce electricity. ... A Dutch tower windmill, sporting sails, surrounded by tulips A windmill is an engine powered by the wind to produce energy, often contained in a large building as in traditional post mills, smock mills and tower mills. ...

Wind power is used in large scale wind farms for national electrical grids as well as in small individual turbines for providing electricity to rural residences or grid-isolated locations. Wind turbines in Neuenkirchen, Dithmarschen (Germany). ...

Wind energy is plentiful, renewable, widely distributed, clean, and reduces toxic atmospheric and greenhouse gas emissions if used to replace fossil-fuel-derived electricity. The intermittency of wind seldom creates problems when using wind power at low to moderate penetration levels.^[4] Renewable energy effectively utilizes natural resources such as sunlight, wind, tides and geothermal heat, which are naturally replenished. ... Top: Increasing atmospheric CO2 levels as measured in the atmosphere and ice cores. ... Intermittent power sources are sources of power generation, primarily electricity, whose power output is either variable or intermittent. ...

Wind energy

There is an estimated 50 to 100 times more wind energy than plant biomass energy available on Earth.^[5][6] Most of this wind energy can be found at high altitudes where continuous wind speeds of over 160 km/h (100 mph) occur. Eventually, the wind energy is converted through friction into diffuse heat throughout the Earth's surface and the atmosphere. For other uses, see Wind (disambiguation). ...

The origin of wind is complex. The Earth is unevenly heated by the sun resulting in the poles receiving less energy from the sun than the equator does. Also the dry land heats up (and cools down) more quickly than the seas do. The differential heating drives a global atmospheric convection system reaching from the Earth's surface to the stratosphere which acts as a virtual ceiling. World map showing the equator in red In tourist areas, the equator is often marked on the sides of roads The equator marked as it crosses Ilhéu das Rolas, in São Tomé and Príncipe. ... Convection in the most general terms refers to the movement of currents within fluids (i. ... Atmosphere diagram showing stratosphere. ...

Wind variability and turbine power

A Darrieus wind turbine.

The power in the wind can be extracted by allowing it to blow past moving wings that exert torque on a rotor. The amount of power transferred is directly proportional to the density of the air, the area swept out by the rotor, and the cube of the wind speed. A Darrieus wind turbine once used for electric power generation in the Magdalen Islands. ... A Darrieus wind turbine once used for electric power generation in the Magdalen Islands. ... Fig. ... Torque applied via an adjustable end wrench Relationship between force, torque, and momentum vectors in a rotating system In physics, torque (or often called a moment) can informally be thought of as rotational force or angular force which causes a change in rotational motion. ... In physics, power (symbol: P) is the rate at which work is performed or energy is transferred. ...

The power P available in the wind is given by:

,

where P = power in watts, alpha = efficiency constant, rho = mass density of air in kilograms per cubic meter, r = radius of the wind turbine in meters, and v = velocity of the air in meters per second. In physics and engineering, including mechanical and electrical engineering, energy efficiency is a dimensionless number, with a value between 0 and 1 or, when multiplied by 100, is given as a percentage. ...

The mass flow of air that travels through the swept area of a wind turbine varies with the wind speed and air density. As an example, on a cool 15 °C (59 °F) day at sea level, air density is 1.225 kilograms per cubic metre. An 8 m/s breeze blowing through a 100 meter diameter rotor would move almost 77,000 kilograms of air per second through the swept area. Mass flow rate is the movement of mass per time. ...

The kinetic energy of a given mass varies with the square of its velocity. Because the mass flow increases linearly with the wind speed, the wind power available to a wind turbine increases as the cube of the wind speed. The power of the example breeze above through the example rotor would be about 2.5 megawatts. The cars of a roller coaster reach their maximum kinetic energy when at the bottom of their path. ...

As the wind turbine extracts energy from the air flow, the air is slowed down, which causes it to spread out and diverts it around the wind turbine to some extent. Albert Betz, a German physicist, determined in 1919 (see Betz' law) that a wind turbine can extract at most 59% of the energy that would otherwise flow through the turbine's cross section. The Betz limit applies regardless of the design of the turbine. Albert Betz (25 December 1885 - 16 April 1968) was a German Engineer and a pioneer of wind energy technology. ... Betz law reflects a theory for flow machines, developed by Albert Betz. ...

Distribution of wind speed (red) and energy (blue) for all of 2002 at the Lee Ranch facility in Colorado. The histogram shows measured data, while the curve is the Rayleigh model distribution for the same average wind speed. Energy is the Betz limit through a 100 meter diameter circle facing directly into the wind. Total energy for the year through that circle was 15.4 gigawatt-hours.

Windiness varies, and an average value for a given location does not alone indicate the amount of energy a wind turbine could produce there. To assess the climatology of wind speeds at a particular location, a probability distribution function is often fit to the observed data. Different locations will have different wind speed distributions. The distribution model most frequently used to model wind speed climatology is a two-parameter Weibull distribution because it is able to conform to a wide variety of distribution shapes, from Gaussian to exponential. The Rayleigh model, an example of which is shown plotted against an actual measured dataset, is a specific form of the Weibull function in which the shape parameter equals 2, and very closely mirrors the actual distribution of hourly wind speeds at many locations. Plot of wind speeds measured in 2002 at the Lee Ranch facility. ... Plot of wind speeds measured in 2002 at the Lee Ranch facility. ... The kilowatt-hour (symbol: kW·h) is a unit for measuring energy. ... In probability theory and statistics, the Weibull distribution (named after Waloddi Weibull) is a continuous probability distribution with the probability density function where and is the shape parameter and is the scale parameter of the distribution. ... In probability theory and statistics, the Rayleigh distribution is a continuous probability distribution. ...

Worldwide installed capacity and prediction 1997-2010, Source: WWEA

Because so much power is generated by higher windspeed, much of the average power available to a windmill comes in short bursts. The 2002 Lee Ranch sample is telling; half of the energy available arrived in just 15% of the operating time. The consequence is that wind energy does not have as consistent an output as fuel-fired power plants; utilities that use wind power must provide backup generation or grid power reception capability for times that the wind is weak. Image File history File links Wind_2006andprediction_en. ... Image File history File links Wind_2006andprediction_en. ...

Since wind speed is not constant, a wind generator's annual energy production is never as much as its nameplate rating multiplied by the total hours in a year. The ratio of actual productivity in a year to this theoretical maximum is called the capacity factor. A well-sited wind generator will have a capacity factor of about 35%. This compares to a typical capacity factors of 90% for nuclear plants (like wind farms, they have negligible fuel cost, and are therefore often run at maximum capacity with the load following relegated to other plants).^[7] The lower values of 70% for coal plants and 30% for oil plants reflect a throttling-back of plants with high cost fuel in times of low demand. The capacity factor of a power plant is the amount of electricity that it produces over a period of time, divided by the amount of electricity it could have produced if it had run at full power over that time period. ...

When comparing the size of wind turbine plants to fueled power plants, it is important to note that 1000 kW of wind-turbine potential power would be expected to produce as much energy in a year as approximately 500 kW of coal-fired generation. Though the short-term (hours or days) output of a wind-plant is not completely predictable, the annual output of energy tends to vary only a few percent points between years. A power station (also power plant) is a facility for the generation of electric power. ...

When storage, such as with pumped hydroelectric storage, or other forms of generation are used to "shape" wind power (by assuring constant delivery reliability), commercial delivery represents a cost increase of about 25%, yielding viable commercial performance.^[8] Electricity consumption can be adapted to production variability to some extent with Energy Demand Management and smart meters that offer variable market pricing over the course of the day. For example, municipal water pumps that feed a water tower do not need to operate continuously and can be restricted to times when electricity is plentiful and cheap. Consumers could choose when to run the dishwasher or charge an electric vehicle, making it very convenient. Electric and plug-in hybrid vehicles also offer a significant demand management tool and could potentially be set to charge automatically during periods of excess wind output. Alternately, charging could be scheduled for the late evening and early morning hours when there will likely be excess generation capacity. Pumped storage hydroelectricity is a method of storing and producing electricity to supply high peak demands by moving water between reservoirs at different elevations. ... Energy demand management is also known as demand side management (DSM). ... A Smart meter generally refers to a type of advanced meter (usually an electrical meter) that identifies consumption in more detail than a conventional meter, and optionally communicates that information via some network back to the local utility for monitoring and billing purposes. ...

How Does Wind Energy Work?

1. The wind blows on the blades and makes them turn.

2. The blades turn a shaft inside the nacelle (the box at the top of the turbine).

3. The shaft goes into a gearbox which increases the rotation speed enough for

4. the generator, which uses magnetic fields to convert the rotational energy into electrical energy. These are similar to those found in normal power stations.

5. The power output goes to a transformer, which converts the electricity coming out of the generator at around 700 Volts (V) to the right voltage for distribution system, typically 33,000 V.

6. The national grid transmits the power around the country.

Turbine placement

Map of available wind power over the United States. Color codes indicate wind power density class.

As a general rule, wind generators are practical where the average wind speed is 10 mph (16 km/h or 4.5 m/s) or greater. Usually sites are pre-selected on basis of a wind atlas, and validated with wind measurements. Meteorology plays an important part in determining possible locations for wind parks but meteorological wind data alone is usually not sufficient for accurate siting of a large wind power project. Site Specific Meteorological Data is crucial to determining site potential. An 'ideal' location would have a near constant flow of non-turbulent wind throughout the year with a minimum likelihood of sudden powerful bursts of wind. A vitally important factor of turbine siting is also access to local demand or transmission capacity. Image File history File links Download high-resolution version (1130x713, 162 KB) Description: U.S. wind power map. ... Image File history File links Download high-resolution version (1130x713, 162 KB) Description: U.S. wind power map. ... A wind atlas contains data on the wind speed and wind direction in a region. ... // Meteorology (from Greek: μετέωρον, meteoron, high in the sky; and λόγος, logos, knowledge) is the interdisciplinary scientific study of the atmosphere that focuses on weather processes and forecasting. ... Power line redirects here. ...

The most crucial step in the development of a potential wind site is the collection of accurate and verifiable wind speed and direction data as well as other site parameters.^[9] To collect wind data a Meteorological Tower is installed at the potential site with instrumentation installed at various heights along the tower. All towers include anemometers to determine the wind speed and wind vanes to determine the direction. The towers generally vary in height from 30 to 60 meters. The towers primarily used in determining site feasibility for potential wind farms are guyed steel-pipe structures which are left to collect data for one to two years and then usually disassembled. Data is collected by a data logging device which stores and transmits data to a server where it is analyzed.

The wind blows faster at higher altitudes because of the reduced influence of drag of the surface (sea or land) and lower air viscosity. The increase in velocity with altitude is most dramatic near the surface and is affected by topography, surface roughness, and upwind obstacles such as trees or buildings. Typically, the increase of wind speeds with increasing height follows a logarithmic profile that can be reasonably approximated by the wind profile power law, using an exponent of 1/7th, which predicts that wind speed rises proportionally to the seventh root of altitude. Doubling the altitude of a turbine, then, increases the expected wind speeds by 10% and the expected power by 34% (calculation: increase in power = (2.0) ^(3/7) – 1 = 34%). The Wind Profile Power Law is an empirical relationship between the wind speeds at one height, and those at another. ...

Wind farms or wind parks often have many turbines installed. Since each turbine extracts some of the energy of the wind, it is important to provide adequate spacing between turbines to avoid excess energy loss. Where land area is sufficient, turbines are spaced three to five rotor diameters apart perpendicular to the prevailing wind, and five to ten rotor diameters apart in the direction of the prevailing wind, to minimize efficiency loss. The "wind park effect" loss can be as low as 2% of the combined nameplate rating of the turbines.

Utility-scale wind turbine generators have minimum temperature operating limits which restrict the application in areas that routinely experience temperatures less than −20 °C. Wind turbines must be protected from ice accumulation, which can make anemometer readings inaccurate and which can cause high structure loads and damage. Some turbine manufacturers offer low-temperature packages at a few percent extra cost, which include internal heaters, different lubricants, and different alloys for structural elements, to make it possible to operate the turbines at lower temperatures. If the low-temperature interval is combined with a low-wind condition, the wind turbine will require station service power, equivalent to a few percent of its output rating, to maintain internal temperatures during the cold snap. For example, the St. Leon, Manitoba project has a total rating of 99 MW and is estimated to need up to 3 MW (around 3% of capacity) of station service power a few days a year for temperatures down to −30 °C. This factor affects the economics of wind turbine operation in cold climates.^{[citation needed]} A hemispherical cup anemometer of the type invented in 2000 by John Thomas Romney Robinson An anemometer is a device for measuring the velocity or the pressure of the wind, and is one instrument used in a weather station. ... St. ... Motto: Gloriosus et Liber (Latin: Glorious and free) Capital Winnipeg Largest city Winnipeg Official languages English French (de facto) Government Lieutenant-Governor John Harvard Premier Gary Doer (NDP) Federal representation in Canadian Parliament House seats 14 Senate seats 6 Confederation July 15, 1870 (5th) Area  Ranked 8th Total 647,797...

Onshore

Onshore turbine installations in hilly or mountainous regions tend to be on ridgelines generally three kilometers or more inland from the nearest shoreline. This is done to exploit the so-called topographic acceleration. The hill or ridge causes the wind to accelerate as it is forced over it. The additional wind speeds gained in this way make large differences to the amount of energy that is produced. Great attention must be paid to the exact positions of the turbines (a process known as micro-siting) because a difference of 30m can sometimes mean a doubling in output. Local winds are often monitored for a year or more with anemometers and detailed wind maps constructed before wind generators are installed. Anemometer installation on roof of Deconism Gallery, using three size 6, schedule 40 pipes in their original uncut 20 foot (6 m) lengths. ...

For smaller installations where such data collection is too expensive or time consuming, the normal way of prospecting for wind-power sites is to directly look for trees or vegetation that are permanently "cast" or deformed by the prevailing winds. Another way is to use a wind-speed survey map, or historical data from a nearby meteorological station, although these methods are less reliable. Prospecting is the physical search for minerals, fossils, precious metals or mineral specimens, and is also known as fossicking. ...

Wind farm siting can sometimes be highly controversial, particularly as the hilltop, often coastal sites preferred are often picturesque and environmentally sensitive (for instance, having substantial bird life).

Near-Shore

Near-Shore turbine installations are generally considered to be inside a zone that is on land within three kilometers of a shoreline or on water within ten kilometers of land. These areas tend to be windy and are good sites for turbine installation, because a primary source of wind is convection caused by the differential heating and cooling of land and sea over the cycle of day and night. Wind speeds in these zones share the characteristics of both onshore and offshore wind, depending on the prevailing wind direction.

Common issues that are shared within near-shore wind development zones are aviary (including bird migration and nesting), aquatic habitat, transportation (including shipping and boating) and visual aesthetics. Local residents in some potential sites have strongly opposed the installation of wind farms due to these concerns. The Parthenons facade showing an interpretation of golden rectangles in its proportions. ...

Offshore

Offshore wind turbines near Copenhagen

Offshore wind development zones are generally considered to be ten kilometers or more from land. Offshore wind turbines are less obtrusive than turbines on land, as their apparent size and noise can be mitigated by distance. Because water has less surface roughness than land (especially deeper water), the average wind speed is usually considerably higher over open water. Capacity factors (utilisation rates) are considerably higher than for onshore and near-shore locations which allows offshore turbines to use shorter towers, making them less visible. Download high resolution version (1024x357, 49 KB)Danish wind turbines near Copenhagen. ... Download high resolution version (1024x357, 49 KB)Danish wind turbines near Copenhagen. ... For other uses, see Copenhagen (disambiguation). ...

In stormy areas with extended shallow continental shelves (such as Denmark), turbines are practical to install — Denmark's wind generation provides about 18% of total electricity production in the country, with many offshore windfarms. Denmark plans to increase wind energy's contribution to as much as half of its electrical supply.

Locations have begun to be developed in the Great Lakes - with one project by Trillium Power approximately 20 km from shore and over 700 MW in size. Ontario, Canada is aggressively pursuing wind power development and has many onshore wind farms and several proposed near-shore locations but presently only one offshore development in fresh water and one on the Pacific west coast.

In most cases offshore environment is more expensive than onshore but this depends on the unique attributes of the specific site. Offshore towers are generally taller than onshore towers once the submerged height is included, and offshore foundations may be more difficult to build and more expensive but again this will be determined by the specific site of the proposed development. Power transmission from offshore turbines is generally through undersea cable, which is more expensive to install than cables on land, and may use high voltage direct current operation if significant distance is to be covered — which then requires yet more equipment. Offshore saltwater environments can also raise maintenance costs by corroding the towers, but fresh-water locations such as the Great Lakes do not. Repairs and maintenance are usually more difficult or slower, and generally more costly, than on onshore turbines due to the location of the offshore site. These costs may vary greatly depending on the exact site of the offshore development. Offshore saltwater wind turbines are outfitted with extensive corrosion protection measures like coatings and cathodic protection, which may not be required in fresh water locations. A submarine communications cable is a cable laid beneath the sea to carry telecommunications between countries. ... HVDC or high-voltage, direct current electric power transmission systems contrast with the more common alternating-current systems as a means for the bulk transmission of electrical power. ... Aluminium anodes mounted on a steel jacket structure Cathodic protection (CP) is a technique to control the corrosion of a metal surface by making that surface the cathode of an electrochemical cell. ...

While there is a significant market for small land-based windmills, offshore wind turbines have recently been and will probably continue to be the largest wind turbines in operation, because larger turbines allow for the spread of the high fixed costs involved in offshore operation over a greater quantity of generation, reducing the average cost. For similar reasons, offshore wind farms tend to be quite large—often involving over 100 turbines—as opposed to onshore wind farms which can operate competitively even with much smaller installations. Fixed costs are un-expired assets or expenses whose total does not change in proportion to the activity of a business, within the relevant time period or scale of production. ... Marginal cost is a term in economics. ... A wind farm is a collection of wind turbines in the same location. ...

Airborne

Main article: Airborne wind turbine

Wind turbines might also be flown in high speed winds at altitude,^[10] although no such systems currently exist in the marketplace. An Ontario (Canada) company, Magenn Power, Inc., is attempting to commercialize tethered aerial turbines suspended with helium^[11] An airborne wind turbine is a design concept for a wind turbine that is supported in the air without a tower. ...

The Italian project called "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. A number of other designs for vertical-axis turbines have been developed or proposed, including small scale commercial or pilot installations. However, vertical-axis turbines remain a commercially unproven technology.

Utilization

Main article: :Category:Wind power by country

Large scale

There are many thousands of wind turbines operating, with a total capacity of 73,904 MW of which Europe accounts for 65% (2006). The average output of one megawatt of wind power is equivalent to the average electricity consumption of about 250 American households. Wind power was the most rapidly-growing means of alternative electricity generation at the turn of the century and world wind generation capacity more than quadrupled between 2000 and 2006 and in some countries (Spain and Denmark) wind can supply 10% or more of the nation´s electricity. 81% of wind power installations are in the US and Europe, but the share of the top five countries in terms of new installations fell from 71% in 2004 to 55% in 2005. Offshore wind turbines near Copenhagen Some 20 per cent of Danish domestic electricity comes from wind [1]and Denmark is a leading wind power nation in the world. ...

By 2010, the World Wind Energy Association expects 160GW of capacity to be installed worldwide^[1], up from 73.9GW at the end of 2006, implying an anticipated net growth rate of more than 21% per year.

Germany, Spain, the United States, India, and Denmark have made the largest investments in wind generated electricity. Denmark is prominent in the manufacturing and use of wind turbines, with a commitment made in the 1970s to eventually produce half of the country's power by wind. Denmark generates over 20% of its electricity with wind turbines, the highest percentage of any country and is fifth in the world in total wind power generation (which can be compared with the fact that Denmark is 56th on the general electricity consumption list). Denmark and Germany are leading exporters of large (0.66 to 5 MW) turbines. Countries by electricity consumption This is a list of countries by electricity consumption mostly based on The World Factbook [1] accessed in March 2006. ...

Wind accounts for 1% of the total electricity production on a global scale (2005). Germany is the leading producer of wind power with 28% of the total world capacity in 2006 (7.3% of German electricity); the official target is that by 2010, renewable energy will meet 12.5% of German electricity needs — it can be expected that this target will be reached even earlier. Germany has 18,600 wind turbines, mostly in the north of the country — including three of the biggest in the world, constructed by the companies Enercon (6 MW), Multibrid (5 MW) and Repower (5 MW). Germany's Schleswig-Holstein province generates 36% of its power with wind turbines. Enercon E-112 Enercon GmbH, based in Aurich, Northern Germany, is the third-largest wind turbine manufacturer in the world and the market leader in Germany. ... Schleswig-Holstein is the northernmost of the 16 Bundesländer in Germany. ...

Spain and the United States, this last with bigger population, are next in terms of installed capacity.

In 2005, the government of Spain approved a new national goal for installed wind power capacity of 20,000 MW by 2012. According to trade journal Windpower Monthly; however, in 2006 they abruptly halted subsidies and price supports for wind power. According to the American Wind Energy Association, wind generated enough electricity to power 0.4% (1.6 million households) of total electricity in US, up from less than 0.1% in 1999. In 2005, both Germany and Spain have produced more electricity from wind power than from hydropower plants. US Department of Energy studies have concluded wind harvested in just three of the fifty U.S. states could provide enough electricity to power the entire nation, and that offshore wind farms could do the same job.[12] Undershot water wheels on the Orontes River in Hama, Syria Saint Anthony Falls Hydropower is the capture of the energy of moving water for some useful purpose. ... The United States Department of Energy (DOE) is a Cabinet-level department of the United States government responsible for energy policy and nuclear safety. ...

In recent years, the United States has added more wind energy to its grid than any other single country, and capacity is expected to grow by 3 gigawatts (3,000 megawatts) in 2007. Texas has become the leader in Wind Energy production, far surpassing California. In 2007, the state expects to add 2 gigawatts to raise its existing capacity to approximately 4.5 gigawatts. Iowa and Minnesota are expected to reach the 1 gigawatt mark by the end of 2007.^[14] Wind power generation in the U.S. was up 31.8% in February, 2007 from February, 2006.^[15] Official language(s) English Capital Sacramento Largest city Los Angeles Largest metro area Greater Los Angeles Area  Ranked 3rd  - Total 158,302 sq mi (410,000 km²)  - Width 250 miles (400 km)  - Length 770 miles (1,240 km)  - % water 4. ...

India ranks 4th in the world with a total wind power capacity of 6,270 MW in 2006. Wind power generates 3% of all electricity produced in India. The World Wind Energy Conference in New Delhi in November 2006 has given additional impetus to the Indian wind industry.^[1] The windfarm near Muppandal, Tamil Nadu, India, provides an impoverished village with energy for work.^[16][17] India-based Suzlon Energy is one of the world's largest wind turbine manufacturers.^[18] Muppandal (Tamil: முப்பந்தல்)is a small village on the southern tip of India in Kanyakumari District, in the state of Tamil Nadu. ... Tamil Nadu (தமிழ் நாடு, Land of the Tamils) is a state at the southern tip of India. ... Suzlon Energy is the worlds largest fully-integrated wind power company. ...

In December 2003, General Electric installed the world's largest offshore wind turbines in Ireland, and plans are being made for more such installations on the west coast, including the possible use of floating turbines. “GE” redirects here. ...

On August 15, 2005, China announced it would build a 1000-megawatt wind farm in Hebei for completion in 2020. China reportedly has set a generating target of 20,000 MW by 2020 from renewable energy sources — it says indigenous wind power could generate up to 253,000 MW. Following the World Wind Energy Conference in November 2004, organised by the Chinese and the World Wind Energy Association, a Chinese renewable energy law was adopted. In late 2005, the Chinese government increased the official wind energy target for the year 2020 from 20 GW to 30 GW.^[19] is the 227th day of the year (228th in leap years) in the Gregorian calendar. ... Year 2005 (MMV) was a common year starting on Saturday (link displays full calendar) of the Gregorian calendar. ...

Mexico recently opened La Venta II wind power project as an important step in reducing Mexico's consumption of fossil fuels. The project (88MW) the first of its kind in Mexico, will provide 13 percent of the electricity needs of the state of Oaxaca and by 2012 will have a capacity of 3500 MW.

Another growing market is Brazil, with a wind potential of 143 GW.^[20] The federal government has created an incentive program, called Proinfa,^[21] to build production capacity of 3300 MW of renewable energy for 2008, of which 1422 MW through wind energy. The program seeks to produce 10% of Brazilian electricity through renewable sources. Brazil produced 320 TWh in 2004. France recently announced a very ambitious target of 12 500 MW installed by 2010. The terawatt hour (TW·h) is a unit for measuring energy. ...

View of wind farm near Muppandal, Tamilnadu in India

Over the 7 years from 2000-2006, Canada experienced rapid growth of wind capacity — moving from a total installed capacity of 137 MW to 1,451 MW, and showing a growth rate of 38% and rising.^[22] Particularly rapid growth has been seen in 2006, with total capacity growing to 1,451 MW by December, 2006, doubling the installed capacity from the 684 MW at end-2005.^[23] This growth was fed by provincial measures, including installation targets, economic incentives and political support. For example, the government of the Canadian province of Ontario announced on 21 March 2006 that it will introduce a feed-in tariff for wind power, referred to as 'Standard Offer Contracts', which may boost the wind industry across the province.^[24] In the Canadian province of Quebec, the state-owned hydroelectric utility plans beside current wind farm projects to purchase an additional 2000 MW by 2013.^[25] Image File history File linksMetadata Download high-resolution version (1280x474, 107 KB) [edit] Summary File links The following pages on the English Wikipedia link to this file (pages on other projects are not listed): Nagercoil Aralvaimozhi Metadata This file contains additional information, probably added from the digital camera or scanner... Image File history File linksMetadata Download high-resolution version (1280x474, 107 KB) [edit] Summary File links The following pages on the English Wikipedia link to this file (pages on other projects are not listed): Nagercoil Aralvaimozhi Metadata This file contains additional information, probably added from the digital camera or scanner... Muppandal (Tamil: முப்பந்தல்)is a small village on the southern tip of India in Kanyakumari District, in the state of Tamil Nadu. ... Motto: Ut Incepit Fidelis Sic Permanet (Latin: Loyal she began, loyal she remains) Capital Toronto Largest city Toronto Official languages English (de facto) Government - Lieutenant-Governor David C. Onley - Premier Dalton McGuinty (Liberal) Federal representation in Canadian Parliament - House seats 106 - Senate seats 24 Confederation July 1, 1867 (1st) Area... is the 80th day of the year (81st in leap years) in the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... This article is about the Canadian province. ...

Wind power in Europe

At the end of 2006 renewable energy in Germany provided 11. ... Offshore wind turbines near Copenhagen Some 20 per cent of Danish domestic electricity comes from wind [1]and Denmark is a leading wind power nation in the world. ...

Small scale

This rooftop-mounted urban wind turbine charges a 12 volt battery and runs various 12 volt appliances within the building on which it is installed.

Small Wind is defined as wind generation systems with capacities of 100 kW or less and are usually used to power homes, farms, and small businesses. Individuals purchase these systems to reduce or eliminate their electricity bills, to avoid the unpredictability of natural gas prices, or simply to generate their own clean power. Download high resolution version (1203x1167, 59 KB)Urbine (rooftop mounted urban wind turbine) The Lakota wind turbine from True North Power has been working well in the 330 Dundas Street location, Toronto, Ontario. ... Download high resolution version (1203x1167, 59 KB)Urbine (rooftop mounted urban wind turbine) The Lakota wind turbine from True North Power has been working well in the 330 Dundas Street location, Toronto, Ontario. ... Symbols representing a single Cell (top) and Battery (bottom), used in circuit diagrams. ...

Wind turbines have been used for household electricity generation in conjunction with battery storage over many decades in remote areas, but increasingly, U.S. consumers are choosing to purchase grid-connected turbines in the 1 to 10 kilowatt range to power their whole homes. Household generator units of more than 1 kW are now functioning in several countries, and in every state in the U.S. Symbols representing a single Cell (top) and Battery (bottom), used in circuit diagrams. ...

To compensate for the varying power output, grid-connected wind turbines may utilise some sort of grid energy storage. Off-grid systems either adapt to intermittent power or use photovoltaic or diesel systems to supplement the wind turbine. Ffestiniog pumped storage power station upper reservoir Grid energy storage lets energy producers send excess electricity over the electricity transmission grid to temporary electricity storage sites that become energy producers when electricity demand is greater. ... A solar cell, a form of photovoltaic cell, is a device that uses the photoelectric effect to generate electricity from light, thus generating solar power (energy). ... This article is about the fuel. ...

Wind turbines range from small four hundred watt generators for residential use to several megawatt machines for wind farms and offshore. The small ones sometimes, but not always, have direct drive generators, direct current output, aeroelastic blades, lifetime bearings and use a vane to point into the wind; while the larger ones 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 and direct current generators are sometimes used. Direct current (DC or continuous current) is the continuous flow of electricity through a conductor such as a wire from high to low potential. ...

In urban locations, where it is difficult to obtain predictable or large amounts of wind energy, smaller systems may still be used to run low power equipment. Distributed power from rooftop mounted wind turbines can also alleviate power distribution problems, as well as provide resilience to power failures. Equipment such as parking meters or wireless internet gateways may be powered by a wind turbine that charges a small battery, replacing the need for a connection to the power grid and/or maintaining service despite possible power grid failures. Distributed generation generates electricity from many small energy sources. ...

While installing a small wind turbine on a roof (rather than a tall tower elsewhere on a property) can be done successfully, there are a few inherent issues that this type of installation faces: Whether the roof can support the turbine's weight, how the building tolerates the vibrations from the spinning rotor, and the turbulence caused by the roof ledge and the resulting unpredictability in wind patterns.

Small-scale wind power in rural Indiana.

Small scale turbines for residential-scale use are available that are approximately 7 feet (2 m) to 25 feet (8 m) in diameter and produce electricity at a rate of 900 watts to 10,000 watts at their tested wind speed. Some units are designed to be very lightweight, e.g. 16 kilograms (35 lb), allowing rapid response to wind gusts typical of urban settings and easy mounting much like a television antenna. It is claimed that they are inaudible even a few feet under the turbine.^{[citation needed]} Dynamic braking regulates the speed by dumping excess energy, so that the turbine continues to produce electricity even in high winds. The dynamic braking resistor may be installed inside the building to provide heat (during high winds when more heat is lost by the building, while more heat is also produced by the braking resistor). The proximal location makes low voltage (12 volt, or the like) energy distribution practical. An additional benefit is that owners become more aware of electricity consumption, possibly reducing their consumption down to the average level that the turbine can produce. Image File history File links Download high resolution version (2560x1920, 1216 KB) File links The following pages link to this file: Wind power ... Image File history File links Download high resolution version (2560x1920, 1216 KB) File links The following pages link to this file: Wind power ... Dynamic braking is the use of the electric traction motors of a railroad vehicle as generators to slow the vehicle. ...

The American Wind Energy Association has released several studies on the small wind turbine market in the U.S. and abroad, showing that the U.S. continues to dominate the Small Wind industry.[13] According to another organization, the World Wind Energy Association, it is difficult to assess the total number or capacity of small-scaled wind turbines, but in China alone, there are roughly 300,000 small-scale wind turbines generating electricity.^[1]

The dominant model on the market, especially in the United States, is the propeller-shaped "Horizontal Axis" type, which resembles the large, utility-scale turbines used in wind "farms." An alternative model is known as "Vertical Axis," and rotates like a top and can come in many different designs.

There have been a number of recent developments of mini-windmills which could be adapted to home use, including:

• The AeroTecture vertical-axis turbine^[26]
• The AeroVironment Architectural Wind Project^[27][28]
• The piezoelectric windmill project^[29]
• The Swift home wind turbine.^[30] The Swift project peaked in 2004 and has had some implementation difficulties while promising to be a low-noise/safe roof-mount/low-cost alternative^[31]
• The Motorwave micro-wind turbine^[32][33][34]

Consumer guides are available to help potential customers learn about residential-scale wind systems, three of which are: This article is about the machine for converting the kinetic energy in the wind into mechanical energy. ... Piezoelectricity is the ability of certain crystals to produce a voltage when subjected to mechanical stress. ...

• "Small Wind Electric Systems: A U.S. Consumer's Guide" by the Dept. of Energy's Wind Powering America program [14]

• "Wind Turbine Buyer's Guide" From Home Power Magazine[15]

• "Apples & Oranges 2002: Choosing a Home-Sized Wind Generator" [16]

Much more information is also available at the American Wind Energy Association's web site at:

• www.awea.org/smallwind [17]
• FAQ: http://www.awea.org/smallwind/faq.html [18]
• www.awea.org/smallwind/toolbox2/index.html[19]

Wind power: key issues

Wind power can be a controversial issue, and several main areas of dispute are debated between supporters and opponents.

Erection of an Enercon E70-4 in Germany

Download high resolution version (1024x1365, 101 KB) Wikipedia does not have an article with this exact name. ... Download high resolution version (1024x1365, 101 KB) Wikipedia does not have an article with this exact name. ... Enercon E-112 Enercon GmbH, based in Aurich, Northern Germany, is the third-largest wind turbine manufacturer in the world and the market leader in Germany. ...

Growth and cost trends

Global Wind Energy Council (GWEC) figures show that 2006 recorded an increase of installed capacity of 15,197 megawatts (MW), taking the total installed wind energy capacity to 74,223 MW, up from 59,091 MW in 2005. Despite constraints facing supply chains for wind turbines, the annual market for wind continued to increase at an estimated rate of 32% following the 2005 record year, in which the market grew by 41%. In terms of economic value, the wind energy sector has become one of the important players in the energy markets, with the total value of new generating equipment installed in 2006 reaching €18 billion, or US$23 billion.^[12]

The countries with the highest total installed capacity are Germany (20,621 MW), Spain (11,615 MW), the USA (11,603 MW), India (6,270 MW) and Denmark (3,136). Thirteen countries around the world can now be counted among those with over 1,000 MW of wind capacity. In terms of new installed capacity in 2006, the US leads with 2,454 MW, followed by Germany (2,233 MW), India (1,840 MW), Spain (1,587 MW), China (1,347 MW) and France (810 MW).^[12]

In 2004, wind energy cost one-fifth of what it did in the 1980s, and some expected that downward trend to continue as larger multi-megawatt turbines are mass-produced.^[35] However, installation costs have increased significantly in 2005 and 2006, and according to the major U.S. wind industry trade group, now average over US$1,600 per kilowatt,^[36] compared to $1200/kW just a few years before. A British Wind Energy Association report gives an average generation cost of onshore wind power of around 3.2 pence per kilowatt hour (2005).^[37] Cost per unit of energy produced was estimated in 2006 to be comparable to the cost of new generating capacity in the United States for coal and natural gas: wind cost was estimated at $55.80 per MWh, coal at $53.10/MWh and natural gas at $52.50.^[38] Other sources in various studies have estimated wind to be more expensive than other sources (see Economics of new nuclear power plants, Clean coal, and Carbon capture and storage). This article is about the machine for converting the kinetic energy in the wind into mechanical energy. ... The Economics of new nuclear power plants is a controversial subject, since multi-billion dollar investments ride on the choice of an energy source. ... Clean coal is the name attributed to coal chemically washed of minerals and impurities, sometimes gasified, burned and the resulting flue gases treated with steam and reburned so as to make the carbon dioxide in the flue gas economically recoverable. ... Carbon capture and storage (CCS) is an approach to mitigating global warming by capturing carbon dioxide (CO2) from large point sources such as power plants and subsequently storing it instead of releasing it into the atmosphere. ...

Most major forms of electricity generation are capital intensive, meaning that they require substantial investments at project inception, and low ongoing costs (generally for fuel and maintenance). This is particularly true for wind and hydro power, which have fuel costs close to zero and relatively low maintenance costs; in economic terms, wind power has an extremely low marginal cost and a high proportion of up-front capital costs. The estimated "cost" of wind energy per unit of production is generally based on average cost per unit, which incorporates the cost of construction, borrowed funds, return to investors (including cost of risk), estimated annual production, and other components. Since these costs are averaged over the projected useful life of the equipment, which may be in excess of twenty years, cost estimates per unit of generation are highly dependent on these assumptions. Figures for cost of wind energy per unit of production cited in various studies can therefore differ substantially. The cost of wind power also depends on several other factors, such as installation of power lines from the wind farm to the national grid and the frequency of wind at the site in question. In economics and finance, marginal cost is the change in total cost that arises when the quantity produced changes by one unit. ... Marginal cost is a term in economics. ... The National Grid is the high-voltage electric power transmission network in Great Britain, connecting power stations and major substations and ensuring that electricity generated anywhere in Great Britain can be used to satisfy demand elsewhere. ...

Estimates for cost of production use similar methodologies for other sources of electricity generation. Existing generation capacity represents sunk costs, and the decision to continue production will depend on marginal costs going forward, not estimated average costs at project inception. For example, the estimated cost of new wind power capacity may be lower than that for "new coal" (estimated average costs for new generation capacity) but higher than for "old coal" (marginal cost of production for existing capacity). Therefore, the choice to increase wind capacity by building new facilities will depend on more complex factors than cost estimates, including the profile of existing generation capacity. In economics and in business decision-making, sunk costs are costs that have already been incurred and which cannot be recovered to any significant degree. ...

Research from a wide variety of sources in various countries shows that support for wind power is consistently between 70 and 80 per cent amongst the general public.^[39]

Scalability

A key issue debated about wind power is its ability to scale to meet a substantial portion of the world's energy demand. There are significant economic, technical, and ecological issues about the large-scale use of wind power that may limit its ability to replace other forms of energy production. Most forms of electricity production also involve such trade-offs, and many are also not capable of replacing all other types of production for various reasons. A key issue in the application of wind energy to replace substantial amounts of other electrical production is intermittency; see the section below on Economics and Feasibility. At present, it is unclear whether wind energy will eventually be sufficient to replace other forms of electricity production, but this does not mean wind energy cannot be a significant source of clean electrical production on a scale comparable to or greater than other technologies, such as hydropower. Most electrical grids use a mix of different generation types (baseload generating capacity and peaking capacity) to match demand cycles by attempting to match the variable nature of demand to the most economic form of production; with the exception of hydropower, most types of production capacity are not used for all production (hydropower usage is limited by the presence of appropriate geographical sites). For example, nuclear power is effective as a baseload technology, but cannot be easily varied in short timeframes, and gas turbine plants are most economically used as peaking capacity; coal generation is primarily considered appropriate for baseload generation with some capacity to cycle to meet demand. Intermittent power sources are sources of power generation, primarily electricity, whose power output is either variable or intermittent. ... Undershot water wheels on the Orontes River in Hama, Syria Saint Anthony Falls Hydropower is the capture of the energy of moving water for some useful purpose. ...

A significant part of the debate about the potential for wind energy to substitute for other electric production sources is the level of penetration. With the exception of Denmark, no countries or electrical systems produce more than 10% from wind energy, and most are below 2% (of course, this is in large part because wind power is a relatively new technology, with the vast majority of installations having taken place within the last 10 years). While the feasibility of integrating much higher levels (beyond 25%) is debated, significantly more wind energy could be produced worldwide before these issues become significant. In Denmark, wind power now accounts for close to 20% of electricity production^[40] and a recent poll of Danes show that 90% want more wind power installed.^[41]

Theoretical potential

Wind's long-term theoretical potential is much greater than current world energy consumption. The most comprehensive study to date^[42] found the potential of wind power on land and near-shore to be 72 TW (~171,000 Mtoe), or over fifteen times the world's current energy use and 40 times the current electricity use. The potential takes into account only locations with Class 3 (mean annual wind speeds ≥ 6.9 m/s at 80 m) or better wind regimes, which includes the locations suitable for low-cost (0.03–0.04 $/kWh) wind power generation and is in that sense conservative. It assumes 6 turbines per square km for 77 m diameter, 1.5 MW-turbines on roughly 13% of the total global land area (though that land would also be available for other compatible uses such as farming). However, the authors are quick to point out that many practical barriers would need to be overcome to reach this theoretical capacity. The calculations of potential assumes a capacity factor of 48% and does not take into account the practicality of reaching the windy sites, of transmission (including 'choke' points), of competing land uses, of transporting power over large distances, or of switching to wind power. For other uses, see Watt (disambiguation). ... The ton of oil equivalent (TOE) is a unit for measuring energy. ...

To determine the more realistic technical potential, it is essential to estimate how large a fraction of this land could be made available to wind power. In the 2001 IPCC report, it is assumed that a use of 4% – 10% of that land area would be practical.

Although the theoretical potential is vast, the amount of production that could be economically viable depends on a number of exogenous and endogenous factors, including the cost of other sources of electricity and the future cost of wind energy farms.^{[weasel words]}

Offshore resources experience mean wind speeds about 90% greater than those on land, so offshore resources could contribute about seven times more energy than land.^[43][44] This number could also increase with higher altitude or airborne wind turbines.^[45]

Economics and feasibility