A summary of the existing field studies compiled in from the National Wind Coordinating Collaborative identified fewer than 14 and typically less than 4 bird deaths per installed megawatt per year, but a wider variation in the number of bat deaths. However, many details as well as the overall impact from the growing number of turbines remain unclear. Wind turbines generate some noise.
Environmental Impacts of Renewable Energy Technologies | Union of Concerned Scientists
The energy return on investment EROI for wind energy is equal to the cumulative electricity generated divided by the cumulative primary energy required to build and maintain a turbine. According to a meta study, in which all existing studies from to were reviewed, the EROI for wind ranges from 5 to 35,  with the most common turbines in the range of 2 MW nameplate capacity -rotor diameters of 66 meters, on average the EROI is Wind turbine manufacturer Vestas claims that initial energy "pay back" is within about 7—9 months of operation for a 1.
Wind power consumes no water  for continuing operation, and has near negligible emissions directly related to its electricity production. Wind turbines when isolated from the electric grid produce negligible amounts of carbon dioxide , carbon monoxide , sulfur dioxide , nitrogen dioxide , mercury and radioactive waste when in operation, unlike fossil fuel sources and nuclear energy station fuel production, respectively.
With the construction phase largely to blame, wind turbines emit slightly more particulate matter PM , a form of air pollution , at an "exception" rate higher per unit of energy generated kWh than a fossil gas electricity station " NGCC " ,   and also emit more heavy metals and PM than nuclear stations, per unit of energy generated.
Wind power externality costs were found to be 0. However these relatively low pollution values begin to increase as greater and greater wind energy is added to the grid, or wind power ' electric grid penetration' levels are reached. Due to the effects of attempting to balance out the energy demands on the grid, from Intermittent power sources e.
With the latter combination presently being the more common. When one includes the total effect of intermittent sources on other power sources in the grid system, that is, including these inefficient start up emissions of backup power sources to cater for wind energy, into wind energy's total system wide life cycle, this results in a higher real-world wind energy emission intensity.
In a paper that appeared in the Journal of Industrial Ecology it states. The thermal efficiency of fossil-based power plants is reduced when operated at fluctuating and suboptimal loads to supplement wind power, which may degrade, to a certain extent, the GHG Greenhouse gas benefits resulting from the addition of wind to the grid. While an increase in emissions due to the practical issues of load balancing is an issue, Pehnt et al. The production of permanent magnets used in some wind turbines makes use of neodymium.
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.
On average, there were 63 hectares acres of total wind farm area per MW of capacity, but only 0. In the UK many prime wind farm sites - locations with the best average wind speeds - are in upland areas which are frequently covered by blanket bog. This type of habitat exists in areas of relatively high rainfall where large areas of land remain permanently sodden. Construction work may create a risk of disruption to peatland hydrology which could cause localised areas of peat within the area of a wind farm to dry out, disintegrate, and so release their stored carbon.
At the same time, the warming climate which renewable energy schemes seek to mitigate could itself pose an existential threat to peatlands throughout the UK. A small kW-turbine with an annual production of 1. With increasing size of the wind turbine the relative size of the foundation decreases. 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. It was the first wind turbine installed in a major North American urban city centre. Both of these projects are in urban locations, but benefit from being on uninhabited lake shore property. 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". In , a first of its kind Veterinary study attempted to determine the effects of rearing livestock near a wind turbine, the study compared the health effects of a wind turbine on the development of two groups of growing geese , preliminary results found that geese raised within 50 meters of a wind turbine gained less weight and had a higher concentration of the stress hormone cortisol in their blood than geese at a distance of meters.
Semi-domestic reindeer avoid the construction activity,  but seem unaffected when the turbines are operating. Environmental assessments are routinely carried out for wind farm proposals, and potential impacts on the local environment e. Any unavoidable impacts can be offset with conservation improvements of similar ecosystems which are unaffected by the proposal.
A research agenda from a coalition of researchers from universities, industry, and government, supported by the Atkinson Center for a Sustainable Future , 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:. The impact of wind energy on birds, which can fly into turbines directly, or indirectly have their habitats degraded by wind development, is complex. Projects such as the Black Law Wind Farm have received wide recognition for its contribution to environmental objectives, including praise from the Royal Society for the Protection of Birds , 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.
The meta-analysis on avian mortality by Benjamin K. Sovacool led him to suggest that there were a number of deficiencies in other researchers' methodologies. The large cumulated footprint of wind turbines, which reduces the area available to wildlife or agriculture, is also missing from all studies including Sovacool's.
Many of the studies also made no mention of avian deaths per unit of electricity produced, which excluded meaningful comparisons between different energy sources. More importantly, it concluded, the most visible impacts of a technology, as measured by media exposure, are not necessarily the most flagrant ones. Sovacool estimated that in the United States wind turbines kill between 20, and , birds per year, and has stated he regards either figure as minimal compared to bird deaths from other causes.
He uses the lower 20, figure in his study and table see Causes of avian mortality table to arrive at a direct mortality rate per unit of energy generated figure of 0.
Wind farms now provide 14% of EU power – these countries are leading the way
Fossil-fueled power plants, which wind turbines generally require to make up for their weather dependent intermittency , kill almost 20 times as many birds per gigawatt hour GWh of electricity according to Sovacool. Bird deaths due to other human activities and cats total between million and 5. Additionally, while many studies concentrate on the analysis of bird deaths, few have been conducted on the reductions of bird births, which are the additional consequences of the various pollution sources that wind power partially mitigates. Of the bird deaths Sovacool attributed to fossil-fuel power plants, 96 percent were due to the effects of climate change.
While the study did not assess bat mortality due to various forms of energy, he considered it not unreasonable to assume a similar ratio of mortality. A meta-analysis by Smallwood identified a number of factors which result in serious under-reporting of bird and bat deaths by wind turbines. These include inefficient searches, inadequate search radius, and carcass removal by predators. To adjust the results of different studies, he applied correction factors from hundreds of carcass placement trials.
His meta-analysis concluded that in in the United States, wind turbines resulted in the deaths of , bats and , birds, including 83, birds of prey. Also in , a meta-analysis by Scott Loss and others in the journal Biological Conservation found that the likely mean number of birds killed annually in the U. S by monopole tower wind turbines was , The authors acknowledged the larger number reported by Smallwood, but noted that Smallwood's meta-analysis did not distinguish between types of wind turbine towers. The monopole towers used almost exclusively for new wind installations have mortality rates that "increase with increasing height of monopole turbines", but as of yet, it remains to be determined if increasingly taller monopole towers result in lower mortality per GWh.
Bird mortality at wind energy facilities can vary greatly depending on the location, construction, and height, with some facilities reporting zero bird fatalities, and others as high as 9. A comprehensive study of wind turbine bird deaths by the Canadian Wildlife Service in analyzed reports from 43 out of the wind farms operating across Canada as of December After adjusting for search inefficiencies, the study found an average of 8.
Actual habitat loss averaged 1. The effective habitat loss, which was not quantified, was observed to be highly variable between species: some species avoided nesting within to m from turbines, while other species were observed feeding on the ground directly under the blades.
The study concluded that, overall, the combined effect on birds was "relatively small" compared to other causes of bird mortality, but noted that mitigation measures might be required in some situations to protect at-risk species. While studies show that other sources, such as cats, cars, buildings, power lines, and transmission towers kill far more birds than wind turbines, many studies and conservation groups have noted that wind turbines disproportionately kill large migratory birds and birds of prey , and are more likely to kill birds threatened with extinction.
The Pine Tree Wind energy project near Tehachapi, California has one of the highest raptor mortality rates in the country; by at least eight golden eagles had been killed according to the U. Large numbers of bird deaths are also attributed to collisions with buildings. In the worst recorded ceilometer lightbeam kill-off during one night in , approximately 50, birds from 53 different species died at the Warner Robins Air Force Base in the United States. In the United Kingdom, the Royal Society for the Protection of Birds RSPB concluded that "The available evidence suggests that appropriately positioned wind farms do not pose a significant hazard for birds.
In 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 wildlife carrying capacity of an area. They have been the subject of an extensive re-introduction programme in Scotland , which could be jeopardised by the expansion of wind turbines. If the system determines that the birds are in danger of running into the rotating blades, the turbines shut down and are restarted when the birds have passed.
The study suggests that migrating birds may avoid large turbines, at least in the low-wind conditions the research was conducted in. In , researchers reported that, based on their four-year radar tracking study of birds after construction of an offshore wind farm near Lincolnshire , that pink-footed geese migrating to the U. 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 bats killed by existing onshore and near-shore facilities have troubled bat enthusiasts. A study produced an estimate that wind turbines killed more than , bats in the U. Some earlier studies had produced estimates of between 33, and , bat deaths per year. Wind farms may affect weather in their immediate vicinity. This turbulence from spinning wind turbine rotors increases vertical mixing of heat and water vapor that affects the meteorological conditions downwind, including rainfall.
This effect can be reduced by using more efficient rotors or placing wind farms in regions with high natural turbulence. 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.
Wind power has a negligible effect on global mean surface temperature, and it would deliver "enormous global benefits by reducing emissions of CO 2 and air pollutants". 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. Author Ron Prinn cautioned against interpreting the study "as an argument against wind power, urging that it be used to guide future research".
Aesthetic considerations of wind power stations have often a significant role in their evaluation process. In the s, wind energy was being discussed as part of a soft energy path. Wind farms are often built on land that has already been impacted by land clearing and they coexist easily with other land uses. Coastal areas and areas of higher altitude such as ridgelines are considered prime for wind farms, due to constant wind speeds. However, both locations tend to be areas of high visual impact and can be a contributing factor in local communities' resistance to some projects.
Both the proximity to densely populated areas and the necessary wind speeds make coastal locations ideal for wind farms. Wind power stations can impact on important sight relations which are a key part of culturally important landscapes, such as in the Rhine Gorge or Moselle valley. Wind turbines require aircraft warning lights , which may create light pollution.
Complaints about these lights have caused the US FAA to consider allowing fewer lights per turbine in certain areas. This can be avoided by locating the wind farm to avoid unacceptable shadow flicker, or by turning the turbine off for the time of the day when the sun is at the angle that causes flicker. If a turbine is poorly sited and adjacent to many homes, the duration of shadow flicker on a neighbourhood can last hours.
Wind turbine syndrome is a psychosomatic disorder largely caused by anxiety about wind farms and not by the turbines themselves. There is limited evidence of anxiety effects caused by low level noise in the close vicinity of the turbines. Some turbine nacelle fires cannot be extinguished because of their height, and are sometimes left to burn themselves out. In such cases they generate toxic fumes and can cause secondary fires below.
Environmental impact of wind power
These autonomous systems, which can be retrofitted to older wind turbines, automatically detect a fire, shut down the turbine unit, and extinguish the fires. 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. Given the increasing size of production wind turbines, blade failures are increasingly relevant when assessing public safety risks from wind turbines.
The most common failure is the loss of a blade or part thereof . Many offshore wind farms have contributed to electricity needs in Europe and Asia for years, and as of the first offshore wind farms are under development in U. While the offshore wind industry has grown dramatically over the last several decades, especially in Europe, there is still some uncertainty associated with how the construction and operation of these wind farms affect marine animals and the marine environment. Traditional offshore wind turbines are attached to the seabed in shallower waters within the near-shore marine environment.
As offshore wind technologies become more advanced, floating structures have begun to be used in deeper waters where more wind resources exist. Common environmental concerns associated with offshore wind developments include: . Germany restricts underwater noise during pile driving to less than dB. Due to the landscape protection status of large areas of the Wadden Sea , a major World Heritage Site with various national parks e.
Lower Saxon Wadden Sea National Park German offshore installations are mostly restricted on areas outside the territorial waters. In January , a comprehensive government environmental study of coastal waters in the United Kingdom concluded that there is scope for between 5, and 7, offshore wind turbines to be installed without an adverse impact on the marine environment. It included analysis of seabed geology, as well as surveys of sea birds and marine mammals.
A study published in suggests that some seals prefer to hunt near turbines, likely due to the laid stones functioning as artificial reefs which attract invertebrates and fish. From Wikipedia, the free encyclopedia. See also: Renewable energy debate —Community debate about wind farms.
See also: Wind turbines on public display and Windfall film. Main article: Wind turbine syndrome. Uinta County Herald. Archived from the original on Retrieved The animals don't care at all. We find cows and antelope napping in the shade of the turbines. Renewable Energy. Archived from the original PDF on 16 June Retrieved 1 August Archived from the original PDF on January Jones, Liba Pejchar, Joseph M. BioScience , Volume 65, Issue 3, March Springer, Knopper, Christopher A. Ollson, Lindsay C. McCallum, Melissa L. Whitfield Aslund, Robert G. June 19, ; 2: British Wind Energy Association.
National Wind Coordinating Collaborative. The Washington Post. Wind is also abundant, inexhaustible, and affordable, which makes it a viable and large-scale alternative to fossil fuels. Despite its vast potential, there are a variety of environmental impacts associated with wind power generation that should be recognized and mitigated. The land use impact of wind power facilities varies substantially depending on the site: wind turbines placed in flat areas typically use more land than those located in hilly areas. However, wind turbines do not occupy all of this land; they must be spaced approximately 5 to 10 rotor diameters apart a rotor diameter is the diameter of the wind turbine blades.
Thus, the turbines themselves and the surrounding infrastructure including roads and transmission lines occupy a small portion of the total area of a wind facility.
A survey by the National Renewable Energy Laboratory of large wind facilities in the United States found that they use between 30 and acres per megawatt of power output capacity a typical new utility-scale wind turbine is about 2 megawatts. However, less than 1 acre per megawatt is disturbed permanently and less than 3. The remainder of the land can be used for a variety of other productive purposes, including livestock grazing, agriculture, highways, and hiking trails [ 2 ].
Alternatively, wind facilities can be sited on brownfields abandoned or underused industrial land or other commercial and industrial locations, which significantly reduces concerns about land use [ 3 ]. Offshore wind facilities require larger amounts of space because the turbines and blades are bigger than their land-based counterparts. Depending on their location, such offshore installations may compete with a variety of other ocean activities, such as fishing, recreational activities, sand and gravel extraction, oil and gas extraction, navigation, and aquaculture.
Employing best practices in planning and siting can help minimize potential land use impacts of offshore and land-based wind projects [ 4 ]. The impact of wind turbines on wildlife, most notably on birds and bats, has been widely document and studied. A recent National Wind Coordinating Committee NWCC review of peer-reviewed research found evidence of bird and bat deaths from collisions with wind turbines and due to changes in air pressure caused by the spinning turbines, as well as from habitat disruption.
The NWCC concluded that these impacts are relatively low and do not pose a threat to species populations [ 5 ]. Additionally, research into wildlife behavior and advances in wind turbine technology have helped to reduce bird and bat deaths. For example, wildlife biologists have found that bats are most active when wind speeds are low.
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Using this information, the Bats and Wind Energy Cooperative concluded that keeping wind turbines motionless during times of low wind speeds could reduce bat deaths by more than half without significantly affecting power production [ 6 ]. Other wildlife impacts can be mitigated through better siting of wind turbines. The U. Fish and Wildlife Services has played a leadership role in this effort by convening an advisory group including representatives from industry, state and tribal governments, and nonprofit organizations that made comprehensive recommendations on appropriate wind farm siting and best management practices [ 7 ].
Offshore wind turbines can have similar impacts on marine birds, but as with onshore wind turbines, the bird deaths associated with offshore wind are minimal. Wind farms located offshore will also impact fish and other marine wildlife. Some studies suggest that turbines may actually increase fish populations by acting as artificial reefs. The impact will vary from site to site, and therefore proper research and monitoring systems are needed for each offshore wind facility [ 8 ]. Sound and visual impact are the two main public health and community concerns associated with operating wind turbines.
Most of the sound generated by wind turbines is aerodynamic, caused by the movement of turbine blades through the air. There is also mechanical sound generated by the turbine itself. Overall sound levels depend on turbine design and wind speed. Some people living close to wind facilities have complained about sound and vibration issues, but industry and government-sponsored studies in Canada and Australia have found that these issues do not adversely impact public health [ 9 ].
Additionally, technological advances, such as minimizing blade surface imperfections and using sound-absorbent materials can reduce wind turbine noise [ 10 ]. Under certain lighting conditions, wind turbines can create an effect known as shadow flicker. This annoyance can be minimized with careful siting, planting trees or installing window awnings, or curtailing wind turbine operations when certain lighting conditions exist [ 11 ]. The Federal Aviation Administration FAA requires that large wind turbines, like all structures over feet high, have white or red lights for aviation safety.
However, the FAA recently determined that as long as there are no gaps in lighting greater than a half-mile, it is not necessary to light each tower in a multi-turbine wind project. Daytime lighting is unnecessary as long as the turbines are painted white. When it comes to aesthetics, wind turbines can elicit strong reactions. To some people, they are graceful sculptures; to others, they are eyesores that compromise the natural landscape. Whether a community is willing to accept an altered skyline in return for cleaner power should be decided in an open public dialogue [ 12 ].
There is no water impact associated with the operation of wind turbines. As in all manufacturing processes, some water is used to manufacture steel and cement for wind turbines. Estimates of total global warming emissions depend on a number of factors, including wind speed, percent of time the wind is blowing, and the material composition of the wind turbine [ 13 ]. Most estimates of wind turbine life-cycle global warming emissions are between 0. To put this into context, estimates of life-cycle global warming emissions for natural gas generated electricity are between 0.
Hand, M. Jackson, and S. Land-use requirements of modern wind power plants in the United States.
Related Wind Energy: Renewable Energy and the Environment
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