Common Concerns About Wind Power - CSE
2nd edn, June 2017Common concernsabout wind power
Common concerns aboutwind power (2nd edn)Written and researched by Iain Cox.Centre for Sustainable Energy, June 2017Written and researched: 2015The Centre for Sustainable Energy is a national charity committedto ending the misery of cold homes and fighting climate change.We share our knowledge and practical experience to empowerpeople to change the way they think and act about energy.We are based in Bristol although most of our work has relevanceand impact across the UK. Our clients and funders include national,regional and local government agencies, energy companies andcharitable sources.PHOTOS: istock.com (cover/p4, p2, p94, p126), Shutterstock (p26, p32);pexels.com (p82), Jasja Dekker (p86), Changhua Coast Conservation Action (p104),Rachel Coxcoon (116)OFFICE3 St Peter’s CourtBedminster ParadeBristol BS3 4AQPHONE0117 934 1400EMAILinfo@cse.org.ukcse.org.ukcse 31979
ContentsIntroductionpage 21 Wind turbines and energy payback timespage 52 Materials consumption and life cycle impacts of wind powerpage 113 Wind power costs and subsidiespage 194 Efficiency and capacity factors of wind turbinespage 275 Intermittency of wind turbinespage 336 Offshore wind turbinespage 417 Wind power and nuclear powerpage 478 Public acceptance and community engagementpage 599 Wind turbines and property pricespage 6910 Siting wind farms on ecologically sensitive landpage 7511 What effect do wind turbines have on wildlife?page 7912 Wind turbines and safetypage 9513 Shadow flicker and epilepsy riskpage 10114 Wind turbines and noisepage 10515 Infrasound, ‘wind turbine syndrome’ and other health concernspage 11716 Wind farms and radarpage 127Common concerns about wind power, June 20171
Introduction 3IntroductionWelcome to the second edition of the Centre forSustainable Energy’s Common Concerns about WindPower. The first edition (2011) is our most widelyaccessed publication both in print and online. It’spopularity reflects the need for a document that helpsthe interested reader, faced with a mass of conflictinginformation, to weigh up the likely impacts of windpower in their locality. We hope this update continues toprovide an independent guide to the issues, backed upby hundreds of peer-reviewed papers and a dozens ofgovernment studies.Every chapter from the first edition makes areappearance, in many cases supplemented by newevidence that allows us to give more detailed andnuanced consideration to those issues. The secondedition contains several new chapters covering topicsthat were not being widely discussed when the firstedition was being prepared.Of all renewable energy sources, wind power occupies aunique place due to a combination of two attributes:technological preparedness (wind is still best placed of allexisting renewable energy technologies to contribute theelectricity needs of the UK whilst simultaneouslyreducing its carbon emissions), and the fact that it isinherently site specific (making wind turbines strikinglyvisible additions to often previously undevelopedlandscapes). The increasing presence of wind farmsacross the country means that communities everywherewill continue needing to address the issues surroundingwind power. Changes to government planning policy in2015 mean that onshore wind developments cannotnow proceed without a site first having been allocated ina local or neighbourhood plan. This publication,therefore, should provide a comprehensive grounding inthe facts for local authorities and communities as theyundertake the development of local policies with regardsto wind power and renewable energy in general.And of course wind power continues to be a highlycontentious and politically charged issue. This is nothelped by articles in the UK media that continue torepeat misstatements which are clearly contrary to theevidence and can easily be refuted, or by emotivelanguage and the tendency to ‘cherry-pick’ evidence topresent a one-sided view.Common concerns about wind power, June 2017Equally, keen proponents of wind power are often tooquick to dismiss any problems raised, levelling the chargeof ‘nimby’ at anyone who speaks out against planneddevelopments. While not necessarily willfully dishonest,both sides of the debate can be accused of reportingexpediently to further their point of view.In this updated and extended publication, we hope thatpertinent research continues to be presented in amanner that leads to informed discussion. As before,this edition of Common Concerns about Wind Powerrelies heavily on academic peer reviewed publicationsand expert reports. Reading this is not intended to bethe end of an interested person’s research: rather, itshould encourage further reading around the subjectand the casting of a critical eye on the source ofinformation. Casual assertions that unambiguously statewind power is good or bad without any supportingevidence should be judged accordingly. As isdemonstrated throughout this document, the reality isfrequently more complicated than that. The agendas ofvested interests too often mean these subtleties are lostand the subject descends into acrimonious debate.What this document aims to show is that, implementedas part of a progressive energy portfolio, wind powercan significantly reduce both the UK’s carbon footprint,and its dependence on fuel sources that may becomeless secure in the future, or that present a costly andunacceptably hazardous legacy for future generations.However, wind power is not appropriate everywhere andcan impact communities in different ways. We hopethat, by publishing this research, communitiesthemselves will engage constructively with the bestavailable evidence to judge if there is a place for windturbines in their own locality. To empower communitiesto make these decisions demands a more mature andresponsible approach from the media, the wind industryand pressure groups on both sides of the debate.Rachel Coxcoon,Centre for Sustainable Energy, June 20163
Chapter 1Wind turbines and energy payback timesSummaryThe harnessing of wind for the generation of electricity may rely on a renewable source of energy, but it must alsoprove to be sustainable. All systems for converting energy into usable forms have energy requirements themselves,where energy must be invested in the myriad activities necessary for extracting and shaping materials, transport ofparts and fuel, building and maintaining power plants and associated infrastructure, and decommissioning orupgrading the site. In its very broadest sense, some even include the expenditure of capital and labour as part of theenergy investment. The amount of energy involved in the manufacture, construction, operation and decommissioningof wind farms is often voiced as a concern over whether wind turbines should be used at all. Since the capture andgeneration of any usable form of energy requires energy to be invested, the question is really one of how effectivelythe generating plant returns energy back to its users (i.e. society) in relation to the energy invested.There are a number of ways of answering this question, but all these methods essentially seek to present informationin a way that is useful in understanding how society can obtain sufficient surplus energy to make its investmentworthwhile. In every case, the evidence shows that wind turbines perform well in this regard, often being the mosteffective of the renewable energy sources after hydropower, and in most situations being comparable or superior toconventional thermal electricity generation (i.e. fossil fuel and nuclear power). Overall, wind is relatively effective – forexample, modern wind farms on average return 18 times the energy invested in them over their lifetime – but specificcases have returned lower values, and many very high estimates are born of optimistic projections for electrical outputor fail to incorporate certain inputs that count as invested energy. Nonetheless, the modern, larger turbines ( 1 MW)typically employed in wind farms today will ‘pay back’ the energy invested in less than a year, in some cases in lessthan six months. Over the remainder of its 20 to 25-year lifespan, the wind turbine will continue to return usefulsurplus energy in the form of electricity back to society.What is this based on?Since the Industrial Revolution, the phenomenal growthand development of global society has been a story ofvast surpluses of energy.1 These surpluses have beenprovided by fossil fuels, and the years since the end ofthe second world war have seen explosive growth drivenby a global economy underpinned by oil (in later yearsaccompanied by natural gas). As readily availablereserves of oil have been depleted since 1900, this glutof available energy has steadily fallen, and the energyobtained through the extraction, refinement and deliveryof oil and gas fuels to where they can be used is nowless than half what it used to be only four decades ago,and this downward trend will continue.1,2Although global reserves of coal continue to see ahealthy energy return that has changed little since the1950s (although energetically favourable extraction isvery region-specific), increasing knowledge about theprofound environmental and health implications ofcontinued coal extraction and combustion means that itis viewed as one of the least sustainable fuels. One farreaching environmental concern is climate change,Common concerns about wind power, June 2017caused largely by rising levels of greenhouse gases in theatmosphere. The prodigious consumption of fossil fuelsby humans has been the single largest contributingfactor to rising levels of CO2 (a major greenhouse gas),and this fact has also made the quest for alternativesources of energy even more pressing.3The current dependency of the world’s economy on oiland gas has prompted much debate about when theseresources might run out.2 This is not meant in the purelyliteral sense of there being no more oil in the ground,but instead seeks to asks when society must invest somuch energy into extracting and delivering oil that theuseful energy obtained is no longer worthwhile.Economic indicators such as market price and costbenefit analysis often fail to adequately assess futureresource issues, such as when depletion of a finiteresource (e.g. oil and gas) means a sufficient surplus ofuseful energy is no longer available.4 Even if thegeological deposits do not physically run out, increasedenergy expenditure to extract lower-quality oil andnatural gas, combined with the necessity of opening upnew deposits, will entail greater environmental impactsdue to resulting emissions and habitat degradation.5
6 Chapter 1,Wind turbines and energy payback timesTo get around these problems, a practical metric todescribe the level of energy surplus is applied, known asenergy return on investment (EROI), which measures thenet energy balance of an ‘energy gathering’ system.Although it is complex variable that can take intoaccount many different factors, the basic formula forEROI is commendably simple:EROI Energy returned to societyEnergy required to get that energyAt its most basic, the denominator and numerator canbe expressed in the same units of energy, so giving aratio with no units. For instance, an EROI of 10:1 (‘ten toone’) tells us a given process or system yields 10 joulesfor every 1 joule that is invested. Hence, an energyresource with a high EROI is considered a more useful orproductive resource than one with a lower EROI. TheEROI measurement can be a helpful indicator of thevalue of an energy source for several reasons. Not onlydoes EROI provide a numerical output that can be easilycompared with other energy sources, but, since itindicates the net level of useful energy that is deliveredto society, it can be used as a proxy for assessing howmuch economic development is possible from the energydelivered, i.e. it can capture the quality of the resource.5This is often reflected in how useful energy is finallydelivered in the system, and is one of the factors thatcomplicates EROI analysis. Consider, for example, thedelivery of a lump of coal to your house compared tomains electricity. Although both forms may contain thesame amount of energy (in joules), the electricity iscleaner and more flexible at point of use than the coal;subsequently, you would be more productive consumingthe electricity for your daily activities than using coal,and the greater value is reflected in the price paid forelectricity.6The quality aspect of EROI provides useful insights intothe historical development of energy resources. Considerthe typical EROI values for major energy sources given inTable 1.1. By looking at how EROI levels have changedover the course of a century, it has become increasinglyclear that major fossil fuel resources are declining inquality, since EROI levels have been dropping steadilysince the 1970s.1 In the USA, which has always beenone of the world’s largest oil-producing nations, theEROI for a barrel of oil has declined by two-thirds sincethe 1970s, dropping from 30:1 to 10:1.Natural gas data are typically aggregated with oilproduction, because the two energy sources areextracted from the same wells. However, data from morerecent nonconventional natural gas deposits (Canadiantar sands, and ‘tight gas’ desposits in the USA) show asimilar range of values, and a pattern of decliningreturns as the best resources are rapidly exploited (seeTable 1.1).6The fall in EROI means that either more energy is neededto deliver a given amount of useful energy, or that theenergy gain from what is currently invested is less than itused to be.5 This has important implications for modernsociety, since it indicates that, despite rising prices thatmight drive increased exploration and extraction, orrising levels of gross production (e.g. more oil is drilled),the inevitable reduction in the quality of fossil fuels – asmeasured by EROI – means that these will soon nolonger be viable resources to exploit as their EROIapproaches a ratio of 1:1.1,7 Even coal, which droppedfrom an EROI of 80:1 to 30:1 by the 1950s beforereturning to 80:1 in the 1990s, has only avoided thistrend of declining EROI via the exploitation of lowerquality deposits that rely on cheaper surface mining. Ascan be seen in Table 1.1, when the value of energy istaken into account, i.e. the value of primary fuelcompared to electricity, and we consider coal-poweredelectricity, the EROI for coal falls to less than 25:1. Thedetriment to climate, the environment and public healththat this renewed extraction brings with it is oneimportant factor not captured by EROI.1This looming ‘net energy cliff’ will have a profoundimpact on global society. The abundance of surplusenergy made available from energy sources withhistorically high EROI ratios has been fundamental totechnological and cultural development, andmaintaining EROI over a certain level is key to theimproved quality of life and well-being of moderncivilisation.8 For instance, when the total energy cost ofextracting and delivering useful energy to the finalconsumers is considered, a ratio of 3:1 EROI is calculatedto be the ‘bare minimum’, but this would leave littlesurplus for other societal activities – essentially, much ofsociety would be invested in helping deliver this energyand to maintaining fundamental services like thegrowing and transportation of food.4,8 The threshold formaintaining greater well-being and quality of life (asmeasured by a combination of indices, such as theHuman Development Index, health expenditure, andfemale literacy rates) is estimated to be in the range of20:1 to 30:1 EROI. It is interesting to note that the uppervalue (30:1) represents a ‘saturation point’ above whichadditional surplus energy offers no further improvementsto society.8 This is perhaps an indication of howprofligate many modern societies have been with theirhistorically high rates of fossil fuel consumption over thecourse of the previous century, when energy wasabundant and, seemingly, never-ending.In the case of wind power, the energy investmentincludes: manufacturing and transporting wind turbinecomponents; constructing, connecting, operating andmaintaining the wind turbine facility (this may bemultiple turbines on a wind farm); and the finaldecommissioning of the site and recycling of the usedcomponents.9 Note that the energy invested in the windCommon concerns about wind power, June 2017
Chapter 1,Wind turbines and energy payback times 7Table 1.1 A range of illustrative EROI values for various energy carriers, divided between primary fuels (unshaded)and electricity (shaded).Average EROI, i.e. x:1(energyout/energyin)CommentsOil35Global averageOil & natural gas3011–1810.1U.S. domestic production in 1970sU.S. domestic production by 2005U.S. domestic production by 2010Natural gas382030Canada domestic production 1993Canada domestic production 2009U.S. domestic production 2005Shale oil5Conventional oil derived from shale formations. Initial high EROIvalues from U.S. extraction in the 1990s declined rapidly once‘sweet spots’ were depletedTar sands crude oil2–5Note that low EROI of tar sands will lower average of oil and gasindustry as a wholeOil shale1.4Oil shale is a low-grade oil precursor, not to be confused with‘shale oil’Oil-fired electricity3.7–10.6Higher value based on oil EROI of 30 (see oil & natural gas above)Coal-fired electricity12.2–24.6Note EROI for coal alone (80:1) not included as it has limited usewithout further energy conversionNuclear-powered electricity5–15May be underestimated due to outdated processes studiedWind-powered electricity18–20Data from meta-analysis of global wind farm installations. Largermodern turbines have higher EROI valuesSolar p.v. electricity6–12Covers several types of modern photovoltaic (p.v.) systems.Generation based on average insolation for southern EuropeHydropower84By far highest EROI with some values reported above 100, butresource geographically constrainedEnergy carrierPrimary fuelsElectricityFigures derived or calculated from data in references 9, 15, and 16. The final EROI for solid fuels used to generate electricity or heat are basedon well-head, mine-mouth or farm-gate values multiplied by typical thermal conversion efficiencies of primary energy inputs. In contrast to allrenewable energy sources, fossil fuels and nuclear power use entirely non-renewable sources of energy both upstream and at point of use.turbine and associated infrastructure is a mix of primaryenergy inputs and energy carriers. What this means isthat primary energy inputs, such as oil, gas or coal, havebeen used alongside forms of energy, e.g. such asrefined oil products and electricity, that themselves havebeen converted from primary energy inputs. Forexample, primary energy inputs (combustion of coal)may be used in heat-intensive processes like steelmanufacture, whereas electricity may be used elsewherein the supply chain in the manufacture of aluminium orto operate machinery during assembly.1These primary energy conversions are another keycomplicating factor in energy ratio calculations, since theenergy inputs have differing values depending onwhether they are primary fuels or energy carriers (likeelectricity) that themselves are the result of energyconversions.5 Each conversion step will require an energyinvestment, and accounting for these energy balances inCommon concerns about wind power, June 2017a meaningful way in relation to the final useful energydelivered is very important. Of particular relevance torenewable energy systems is the fact that the energygathering process itself consumes some of the energybeing extracted, i.e. the system needs energy to makeenergy.10 This ‘autocatalytic’ nature of energy generation(a product of the process is used in the process itself)means that the mix of energy types invested in a powerplant assume great impor
Common concerns about wind power, June 2017 1 Contents Introduction page 2 1 Wind turbines and energy payback times page 5 2 Materials consumption and life cycle impacts of wind power page 11 3 Wind power costs and subsidies page 19 4 Efficiency and capacity factors of wind turbines page 27 5 Intermittency of wind turbines page 33 6 Offshore wind turbines page 41
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Wind power: social concerns Wind, solar and biofuels. Technologies in the wind chain 2017-09-26 Wind, solar and biofuels 10 On-shore wind Off-shore wind. 2017-09-26 Wind, solar and biofuels 11 Sample Reference Energy System Oil Gas Coal Gasification Import / Production of biomass Uranium enrichment
DTU Wind Energy E-0174 5 1 0BIntroduction Wind resource assessment is the process of estimating the wind resource or wind power potential at one or several sites, or over an area. One common and well-known result of the assessment could be a wind resource map, see Figure 1. Figure 1. Wind resource map for Serra Santa Luzia region in Northern .
the wind speed is reducedto 14m/s.Finally the wind speed is reduced to zero at 6Sec.Thus a varying wind speed is applied to the wind turbine. Fig.6 Wind Speed Variations . 6.2 Active Power in the Grid . Initially the wind speed is 10m/s then power injected to the grid is nearly 300W.If the wind speed is increased to 20m/s,at
boat wind turbines and make them facing the wind [3]. The number of blades of boat wind turbines is often 3. Three-bladed boat wind turbines can produce power at low wind speed and can be self-started by the wind. This paper is focused on three-bladed boat wind turbines with passive yaw motion.
Small Wind Turbines Are Different Utility-Scale Wind Power, 600 - 1,800 kW wind turbines – Professional maintenance crews – 15 mph (7 m/s) average wind speed Small, “Distributed” Wind Power 0.3 - 50 kW wind turbines – Installed at individual homes, farms, busine
wind energy. The office pursues opportunities across all U.S. wind sectors—land-based utility-scale wind, offshore wind, distributed wind—as well as addressing market barriers and system integration. As we usher in 2021, we'd like to share some of the most notable wind energy research and development accomplishments from 2020. Offshore Wind
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