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| Wind farm myths | |||
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This section covers the following topics: |
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Availability of Wind Supply |
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| Extensive wind speed records were used to identify patterns of wind power availability. These records show that: | |||
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Wind power availability is greater during winter than at any other times of the year, and is on average stronger during the day than overnight | ||
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Wind power delivers around two and a half times as much electricity during periods of high electricity demand as during low demand periods | ||
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The recorded capacity factor of onshore wind turbines in the UK is around 27% - this is higher than that recorded in Denmark and Germany, and emphasises the need to use UK data in wind power assessments | ||
Extreme lows or highs in wind speed are a natural feature of the UK wind climate; however a diversified wind power system would be less affected as it is rare that these extreme events affect large areas of the country at the same time. This report found that: |
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Low wind speed conditions affecting 90% or more of the UK would occur in around one hour in every five years during winter | ||
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The chance of wind turbines shutting down due to high wind speed conditions is very rare - high winds affecting 40% or more of the UK would occur around one hour in every 10 years. | ||
So how much wind is there and can it meet our electricity needs in the future? At the moment, wind only meets less than 1% of the UK's electricity needs, but the UK wind resource is enormous. The Department of Trade and Industry (DTI) calculates that onshore wind could theoretically meet 80% of our current electricity demand, and that the offshore wind resource could supply 10 times our needs. Yet the UK remains close to the bottom of the "league table" compared with other European countries in terms of the % of our electricity consumption met by renewable energy. This is despite the fact that the UK has the largest renewable resources in Europe. Germany for example has only a quarter of the UK's offshore wind resource, but German plans for offshore wind far outstrip the UK's ambitions. Meanwhile Denmark already generates 20% of its electricity from wind power. A report in 2002 by AEA technology for Greenpeace - Sea Wind East - shows that nuclear power's contribution to our electricity needs (currently around a quarter) could be replaced by 2020 by wind farms off the coast of East Anglia. That's just one region, and one renewable technology. |
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| The Intermittency of wind The EWEA have produced a website www.no-fuel.org which commented the following on intermittency of wind: It is widely perceived that because the wind resource is intermittent, the wind technology is not ‘reliable’ enough to be a major power source. Watching a single wind turbine stop and start, it might seem logical to conclude that, as more of these machines are built, the result can only be an unreliable supply. The entire electricity system is variable, like wind energy. Both supply and demand of electricity are influenced by a large number of planned and unplanned factors. The changing weather makes millions of people switch on and off their supply. Millions of others expect instant power for lights, TVs, computers. i. Conventional power sources are intermittent. On the supply side, no power station of whatever type is completely reliable. Large power stations that go off-line, whether by accident or for maintenance, do so instantaneously, causing immediate loss of power. When a fossil fuel or nuclear power plant trips unexpectedly, it takes a capacity of up to 1,000 MW off the network instantly. That is true intermittency. Power systems have always had to deal with these sudden output variations, as well as variable consumption, and the procedures put in place by network operators can be applied to deal with variations in wind power production as well. ii. Variability and intermittency are different concepts. Variations in wind energy are smoothed by the fact that there are hundreds or thousands of units in operation, making it easier for the system operator to predict and manage changes as they occur. The system will not notice the shut down of a 2 MW wind turbine, but it will have to respond to the removal of a 500 MW coal fired plant or a 1,000MW nuclear plant. Wind energy does not suddenly trip off the system. So the issue is not one of variability in itself, but how to predict, manage and ameliorate electricity variability and what tools can be utilised to improve efficiency. Wind power is variable in output, but this can be predicted to an increasingly accurate extent. iii. The electricity system, not the turbine is what matters. It is the net output of all wind turbines on the system or large groups of wind farms that matters for electricity needs. Wind power has to be considered relative to the overall variability of demand and the intermittency of other power generators. The wind does not blow continuously in one place, yet there is little overall impact if the wind stops blowing somewhere – it is always blowing somewhere else. Therefore wind can be harnessed to provide reliable electricity even though the wind is not available 100% of the time at one particular site. In terms of overall power supply it is largely unimportant what happens when the wind stops blowing at a single wind turbine or wind farm site. The more wind farms that are built over a wider geographical location, the more reliable wind energy is. |
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| Noise The Friends of the Earth stated the following on noise; Aren’t wind Turbines Noisy? This is now very rarely the case, due to advances in technology. Well-designed, well-sited turbines can be quiet enough to cause no disturbance to people living even just a few hundred metres away. At these distances, the noise they do make is usually drowned out by the natural noise of the wind itself in trees and vegetation. The frequency and pitch of the noise should be considered and Friends of the Earth recommends that potential noise impacts are examined as part of a thorough Environmental Impact Assessment (EIA) for each proposed project. To protect nearby residents, companies wanting to put up wind turbines should have to meet tough noise standards set by the local planning authority. The Department of Trade and Industry (DTI) Wind Turbine Noise Working Group set up in 1993, has issued a guidance report providing information and advice for developers and local authorities when considering noise levels. Having read exaggerated claims in the press, people visiting wind farms are often surprised at how quiet they actually are. The Delabole public opinion survey demonstrates that concerns about noise are often unfounded. Before construction of the farm, 42% of people living near the site thought that the turbines would cause a noise nuisance. After construction, when people had experience of the wind farm operating, less than 10% thought they were noisy. With regard to claims about low frequency noise and health issues the BWEA produced a report "Low Frequency Noise and Wind Turbines" in February 2005. In summary they stated that: "To date, there is no scientific evidence which links the levels of low frequency noise emitted by wind turbines with impacts on human health. With over 68,000 wind turbines in operation around the world, some of which have been in place for over 20 years, there has been ample opportunity for any ill effects to have been identified; that none have is further proof of the benign nature of this technology." Dr Geoff Leventhall, consultant in Noise Vibration and Acoustics said in a personal communication: “I can state quite categorically that there is no significant infrasound from current designs of wind turbines. To say that there is an infrasound problem is one of the hares which objectors to wind farms like to run. There will not be any effects from infrasound from the turbines." The Silent Workhorses of Ardrossan - Cllr Margaret Munn of Adrossan, Scotland was quoted as saying of the Adrossan wind farm: "The Adrossan wind farm has been overwhelmingly accepted by local people - instead of spoiling the landscape, we believe it has been enhanced. The turbines are impressive looking, bring a calming effect to the town, and contrary to the belief that they would be noisy, we have found them to be silent workhorses" |
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| Payback time The comparison of energy used in manufacture with the energy produced by a power station is known as the 'energy balance'. It can be expressed in terms of energy 'pay back' time, i.e. as the time needed to generate the equivalent amount of energy used in manufacturing the wind turbine or power station. The average wind farm in the UK will pay back the energy used in its manufacture within three to five months, and over its lifetime a wind turbine will produce over 30 times more energy than was used in its manufacture. This is quicker than coal or nuclear power stations, which take about six months. When the energy used to supply the fuel for nuclear and coal power plants is included, the energy balance for those conventional source is even poorer still. This year the Department for Trade and Industry (DTI) calculated that onshore wind farms recover around 80 times the input energy required. |
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| Property values Reports by the Royal Institution of Chartered Surveyors and the BWEA Knight Frank report, demonstrate that wind farms have no long-term effect on house values. A significant minority of surveyors (40%) reported no impact from wind farm developments on residential property values. The negative impact of wind farms on property values appears to decline over time. This may suggest that the impact lessens, as wind farms become a more established part of the rural landscape. The BWEA goes on to say that: There is currently no evidence in the UK showing that wind farms impact house prices. However, there is evidence following a comprehensive study by the Scottish Executive that those living nearest to wind farms are their strongest advocates. Meridian Energy summarised the report by Renewable Energy Policy Project on the effect on wind developments on local property values: What appears to be the most extensive and scientific property value effects study was completed by a United States Government-funded agency in 2003. The study examined around 25,000 property sales records near wind farm sites and in comparable communities. The analysis spanned approximately six years of sales records, straddling the pre- and post-construction periods of individual wind farms. The wind farms examined were built between 1998 and 2001. The study undertook three types of statistical assessment for each of 10 wind farm developments (a total of 30 analyses), looking at the immediate vicinity of the wind farm and at comparable communities without a wind farm. The study found that in 26 of these analyses, property values in the affected viewshed (defined as within 5 miles [8km] of the turbines) actually performed better than in the comparable community. The study drew no conclusions about why property values in wind farm viewsheds performed better than in comparable communities. Similarly, it could draw no firm conclusions about those cases where property values performed poorly, as in those instances the available data provided a poor fit to the statistical method used. |
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| The REPP report can be downloaded at: www.crest.org | |||
spinning reserve National Grid operate on a system were a power station is held in a warm state to come on line at short notice. These plants operate irrespective of wind farm developments. The BWEA explain the need for "spinning reserve": Some electricity generating plant is held in a 'warm' state in which it can increase electricity output at short notice. Coal fired power stations take several hours to warm up from cold. To ensure that there is sufficient capacity available to respond rapidly to a sudden increase in electricity demand, some thermal power stations are kept in a condition known as 'spinning reserve'. These plants are burning fuel and are generating electricity, but are not running at full load. Keeping a certain amount of plant as spinning reserve is necessary to ensure that electricity supply can maintained should there be an unexpected loss of generating capacity. For example one of the two 1000MW cross channel links importing electricity from France could fail, a steam turbine could trip out, or a supergrid line could be hit by lightening. To provide an acceptable margin of safety enough plant is held in spinning reserve to cater for the failure of the single largest power source. There does not need to be any extra spinning reserve to cater for the unpredictable nature of the wind: "At the present low levels of wind power, the reserve requirement is not significantly affected, but with higher levels of wind capacity the unpredictability of wind generation might increase the reserve requirements. A study by the former CEGB (Central Electricity Generating Board) estimated that additional reserve might be required once intermittent sources supplied more than 20% of peak demand in England and Wales" Quote from paragraph 23 of the Welsh Affairs Committee report on Wind Energy. Volume 1, HMSO 1994. "Wind energy does have a capacity credit and can therefore be relied upon, even although the wind isn't always available. The 360+ MW of wind energy currently operating in the UK has a capacity credit of over 100 MW, replacing or avoiding the need to build an equivalent amount of thermal or nuclear capacity. Although this capacity credit falls as penetration of wind and other non-firm technologies into the system increases, this will not be an issue until levels reach approximately 20% penetration. The criticism that extra spinning reserve is necessary to take into account the intermittent nature of wind is not valid. Spinning reserve will always be needed to cater for unexpected unavailability of the largest single power source, and not just to cater for the currently low levels of electricity generated from the wind." |
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| The DTI response to the myth that wind farms keep tourists away was: |
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The facts: |
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| The BWEA response to the myth that wind farms negatively affect tourism numbers was: There is no evidence to suggest this. The UK's first commercial wind farm at Delabole received 350,000 visitors in its first ten years of operation, while 10,000 visitors a year come to take the turbine tour at the EcoTech Centre in Swaffham, Norfolk. A MORI poll in Scotland showed that 80% of tourists would be interested in visiting a wind farm. Wind farm developers are often asked to provide visitor centres, viewing platforms and rights of way to their sites. Extract from the Whinash Public Inquiry Report February 2006: "Concerns have been expressed about the possible impact of the turbines on tourism; but, despite the construction of wind farms in various parts of the country, there is no cogent evidence to show a resulting reduction in visitor numbers. Indeed, Cornwall and Cumbria have the largest concentration of wind farms of any of the counties in England, yet, in both cases, the numbers of visitors attracted has increased since the turbines were erected. Various studies fail to support the Objectors’ concerns; a Department of Trade and Industry publication describes this as one of the ‘10 myths’ about wind farms; and the North West Regional Assembly identify it as a ‘non-planning issue’:- ‘…… the considerable evidence reviewed …… does not support the contention that there is any significant adverse impact or relationship between wind power and tourism. It should also be noted that some respondents to the survey undertaken for the Cumbria Tourist Board considered that the wind farm would be an additional attraction." |
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| Turbines and birds The RSPB state in their leaflet, Wind farms and birds commented: "Climate change is the most significant, long-term threat to biodiversity worldwide. To help meet this threat, the RSPB strongly supports moves to increase energy efficiency, reduce energy demand and supply more of our energy needs from renewable sources, including wind power, provided they do not harm birds or their habitats." They went on to say that: "in the UK, we have not so far witnessed any major adverse effects on birds associated with wind farms" The Friends of the Earth commented on the effect of wind farms on birds and other wildlife: There is no conclusive evidence that wind turbines present more of a danger to birds than other structures, such as pylons or roads, when properly sited. Years of overseas experience have highlighted some problems arising where wind farms have been sited prominently where high concentrations of migrant birds are feeding or roosting nearby. However, exaggerated claims about bird deaths at the Altamont Pass, California, have been shown by reputable scientists to be unfounded, as noted by the Welsh Affairs Committee. The RSPB has said that from its own studies at three wind farms in Wales, "the scale of bird strike does not seem to be of serious concern", and that wind turbines will have little impact on birds outside main migration routes. Siting is a crucial issue and developers should contact specialists such as the RSPB and conduct a thorough analysis of the risk to birdlife as part of the EIA. Similarly, there is no evidence to suggest damage to other wildlife or agricultural livestock, which often graze right up to the turbines. As an example, the 9 harbour-wall turbines at Blyth are in a busy bird area. Of the bird flights through the wind farm, only 1 in 10,000 have resulted in a collision. This translates to 1-2 collisions per year per turbine. To put that into perspective, every year more than 10 million birds are killed by cars in the UK. |
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| Visual impact Friends of the Earth commented on the visual impact of wind farms: "This is a highly subjective issue - being visible is not the same as being intrusive. While some people have expressed concern about the impact of wind turbines on the beauty of our landscape, others see them as symbols of the better, less polluted future they can help to deliver. For example, the Planning Inspector for the Cemmaes wind farm in Wales, described turbines as “elegantly designed, having clean lines with no extraneous features or visual clutter”. Visitors to farms have also described them as visions of the future, relaxing, elegant and utterly beautiful. A survey of public opinion around the Delabole wind farm in Cornwall showed that more than 84% either approved or approved strongly of wind energy. Nearly three-quarters of people living near the wind farm once it was up and running thought that wind turbines did not spoil the scenery." The BWEA said that: "Beauty is in the eye of the beholder, and whether you think a wind turbine is attractive or not will always be your personal opinion. However, studies regularly show that most people find turbines an interesting feature of the landscape10. On average 80% of the public support wind energy, less than 10% are against it, with the remainder undecided. Surveys conducted since the early 1990's across the country near existing wind farms have consistently found that most people are in favour of wind energy, with support increasing among those living closer to the wind farms." |
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