Wind power facts for kids
Wind power is the use of wind energy to generate useful work. Historically, wind power was used by sails, windmills and windpumps, but today it is mostly used to generate electricity. Wind power is considered a sustainable, renewable energy source, and has a much smaller impact on the environment compared to burning fossil fuels.
Contents
History
Wind power has been used as long as humans have put sails into the wind. King Hammurabi's Codex (reign 1792 - 1750 BC) already mentioned windmills for generating mechanical energy. Wind-powered machines used to grind grain and pump water, the windmill and wind pump, were developed in what is now Iran, Afghanistan, and Pakistan by the 9th century. Wind power was widely available. Wind-powered pumps drained the polders of the Netherlands, and in arid regions such as the American mid-west or the Australian outback, wind pumps provided water for livestock and steam engines.
The first windmill used for the production of electric power was built in Scotland in July 1887 by Prof James Blyth of Anderson's College, Glasgow (the precursor of Strathclyde University). Blyth's 10 metres (33 ft) high cloth-sailed wind turbine was installed in the garden of his holiday cottage at Marykirk in Kincardineshire, and was used to charge accumulators developed by the Frenchman Camille Alphonse Faure, to power the lighting in the cottage, thus making it the first house in the world to have its electric power supplied by wind power. Blyth offered the surplus electric power to the people of Marykirk for lighting the main street, however, they turned down the offer as they thought electric power was "the work of the devil." Although he later built a wind turbine to supply emergency power to the local Lunatic Asylum, Infirmary, and Dispensary of Montrose, the invention never really caught on as the technology was not considered to be economically viable.
Across the Atlantic, in Cleveland, Ohio, a larger and heavily engineered machine was designed and constructed in the winter of 1887–1888 by Charles F. Brush. This was built by his engineering company at his home and operated from 1886 until 1900. The Brush wind turbine had a rotor 17 metres (56 ft) in diameter and was mounted on an 18 metres (59 ft) tower. Although large by today's standards, the machine was only rated at 12 kW. The connected dynamo was used either to charge a bank of batteries or to operate up to 100 incandescent light bulbs, three arc lamps, and various motors in Brush's laboratory.
With the development of electric power, wind power found new applications in lighting buildings remote from centrally generated power. Throughout the 20th century parallel paths developed small wind stations suitable for farms or residences.
From 1932 many isolated properties in Australia ran their lighting and electric fans from batteries, charged by a "Freelite" wind-driven generator, producing 100 watts of electrical power from as little wind speed as 10 miles per hour (16 km/h).
The 1973 oil crisis triggered the investigation in Denmark and the United States that led to larger utility-scale wind generators that could be connected to electric power grids for remote use of power. By 2008, the U.S. installed capacity had reached 25.4 gigawatts, and by 2012 the installed capacity was 60 gigawatts.
Today, wind-powered generators operate in every size range between tiny stations for battery charging at isolated residences, up to gigawatt-sized offshore wind farms that provide electric power to national electrical networks.
Wind farms and how they work
Wind is air movement in the earth's atmosphere. To convert the kinetic energy of wind into mechanical energy, which is then converted into electrical energy, wind turbines are used. The basic components of a wind turbine include a rotor, blades, a shaft, a gearbox, a generator, and a tower.
Wind turns the blades, which spins a rotor that is connected to a generator. The output of the generator is collected through electric power cables.
| Wind farm | Capacity (MW) |
Country | Refs |
|---|---|---|---|
| Gansu Wind Farm | 7,965 |  China |
|
| Muppandal wind farm | 1,500 |  India |
|
| Alta (Oak Creek-Mojave) | 1,320 |  United States |
|
| Jaisalmer Wind Park | 1,064 | India |
Turbines are generally grouped into wind farms and connected to the electrical grid. A wind farm is a group of wind turbines in the same location. A large wind farm may consist of several hundred wind turbines. In general, a distance of 7D (7 times the rotor diameter of the wind turbine) is set between each turbine in a fully developed wind farm. The land between the turbines may be used for agricultural or other purposes. A wind farm may also be located offshore.
Almost all large wind turbines have the same design — a horizontal axis wind turbine having an upwind rotor with 3 blades, attached to a nacelle on top of a tall tubular tower.
Offshore wind power
Offshore wind power is wind farms in large bodies of water, usually the sea. These farms have less visual impact on the landscape than land-based projects. However, the construction and maintenance costs are considerably higher.
As of November 2021, the Hornsea Wind Farm in the United Kingdom is the largest offshore wind farm in the world at 1,218 MW.
Small-scale wind power
Small-scale wind power is the name given to wind generation systems with the capacity to produce up to 50 kW of electrical power. Isolated communities, that may otherwise rely on diesel generators, may use wind turbines as an alternative. Individuals may purchase these systems to reduce or eliminate their dependence on grid electric power for economic reasons, or to reduce their carbon footprint. Wind turbines have been used for household electric power generation in conjunction with battery storage over many decades in remote areas.
Examples of small-scale wind power projects in an urban setting can be found in New York City, where, since 2009, several building projects have capped their roofs with Gorlov-type helical wind turbines. Although the energy they generate is small compared to the buildings' overall consumption, they help to reinforce the building's 'green' credentials in ways that "showing people your high-tech boiler" cannot, with some of the projects also receiving the direct support of the New York State Energy Research and Development Authority.
Impact on environment and landscape
Advantages
Wind power stations have the advantage over fossil fue power stations as they do not produce any greenhouse gases such as carbon dioxide or water vapour. They also do not produce gases that helps to make acid rain, such as sulphur dioxide. They also make the environment safer and less pollution is caused.
Disadvantages
Wind turbines have to be carefully placed. They must be in positions where there is a constant, steady supply of wind. In fact, the wind must not become too strong or it may damage the turbine. Because wind is uncontrollable, so is the amount of power that wind turbines will produce, making them a possibly unreliable source of energy.
Onshore wind farms can have a significant visual impact. Also, wind farms typically need to be spread over more land than other power stations and need to be built away from urban areas. Some wind farms can potentially spoil protected scenic areas, archaeological landscapes and heritage sites. A report by the Mountaineering Council of Scotland concluded that wind farms harmed tourism in areas known for natural landscapes and panoramic views.
Wind farms have a negative impacts on wildlife. Thousands of birds and bats, including rare species, have been killed by wind turbine blades, though wind turbines are responsible for far fewer bird deaths than fossil-fueled power stations. This can be mitigated with proper wildlife monitoring.
Many wind turbine blades are made of fiberglass, and have a lifetime of 20 years. However, many of them are non-recyclable.
Interesting facts about wind power
- In 2021, wind supplied over 1800 TWh of electricity, which was over 6% of world electricity and about 2% of world energy.
- Wind power is one of the lowest-cost electricity sources per unit of energy produced.
- Regions in the higher northern and southern latitudes have the highest potential for wind power.
- In most regions, wind power generation is higher in nighttime and in winter.
- In 1919, the German physicist Albert Betz showed that for a hypothetical ideal wind-energy extraction machine, the fundamental laws of conservation of mass and energy allowed no more than 16/27 (59%) of the kinetic energy of the wind to be captured.
- Wind power is variable, and during low wind periods, it may need to be replaced by other power sources.
- The energy payback time of a wind farm is typically around a year.
- An estimated 1.25 million people were employed in wind power in 2020.
- Wind turbines generate noise. At a distance of 300 metres (980 ft), this may be around 45 dB, which is slightly louder than a refrigerator. At 1.5 km (1 mi), they become inaudible.
- There are anecdotal reports of negative health effects on people who live very close to wind turbines. Peer-reviewed research has generally not supported these claims.
- Wind cannot be cut off unlike oil and gas so can contribute to energy security.
- Surveys of public attitudes across Europe and in many other countries show strong public support for wind power.
See also
In Spanish: Energía eólica para niños
Images for kids
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Global map of wind speed at 100 meters on land and around coasts.
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Wind energy generation by region over time
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Wind generation by country
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Share of electricity production from wind, 2022
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Wind turbines are typically installed in windy locations. In the image, wind power generators in Spain, near an Osborne bull.
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Seasonal cycle of capacity factors for wind and photovoltaics in Europe under idealized assumptions. The figure illustrates the balancing effects of wind and solar energy at the seasonal scale (Kaspar et al., 2019).
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Onshore wind cost per kilowatt-hour between 1983 and 2017
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A turbine blade convoy passing through Edenfield in the U.K. (2008). Even longer 2-piece blades are now manufactured, and then assembled on-site to reduce difficulties in transportation.
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Wind turbine floating off France
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Wind turbines such as these, in Cumbria, England, have been opposed for a number of reasons, including aesthetics, by some sectors of the population.
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A panoramic view of the United Kingdom's Whitelee Wind Farm with Lochgoin Reservoir in the foreground.
