Environmental effects of wind power - AbsoluteAstronomy.com

Compared to the environmental impact of traditional energy sources, the environmental impact of wind power is relatively minor. Wind power

Wind power

Wind power is the conversion of wind energy into a useful form of energy, such as using wind turbines to make electricity, windmills for mechanical power, windpumps for water pumping or drainage, or sails to propel ships....

consumes no fuel, and emits no air pollution

Air pollution

Air pollution is the introduction of chemicals, particulate matter, or biological materials that cause harm or discomfort to humans or other living organisms, or cause damage to the natural environment or built environment, into the atmosphere....

, unlike fossil fuel power sources. The energy consumed to manufacture and transport the materials used to build a wind power plant is equal to the new energy produced by the plant within a few months. While a wind farm may cover a large area of land, many land uses such as agriculture are compatible, with only small areas of turbine foundations and infrastructure made unavailable for use.

There are reports of bird and bat mortality at wind turbines as there are around other artificial structures. The scale of the ecological impact may or may not be significant, depending on specific circumstances. Prevention and mitigation of wildlife fatalities, and protection of peat bogs, affect the siting and operation of wind turbines.

There are anecdotal reports of negative effects from noise on people who live very close to wind turbines. Peer-reviewed research has generally not supported these statements.

Carbon dioxide emissions and pollution

Wind power consumes no fuel and no water for continuing operation, and has no emissions directly related to electricity production. Wind turbines produce no carbon dioxide

Carbon dioxide

Carbon dioxide is a naturally occurring chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom...

, carbon monoxide

Carbon monoxide

Carbon monoxide , also called carbonous oxide, is a colorless, odorless, and tasteless gas that is slightly lighter than air. It is highly toxic to humans and animals in higher quantities, although it is also produced in normal animal metabolism in low quantities, and is thought to have some normal...

, sulfur dioxide

Sulfur dioxide

Sulfur dioxide is the chemical compound with the formula . It is released by volcanoes and in various industrial processes. Since coal and petroleum often contain sulfur compounds, their combustion generates sulfur dioxide unless the sulfur compounds are removed before burning the fuel...

, nitrogen dioxide

Nitrogen dioxide

Nitrogen dioxide is the chemical compound with the formula it is one of several nitrogen oxides. is an intermediate in the industrial synthesis of nitric acid, millions of tons of which are produced each year. This reddish-brown toxic gas has a characteristic sharp, biting odor and is a prominent...

, mercury

Mercury (element)

Mercury is a chemical element with the symbol Hg and atomic number 80. It is also known as quicksilver or hydrargyrum...

, radioactive waste

Radioactive waste

Radioactive wastes are wastes that contain radioactive material. Radioactive wastes are usually by-products of nuclear power generation and other applications of nuclear fission or nuclear technology, such as research and medicine...

, particulates, or any other type of air pollution

Air pollution

, unlike fossil fuel power sources. Wind power plants consume resources in manufacturing and construction. During manufacture of the wind turbine, steel

Steel

Steel is an alloy that consists mostly of iron and has a carbon content between 0.2% and 2.1% by weight, depending on the grade. Carbon is the most common alloying material for iron, but various other alloying elements are used, such as manganese, chromium, vanadium, and tungsten...

, concrete

Concrete

Concrete is a composite construction material, composed of cement and other cementitious materials such as fly ash and slag cement, aggregate , water and chemical admixtures.The word concrete comes from the Latin word...

, aluminium

Aluminium

Aluminium or aluminum is a silvery white member of the boron group of chemical elements. It has the symbol Al, and its atomic number is 13. It is not soluble in water under normal circumstances....

and other materials will have to be made and transported using energy-intensive processes, generally using fossil energy sources. The wind turbine manufacturer Vestas states that initial carbon dioxide emissions "pay back" is within about 9 months of operation for off shore turbines.

A 2006 study found the emissions of wind power to range from 14 to 33 t (15.4 to 36.4 ST) per GWh of energy produced. Most of the emission comes from producing the concrete for wind-turbine foundations.

A study by the Irish national grid stated that "Producing electricity from wind reduces the consumption of fossil fuels and therefore leads to emissions savings", and found reductions in emissions ranging from 0.33 to 0.59 t (0.363762732605048 to 0.650363673445389 ST) of per MWh.

The UK Energy Research Centre

UK Energy Research Centre

The UK Energy Research Centre is the focal point for UK research on sustainable energy, and is central to the Research Councils' Energy Programme...

(UKERC) study of intermittency also states that wind energy can displace fossil fuel-based generation, reducing both fuel use and carbon dioxide emissions.
The production of permanent magnets used in some wind turbines makes use of neodymium

Neodymium

Neodymium is a chemical element with the symbol Nd and atomic number 60. It is a soft silvery metal that tarnishes in air. Neodymium was discovered in 1885 by the Austrian chemist Carl Auer von Welsbach. It is present in significant quantities in the ore minerals monazite and bastnäsite...

. Primarily exported by China, pollution concerns associated with the extraction of this rare-earth element have prompted government action in recent years, and international research attempts to refine the extraction process. Research is underway on turbine and generator designs which reduce the need for neodymium, or eliminate the use of rare-earth metals altogether.
However, Enercon did choose very early not to use permanent magnets for its direct drive turbines, in order to avoid responsibility in the bad environmental imprint of rare earth mining.

Net energy gain

The initial carbon dioxide emission from energy used in the installation is "paid back" within about 9 months of operation for off shore turbines. Any practical large-scale energy source must replace the energy used in its construction. The energy return on investment

EROEI

In physics, energy economics and ecological energetics, energy returned on energy invested ; or energy return on investment , is the ratio of the amount of usable energy acquired from a particular energy resource to the amount of energy expended to obtain that energy resource...

(EROI) for wind energy is equal to the cumulative electricity generated divided by the cumulative primary energy required to build and maintain a turbine. The EROI for wind ranges from 5 to 35, with an average of around 18, according to wind-energy advocates. EROI is strongly proportional to turbine size, and larger late-generation turbines are at the high end of this range, at or above 35. Since energy produced is several times energy consumed in construction, there is a net energy gain

Net energy gain

Net Energy Gain is a concept used in energy economics that refers to the difference between the energy expended to harvest an energy source and the amount of energy gained from that harvest. The net energy gain, which can be expressed in joules, differs from the net financial gain that may result...

Land use

Wind farms are often built on land that has already been impacted by land clearing. The vegetation clearing and ground disturbance required for wind farms is minimal compared with coal mines and coal-fired power stations. If wind farms are decommissioned, the landscape can be returned to its previous condition, although the concrete foundations will be left in place and access tracks may also be retained.

Farmers and graziers often lease land to companies building wind farms. In the U.S., farmers may receive annual lease payments of two thousand to five thousand dollars per turbine, and wind farms may also provide additional community payments "...to reward residents who have made no financial gains [directly] from wind energy development, but whose views of... [the] landscape now include a panorama of turbines".

The land can still be used for farming and cattle grazing. Livestock are unaffected by the presence of wind farms. International experience shows that livestock will "graze right up to the base of wind turbines and often use them as rubbing posts or for shade".

Wind-energy advocates contend that less than 1% of the land would be used for foundations and access roads, the other 99% could still be used for farming. Critics point out that the clearing of trees around tower bases may be necessary for installation sites on mountain ridges, such as in the northeastern U.S.

Turbines are not generally installed in urban areas. Buildings interfere with wind, turbines must be sited a safe distance ("setback") from residences in case of failure, and the value of land is high. There are a few notable exceptions to this. Toronto Hydro

Toronto Hydro

The Toronto Hydro-Electric System is the local distributor of electric power in the City of Toronto. In 2005 the utility served a peak load of over 5,000 MW and had nearly 600,000 residential and 70,000 commercial and industrial customers, and had around 1,600 employees. In 2005 the corporation...

has built a lake shore demonstration project, and Steel Winds

Steel Winds

Steel Winds is a wind energy project located on the coast of Lake Erie in Lackawanna, New York, just south of the City of Buffalo proper in Erie County. The project is situated on of the brownfield that was the former Bethlehem Steel Plant...

is a 20 MW urban project south of Buffalo, New York

Buffalo, New York

Buffalo is the second most populous city in the state of New York, after New York City. Located in Western New York on the eastern shores of Lake Erie and at the head of the Niagara River across from Fort Erie, Ontario, Buffalo is the seat of Erie County and the principal city of the...

. Both of these projects are in urban locations, but benefit from being on uninhabited lake shore property.

In the UK there has also been concern about the damage caused to peat bogs, with one Scottish MEP

Member of the European Parliament

A Member of the European Parliament is a person who has been elected to the European Parliament. The name of MEPs differ in different languages, with terms such as europarliamentarian or eurodeputy being common in Romance language-speaking areas.When the European Parliament was first established,...

campaigning for a moratorium on wind developments on peatlands saying that "Damaging the peat causes the release of more carbon dioxide than wind farms save".

Offshore locations use no land and avoid shipping channels.

Impact on wildlife

Environmental assessments are routinely carried out for wind farm proposals, and potential impacts on the local environment (e.g. plants, animals, soils) are evaluated. Turbine locations and operations are often modified as part of the approval process to avoid or minimise impacts on threatened species and their habitats. Any unavoidable impacts can be offset with conservation improvements of similar ecosystems which are unaffected by the proposal.

Projects such as the Black Law Wind Farm

Black Law Wind Farm

The 42-turbine Black Law Wind Farm has a total capacity of 97 megawatts , sufficient to meet the average electricity needs of 70,000 homes each year - or a town the size of Paisley - and is estimated to save around 200,000 tonnes of carbon dioxide emissions a year.The £90 million wind farm is...

have received wide recognition for its contribution to environmental objectives, including praise from the Royal Society for the Protection of Birds

Royal Society for the Protection of Birds

Bird Notes and News was first published in April 1903.The title changed to 'Bird Notes' in 1947. In the 1950s, there were four copies per year . Each volume covered two years, spread over three calendar years...

, who describe the scheme as both improving the landscape of a derelict opencast mining site and also benefiting a range of wildlife in the area, with an extensive habitat management projects covering over 14 square kilometres.

A research agenda from a coalition of researchers from universities, industry, and government, supported by the Atkinson Center for a Sustainable Future

Atkinson Center for a Sustainable Future

The David R. Atkinson Center for a Sustainable Future is a research organization created in Fall 2007 at Cornell University. ACSF advances multidisciplinary research in Energy, the Environment and Economic Development, and cultivates collaborations within and beyond Cornell.- History :ACSF,...

, suggests modeling the spatiotemporal patterns of migratory and residential wildlife with respect to geographic features and weather, to provide a basis for science-based decisions about where to site new wind projects. More specifically, it suggests:

Use existing data on migratory and other movements of wildlife to develop predictive models of risk.
Use new and emerging technologies, including radar, acoustics, and thermal imaging, to fill gaps in knowledge of wildlife movements.
Identify specific species or sets of species most at risk in areas of high potential wind resoures.

Birds

A study estimates that wind farms are responsible for 0.3 to 0.4 fatalities per gigawatt-hour (GWh) of electricity while fossil-fueled power stations are responsible for about 5.2 fatalities per GWh. The study therefore states that fossil fuel

Fossil fuel

Fossil fuels are fuels formed by natural processes such as anaerobic decomposition of buried dead organisms. The age of the organisms and their resulting fossil fuels is typically millions of years, and sometimes exceeds 650 million years...

based electricity causes about 10 times more fatalities than wind farm

Wind farm

A wind farm is a group of wind turbines in the same location used to produce electric power. A large wind farm may consist of several hundred individual wind turbines, and cover an extended area of hundreds of square miles, but the land between the turbines may be used for agricultural or other...

based electricity, primarily due to habitat alteration from pollution and mountain-top removal for coal mining. In Denmark, where wind turbines generate 9% of electricity, wind turbines kill about 30,000 birds per year. In the United States, the U.S. Fish and Wildlife Service estimated in 2009, that turbines kill 440,000 birds per year, though mortality is expected to increase significantly as wind power generation expands by 2030 to levels about 12 times higher than 2009 levels. In comparison, 80,000 birds are killed by aircraft, and 500 million killed by cats every year. Even greater numbers of bird deaths are attributed to collisions with buildings. Other studies have stated that 57 million are killed by cars, 97.5 million killed by collisions with plate glass, and hundreds of millions killed by cats. An article in Nature
Nature (journal)
Nature, first published on 4 November 1869, is ranked the world's most cited interdisciplinary scientific journal by the Science Edition of the 2010 Journal Citation Reports...

stated that each wind turbine kills an average of 4.27 birds per year.

In the UK, the Royal Society for the Protection of Birds (RSPB

Royal Society for the Protection of Birds

) concluded that "The available evidence suggests that appropriately positioned wind farms do not pose a significant hazard for birds." It notes that climate change poses a much more significant threat to wildlife, and therefore supports wind farms and other 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...

. In 2009 the RSPB warned that "numbers of several breeding birds of high conservation concern are reduced close to wind turbines," probably because "birds may use areas close to the turbines less often than would be expected, potentially reducing the carrying capacity of an area." The National Audubon Society

National Audubon Society

The National Audubon Society is an American non-profit environmental organization dedicated to conservation. Incorporated in 1905, Audubon is one of the oldest of such organizations in the world and uses science, education and grassroots advocacy to advance its conservation mission...

in the U.S. takes a similar position, broadly supporting wind power to help mitigate global warming

Mitigation of global warming

Climate change mitigation is action to decrease the intensity of radiative forcing in order to reduce the potential effects of global warming. Mitigation is distinguished from adaptation to global warming, which involves acting to tolerate the effects of global warming...

, while cautioning against siting wind farms in areas especially important to birds and other affected wildlife.

Concerns have been expressed that wind turbines at Smøla

Smøla

Smøla is a municipality in Møre og Romsdal county, Norway. It is part of the Nordmøre region. The administrative centre of the municipality is the village of Hopen, other villages include Dyrnes, Råket, and Veiholmen.-General information:...

in Norway

Norway

Norway , officially the Kingdom of Norway, is a Nordic unitary constitutional monarchy whose territory comprises the western portion of the Scandinavian Peninsula, Jan Mayen, and the Arctic archipelago of Svalbard and Bouvet Island. Norway has a total area of and a population of about 4.9 million...

are having a deleterious effect on the population of White-tailed Eagle

White-tailed Eagle

The White-tailed Eagle , also known as the Sea Eagle, Erne , or White-tailed Sea-eagle, is a large bird of prey in the family Accipitridae which includes other raptors such as hawks, kites, and harriers...

s, Europe's largest bird of prey

Bird of prey

Birds of prey are birds that hunt for food primarily on the wing, using their keen senses, especially vision. They are defined as birds that primarily hunt vertebrates, including other birds. Their talons and beaks tend to be relatively large, powerful and adapted for tearing and/or piercing flesh....

. They have been the subject of an extensive re-introduction programme 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...

, which could be jeopardised by the expansion of wind turbines.

The Peñascal Wind Power Project

Peñascal Wind Power Project

The 404 megawatt Peñascal Wind Farm is located in Kenedy County, Texas and was completed in April 2010.The wind farm has 168 Mitsubishi MHI 92 wind turbines, each with a capacity of 2.4 MW. The facility created some 20 direct jobs in maintenance and operation of the wind farms. Around 200 people...

in Texas is located in the middle of a major bird migration

Bird migration

Bird migration is the regular seasonal journey undertaken by many species of birds. Bird movements include those made in response to changes in food availability, habitat or weather. Sometimes, journeys are not termed "true migration" because they are irregular or in only one direction...

route, and the wind farm uses avian

Bird

Birds are feathered, winged, bipedal, endothermic , egg-laying, vertebrate animals. Around 10,000 living species and 188 families makes them the most speciose class of tetrapod vertebrates. They inhabit ecosystems across the globe, from the Arctic to the Antarctic. Extant birds range in size from...

radar originally developed for NASA

NASA

The National Aeronautics and Space Administration is the agency of the United States government that is responsible for the nation's civilian space program and for aeronautics and aerospace research...

and the United States Air Force

United States Air Force

The United States Air Force is the aerial warfare service branch of the United States Armed Forces and one of the American uniformed services. Initially part of the United States Army, the USAF was formed as a separate branch of the military on September 18, 1947 under the National Security Act of...

to detect birds as far as four miles away. If the system determines that the birds are in danger of running into the rotating blades, it shuts down the turbines. The system automatically restarts the turbines when the birds have passed.

At the Altamont Pass Wind Farm

Altamont Pass Wind Farm

The Altamont Pass Wind Farm is located in the Altamont Pass of the Diablo Range in Central California. It is one of the earliest wind farms in the United States. The wind farm is composed of 4930 relatively small wind turbines of various types, making it at one time the largest farm in the world in...

in California, a settlement has been reached between the Audubon Society, Californians for Renewable Energy and NextEra Energy Resources (who operate some 5,000 turbines in the area). Nearly half of the smaller turbines will be replaced by newer, more bird-friendly models. The project is expected to be complete by 2015 and includes $2.5 million for raptor habitat restoration.

Some paths of bird migration

Bird migration

, particularly for birds that fly by night, are unknown. A study suggests that migrating birds may avoid the large turbines, at least in the low-wind non-twilight conditions studied. A Danish 2005 (Biology Letters

Biology Letters

Biology Letters is a peer-reviewed scientific journal. It was split off as a separate journal from the Philosophical Transactions of the Royal Society B: Biological Sciences in 2005 after having been published as a supplement. Originally it was published quarterly, but from 2007 it has been...

2005:336) study showed that radio tagged migrating birds traveled around offshore wind farms. Less than 1% of migrating birds passing an offshore wind farm in Rønde, Denmark, got close to collision, though the site was studied only during low-wind non-twilight conditions.

Bats

Bats may be injured by direct impact with turbine blades, towers, or transmission lines. Recent research shows that bats may also be killed when suddenly passing through a low air pressure region surrounding the turbine blade tips.

The numbers of bat

Bat

Bats are mammals of the order Chiroptera "hand" and pteron "wing") whose forelimbs form webbed wings, making them the only mammals naturally capable of true and sustained flight. By contrast, other mammals said to fly, such as flying squirrels, gliding possums, and colugos, glide rather than fly,...

s killed by existing onshore and near-shore facilities has troubled bat enthusiasts. A study in 2004 estimated that over 2,200 bats were killed by 63 onshore turbines in just six weeks at two sites in the eastern U.S. This study suggests some onshore and near-shore sites may be particularly hazardous to local bat populations and more research is needed. Migratory bat species appear to be particularly at risk, especially during key movement periods (spring and more importantly in fall). Lasiurines such as the hoary bat

Hoary bat

The hoary bat is a species of bat in the vesper bat family, Vespertilionidae. It occurs throughout most of North America and much of South America, with disjunct populations in the Galapagos and Hawaiian Islands...

, red bat

Red bat

Red bat may refer to:*Eastern Red Bat , a species of bat found in the Eastern United States*Western Red Bat , a species of bat found in Western United States, also called the "Desert red bat"...

, and the silver-haired bat

Silver-Haired Bat

The Silver-haired Bat is a species of vesper bat in the family Vespertilionidae and the only member of the genus Lasionycteris.- Habitat :...

appear to be most vulnerable at North American sites. Almost nothing is known about current populations of these species and the impact on bat numbers as a result of mortality at windpower locations. It has been suggested that bats are attracted to these structures in search of roosts. Offshore wind sites 10 km (6 mi) or more from shore do not interact with bat populations.

Scientists at the U.S. Geological Survey have already conducted research using stable isotope analysis

Isotope analysis

Isotope analysis is the identification of isotopic signature, the distribution of certain stable isotopes and chemical elements within chemical compounds. This can be applied to a food web to make it possible to draw direct inferences regarding diet, trophic level, and subsistence...

to track migration among terrestrial mammals. USGS scientists are currently applying this technique in their efforts to figure out the geographic origins of bats killed by wind turbines.

In April 2009 the Bats and Wind Energy Cooperative released initial study results showing a 73% drop in bat fatalities when wind farm operations are stopped during low wind conditions, when bats are most active.

Bats avoid radar transmitters, and placing microwave transmitters on wind turbine towers may reduce the number of bat collisions.

Climate change

Wind farms may affect weather in their immediate vicinity. Spinning wind turbine rotors generate a lot of turbulence in their wakes like the wake of a boat. This turbulence increases vertical mixing of heat and water vapor that affects the meteorological conditions downwind. The first study to demonstrate impacts of wind farms on weather and climate used a regional climate model. Data from an operational wind farm in Palm Springs, California, confirmed the model results. Overall, wind farms lead to a warming at night and cooling during the day time. This effect can be reduced by using more efficient rotors or placing wind farms in regions with high natural turbulence. Somnath Baidya Roy, the author of the study suggested that the warming at night could "benefit agriculture by decreasing frost damage and extending the growing season. Many farmers already do this with air circulators".

A number of studies have used climate models to study the effect of extremely large wind farms. One study reports simulations that show detectable changes in global climate for very high wind farm usage, on the order of 10% of the world's land area. Wind power has a negligible effect on global mean surface temperature, and it would deliver "enormous global benefits by reducing emissions of CO2 and air pollutants". Another study published in Atmospheric Chemistry and Physics suggested that using wind turbines to meet 10 percent of global energy demand in 2100 could actually have a warming effect, causing temperatures to rise by 1 C-change in the regions on land where the wind farms are installed, including a smaller increase in areas beyond those regions. This is due to the effect of wind turbines on both horizontal and vertical atmospheric circulation. Whilst turbines installed in water would have a cooling effect, the net impact on global surface temperatures would be an increase of 0.15 C-change. Author Ron Prinn cautioned against interpreting the study "as an argument against wind power, urging that it be used to guide future research". "We’re not pessimistic about wind," he said. "We haven’t absolutely proven this effect, and we’d rather see that people do further research".

Hazardous waste

In 2011, a Minnesota wind-turbine blade manufacturing plant was fined $490,000 for air quality, hazardous waste, and stormwater violations.

Safety

Operation of any utility-scale energy conversion system presents safety hazards. Wind turbines do not consume fuel or produce pollution during normal operation, but still have hazards associated with their construction, operation and maintenance.

With the installation of industrial sized wind turbines numbering in the thousands, there have been at least 40 fatalities of workers due to the construction, operation, and maintenance of wind turbines, and other injuries and deaths attributed to the wind power life cycle. Most worker deaths involve falls or becoming caught in machinery while performing maintenance inside turbine housings.

If a turbine's brake fails, the turbine can spin freely until it disintegrates or catches fire. Often turbine fires cannot be extinguished because of the height, and are left to burn themselves out. In the process, they generate toxic fumes and can scatter flaming debris over a wide area, starting secondary fires below. Several turbine-ignited fires have burned hundreds of acres of vegetation each, and one burned 800 square kilometres (197,684.1 acre) of Australian National Park.

During winter ice may form on turbine blades and subsequently be thrown off during operation. This is a potential safety hazard, and has led to localised shut-downs of turbines.. Modern turbines can detect ice formation, and shut down.

Electronic controllers and safety sub-systems monitor many different aspects of the turbine, generator, tower, and environment to determine if the turbine is operating in a safe manner within prescribed limits. These systems can temporarily shut down the turbine due to high wind, ice, electrical load imbalance, vibration, and other problems. Recurring or significant problems cause a system lockout and notify an engineer for inspection and repair. In addition, most systems include multiple passive safety systems that stop operation even if the electronic controller fails.

In his book Wind Energy Comes of Age, Paul Gipe estimated that the mortality rate for wind power from 1980–1994 was 0.4 deaths per terawatt-hour. Paul Gipe's estimate as of end 2000 was 0.15 deaths per TWh, a decline attributed to greater total cumulative generation.

Aesthetics

Newer wind farms have larger, more widely spaced turbines, and have a less cluttered appearance than older installations. Wind farms are often built on land that has already been impacted by land clearing and they coexist easily with other land uses (e.g. grazing, crops). They have a smaller footprint than other forms of energy generation such as coal and gas plants. Wind farms may be close to scenic or otherwise undeveloped areas, and aesthetic issues are important for onshore and near-shore locations.

Aesthetic issues are subjective and some people find wind farms pleasant and optimistic, or symbols of energy independence

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...

and local prosperity. While some tourism officials predict wind farms will damage tourism, some wind farm

Wind farm

s have themselves become tourist attractions, with several having visitor centers at ground level or even observation decks atop turbine towers.

Residents near turbines may complain of "shadow flicker" on nearby residences caused by rotating turbine blades, when the sun passes behind the turbine. This can easily be avoided by locating the wind farm to avoid unacceptable shadow flicker, or by turning the turbine off for the few minutes of the day when the sun is at the angle that causes flicker.

Wind towers require aircraft warning lights

Aircraft warning lights

Aircraft warning lights are high-intensity lighting devices that are attached to tall structures and are used as collision avoidance measures. Such devices make structures more visible to passing aircraft and are usually used at night, although they may be used during the day as well...

, which may create light pollution

Light pollution

Light pollution, also known as photopollution or luminous pollution, is excessive or obtrusive artificial light.The International Dark-Sky Association defines light pollution as:...

. Complaints about these lights have caused the FAA to consider allowing fewer lights per turbine in certain areas.

Noise

Modern wind turbines produce significantly less noise than older designs. Turbine designers work to minimise noise, as noise reflects lost energy and output. Noise levels at nearby residences may be managed through the siting of turbines, the approvals process for wind farms, and operational management of the wind farm.

Renewable UK, a wind energy trade organization, has said that the noise measured 305 metres (1,000.7 ft) from a wind farm is less than that from normal road traffic or in an office; some physicians and acoustic engineers have reported problems from wind turbine noise, including sleep deprivation, headaches, dizziness, anxiety, and vertigo.

Nina Pierpont, a New York pediatrician and wife of an anti-wind energy activist, states that noise can be an important disadvantage of wind turbines, especially when building the wind turbines very close to urban environments. The controversy around Pierpont's work centers around her statements made in a self-published, non-peer-reviewed book that ultra-low frequency sounds affect human health, which are based on a very small sample of self-selected subjects with no control group for comparison. She asserts that wind turbines affect the mood of people and may cause physiological problems such as insomnia, headaches, tinnitus, vertigo and nausea.

In December 2006, a Texas jury denied a noise pollution suit against FPL Energy, after the company demonstrated that noise readings were not excessive. The highest reading was 44 decibels, which was characterized as about the same level as a 10 miles per hour (16.1 km/h) wind. The nearest residence among the plaintiffs was 1700 feet (518.2 m) from one of the turbines. More recent lawsuits have been brought in Missouri, Pennsylvania, and Maine.

In the Canadian Province of Ontario, the Ministry of the Environment

Ministry of the Environment (Ontario)

The Ministry of the Environment, established in 1972, is the portfolio in the Executive Council of Ontario responsible for addressing the environmental issues affecting the environmental protection of the Canadian province of Ontario and the World...

created noise guidelines to limit wind turbine noise levels 30 metres away from a dwelling or campsite to 40 dB(A). These regulations also set a minimum distance of 550 metres (1,804.5 ft) for a group of up to five relatively quiet [102 dB(A)] turbines within a 3 kilometres (1.9 mi) radius, rising to 1500 metres (4,921.3 ft) for a group of 11 to 25 noisier (106-107 dB(A)) turbines. Larger facilities and noisier turbines would require a noise study.

In a 2009 report about "Rural Wind Farms", a Standing Committee of the Parliament of New South Wales, Australia, recommended a minimum setback of two kilometres between wind turbines and neighbouring houses (which can be waived by the affected neighbour) as a precautionary approach. In July 2010, Australia's National Health and Medical Research Council

National Health and Medical Research Council

The National Health and Medical Research Council is Australia's peak funding body for medical research, with a budget of roughly 700 million dollars a year...

reported that "there is no published scientific evidence to support adverse effects of wind turbines on health".

A 2008 guest editorial in Environmental Health Perspectives
Environmental Health Perspectives
Environmental Health Perspectives is a peer-reviewed open-access medical journal published monthly by the National Institute of Environmental Health Sciences. According to the Journal Citation Reports, the journal has a 2009 impact factor of 6.191....

published by the National Institute of Environmental Health Sciences

National Institute of Environmental Health Sciences

The National Institute of Environmental Health Sciences is a part of the National Institutes of Health , which is in turn a part of the Department of Health and Human Services ....

, the U.S. National Institutes of Health

National Institutes of Health

The National Institutes of Health are an agency of the United States Department of Health and Human Services and are the primary agency of the United States government responsible for biomedical and health-related research. Its science and engineering counterpart is the National Science Foundation...

, stated: "Even seemingly clean sources of energy can have implications on human health. Wind energy will undoubtedly create noise, which increases stress, which in turn increases the risk of cardiovascular disease and cancer."

The Japanese Environment Ministry will begin a "major study into the influence of sounds of wind turbines on people's health" in April 2010, because "people living near wind power facilities are increasingly complaining of health problems". They plan a four-year examination of all 1,517 wind turbines in the country.

A 2007 report by the U.S. National Research Council noted that noise produced by wind turbines is generally not a major concern for humans beyond a half-mile or so. Low-frequency vibration and its effects on humans are not well understood and sensitivity to such vibration resulting from wind-turbine noise is highly variable among humans. There are opposing views on this subject, and more research needs to be done on the effects of low-frequency noise on humans.

Research by Stefan Oerlemans for the University of Twente and the Dutch National Aerospace Laboratory

National Aerospace Laboratory

The Nationaal Lucht- en Ruimtevaartlaboratorium is the National Aerospace Laboratory of the Netherlands and is one of the Major Technological Institutes of the country. These institutes perform a large part of the applied research in the Netherlands, each within its own specific field of technology...

suggests that noise from existing wind turbines may be reducible by up to half by adding "saw teeth" to the trailing edges of the blades, although research is not complete.

2009 review

A 2009 expert panel review, described as being the most comprehensive to date, delved into the possible adverse health effects of those living close to wind turbines. Their report findings concluded that 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...

s do not directly make people ill.

The 85-page study was sponsored by the Canadian Wind Energy Association and American Wind Energy Association

American Wind Energy Association

Formed in 1974, the American Wind Energy Association is a Washington, D.C.-based national trade association representing wind power project developers, equipment suppliers, service providers, parts manufacturers, utilities, researchers, and others involved in the wind industry.With over 2,500...

. The academic and medical experts who conducted the study stated that they reached their conclusions independent of their sponsors. "We were not told to find anything," said panel expert David Colby, a public health officer in Chatham-Kent and a Professor of Medicine at the University of Western Ontario

University of Western Ontario

The University of Western Ontario is a public research university located in London, Ontario, Canada. The university's main campus covers of land, with the Thames River cutting through the eastern portion of the main campus. Western administers its programs through 12 different faculties and...

. "It was completely open ended."

The study did allow that some people could experience stress or irritation caused by the swishing sounds wind turbines produce. "A small minority of those exposed report annoyance and stress associated with noise perception

Psychoacoustics

Psychoacoustics is the scientific study of sound perception. More specifically, it is the branch of science studying the psychological and physiological responses associated with sound...

..." [however] "Annoyance is not a disease." The study group pointed out that similar irritations are produced by local and highway vehicles

Roadway noise

Roadway noise is the collective sound energy emanating from motor vehicles. In the USA it contributes more to environmental noise exposure than any other noise source, and is constituted chiefly of engine, tire, aerodynamic and braking elements...

, as well as from industrial operations

Industrial noise

Industrial noise is usually considered mainly from the point of view of environmental health and safety, rather than nuisance, as sustained exposure can cause permanent hearing damage. Traditionally, occupational noise has been a hazard linked to heavy industries such as ship-building and...

and aircraft

Aircraft noise

Aircraft noise is noise pollution produced by any aircraft or its components, during various phases of a flight: on the ground while parked such as auxiliary power units, while taxiing, on run-up from propeller and jet exhaust, during take off, underneath and lateral to departure and arrival paths,...

.

The report found, amongst other things, that:

"Wind Turbine Syndrome" symptoms are the same as those seen in the general population due to stresses of daily life. They include headache
Headache
A headache or cephalalgia is pain anywhere in the region of the head or neck. It can be a symptom of a number of different conditions of the head and neck. The brain tissue itself is not sensitive to pain because it lacks pain receptors. Rather, the pain is caused by disturbance of the...

s, insomnia
Insomnia
Insomnia is most often defined by an individual's report of sleeping difficulties. While the term is sometimes used in sleep literature to describe a disorder demonstrated by polysomnographic evidence of disturbed sleep, insomnia is often defined as a positive response to either of two questions:...

, anxiety
Anxiety
Anxiety is a psychological and physiological state characterized by somatic, emotional, cognitive, and behavioral components. The root meaning of the word anxiety is 'to vex or trouble'; in either presence or absence of psychological stress, anxiety can create feelings of fear, worry, uneasiness,...

, dizziness
Dizziness
Dizziness refers to an impairment in spatial perception and stability. The term is somewhat imprecise. It can be used to mean vertigo, presyncope, disequilibrium, or a non-specific feeling such as giddiness or foolishness....

, etc...
low frequency
Low frequency
Low frequency or low freq or LF refers to radio frequencies in the range of 30 kHz–300 kHz. In Europe, and parts of Northern Africa and of Asia, part of the LF spectrum is used for AM broadcasting as the longwave band. In the western hemisphere, its main use is for aircraft beacon,...

and very low-frequency "infrasound
Infrasound
Infrasound is sound that is lower in frequency than 20 Hz or cycles per second, the "normal" limit of human hearing. Hearing becomes gradually less sensitive as frequency decreases, so for humans to perceive infrasound, the sound pressure must be sufficiently high...

" produced by wind turbines are the same as those produced by vehicular traffic
Roadway noise
Roadway noise is the collective sound energy emanating from motor vehicles. In the USA it contributes more to environmental noise exposure than any other noise source, and is constituted chiefly of engine, tire, aerodynamic and braking elements...

and home appliance
Home appliance
Home appliances are electrical/mechanical machines which accomplish some household functions, such as cooking or cleaning. Home appliances can be classified into:*Major appliances, or White goods*Small appliances, or Brown goods...

s, even by the beating of people's hearts. Such 'infrasounds' are not special and convey no risk factors;
Colby stated that evidence of harm was so minuscule that the wind associations were unable to initiate other independent collinear studies by government agencies. It was not surprising that their requests met with complete blanks on the need to examine the issues further;
one study member noted: "You can't control the amount of cars going by and wind turbine noise is generally quieter than highway noise";
the power of suggestion, as conveyed by news media
News media
The news media are those elements of the mass media that focus on delivering news to the general public or a target public.These include print media , broadcast news , and more recently the Internet .-Etymology:A medium is a carrier of something...

coverage of perceived 'wind-turbine sickness', might have triggered "anticipatory fear
Fear
Fear is a distressing negative sensation induced by a perceived threat. It is a basic survival mechanism occurring in response to a specific stimulus, such as pain or the threat of danger...

" in those close to turbine installations.

The study panel members included: Robert Dobie, a doctor and clinical professor at the University of Texas, Geoff Leventhall, a noise vibration

Noise, Vibration, and Harshness

Noise, vibration, and harshness , also known as noise and vibration , is the study and modification of the noise and vibration characteristics of vehicles, particularly cars and trucks...

and acoustics

Acoustics

Acoustics is the interdisciplinary science that deals with the study of all mechanical waves in gases, liquids, and solids including vibration, sound, ultrasound and infrasound. A scientist who works in the field of acoustics is an acoustician while someone working in the field of acoustics...

expert in the United Kingdom, Bo Sondergaard, with Danish Electronics Light and Acoustics, Michael Seilo, a professor of audiology

Audiology

Audiology is the branch of science that studies hearing, balance, and related disorders. Its practitioners, who treat those with hearing loss and proactively prevent related damage are audiologists. Employing various testing strategies Audiology (from Latin , "to hear"; and from Greek , -logia) is...

at Western Washington University

Western Washington University

Western Washington University is one of six state-funded, four-year universities of higher education in the U.S. state of Washington. It is located in Bellingham and offers bachelor's and master's degrees.-History:...

, and Robert McCunney, a biological engineering

Biological engineering

Biological engineering, biotechnological engineering or bioengineering is the application of concepts and methods of biology to solve problems in life sciences, using engineering's own analytical and synthetic methodologies and also its traditional...

scientist at the Massachusetts Institute of Technology

Massachusetts Institute of Technology

The Massachusetts Institute of Technology is a private research university located in Cambridge, Massachusetts. MIT has five schools and one college, containing a total of 32 academic departments, with a strong emphasis on scientific and technological education and research.Founded in 1861 in...

. McCunney contested statements that infrasounds from wind turbines could create vibration

Vibration

Vibration refers to mechanical oscillations about an equilibrium point. The oscillations may be periodic such as the motion of a pendulum or random such as the movement of a tire on a gravel road.Vibration is occasionally "desirable"...

s causing ill health: "It doesn't really have much credence, at least based on the literature out there" he stated.

Offshore

Many offshore wind farms are being built in UK waters. In January 2009, a comprehensive government environmental study of coastal waters in the United Kingdom concluded that there is scope for between 5,000 and 7,000 offshore wind turbines to be installed without an adverse impact on the marine environment. The study – which forms part of the Department of Energy and Climate Change's Offshore Energy Strategic Environmental Assessment – is based on more than a year's research. It included analysis of seabed geology, as well as surveys of sea birds and marine mammals.

Carbon dioxide emissions and pollution

Net energy gain

Land use

Impact on wildlife

Birds

Bats

Climate change

Hazardous waste

Safety

Aesthetics

Noise

2009 review

Offshore

See also