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Common concerns about wind power

Centre for
Sustainable Energy
Common concerns
about wind power

A research paper commissioned by CSE drawing on peer-reviewed
articles and government-funded analysis to address some of the
concerns that are expressed in relation to wind power.

May 2011

3 St Peter’s Court www.cse.org.uk We are a national charity that shares
Bedminster Parade 0117 934 1400 our knowledge and experience to
Bristol info@cse.org.uk help people change the way they
BS3 4AQ reg charity 298740 think and act on energy.

Common concerns about wind power

Common concerns
about wind power

Published May 2011 by the
Centre for Sustainable Energy

ISBN 978-0-9568981-1-1

This publication was written in response to requests
from community groups for factual information about
wind energy, in part to counter the many myths and
misconceptions surrounding this technology. It was
produced as part of PlanLoCaL, a project that aims to
give communities the knowledge and confidence to
influence local planning policy and contribute to a low-
carbon future (www.planlocal.org.uk).

The Centre for Sustainable Energy (CSE) is a national
charity that helps people and organisations from the
public, private and voluntary sectors meet the twin
challenges of rising energy costs and climate change.

We share our knowledge and practical experience to
empower people to change the way they think and act
about energy.We do this by giving advice, managing
innovative energy projects, training others to act, and
undertaking research and policy analysis.

At any one time we have between 50 and 60 different
and separately funded projects under way. All of these
are helping people and communities to meet real
needs for both environmentally sound and affordable
energy services.You can read more about what we do
at www.cse.org.uk

We are based in Bristol although much of our work has
relevance and impact across the UK. Our clients and
funders include national, regional and local
government and associated agencies, energy
companies and charitable sources.

Charity | 298740
Registered company | 2219673
VAT | GB 609 6290 27

Centre for Sustainable Energy www.cse.org.uk

Common concerns about wind power

Contents

1. Wind turbines and energy payback times

2. Wind turbines, costs and subsidies

3. Efficiency of wind turbines

4. Intermittency of wind turbines

5. The need for onshore as well as offshore turbines

6. Wind power and nuclear power

7. Public acceptance of wind turbines

8. Wind turbines and property prices

9. Wind turbines and safety

10. Wind turbines, shadow flicker and epilepsy

11. Wind turbines and noise

12. Infrasound from wind turbines and ‘Wind Turbine Syndrome’

13. Bat and bird mortality in relation to wind turbines

www.cse.org.uk Centre for Sustainable Energy

---------------------------------------------------------------
Common concerns about wind power

Introduction

The Centre for Sustainable Energy commissioned this
research with the aim of explaining some of the concerns
that typically arise in relation to wind power and other
aspects of energy generation.

Of all renewable energy sources, wind power occupies a
unique place due to a combination of two attributes:
technological preparedness (wind is best placed of all
existing renewable to contribute the electricity needs of the
UK while simultaneously reducing its carbon dioxide, or
CO2, emissions); and the fact that it is inherently site-
specific (making wind turbines strikingly visible additions to
often previously undeveloped landscapes). The increasing
presence of wind farms across the country means that
communities everywhere will need to address the issues
surrounding wind power.

In particular, an individual’s attachment to the landscape
and their concept of what constitutes ‘unspoiled’
countryside is inextricably entwined with the need to
balance the transition to a low-carbon economy.

Wind power is not an all-encompassing solution, able to
replace all other forms of electricity generation. However, it
will play a significant role in the nation’s policy toward
helping divert the worst effects of anthropogenic (human
induced) climate change, and to ensuring energy security in
future decades.1 By 2020, wind power alone will be helping
to displace over 50MtC, more than a third of the UK’s
current annual CO2 emissions from electricity generation
and over 10% of the UK’s total CO2 emissions for all forms
of energy. Just one component of the renewable energy
mix, wind power obviously has clear benefits.

Despite the advantages offered by wind power, its place at
the centre of landscape development as outlined above
often makes it a contentious issue. This is exacerbated by
articles in the UK news media that continue to repeat
misstatements put forward by opponents of wind power
which are clearly contrary to the evidence and can easily be
refuted (see sections on house prices, infrasound, net
energy cost).

However, some of these issues are more subtle and critically
dependent on the way in which they are presented.
Emotive language is frequently employed by journalists to
enhance the impact of a news story, and the authors of
opinion pieces can ‘cherry-pick’ evidence to present a one-
sided view.

As media platforms have to compete in a progressively
more fragmented marketplace, creating a narrative that has
an easily identifiable cause célèbre – in this case, wind
turbines – helps attract fierce debate, thereby driving
circulation and, increasingly, online traffic. On the reverse
side, keen proponents of wind power are sometimes too
quick to dismiss any problems raised, levelling the charge of
‘nimby’ at any concerned group who voice a protest over
planned developments. While not willfully dishonest, both
sides of the debate can be accused of reporting expediently
to further their point of view.

In this document, we hope that pertinent research has
been presented in a more balanced manner in anticipation
that informed discussion can ensue. The reader will notice
that it relies heavily on academic peer-reviewed
publications and expert reports. Reading this is not
intended to be the end of an interested person’s research:
rather, it should encourage further reading around the
subject, casting a critical eye on the source of information.
Casual assertions that unambiguously state wind power is
good or bad without any supporting evidence should be
judged accordingly. As is demonstrated throughout this
document, the reality is frequently more complicated than
that. The agendas of vested interests too often mean these
subtleties are lost, and the subject descends into
acrimonious debate.

What this document aims to show is that, implemented as
part of a progressive energy portfolio, wind power can
significantly reduce both the UK’s carbon footprint, and its
dependence on fuel sources that may become less secure in
the future, or that present a costly and unacceptably
hazardous legacy for future generations.

However, wind power is not appropriate everywhere, and
we hope that by publishing this research communities
themselves will engage constructively with the best
available evidence to judge if there is a place for wind
turbines in their own locality. To empower communities to
make these decisions demands a more mature and
responsible approach from the media, the wind industry
and pressure groups on both sides of the debate.

----------------------------------------------------------

1. Wind turbines and energy payback times

Despite having fallen short of government targets, in 2010 there was still more than 5GWe of installed onshore wind capacity in the UK. Given typical load
factors, this equates to roughly 13TW of electricity generated in a year, meaning some 7.8 million tonnes of CO2 (MtC) otherwise created by fossil fuel
generation has been displaced. By 2020, the capacity of the UK’s onshore wind power is expected to more than double to 11.5GWe – that will displace
approximately 18MtC. Offshore wind is expected to contribute almost twice that again.

Centre for Sustainable Energy
www.cse.org.uk

Common concerns about wind power

Wind turbines and energy
payback times

Summary

Concerns about the amount of energy (and subsequent
CO2 emissions) involved in the manufacture, construction
and operation of a wind farm are often voiced as an
argument against its installation. It is true, of course, that
some energy will be required over the whole life cycle of a
wind farm. This includes the manufacture of materials; the
transportation of parts to the site; construction of the
turbines and supporting infrastructure like foundations; site
operations and maintenance; and, finally, in
decommissioning the site. However, this is true of all forms
of energy generation.

The issue, therefore, lies in whether the plant will generate
sufficient useable energy over its lifetime to justify the
energy involved in its installation. In the case of wind farms,
all the evidence suggests that this is the case: the average
wind farm is expected to generate at least 20–25 times1 the
energy required in its manufacture and installation over its
lifetime, and the average energy payback time for a wind
farm is in the region of 3–6 months.1,2 These figures
compare favourably with other forms of power generation,
as discussed in more detail below.

What is this based on?

Those opposed to wind power (be it onshore or offshore)
often allude to the energy required in the construction and
operation, with little consideration or comparison to other
forms of large-scale power generation. The amount of
energy required in installation is an important consideration
when assessing the suitability and cost-effectiveness of any
new energy development. As such, it is useful to be able to
compare the amount of energy used in site installation with
the amount of energy that the installation is expected to
generate over its lifetime (i.e. the ‘net energy’ of the system

– see the diagram in reference 1). This is often referred to
as the ‘energy balance’ or ‘energy return on investment’
(EROI). The time taken for an installation to generate as
much energy as was needed in its manufacture and
construction is the ‘energy payback period’.
A number of factors will affect the energy balance and
energy payback period of a wind farm, including wind
speed at the site and the size, number and type of turbines
installed. Furthermore, in calculating the energy balance or
payback period, a number of assumptions have to be made
about, for example, the power rating, lifetime and capacity
factor (section 3) of the turbines, and the 'system
boundary' of the wind farm. The system boundary
describes the number of different stages in the life cycle of
the wind farm, all of which are taken into account when

assessing a site’s energy payback. These stages may include:
business management; design and manufacture of
component parts; transportation; construction; connection
to the electricity grid; operation and maintenance; and final
decommissioning and restoration of the site. These key
steps are illustrated diagrammatically in reference 1.

What is current evidence?

Given the number of assumptions that have to be made in
assessing and comparing the energy requirements of wind
farms with the energy they generate, it is not surprising
that a range of estimates exist about payback. However, a
recent study provides a useful and comprehensive review of
the net energy return for electric power generation by wind
turbines.1

The review (published in 2010 in the journal Renewable
Energy) includes data from 119 wind turbines, from 50
different analyses (of both real and conceptual wind farm
sites), going back some 30 years. The range of assumptions

(e.g. of power load, capacity, lifetime and system
boundaries) and methods employed by the different studies
is very evident – the review captures this breadth and helps
in highlighting the impact of these assumptions and
approaches on the resulting estimate of energy return.
The study refers to the ‘energy return on investment’
(EROI), which is simply the ratio of energy delivered by the
technology to energy required in running the site over its
lifetime (i.e. energy generated/energy required). A higher
value indicates a better performing system. The results of
the survey show an average EROI across all studies
(operational and conceptual) of 25.2 (falling to 20 for
operational only).

In other words, it shows that the average wind farm is
expected to generate some 20-25 times more energy over
its lifetime than was required in building and running it.
This compares well with other forms of power generation
systems. For example, coal offers a lower energy return on
investment of around 8 and nuclear around 9.3 The paper
also shows the energy payback in years for the studies
where this data is available. Figures referenced range from

0.29 to 0.53 years, or 3.5 to 6.4 months, suggesting on
average a wind farm will have generated sufficient energy
in just half a year to account for all the energy that is
required in its construction and operation. This figure is
broadly consistent with the 3–10 month payback period
quoted by the Sustainable Development Commission.4
Conclusion

All electricity generation systems require some amount of
energy for their manufacture, construction and operation.
It is important to consider how this energy requirement
compares with the expected energy output of the system
over its lifetime. If the former is almost on a par with the
latter, the system is clearly not a sustainable choice
(environmentally or economically). In terms of energy

www.cse.org.uk Centre for Sustainable Energy

Common concerns about wind power

payback, wind farms do compare favourably with other
power generation systems. Furthermore, there is significant
potential for technological development in wind energy –
particularly relative to other, more mature systems – which
could further improve the cost-effectiveness and
performance of installations.

1 Kubiszewski, I., Clevelan, C.J., Endres, P.K. (2010). Meta-analysis of net energy return for wind power systems. Renewable Energy, 35, pp.218-225
2 Milborrow, D. (1998). Dispelling the Myths of Energy Payback Time. Wind Stats Newsletter, vol. 11, no. 2 (Spring 1998).
3 Kubiszewski, I., Clevelan, C.J., Endres, P.K. (2010). Meta-analysis of net energy return for wind power systems. Renewable Energy, 35, pp.218-225, [Figure 6].
4 Sustainable Development Commission, (2005). Wind Power in the UK. A guide to the key issues surrounding onshore wind power development in the UK.

Available at: www.sd-commission.org.uk/publications/downloads/Wind_Energy-NovRev2005.pdf

Centre for Sustainable Energy www.cse.org.uk

Common concerns about wind power
---------------------------------------------------------
2. Wind turbines, costs and subsidies

Summary

It is often argued by organised groups opposed to wind
energy – and repeated in the national press – that wind
power is both expensive and is heavily subsidised by the
taxpayer. In fact, onshore wind is already cost-competitive
with conventional large-scale generation. And while it is
true that all forms of renewable energy generation benefit
from specific government support, it must be recognised
that all forms of large-scale generation – whether low
carbon or conventional – receive some kind of state support
(in the form of subsidies, capital grants and allowances, etc).
It is the case that, so long as the ‘externalities’ related to
power generation from conventional fuel sources (from the
plant itself or from the fuel supply chain impacts) are not
included in the cost of those activities, government support
will be needed to incentivise the low carbon but capital
intensive forms of generation.

What is this based on?

Those opposed to wind power (be it onshore or offshore)
often highlight the high costs involved in this form of large-
scale electricity generation without consideration or
comparison with other ways of generating power. These are
then used to claim that wind power is an extremely
expensive way of generating electricity and that without
significant subsidies, ultimately from the tax-payer, wind
power development would be unable to continue.1, 2 In
addition, there is a well organised opposition to the
mechanisms by which all forms of renewables are supported

– e.g. the Renewables Obligation (or RO) and, to a lesser
extent, the exemption that all forms of renewables receive
from the Climate Change Levy (CCL).
What’s the current evidence?

Cost

Figures from the government-funded Sustainable
Development Commission in 2005 showed that the
generation cost of wind power was around 3.2p/kWh
onshore and 5.5p/kWh offshore – this compared at the
time to a wholesale electricity price of 3.0p/kWh. As an
increasing amount of wind power is added to the system,
there are some additional costs associated with
accommodating it. These ‘system costs’ are estimated to be
around 0.17p/kWh if wind power were to supply 20% of
total output – this is equal to a 3.8% increase in the
current cost of electricity, or £13 extra per year on the
average domestic bill.3 A previous government report in
2002 stated that onshore wind was competitive with new
coal and cheaper than new nuclear.4

The generation costs of wind power have increased by
20% over the past three years due to increased demand
and rising prices of key raw materials, though a European
Commission Strategic Energy Review predicts a long term
decline in capital cost.5 This must be compared to increases
in conventional fuel prices and the fact that there are no
ongoing ‘fuel’ costs for wind power – as a renewable
resource it will become comparatively even cheaper.

The most recent report looking at cost estimates of
generating electricity from a range of large scale
technologies commissioned by the Department of Energy
and Climate Change in 2010 showed that estimates for
onshore wind are now 9.4p/kWh. However, to put this in
context electricity from nuclear power is estimated to be
9.9p/kWh and electricity from gas 8.0p/kWh. Offshore
wind is estimated to be more expensive, with costs of
15.7–18.6p/kWh (depending on wind farm location),
although this is expected to fall to 11.0–12.5p/kWh for
projects commissioned from 2020.6

Subsidies

Claims that onshore wind energy is competitively priced
only because of government subsidy, or that wind power is
disproportionately subsidised, are not supported by the
evidence. In order to meet the UK’s targets for reducing
carbon emissions electricity suppliers are required to
purchase an increasing number of Renewable Obligation
Certificates (ROCs) each year from renewable energy
generators. A fine is paid by those suppliers who have not
met their obligation, with the revenue being distributed to
those suppliers who have (in proportion to how many ROCs
they purchased) therefore rewarding those who are
purchasing more renewable energy.7

The only financial support from government for the
Renewable Obligation is the administration and regulation
by Ofgem, which for 2008–09 was only £988,500,
representing less than 0.1% of the scheme’s total value.8
While the costs are ultimately reflected in customer’s bills,
one aspect of the policy ensures that this is never more
than an additional 3p/kWh on a maximum 10% of the
customer’s electricity use, meaning that 90% of a
customer’s bill is unaffected by the Renewable Obligation.7
Furthermore, ROCs are a market mechanism and non-
technology specific so it is most economical for suppliers to
meet their Renewable Obligation by purchasing the
cheapest renewable energy, thereby supporting the case
that onshore wind is a cost-effective method of increasing
renewable capacity.7

A different kind of subsidy which is inherently not
accounted is found in the externalities of fossil fuel and
nuclear generation. Externalities refer to wider
environmental, social and economic costs of an activity
which are not accounted for in that activity’s price. These
costs, or impacts, are typically felt outside the traditional
economic accounting system, or in what is often referred to
as ‘the commons’, such as the atmosphere, land and

www.cse.org.uk Centre for Sustainable Energy

Common concerns about wind power

water.9 These costs include pollution, fuel spills, accidents,
clean ups, health costs and, ultimately, climate change.
Where the industry responsible does not fully cover these
externalities, they are effectively subsidised by society
through taxation.9

In an attempt to quantify these externalities, The EU’s
ExternE report claims that if all environmental and social
costs of burning coal and oil were ‘internalised’, the price
would double.10 This assertion is made even though the
impacts of natural resource depletion are not included in
the analysis;11 accounting for the full impacts of mining,
processing and transporting the raw materials would
internalise significantly more costs, particularly for coal and
nuclear, given the processes involved (see also section 6).

A 2011 paper aiming to quantify the full costs of coal
generated electricity uses a more comprehensive life cycle
analysis than the ExternE report – which includes the
impacts of natural resource depletion, wider ecological
impacts and its contribution to climate change – and
suggests that the true cost of coal generated electricity
could be tripled.12 And there are yet further impacts which
are not accounted for, such as the long-term effects of
toxic chemicals and heavy metals on ecosystems, the health
and ecological risks posed by sludge and slurry, the full
contribution of nitrogen deposition to eutrophication in
fresh and sea water, the prolonged impacts of acid rain and
the full assessment of impacts on an increasingly unstable
climate.12 As true cost accounting improves, the relative
costs of fossil fuels compared to renewables will increase;
however, there will always be impacts that cannot be
adequately quantified.

While overall subsidies to conventional generation have
been considerably greater than those to renewables, on a
per unit energy basis renewables in general have received
significantly more.13 However, a comprehensive study into
worldwide energy subsidies revealed that wind ‘has
registered a spectacular success story in reducing the need
for subsidisation’ and among renewables only hydro (which
receives the least per unit of electricity of all generation
types) receives less; moreover, coal-fired generation received

the highest subsidies per unit generated, despite its
widespread deployment11. Furthermore, this only includes
the externalities as accounted for by the ExternE report,
which does not represent the true overall cost (see above).

The bulk of subsidies to renewables go into research and
development and the significant capital needed to bring
emerging technologies into the market.11 Not only were
such subsidies necessary for the development of much
conventional generation during its equivalent early
years11, 13 but the social and environmental costs of both
the fuel supply chain and the resultant pollution of those
energy sources are ongoing. Once wind farms are up and
running, on the other hand, there is no fuel input or
pollution and therefore no similar associated impacts.

Conclusion

A recent report for the Department for Energy and Climate
Change (DECC) characterised the cost trade-off to be
considered by stating that “Plant can be broadly
categorised either as being expensive machines for
converting free or low cost energy into electrical energy or
else lower cost machines for converting expensive fuels into
electrical energy. The former group comprises most
renewable generation and nuclear plant, while the later
group comprises plant running on fossil fuels.”14

The evidence demonstrates that wind energy is already cost
competitive with conventional electricity generation over
the lifetime of the plant.3, 14 Furthermore, there are no fuel
costs associated with operating a wind farm, unlike fossil
fuel plants. Fossil fuel prices are set to increase now that
less accessible fuel reserves need to be extracted to meet
global demand. This means the relative price of wind
energy is likely to become even cheaper."

Much of the environmental and social cost of conventional
fuels is not reflected in the cost of generating electricity
from conventional large scale plant, and effectively amount
to additional public subsidies. Internalising these costs
completely would further increase the costs energy
generated from conventional fuel sources.

1 Leach, b, Gray, R. Wind farm subsidies top £1 billion a year. The Telegraph. Sunday 23rd January 2011. http://tinyurl.com/y8m7vxp. (Accessed 24/1/2011).
2 Leake, J. Wind farms turn huge profit with help of subsidies. The Sunday Times. Sunday 23rd January 2011. http://tinyurl.com/yaofrfn. (Accessed 24/1/2011).
3 Sustainable Development Commission. Wind Power in the UK. http://tinyurl.com/4dvso57. (Accessed 24/1/2011).
4 DTI. 2002. Renewables Innovation Review. www.dti.gov.uk/renewables/policy/oxeraresults.pdf. (Accessed 24/1/2011).
5 Department of Energy and Climate Change. UK Electricity Generation Costs Update: A report by Mott MacDonald. http://tinyurl.com/4lfwppe (Accessed

02/02/2011).

6 Blanco, M, I. 2009. The economics of wind energy. Renewable and Sustainable Energy Reviews. 13: 1372-1382.

7 Mitchell, C, Bauknecht, D, Connor, P, M. 2006. Effectiveness through risk reduction: a comparison of the renewable obligation in England and Wales and the

feed-in system in Germany. Energy Policy. 34: 297-305.

8 OFGEM. 2010. Renewables Obligation: Annual Report 2008-2009. http://tinyurl.com/2wuunon (Accessed 07/02/2011).

9 Templet, P. 1995. Grazing the commons: an empirical analysis of externalities, subsidies and sustainability. Ecological Economics. 12: 141-159.

10 ExternE. 2003. External Costs, Research Results on Socio-Environmental Damages due to Electricity and Transport. www.externe.info/externpr.pdf. (Accessed

24/1/2011).

11 Badcock, J, Lenzen, M. 2010. Subsidies for electricity-generating technologies: A review. Energy Policy. 38: 5038-4047.

12 Epstein, P, Buonocore, J, Eckerle, K, Hendryx, M, Stout III, B, Heinberg, R, Clapp, R, May, B, Reinhart, N, Ahern, M, Doshi,S, Glustrom, L. 2011. Ecological

Economics Reviews. 73-98.

13 European Environment Agency. 2004. Energy subsidies in the European Union: A brief overview. EEA Technical report. http://tinyurl.com/46nobx4 (Accessed
24/1/2011).

14 Department of Energy and Climate Change. UK Electricity Generation Costs Update: A report by Mott MacDonald. http://tinyurl.com/4lfwppe (Accessed
02/02/2011)

Centre for Sustainable Energy www.cse.org.uk

Common concerns about wind power
----------------------------------------------------------
3. Efficiency of wind turbines

Summary

It is sometimes alleged that wind turbines are inefficient and
‘only work 30% of the time’. This figure is based on the
‘load factor’ for onshore wind farms, but is erroneously used
to imply wind power is inefficient. This is wrong – load factor
and efficiency are not the same; in fact, conventional
power stations in the UK run with an average load factor of
50–55%, but these are not described as running “half the
time”. Wind farms actually generate electricity around 80–
85% of the time, and power is converted to electricity very
efficiently, with none of the thermal waste inherent in fossil
fuel plants. So, wind power is an efficient way to generate
electricity, employing a free energy source that is also renewable.

What is this based on?

Any device capable of generating power is given a rating or
‘nameplate capacity’ measured in watts. This is simply how
much power the device can produce at its full, or peak,
capacity – it does not take into account how that power is
converted into useful energy. The capacity factor, or ‘load
factor’, is the average power output (i.e. actual output
measured over a period of time, usually measured in hours)
divided by what could have been produced had the
generator run continuously at peak capacity over the same
period. It is from this calculation that the 30% figure for
wind turbines is drawn, but capacity factor should not be
confused with efficiency; that is to say, this does not mean
wind turbines are 70% inefficient, or that they only run for
seven hours every day. No generator is designed to run at
full capacity continuously, and conventional power plants as
a whole usually run with an average load factor of 50–55%.

What is the current evidence?

Medium to large scale power generators of any kind (e.g.
fossil fuel, nuclear, wind or hydro) have capacities measured
in megawatts (MW). When discussing electrical power
generation from power plants, it is common to draw a
further distinction between megawatts electrical (MWe) and
megawatts thermal (MWt). To give a few examples: typical
capacity ratings for a large coal-fired power station or large
combined-cycle gas turbine plant in the UK would be in the
1–2,000 MW range; nuclear power plants are around 1,000

MW; gas/oil plants go from 10–50 MW; and the ratings for
individual modern large wind turbines are commonly
between 1.5–3.0 MWe. Table 4.1 (overleaf) gives load
factors for various conventional plants and renewable
power sources in the UK for years 2007–09.1

Conclusion

When discussing wind power, load factor is frequently
equated with efficiency. This is incorrect, and paints a
misleading picture of wind turbines being inefficient
compared to more traditional sources of power. Onshore
wind power generation has a load capacity of around 27%,
but this is not an indication that something is wrong with
the functioning of the turbines, and is hardly calamitous
when compared to the ~38% average load factor of
conventional thermal power stations.

The UK continues to offer the best wind resource in Europe,
and the power output from a wind farm can be calculated
with considerable accuracy.2 In fact, wind turbines typically
produce electricity 80–85% of the time, and periods of peak
generation from onshore wind can be used as an
opportunity to sell electricity back to the national grid.1,3
Furthermore, the efficiency of a wind turbine can be
considered very good in comparison to non-renewable
sources, as they are capable of turning a free resource (wind)
into electricity without the considerable thermal inefficiencies
inherent in most conventional plants that consume fossil
fuels or use nuclear power.

1
National Statistics, 2010. Digest of United Kingdom Energy Statistics 2010. London:TSO. Published with permission of Department of Energy and Climate
Change. www.decc.gov.uk/assets/decc/statistics/publications/dukes/348-dukes-2010... (accessed 23 Nov 2010)

2
Sinden, G. 2005. Wind power and the UK wind resource. Oxford: Environmental Change Institute. On behalf of the Department of Trade and Industry (DTi).
www.eci.ox.ac.uk/publications/downloads/sinden05-dtiwindreport.pdf (accessed 17 Nov 2010)

3
Domínguez, T., de la Torre, M., Juberías, G., Prieto, E., Rivas, R., Ruiz, E. 2008. Renewable energy supervision and real time production control in Spain.
www.leonardo-energy.org/webfm_send/256 (accessed 23 Nov 2010)

www.cse.org.uk
Centre for Sustainable Energy

Table 3.1 2007 2007 2008 2008 2009 2009
Source of electricity generated Installed Load factor Installed Load factor Installed Load factor
capacity (%) capacity (%) capacity (%)
(MW) (MW) (MW)
Conventional thermal stations 36,658 44.3 35,145 39.1 35,151 32.9
– of which coal-fired 23,008 66.0 23,069 59.9 23,077 49.8
Nuclear stations 10,979 59.6 10,979 49.4 10,858 65.4
Combined cycle gas turbine stations 26,930 64.3 28,593 70.9 29,878 62.8
Hydroelectric stations (natural flow) 1,419 36.3 1,519 35.7 1,526 35.0
Onshore wind 2,083 27.5 2,820 27.0 3,483 27.4
– on unchanged configuration basis 27.3 29.4 26.9

Unchanged configuration uses load factors of wind turbines that have operated throughout the calendar year. This avoids biases created by the introduction of
new turbines partway through the year. As this mainly applies to commercial scale wind farms, units of <100kW rating are excluded.

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Common concerns about wind power
------------------------------------------------------
4. Intermittency of wind turbines

Summary

Weather patterns can be forecast with some degree of
accuracy, but there is no denying that wind power is an
intermittent source of energy when focusing on isolated
sites. This notwithstanding, the problem of ‘dispatch’,
whereby supply of electricity is tailored to meet constantly
changing demand, is not new to the industry. Large
unpredictable swings in the system are already balanced on
a daily basis, and the grid is prone to critical failures for
which significant reserve capability already exists. On
balance of the evidence, there appears little need to expand
this overall reserve in response to increased wind capacity.

The uncertainty of supply when considering wind is a
problem of availability that presents novel statistical
challenges to the transmission operator when compared
with conventional generators, but not one that cannot be
forecast and integrated effectively into the national grid. It
should be made clear that these challenges do require a
moderate financial cost, although the external benefits of
reduced total CO2 emissions from electricity generation and
the resilience provided by a distributed network of wind
farms should not be underestimated.

What is this based on?

One major disadvantage often stated for wind power is
that this resource is not available as a smooth,
uninterrupted supply, i.e. it is intermittent. This is a critical
factor when dealing with electricity generation because
output must be balanced exactly with demand (electricity,
uniquely for a major energy supply, cannot be easily or
efficiently stored). Traditional power generation in the form
of fossil fuel plants operate in a load-following capacity,
whereby output is lowered or “ramped up” according to
the demand placed on the national grid. In the main, this
role is performed by gas-fired power stations, which can be
rapidly fired up to meet increased demand.

In the UK, peak demand – and thus, electricity production –
is typically just below 80% of the nation’s total capacity.1
Therefore, no system of electricity generation is designed to
run at maximum capacity, as it must have the flexibility to
cope with fluctuations in demand at the same time as
providing for unforeseen events such as plant failure. The
variability of wind is a significant issue, but is not an
unprecedented challenge for an industry that already copes
with greater fluctuations in the national grid on a daily
basis. The argument should be considered with regard to
the cost society is prepared to accept for carbon-free
electricity ( of which wind is the major contributor at
present).2,3

The UK is considered to have one of the best available
onshore and offshore wind resources in Europe, with
installed capacity notably higher than rates achieved with
comparable facilities in Denmark and Germany.4 Care
should be taken not to extrapolate average data for wind
resources across the entire country when discussing wind
power.

However, this caveat should not be applied simply to argue
that a UK wind power grid will be undermined by periods
of inactivity (caused by low or high winds),5 since this can
also work in favour of wind power when implemented as
part of a diversified network.6 In the context of a
nationwide, diversified system of wind farms the effect of
this variability is largely evened out – the lack of control
with regards to when the wind blows over a specific wind
farm is what creates the perception of an insuperable
problem.2 A nationwide “geo-spread” of wind capacity,
provided it is balanced across the whole grid, means that:

“...the sudden loss of all wind power over an entire

power system at the same instant – due to a drop in

the resource – is not a credible event.”3

To discuss the issues involved with intermittency, this
section will deal mainly with wind generation as a whole

(i.e. onshore and offshore) as this phenomenon is inherent
in any form of wind power.
What is the evidence?

The output of electrical power across the grid must exactly
balance the demand, as there are only very limited means
to store electrical energy that is not used.2 Onshore wind
power generated 2% of the UK’s total electricity
production in 2009: this was 7,564 GWh (which can be
expressed in terrawatt hours as 7.56 TWh) out of a UK total
gross production of 359,189 GWh (or 359.2 TWh).1 The UK
target is for renewables to make up over 30% of the
country’s total electricity production by 2020, estimated to
be a demand of 399 TWh.7

Conservative estimates say onshore wind will have an
installed capacity of 11.5 GWe and offshore wind will rise
to 21.5 GWe.8 We have seen already (section 3) that power
plants only ever provide a fraction of their theoretical
capacity – the load factor – and this is around 30% for
wind power as a whole. Given the 33 GWe capacity
predicted above for 2020, wind will generate 86TWh of
electricity. To put this in perspective, every TWh of
electricity generated by wind in place of fossil fuels would
displace 598,000 tonnes of carbon dioxide, saving over 50
million tonnes (MtC) in total if 2020 targets were reached.1

There is no denying that wind is an intermittent power
source: the figure below illustrates a typical power curve of
a modern wind turbine, illustrating that a wind turbine
ramps up its output from <10% of its capacity to almost
full capacity (>85%) between wind speeds of 4m/s (9mph)
and 12m/s (27mph)9. This output tends toward maximum

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Common concerns about wind power

Fig 4.1
Indicative power curve of a typical modern turbine

100%
75%
50%
25%
5 10 15 20 25 30
Sub-optimal
operation
Optimal
operation
Safety cut-off
Power
Wind speed m/s

capacity between 12–25m/s (27–55mph), after which the
turbine cuts out to prevent damage due to high wind
speed. Weather patterns across the British Isles can often
result in wind power output varying by 0–100% for a
particular wind turbine (or wind farm) on any given day,
since the window of operation is 4–25m/s; typically
individual wind turbines are on average non-productive for
20% of the year, almost always due to lack of wind.6

What problems does this pose for managing wind power
on a national scale? The present level of capacity in the UK
system for wind in both onshore and offshore platforms is

4.4 GWe (around 5%), and any period when these
installations are not providing enough energy can be easily
adjusted for by the grid using more responsive plants such
as natural gas-fired turbines. However, as wind penetrates
the electricity generating capacity to a much more
significant level (up to 33 GWe – 39% of the UK’s total
installed capacity1) then the fluctuations inherent in the
system will require careful management to maintain
security of supply.
Consider a future grid that contains 10 GWe of installed
wind capacity: with existing conventional non-intermittent
plant it is accepted that demand forecast over a half hour
(0.5h) window will be subject to a 0.34 GW standard
deviation (s.d.), but with 10 GW installed wind capacity
there is also a calculated s.d. of 0.14 GW across the same
period of time; adding these independent forecast errors
together, that amounts to 0.37 GW [for combining s.d.
values solve the formula v(3402 + 1402)]. Reserve capacity
to deal with uncertainty between demand and output is
taken to be three standard deviations of the overall forecast
error: for our system here that contains 10 GW of wind
capacity this is equal to 1.14GW (= 3 × 0.37).

In summary, a grid with 10GWe of installed wind capacity
must be able to cope with a potential mismatch of 1.14 GW
in every 0.5 hour period.10 Across a 4-hour window these
fluctuations amount to just under 3 GW. As the forecast
window increases the s.d. for the forecast error levels off, so

0.5 hours and 4 hours are considered appropriate periods to
take account of uncertainty in output.
The above example shows that, above a certain
penetration, installing 1 MW of wind capacity does not
necessarily equate to 1 MW of conventional plant being
replaced. Due to the inherent uncertain availability of wind
at various operating time windows, a high penetration of
wind capacity places a significant burden on the grid
operator to manage reserve capacity and ancillary services.
This is not just for shortfalls in power output – it can also
be the case that highly concentrated centres of wind power
generation will cause other problems due to supply
outstripping production.5

In large wind power systems in continental Europe this can
largely be offset by exporting electricity to neighbouring
countries via well-established inter-country networks; but
this is not so straightfoward for the UK (although
interconnected grids between the UK and Ireland offer a
limited ‘smoothing’ facility).9,11 The British Isles does have
the advantage that summer and winter weather patterns
broadly coincide with annual peak demand, i.e. wind
capacity factor (load) is considerably higher than the yearly
average during winter months, which is the period of
highest demand. Aggregating wind power generation over
the entire UK grid allows local supply/demand mismatch to
be smoothed out and reduces the need for large levels of
balancing capacity.6 Indeed, the creation of continuous
geographical ‘balancing regions’ allows more accurate
forecasting to meet the needs of the transmission (grid)
operator.12

As mentioned above, an increased wind capacity creates a
special requirement for reserve capacity that can be easily
brought into action or, alternatively, curtailed, to meet
constantly fluctuating demand. Reserve capacity is
traditionally heavily reliant on a synchronised or ‘spinning’
reserve, i.e. conventional thermal plant that is kept part-
loaded (around 20% capacity) to be instantaneously
ramped up when needed and subsequently returned to
standby when demand drops. Additional capacity is
provided by standing reserve, which, as its name implies,
employs smaller generators (typically diesel) that are
switched on and off. This is usually in response to a large
drop in power caused by a power plant outage.

There are negative aspects to keeping spinning reserve as a
backup to compensate for greater penetrance of wind
power: power plants that run part-loaded are less efficient
and thus create more CO2 emissions per unit electricity; and
the most efficient conventional thermal plants are not
designed for ‘load-cycling’ at the degree needed to cope
with demand/supply mismatch, which means they will run
less reliably due to physical stress placed on these units9.
Previous estimates of the cost of increased wind capacity
may not have taken these factors into account; but, the
underestimation of availability of wind-generated electricity
at times of higher demand means that the need for
spinning reserve has been overestimated as a result.6

In fact, the grid already has reserve in place to cope with
existing intermittency – a fact often overlooked is that

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Common concerns about wind power

conventional plant can be the cause of unplanned, and at
times very considerable, power loss.

The resilience of a distributed network of wind turbines can
even be considered superior to large conventional plants
that may go offline without warning, creating an instant
gigawatt ‘hole’ in the national grid’s supply (for instance
due to the inherent risk nuclear plants must shutdown
completely if there is a serious fault).6,13

Conclusions

The increasing installed capacity of wind power across the
UK poses a considerable technical challenge to ensure the
balance of demand and supply is maintained at all times
across the grid. However, while availability of wind is to
some extent uncertain for any one area, coping with large
swings in supply and demand is a problem transmission
operators have been familiar with for some time. While this
extra burden on existing plant required to provide some
reserve capacity causes some concern, it is clear that
national installed wind capacity can form an aggregated
‘balancing region’ whereby its perceived unreliability due to
site-specific variability has been overestimated.6,9,10

However, the need to create a diversified network of wind
installations is essential, and the practical issues of
distribution from low to high-load areas within the grid
should not be underestimated.5,11 The need for extra
investment should not be dismissed. There will be
additional costs to improve distribution infrastructure and
maintain sufficient conventional reserve, although these are
thought to contribute only a moderate increase (5%) to the
cost of electricity generated by wind.2,10

The ‘social resource cost’ is arguably the most important
consideration for the decision to commit to optimum
penetration of wind power capacity across the UK

(generally estimated to be 26–33 GWe).2,8,10 Wind power
currently offers the most commercially viable and well-
established renewable resource for electricity generation to
meet national targets for the reduction of CO2 emissions,
and attempts to compare its ‘capacity credit’ on a like-forlike
basis with fossil fuels is misguided, not to mention
largely unnecessary given the capability of the industry
already to cope with uncertainty in supply and demand2,6.
In fact, a diversified wind power network would go some
way to assist the transmission operators in achieving an
overall probability level of meeting demand throughout the
year, meaning its capacity credit may be underestimated in
any case.3,6,14

There are concerns that increased reliance on more flexible
gas-fired power plants playing a load-cycling role will create
increased unreliability and inefficiencies in operation of
conventional plant, and this should be accounted for in any
implementation cost estimates. However, the displacement
of larger, inflexible baseload plant across the system goes
some way to offset this.6,9,10 It should not be forgotten that
the UK government’s targets include all renewables
contributing 127 TWh by 2020 – increasing investment in
biomass and marine/tidal would create less volatile capacity
that could be used in place of traditional fossil fuel reserve
when needed.7,8

Wind farms offer a flexible, modular system that if
implemented as a diversified resource with effective
geographic spread can offer a reliable source of low-carbon
energy, forming a core part of a mixed renewables portfolio
in combination with a reduced platform of responsive
conventional capacity.

1
National Statistics, 2010. Digest of United Kingdom Energy Statistics 2010. London:TSO. Published with permission of Department of Energy and Climate
Change. www.decc.gov.uk/assets/decc/statistics/publications/dukes/348-dukes-2010... (accessed 23 Nov 2010.)

2
Boccard, N. 2010. Economic properties of wind power: A European assessment. Energy Policy; 38: 3232–44.

3
Projected Costs of Generating Electricity – 2010 Edition. Paris, and Issy-les-Moulineaux, France: Organisation for Economic Co-operation and Development
(OECD)/InternationalEnergy Agency (IEA)/Nuclear Energy Agency (NEA); 2010 March. 218 p.

4
Sinden, G. 2005. Wind power and the UK wind resource. Oxford: Environmental Change Institute. On behalf of the Department of Trade and Industry (DTi).
www.eci.ox.ac.uk/publications/downloads/sinden05-dtiwindreport.pdf (accessed 17 Nov 2010)

5
Sharman, H. 2005. Why UK wind power should not exceed 10 GW. Proceedings of ICE – Civil Engineering; 158: 161–9.

6
Sinden, G. 2007. Characteristics of the UK wind resource: Long-term patterns and relationship to electricity demand. Energy Policy; 35: 112–27.

7
The UK low carbon transition plan: national strategy for climate and energy. London: HMSO; 2009 July 20. URN 09D/716. http://tinyurl.com/6z5p6yvf
(accessed 16 Jan 2011)

8
Growth scenarios for UK renewables generation and implications for future developments and operation of electricity networks. Newcastle upon Tyne:
Sinclair Knight Merz; 2008 June. Report for the Department for Business Enterprise and Regulatory Reform (BERR). BERR publication URN 08/1021.

9
Oswald, J., Raine, M., Ashraf-Ball, H. 2008. Will British weather provide reliable electricity? Energy Policy; 36: 3212–25.

10 Strbac, G., Shakoor, A., Black, M., Pudjianto, D., Bopp, T. 2007. Impact of wind generation on the operation and development of the UK electricity systems.
Electric Power Systems Research; 77: 1214–27.

11 Sharman, H. 2005. Why wind power works for Denmark. Proceedings of ICE – Civil Engineering; 158: 66–72.

12 Accommodating high levels of variable generation. Princeton: North American Electric Reliability Corporation (NERC); 2009 April 16. Special report by the
NERC Integration of Variable Generation Task Force (IVGTF). 98 p. www.nerc.com/files/IVGTF_Report_041609.pdf (accessed 24 November 2010)

13 Andrews, D. [Internet]. 2008. Claverton Group; c.2011. [Cited on 23 Jan 2011.] National Grid’s use of emergency diesel standby generator’s in dealing with
grid intermittency and variability – potential contribution in assisting renewables. Available at www.claverton-energy.com/?dl_id=131.

14 Gross, R., Heptonstall, P., Anderson, D., Green, T., Leach, M., Skea, J. The costs and impacts of intermittency: an assessment of the evidence on the costs and
impacts ofintermittent generation on the British electricity network. London: UKERC; 2006, March. UK Energy Research Centre’s Technology and Policy
Assessment (TPA) report. www.ukerc.ac.uk/Downloads/PDF/06/0604Intermittency/0604IntermittencyRepo... (accessed 23 Jan 2011)

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Centre for Sustainable Energy

Common concerns about wind power
---------------------------------------------------
5. The need for onshore as well as offshore turbines

Summary

It is argued that because there is a superior wind resource
off the coast of the United Kingdom that all efforts should
go into offshore wind power rather than onshore.
However, various reports maintain the importance of
continuing onshore wind’s expansion alongside the
development of offshore wind.

What is this based on?

Opposition to onshore wind and the typically higher speed
and regularity of the wind regime offshore leads to claims
that the UK should not bother with onshore wind, and
should put all its efforts into developing offshore wind
capacity. The potential to generate substantial amounts of
renewable energy from offshore projects is also used as a
justification for setting much lower targets for onshore
projects. Proponents of this view argue that, because the
visual impact of wind turbines offshore is much reduced,
this is the right location for wind power.

What is the current evidence?

Offshore wind is forecast to be a major component of our
future renewable capacity and, while the UK is a leader in
its development, it is in its early stages compared to
onshore. Onshore wind is already cost competitive with
conventional electricity generation without subsidies (see
section 2) and is currently the cheapest way for electricity
companies to meet their renewable obligations and for the
UK to meet its legally binding commitments to cut CO2
emissions. Given government projections that onshore
wind will become the cheapest way to generate electricity
by 2020,1 it will remain a crucial component of the UK’s
renewable strategy.

Both the capital cost and ongoing operational and
management costs of offshore wind are up to twice that of
onshore2. The former is due to the considerable costs of
foundations, submarine transmission cables and installation
facilities, while the latter reflects the remote and harsh sea
environment in which they operate. High capital costs
demand government financial support for this developing
industry, though the technology is established and it is

believed that economies of scale will reduce costs as
production and investment increases with rounds two and
three of offshore wind development.1,4 However, despite
the higher energy generation per MW installed, a recent
analysis maintained that overall, offshore wind will remain
more expensive than onshore as operating costs will always
be significantly higher for reasons of gaining access and
maintenance.1

The fact remains that the UK will need to continue
increasing onshore wind capacity alongside huge offshore
development if we are to meet the ambitious targets of
15% renewable electricity by 2020.2 The European Wind
Energy Association’s high capacity scenario predicts 20GW
offshore and 14GW onshore,3 so they are both essential for
increasing renewable generation.

Conclusion

The evidence demonstrates that the capacity of both
onshore and offshore wind needs to expand if ambitious
renewable and carbon reduction targets are to be met. The
cost-competitiveness of onshore wind mean its continued
expansion can continue, and while offshore wind still needs
significant government support, its development will be a
core component of the UK’s longer-term renewable
generation capacity.

1 Blanco, M, I. 2009. The economics of wind energy. Renewable and Sustainable Energy Reviews. 13: 1372-1382.
2 Department of Energy and Climate Change. 2009. A Prevailing Wind. Advancing UK Offshore Wind Deployment. www.tinyurl.com/5wq4zo3. (accessed

25/1/2011).

3 Green, R. Vasilakos, N. 2011. The economics of offshore wind. Energy Policy. 39: 496-502.

4 Department of Energy and Climate Change. UK Electricity Generation Costs Update: A report by Mott MacDonald. www.tinyurl.com/4lfwppe (accessed

02/02/2011).

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Common concerns about wind power
---------------------------------------------
6. Wind power and nuclear power

Introduction

There is a wide and respected body of analysis which shows
that the UK needs to develop its excellent wind energy
resources – both on and offshore – if the country is to
achieve its ambition of significantly cutting its carbon
emissions and improve energy security.1 Indeed, there are
precious few credible projections of UK energy supply and
demand that meet these objectives which do not include a
large tranche of onshore wind power over the next 20
years, whatever other energy sources they also include.

In spite of this evidence, there are some who argue that we
do not need wind power because we could replace the low
carbon electricity it produces by developing more nuclear
power stations. These, it is argued, avoid the intermittency
associated with wind power, producing steady ‘base-load’
electricity at a cost at least comparable with onshore wind
power.

However, in the context of forward projections for UK
energy supply, which include a large tranche of onshore
wind power over the next 20 years (and, in some cases, an
assumption of new nuclear power stations), this is not an
argument against wind power but an argument in favour
of nuclear power also making a contribution.

This briefing explores the validity of this argument that
nuclear power can sensibly be considered a replacement to
the development of wind power in the UK. It should be read
as neither for nor against nuclear power. It is instead
designed to provide evidence which challenges the
assertions that appear to underlie the argument that nuclear
power is an alternative to wind power. These assertions are
that: (a) nuclear power can contribute enough to UK
electricity demand such that wind power is not needed to
meet low carbon objectives; (b) nuclear power’s ‘low
carbon’ status is reliable and equivalent to renewable energy
sources such as wind power; (c) nuclear power’s own
environmental impacts and safety risks are either resolved or
resolvable and can therefore be dismissed in any discussion
about its suitability as a sustainable electricity supply.

Summary

Nuclear power has been used to generate electricity since
the 1950s, and purports to be a tried and tested method of
power generation. The use of nuclear power stations has
been hailed in recent years as the most efficient way to
produce electricity without relying on traditional fossil fuels,
thus creating a relatively ‘carbon-free’ grid. While not
strictly renewable, the potential stockpile of nuclear fuel
available for extraction means its supporters describe

nuclear power as a viable means to meet the world’s
energy needs for hundreds of years at least, based on the
fraction of physical fuel (enriched uranium) required by a
nuclear plant in comparison by bulk with coal or gas.

However, nuclear power’s status as a low-carbon source of
electricity is doubtful: while it compares favourably to
traditional fossil fuels such as coal, the logistical chain
required for extracting and processing uranium, plant
construction and plant decommissioning create a carbon
footprint for nuclear power that is significantly greater than
renewable sources. In addition, the nuclear power industry
in the UK and abroad has been traditionally beset with
problems involving the start-up, operation and
decommissioning of nuclear plants, resulting in economic
inefficiency and threats to public health. Despite decades of
experience, the unique problem of storage and disposal of
hazardous radioactive waste remains a concern for the
nuclear industry, with the cost and potential health
implications to be borne by future generations for centuries
to come.

Even without the concerns already raised, the long start up
time required to make a nuclear power station operational
means that nuclear power is irrelevant to the UK’s target to
cut CO2 emissions by 2020. The cost of electricity per unit
generated by nuclear power is currently no better than
onshore wind power, without taking into account the
future costs of cleaning up when a plant is finally
decommissioned. In comparison, the generation of
electricity from wind power poses an insignificant threat to
public health, requires a fraction of the start up costs and is
a true renewable energy source.

What is this based on?

A typical nuclear reactor will generate the same energy as a
coal fired plant using less than 0.001% of fuel by weight.
For example, a 1,000 MWe coal station will burn 3.1
million tonnes (Mt) of coal per year, compared with just 24
tonnes of enriched uranium oxide per year for a 1,000
MWe nuclear power station (although it should be
remembered that this comes from 25,000–100,000 tonnes
of mined ore).2 The heat created in a nuclear fission
reaction with uranium is used to generate steam which
drives the plant turbine to produce electricity; hence, no
CO2 is emitted as a waste product, making nuclear
electricity ‘on a par’ with renewables such as hydro and
wind power.

The operating carbon footprint does neglect the life cycle
analysis (LCA) of nuclear power created by the mining,
construction and decommissioning activities necessary for a
nuclear plant’s operation – an analysis that calls into
question the nuclear industry’s low-carbon claims.3 This is
of particular concern if global installations of nuclear
capacity increase: as the readily available uranium ore is
used up, efforts to extract lower-quality ore will create even
larger environmental burdens. When compared with fossil
fuels, the relatively small amounts of uranium needed (once

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Common concerns about wind power

it is suitably enriched) does mean that nuclear power is less
subject to market forces that affect fossil fuel prices; and
the global nuclear fuel supply is, in the early 21st century at
least, relatively secure.4 It should be remembered that wind
energy is also largely immune to market forces, since its
‘fuel’, i.e. wind, is free and renewable, and start-up costs
are considerably less than for nuclear.

Nuclear power stations supply baseload capacity and
typically run with a load capacity of more than 80% –
although the UK’s current nuclear plant actually runs
between 50% and 70%.5 Traditionally, nuclear power
stations offer less flexibility during off-peak times because
output cannot efficiently be adjusted to follow load, which
is the main reason they are employed in a baseload
capacity only.

There is one market that shows it is possible to manage
load-following electricity generation through careful
integration of a fleet of nuclear power stations: France. This
model offers valuable insights to management, but it
should be noted that as the plants get older they lose their
flexibility and have to be operated at baseline load.
Furthermore, the French system generates 78% of its
electricity by nuclear power, and can call upon a large
network of 58 reactors overseen by a centrally controlled
(and largely state-owned) administrator to provide load-
following capacity.6 Even with existing conventional thermal
plant (fossil fuel and nuclear) national transmission
operators in the UK and elsewhere must always rely on a
flexible reserve to cope with a constantly fluctuating
demand, a role which nuclear power is not suited to. The
issue of balancing electricity across the grid is dealt with in
the section on the intermittency of wind (section 4).

In the UK the most recent nuclear power plant to be
commissioned and built was Sizewell B between 1987–95.
Since the privatisation of the UK energy industry it has been
acknowledged that investment new-build for nuclear plants
has not been forthcoming.7 The reluctance of investors in
the UK has been blamed largely on negative perceptions of
the economic and safety record of the industry in this
country,8 although even in European markets traditionally
more open to nuclear power, the two most recent
construction projects of new ‘Generation III’ reactors
(Olkiluoto in Finland, and Flamanville in France) are
bedevilled with safety issues and rising costs, causing
repeated delays and leading to increased risk of electricity
shortfalls in France at critical times of the year.7, 9

Despite high-profile incidents in the past, the nuclear
industry safety record is in fact very good, with a worldwide
fatality rate expressed as 0.048 deaths per gigawatt of
electricity per year (0.048 deaths/GWey) due to accidents –
a statistic that compares favourably with coal (6.921;
although 90% of this is from China), oil (0.917), gas

(0.197) and liquefied petroleum gas (15.058).10 Wind
power, between 1975 and 2010, has 44 recorded fatalities,
an average of 0.054 deaths/ GWey11 It should be
remembered that the figure for nuclear energy drops to an
estimated 0.02 deaths/GWey when discounting the much
poorer safety record of non-OECD nations.12

What is the current evidence?

Since the Government’s commitment to reducing the UK’s
carbon emissions, nuclear energy has gone through a
turbulent period of initial optimism followed by
despondency. Despite being a mature technology with low
operating carbon emissions, the question of whether the
UK should invest in more nuclear power is dogged by
concerns about environmental impact, economic viability
and implementation, and safety.3, 8

Environmental impact: is nuclear power a low-carbon
energy source?

Nuclear energy’s hoped-for renaissance was based largely
on its role in the shift to low-carbon energy production,
based on its neglible operational CO2 emissions.8 This
selective view of nuclear power’s carbon footprint has been
questioned by recent research, which points out that the
life cycle analysis (LCA) of the ‘nuclear chain’ does in fact
create significant environmental burdens.13, 14 The LCA of
nuclear power must take into account both the ‘front-end’
(the mining of uranium ore, the milling process, chemical
conversion, and enrichment through centrifugal treatment
and construction and operating of the plant itself) and the
‘back-end’ (the spent-fuel processing, transport, interim
storage, and eventual disposal. Finally, there is the
decommissioning and dismantling of the retired power
plant, a costly financial and environmental stage that places
liability on future generations.

It should be noted that the CO2 emissions (CO2e) generated
by nuclear power are still a tremendous improvement over
traditional fossil fuels, at 66g CO2e/kWh compared to 960g
CO2e/kWh for coal, but they are higher than the rate of
CO2 emissions from true renewable energy sources: e.g.,
biomass generators of various kinds have life cycle carbon
emissions between 14–41g CO2e/kWh; a 3.5MW
hydroelectric reservoir generates 10g CO2e/kWh; and a
onshore wind turbine of 1.5MW also creates just 10g
CO2e/kWh.13 Looking to the future, if nuclear power
capacity increases worldwide the environmental impact due
to its LCA will only get worse. The quality of uranium ore
plays a significant part in the life cycle emissions of nuclear-
generated electricity, a crucial factor as the easily
obtainable stores of uranium are used up.14 This is a
reminder that nuclear power is ultimately neither carbon-
neutral nor renewable.

Economics and efficacy of implementing new nuclear build

Supporters of nuclear energy point out that renewables
receive a greater boost from the government under the
Renewables Obligations (RO) scheme introduced in 1998,
despite the fact that RO grew out of the Non-Fossil Fuel
Obligations (NFFO), designed to bolster the nuclear power
industry, following privatisation of energy markets in

Centre for Sustainable Energy www.cse.org.uk

Common concerns about wind power

1989.8,15 Due to the private sector’s reluctance to take on
the risk of lifetime costs of the nuclear-generated electricity
industry the state-owned Nuclear Electric received 95% of
the funds (£1.2 billion) gathered from the NFFO levy on
electricity bills. Renewables are therefore disadvantaged
until further NFFO orders redressed the balance.15, 16 In
fairness, it was reported that across Europe (EU-15 nations),
renewables enjoyed subsidies almost 2½ times those
received by nuclear, amounting to €5.3 billion and €2.2
billion respectively in 2001 (although the nuclear industry
was able to waive the cost of full-liability insurance cover
for critical accidents as such risks are not commercially
insurable according to international treaty).17, 33

One might also add that this subsidy share is unsurprising if
you consider that renewable energy technologies are in
their infancy compared to nuclear, and that in its nascent
years nuclear received enormous subsidies thanks to the
weapons potential that came from it.17

In the UK, there has been no new nuclear capacity
introduced since 1995, despite the retirement of nine
plants since 1989 (not including research facilities such as
Windscale and Dounreay), not to mention the projected
retirement of more than 9 GWe of capacity by 2025 (the
latter date being met by the extension of some of these
power plants past their original scheduled retirement
date).18, 19 As already discussed, private investors are wary
of spending huge amounts of money on new nuclear build
given the UK industry’s economic history and the difficulty
of estimating the complete life cycle cost of a nuclear
facility.7, 15 These fears are being borne out by the recent
experience at Flamanville and Olkiluoto.

In France – arguably the most experienced market when it
comes to commissioning nuclear plants – the Flamanville
reactor is due to come online in 2013, over a year late and
with costs 50% above the original €3.3 billion. The
situation with the Olkiluoto plant is worse, being at least
four years overdue and having a final budget over double
the original €3 billion forecast.7 The hidden financial
burden of decommissioning also inhibits investment, with
the UK cost set by the Nuclear Decommissioning Authority
(NDA) at £73 billion in 2007, representing an average
increase of 9% every year since government estimates in
2002.19, 20, 21 Although there is some merit in the idea that
the UK nuclear industry as a whole can make a profit
through spin-off technologies involved with commissioning
and decommissioning, this contribution is small in
comparison with the public cost to manage the legacy of
existing UK plant.22

The barriers to new investment outlined above, coupled
with the lead-time for new nuclear plants to come on
stream (around 11 years) make nuclear power irrelevant to
the government’s 2020 carbon-reduction targets,18 though
not necessarily the 2050 ones. However, given the
enormous technological and financial resources required,
the capital-intensive start-up costs of nuclear power plants
and the lengthy lead-times before shareholders begin to

see returns, it is difficult to see how a genuinely private UK
nuclear sector can function in today’s liberalised electricity
market. Continued calls for stronger government support
will also mean, in the words of one commentator:

“...alternative options for meeting the policy goals of
making electricity affordable, reliable and sustainable will
not be vigorously pursued while the nuclear option is preempting
the available resources.” 7

Safety of nuclear power

In addition to the imposing financial cost of nuclear energy,
there is the safety and environmental record to take into
account.

Purely in terms of associated deaths, the nuclear industry
has a safety record (calculated as 0.048 deaths/GWey.10)
that compares favourably with other energy production
methods. However, the failure of the nuclear industry (and
government) to show to the public’s satisfaction that it has
a high degree of safety is one of the main mitigating
factors preventing the acceptance of nuclear-generated
electricity as a valid source of low-carbon energy.8 This is
not surprising: despite promises that things are now much
safer, as recently as 2005 the Thermal Oxide Reprocessing
Plant (THORP) plant at Sellafield was found to have leaked
83,000 litres of liquid containing 22 tonnes of uranium fuel
into a sump for a period of eight months before being
discovered; the leak only came to light at the plant because
the follow up accountancy system noticed there was
missing nuclear material. The contents did not escape into
the environment, but the inspector’s report made it clear
that the plant operated under an “alarm-tolerant culture”,
at one point stating:

“The HSE investigation team found that there were
significant operational problems with the management of a
vast number of alarms in THORP, resulting in important
alarms being missed.”24

The delays with the Olkiluoto plant are also caused
primarily by safety concerns of the Finnish regulatory
authority (STUK), although there was also some public
disquiet among independent parties over why it took STUK
so long to discover non-compliant components.25, 26
Although it can be said that operational fatalities are
relatively low for the nuclear power industry across its
history, the consequences of failure can be catastrophic,
causing not just immediate loss of life, but also ‘latent’
mortality of many others (although care should be taken
not to overstate these figures).27 To be considered
“politically unremarkable”8 the nuclear industry must
maintain “the high standards demanded for the unique
nature of nuclear operations”.12, 24

The 2011 disaster at the Fukushima nuclear power station
in Japan demonstrates just how difficult such ‘politically
unremarkable’ status will be to achieve. An 8.9 magnitude
earthquake and subsequent tsunami completely

www.cse.org.uk Centre for Sustainable Energy

Common concerns about wind power

overwhelmed a highly sophisticated, multi-layered safety
system and left the nation’s technologically very capable
nuclear industry improvising its response on an hour-byhour
basis. The Fukushima emergency shows that even the
most considered ‘belt-and-braces’ safety system can be
undermined by extreme natural events. It also illustrates
how quickly the potential scale of the resulting nuclear risk
captures public and political attention and how one high
impact event focuses concerns on the continued operation
of all nuclear power stations worldwide.

Radioactive waste

The problem of radioactive waste is another concern that
impinges on both safety and the environment. Nuclear waste
in the form of spent uranium contains a mixture of fission
products, which can be grouped into either medium-lived or
long-lived fission products. The medium-lived products have
a half-life (t½) of up to 90 years; for example, iodine-131
(131I) lasts for only eight days, whereas caesium-137 (137Cs)
and strontium-90 (90Sr) both have half-lives of roughly 30
years. Those that are long-lived can last for 211,000 years in
the case of technetium-99 (99Tc), 2.14 million years for
neptunium-237 (237Np), 15.7 million years for iodine-129
(129I), and 700 million years for any unspent uranium-235
(235U) itself. Those listed here are some of the most
problematic due to their activity in biological and geological
systems, but it is by no means an comprehensive list.

The problem inherent with nuclear fission is that the waste
produced must be isolated and contained for a sufficient
period such that it no longer poses a threat to human
health and the environment if exposed. In fact, the majority
of what is termed radioactive waste is ‘low-level’ and can
be safely stored for several decades to allow any
contaminants to decay, after which point it can be disposed
of as would any other waste.28 However, long-lived fission
products need to be treated and a solution found whereby
they can be subsequently removed from the biosphere. In
the short-term this is a troublesome issue itself, as the NDA
is finding that many of the decommissioned sites around
the UK contain a mixture of toxic and radioactive materials
that generate a great deal of heat and require careful
handling and storage to minimise the danger (a costly
exercise, as discussed above).19, 29

Some fuel can be reprocessed and the reclaimed uranium
put back into the reactor, although this itself is incredibly
specialised and employs a range of highly toxic chemicals.28
The UK’s high-level waste is predicted to be 478,000 m3 by
the 22nd century29 (equivalent to filling the Albert Hall five
times over). This waste is highly toxic and must be made
safe: it is generally solidified in borosilicate glass, a process
called ‘vitrification’ that is mainly carried out at Sellafield.19
What to do with this waste after that is still a moot point,
and one that government and the industry have not been
able to resolve completely.

The most attractive option for the nuclear industry in
general appears to be a geological repository, and this is

certainly the preferred recommendation of the UK
government.28, 29 However, the govenment’s Committee on
Radioactive Waste Management has taken pains to point
out that the position adopted on the issue is presented to
the public in terms that are too simplistic and optimistic,
and that to date there has been just a single area of the UK
to offer itself as a geological disposal facility.30 Following
the publication of this recommendation, the Scottish
Parliament announced that it had opted out of the report
as they have ruled out geological disposal as a method of
long-term storage.31 The most well known case study, that
of the Yucca Mountain repository in the USA, has also
suffered a setback despite billions of dollars spent on years
of consultation and research by the US Department of
Energy.32 The current American administration has declared
the Yucca Mountain site is now “off the table”.

Conclusions

Investment in nuclear energy represents an enormous
commitment, with any meaningful expansion of the UK’s
nuclear capacity likely to come from the public purse. The
benefits of such a policy are by no means clear, but what is
certain is that the legacy of such a policy would place a
financial and environmental burden on future generations
that is difficult to predict. Nuclear only contributes to the
electricity energy needs of the UK – it cannot meet the
demand for transport or heating which are dominated by
fossil fuels. At most, this is a theoretical maximum of 20%
of the UK’s total energy demand.5, 7 Much the same can be
argued for wind power (and other renewables), but wind
does not have the same safety and environmental
problems, and can be removed more cheaply and quickly.
Furthermore, in the words of one expert commentator:

“...the financial and political resources that [nuclear]
consumes so voraciously can be diverted to the painstaking
work that will be needed to ensure that the energy
efficiency of every dwelling in the UK is transformed, as
can readily be technically achieved.” 7 [emphasis added]

The flexible, modular approach that wind power and other
renewables offer means that technology and policy can be
fine-tuned or redirected as the situation requires, without
entrenching UK energy sector in a costly and potentially
risky enterprise that would draw on resources for years to
come.

Notwithstanding the environmental concerns about the
‘nuclear chain’ and the long-term problems created by
radioactive waste,13, 14, 28–32 there are compelling arguments
that modern nuclear reactors are both safe and exhibit a
relatively low carbon footprint during their operational
lifetime.12 Despite this, the industry in the UK has not
shown that it has learnt from mistakes of the past, and
seems poorly placed to compete in the privatised electricity
market of today.7, 24 There is some hope that economically
viable technologies can be encouraged through expertise in
decommissioning and cleanup, including limited import and
export arrangements of certain types of waste, but it is

Centre for Sustainable Energy www.cse.org.uk

Common concerns about wind power

difficult to see how these will make up for the cost of
operating and subsequently retiring the existing
capacity.19–21 Successful state-owned models of operation in
France belie the free-market approach of the UK, which
would require a centralising of the nuclear industry at the
expense of less risky, low-carbon policies that seek to
integrate efficiency savings and renewable energy
effectively.

1
See, for example, DECC 2010. 2050 Pathways Analysis, for a wide range of future scenarios. Available at
www.decc.gov.uk/en/content/cms/what_we_do/lc_uk/2050/calculator_exc/ calculator_exc.aspx

2
World Nuclear Association [Internet]. 2001. London: World Nuclear Association; c.2010 [cited 2010 Nov 15]. Energy for the World – Why Uranium? Available
at www.world-nuclear.org/education/whyu.htm.

3
Kleiner, K. 2008. Nuclear energy: assessing the emissions. Nature Reports Climate Change; 2: 130–1.

4
Projected Costs of Generating Electricity – 2010 Edition. Paris, and Issy-les-Moulineaux, France: Organisation for Economic Co-operation and Development
(OECD)/InternationalEnergy Agency (IEA)/Nuclear Energy Agency (NEA); 2010 March. 218 p.

5
National Statistics, 2010. Digest of United Kingdom Energy Statistics 2010. London: The Stationary Office. Published with permission of Department of
Energy and ClimateChange. www.decc.gov.uk/assets/decc/statistics/publications/dukes/348-dukes-2010... (Accessed 23 Nov 2010.)

6
World Nuclear Association [Internet]. 2008. London: World Nuclear Association; c.2010 [cited 2010 Dec 16]. Nuclear power in France. Available at
www.world-nuclear.org/info/inf40.html.

7
Thomas, S. 2010. The future of energy: are competitive markets and nuclear power the answer? London: University of Greenwich. Inaugural Professorial
Lecture; 2010 Feb 4.

8
MacKerron, G. 2004. Nuclear power and the characteristics of .ordinariness.—the case of UK energy policy. Energy Policy; 32: 1957–65.

9
Generation Adequacy Report on the electricity supply–demand balance in France: Update 2010. Paris-La Défense: Réseau de Transport d.Électricité (RTE);
2010 July. www.rte-france.com (Accessed 17 Dec 2010.)

10 Burgherr, P., Hirschberg, S. 2008. A Comparative Analysis of Accident Risks in Fossil, Hydro, and Nuclear Energy Chains. Human and Ecological Risk
Assessment; 14: 947–73.

11 Gipe, P. Contemporary mortality (death) rates in wind energy [Online database]. 2010. Paul Gipe; c.2010 [cited 2010 Dec 15]. Avaliable www.windworks.
org/LargeTurbines/WindMortalityStatisticsNeedUpdates.html.

12 Severe Accidents in the Energy Sector. Villigen: Paul Scherrer Institut; 2005 May. Energie-Spiegel no.13. http://gabe.web.psi.ch/pdfs/Energiespiegel_13e.pdf
(Accessed 16 Jan2011.)

13 Sovacool, B.K. Valuing the greenhouse gas emissions from nuclear power: A critical survey. 2008. Energy Policy; 36: 2940–53.

14 Mudd, G., Diesendorf, M. 2008. Sustainability of uranium mining and milling: toward quantifying resources and eco-efficiency. Environ Sci Technol; 42:
2624–30.

15 Douglas, N.G., Saluja, G.S. 1995. Wind energy development under the UK non-fossil fuel and renewables obligations. Renewable Energy; 6(7): 701–11.

16 Elliott, D. 1996. Renewable energy policy in the UK: problems and opportunities. Renewable Energy; 9: 1308–11.

17 Energy subsidies in the European Union: a brief overview. Copenhagen: European Environment Agency; 2004 June 2. EEA Technical Report 1/2004.
www.eea.europa.eu/publications/technical_report_2004_1 (Accessed 17 Dec 2010.)

18 Kennedy, D. 2007. New nuclear power generation in the UK: cost benefit analysis. Energy Policy; 35: 3701–16.

19 The Nuclear Decommissioning Authority. Taking forward decommissioning. London: The Stationary Office. Published with permission of National Audit Office;
2008 Jan 30. HC238 Session 2007–2008. www.nao.org.uk/publications/0708/the_nuclear_decommissioning_au.aspx (Accessed 16 Jan 2011.)

20 Jackson, I. [Internet]. 2008. London: Nuclear Engineering International; c.2010 [cited 2010 Dec 14]. Buried costs. Available at
www.neimagazine.com/story.asp?storyCode=2049209.

21 Managing the nuclear legacy: a strategy for action. London: Department of Trade and Industry; 2002 July. Cm 5552.
www.nda.gov.uk/documents/upload/white_paper_managing_the_nuclear_legacy_... (Accessed 16 Jan 2011.)

22 Sherry, A.H., Howarth, P.J.A., Kearns, P., Waterman, N. A review of the UK's nuclear R&D capability. Swindon, UK: The Technology Strategy Board, in
association with Materials UK and Regional Development Agencies; 2009. www.innovateuk.org/_assets/pdf/corporate-publications/uk_nuclear_rd_
review_web.pdf (Accessed 16 Dec 2010.)

23 The UK low carbon transition plan: national strategy for climate and energy. London: HMSO; 2009 July 20. URN 09D/716. http://tinyurl.com/6z5p6yv
(Accessed 16 Jan 2011.)

24 Weightman, M. Report of the investigation into the leak of dissolver product liquor at the Thermal Oxide Reprocessing Plant (THORP), Sellafield, notified to
HSE on 20 April 2005.Report by HM Chief Inspector of Nuclear Installations (M.W.). Published by the Health and Safety Executive; 2007 February.

25 Management of safety requirements in subcontracting during the Olkiluoto 3 nuclear power plant construction phase. Helsinki: Radiation and Nuclear Safety
Authority (STUK);2006 July 10. Investigation Report 1/06 [Translated 2006 Sep 1.]
www.stuk.fi/ydinturvallisuus/ydinvoimalaitokset/olkiluoto3/en_GB/olkiluo... (Accessed 16 Jan
2011.)

26 Large, J.H. 2006. Brief and interim review of the porosity and durability properties of the in situ cast concrete at the Olkiluoto EPR construction site. Prepared
by Large & Associates on behalf of Greenpeace International. Report no. R3149-A1. www.largeassociates.com/3149%20Olkiluoto/R3149A1%
20Final%20Issue.pdf (Accessed 16 Jan2011.)

27 Hirschberg, S., Spiekerman, G., Dones, R. Severe accidents in the energy sector. Villigen: Paul Scherrer Institut; 1998 November. Report no. 98-16.
http://gabe.web.psi.ch/pdfs/PSI_Report/ENSAD98.pdf (Accessed 15 Jan 2011.)

28 Rao, K.R. 2001. Radioactive waste: The problem and its management. Current Science; 81: 1534–46.

29 MacKerron, G. and the Committee on Radioactive Waste Management (CoRWM). Managing our radioactive waste safely. CoRWM.s recommendations to
Government; 2006 July.Cm 700. http://tinyurl.com/5sd4u48 (Accessed 15 Jan 2011.)

30 Geological disposal of higher activity radioactive wastes. CoRWM Report to Government; 2009 July. URN Cm 2550. http://tinyurl.com/67uzhzs (Accessed15
Jan 2011.)

31 Review of MRWS White paper: September 2008. CoRWM report to Government; 2008 Sep 8. URN Cm 2431. http://tinyurl.com/63dqa2x (Accessed 15 Jan
2011.)

32 Supplemental Environmental Impact Statement for a Geologic Repository for the Disposal of Spent Nuclear Fuel and High-Level Radioactive Waste at Yucca
Mountain, NyeCounty, Nevada, Washington DC: Department of Energy; 2008 June. DOE/EIS-0250F-S1.

33 Convention on Third Party Liability in the Field of Nuclear Energy of 29th July 1960, as amended by the Additional Protocol of 28th January 1964 and by the
Protocol of 16th November 1982. www.oecd-nea.org/law/nlparis_conv.html (accessed 15 April 2011)

www.cse.org.uk
Centre for Sustainable Energy

Common concerns about wind power
----------------------------------------------
7. Public acceptance of wind turbines

Summary

Attitudes toward wind power are fundamentally different
from attitudes toward wind farms, a divergence that has
created what is sometimes called the ‘social gap’. Despite
the move to renewable energy sources having broad public
support (wind included), implementation of wind farm
projects is often met with stiff opposition at a local level.
Although some opposition is based on misconceptions about
wind power in general, local resistance to wind farms is a
complex interconnection between a position of being ‘for
the greater good’ and negativity toward what is seen as an
unwelcome imposition on the visual landscape to which
residents have a strong emotional attachment.

The pejorative term ‘nimby’ (from ‘not in my back yard’) has
regularly been levelled at residents when negative opinions
about planned wind farms have been raised. This term is
inaccurate, unfair and has no explanatory value, serving only
to increase antagonism if it achieves anything at all.
Understanding the issues involved, namely what lies behind
the concerns and preconceptions of residents, is crucial if a
community is to accept and even welcome the installation of
a wind farm nearby.

What is this based on?

Beginning with the 1989 Electricity Act, the UK government
has steadily moved towards a policy of greater dependence
on low-carbon energy generation. In its most recent policy
statement (2009) the government hopes to achieve more
than a one third reduction in CO2 emissions from 1990 levels
by 2020; a large part of this requires generating 30% of the
nation’s electricity needs using renewable energy.1
Notwithstanding targets for 2020, it is clear that previous
targets set by government for 2010 have not been met,
despite large increases in installed renewable capacity.2,3

One of the key factors identified as necessary for the UK to
meet its renewable energy targets is the support of local
communities; conversely, failure of renewable energy projects
to achieve planning permission in a streamlined and timely
manner is identified as one of the major obstacles2. Wind
power is not the only renewable energy source to have met
with opposition: in Europe and the USA, biomass,
geothermal and tidal energy projects have all met with
resistance at a local level.4 It is important to note that,
contrary to initial assumptions by the industry, offshore wind
power is also subject to opposition by local communities.5,6

Clearly, there is a need to address the concerns of local
communities when a wind farm is being built; but, the
community should be engaged from the start so that the

pros and cons of local developments are fully discussed. The
dismissing of the problem by regulators and the energy
industry as ‘nimbyism’ reveals that a ‘barrier-oriented’ view
prevails. This can leave residents feeling disempowered and
unable to control their own landscape.5,7 Balanced dialogue
and direct community involvement to redress perceived
inequities are needed if renewables are to realise national
and international policy goals for cleaner energy.1,8

What is the evidence?

What lies behind the ‘social gap’ – the divide between the
public’s support for wind energy and its opposition to local
projects?9 This is not a new problem, as modern society has
dealt with the integration of infrastructure for many years. A
common theme for policy-makers and regulators is that local
opposition is motivated by a selfish view that while society as
a whole can benefit from the implementation of improved
infrastructure, this is only welcome when these
developments take place elsewhere.7 This is epitomised by
the term ‘nimby’. Wind energy proponents have been guilty
of this in the past, when developers found that local support
did not reflect public opinion in favour of clean energy.4,10 In
the last decade, many commentators have rightly disparaged
this view, which makes little attempt to understand the
complex interaction of local communities with society and
national policy.4,7,9

What is implied by the term ‘nimby’? It is best defined as the
dichotomy between the public good and an individual’s
attempt to maximise their own utility.7 In this case, the
implementation of wind power as a clean source of energy is
the public good; and local opposition to wind farms is the
manifestation of the individuals’ desire to minimise the
impact on them personally. However, studies on community
views relating to the installation of wind farms reveal that
opposition – while instigated largely by the announcement
of an impending local development – is not driven by local
considerations alone, but by the perceived gap in
understanding how wind power will benefit society as a
whole.

For instance, a major wind farm development off Cape Cod in
the USA has been floundering at the planning stage for nearly
a decade due to a highly-motivated and high-profile
opposition campaign. A compelling statistic from the
community involved reveals that when placed in the context
of a nationwide move toward wind power that has a larger
benefit to society as a whole, support for the Cape Cod
project increased dramatically.5

While it can be asserted that some opponents of local
developments gain from the ‘free ride’ to be had by
strenuously arguing against a local development while at the
same supporting wind energy elsewhere, the significance of
such self-interested groups should not overshadow the
genuine site-specific concerns that residents might have.4,9 It
must be remembered that public opinion is consistently
highly favourable toward wind energy, and only a tiny
fraction of opposition by local groups can be attributed to

www.cse.org.uk Centre for Sustainable Energy

Common concerns about wind power

true nimbyism, almost invariably by those who dislike wind
power generally.8

As discussed elsewhere (sections 8 and 11), there are many
negative preconceptions voiced when an installation is
proposed and built, which decline once the wind farm is
operational11. Concerns over noise and environmental
impact are significant, but it is changes to the visual
landscape that is believed to be the driving force behind
additional objections surrounding the development of a new
wind farm.6,7 Although generally true, the maxim that public
acceptance of a new wind farm follows a ‘U-shaped curve’ –

i.e. broad support before planning, declining support during
planning and construction, followed by rising acceptance
afterwards – should be treated with caution, as this is by no
means a universal response.4
In the UK, lack of community involvement is regarded as a
contributing factor to the continuing difficulties wind farms
face during planning applications. Elsewhere in Europe,
where local authorities are often the motivating force behind
wind farm developments (e.g. Denmark and Germany),
direct involvement in the planning process – and a share in
the economic benefits – mean that communities express fewer
of the feelings of unfairness and inequity than communities
in countries where the siting and construction of wind farms
is largely driven by the private commercial sector (e.g. UK and
Netherlands).4,8 In particular, the adversarial style of the UK
planning process means that local opinion only crystallizes in
response to a planning application that is made public
expressly to prompt any objections residents might have.9

Efforts by wind developers to address the root cause of local
opposition to wind farms too often ends up with them
stressing the ‘greater good’ but seemingly offering nothing
but detrimental effects on the landscape.4 What residents
see is a developer’s attempts to hide the turbines away:

“The wind industry adjusted to public resistance with a

series of initiatives, ... pointing out that wind power

produces no toxic waste, no radiation, no acid rain, no

greenhouse gases, no thermal discharges, and no

irreversible landscape changes. Though correct on all

counts, there was still nothing the industry could do or

say that would make the turbines invisible, and this left

the most glaring infraction of wind power unresolved.”10

There is compelling evidence that most residents who come
into contact with them on a regular basis do not find the
presence of wind turbines objectionable4,11. Provided the
benefits to both the community and wider society are
properly explained and taken on board, most people display
a surprisingly unselfish view of the need for such installations
and close correlation is found between local community
perspectives on wind farm developments and public support
for clean energy as a whole7,8. Treating wind farms simply as
a burden that must be imposed on local communities
suggests that many proponents of wind energy are perhaps
missing the point.4,9,10

Conclusion

The visual aspects of wind farm developments affect the
fundamental views of local residents with regards to clean
energy sources and the role they must play in society as a
whole. The need for an increased reliance on wind energy
continues to have widespread support, but the reality of a
wind farm being built in any particular area often creates a
marked divergence from this viewpoint. This gap between
acknowledging the benefits of wind power whilst objecting
to it on a local level has often been dismissed simply as
nimbyism, but this fails to address the complex interactions
between communities, national policy and the wider society,
and is rightly seen as a defunct hypothesis.

Rather than focusing purely on ‘free rider’ motives that push
the onus on clean energy to other communities, the
objections to wind farm developments put forward by
individuals are intimately tied up with their unique concerns
about the local landscape and poor understanding of the
principles of wind energy.

In the UK a top-down approach has driven much of the
country’s wind farm developments so far, creating a
democratic deficit that is often filled by vociferous opposition
groups. Involving communities in the decision-making and
planning process for wind farms not only reduces the need
to combat such opposition, but creates a better
understanding of the wider issues involved in energy policy
and the environment. An informed and motivated
community with a real investment in a wind farm project will
be well-equipped to integrate renewable technologies
effectively in a manner that reduces social inequity.

1
The UK low carbon transition plan: national strategy for climate and energy. London: HMSO; 2009 July 20. URN 09D/716. http://tinyurl.com/6z5p6yvf
(accessed 16 Jan 2011)

2
Our energy future – creating a low carbon economy. London: TSO; 2003 February. DTi Energy White Paper. www.dti.gov.uk/files/file10719.pdf

3
National Statistics, 2010. Digest of United Kingdom Energy Statistics 2010. London: The Stationary Of.ce. Published with permission of Department of
Energy and ClimateChange. http://www.decc.gov.uk/assets/decc/statistics/publications/dukes/348-duk... (Accessed 23 Nov 2010.)

4
Devine-Wright, P. 2005. Beyond NIMBYism: towards an integrated framework for understanding public perceptions of wind energy. Wind Energy; 8: 125–39.

5
Firestone, J., Kempton, W. 2007. Public opinion about large offshore wind power: Underlying factors. Energy Policy; 35: 1584–98.

6
Devine-Wright, P., Howes, Y. 2010. Disruption to place attachment and the protection of restorative environments: A wind energy case study. J Environ
Psychol; 30: 271–80.

7
Wolsink, M. 2000. Wind power and the NIMBY-myth: institutional capacity and the limited signi.cance of public support. Renewable Energy; 21: 49–64.

8
Wolsink, M. 2007. Wind power implementation: The nature of public attitudes: equity and fairness instead of .backyard motives.. Renewable Sustainable
Energy Rev; 11: 1188– 1207.

9
Bell, D., Gray, T., Haggett, C. 2005. The 'Social Gap' in wind farm siting decisions: Explanations and policy responses, Environmental Politics; 14: 460–77.

10 Pasqualetti, M.J. 2001. Wind energy landscapes: Society and technology in the California desert. Society Natural Resources; 14: 689–99.

11 Braunholtz, S. 2003. Public Attitudes to windfarms: a survey of local residents in Scotland. Edinburgh: MORI Scotland. On behalf of Scottish Executive Social
Research. www.scotland.gov.uk/Publications/2003/08/18049/25579 (Accessed 24 Nov 2010.)

Centre for Sustainable Energy
www.cse.org.uk

Common concerns about wind power

8. Wind turbines and property prices

Summary

As the number of proposals for wind farms across the UK
increases, detractors fear that nearby residents will see their
property values drop. Given the negative press that wind
turbines often receive in the mainstream media, it is not
surprising that this becomes a concern for local residents
during the planning and development of a wind farm. In
fact, a great deal of research in the UK and abroad shows
that there is no devaluation in property prices nearby once
a wind farm is operating. These fears are driven largely by
the “anticipation stigma” found to exist during the
planning and construction of wind farms, often bearing
little relation to the actual community opinion or local
property markets.

What is this based on?

This is a common objection raised against the siting of
onshore wind farms. The premise seems obvious: why
would someone be willing to pay as much for a property
(inevitably in a rural area) that has wind turbines in view,
when compared with a property that does not? As property
is the single largest financial and emotional investment a
person is likely to make, residents’ concerns are legitimate
and understandable. It is no great surprise that opponents
of wind farms are quick to seize on this sensitive issue, but
the evidence does not support the view that wind turbines
will cause house prices in the surrounding area to fall.

What is current evidence?

Since the first UK commercial wind farm began operation
in Delabole, Cornwall in 1991, wind turbines have become
an increasingly common feature of the landscape in many
areas of the UK, particularly Scotland.1 In 2003 the Scottish
Executive commissioned a study to assess the impact of
wind farms on nearby residents, using ten major sites
across the region.2 This was an extensive survey that took
into account how close to the wind farms residents lived,
covering a surrounding ‘zone’ of 20km in total. Overall,
only 7% of those questioned said their local wind farm had
had a negative impact on the area; this is compared to
20% who said the impact was positive, and 73% who felt
it had no impact either way.

Perhaps most surprisingly of all, respondents who lived
closest to the wind farm (< 5km) and could see the turbines
most often comprised the highest proportion of those who
responded positively. Those respondents who were already
living in their house prior to the wind farm being built were
asked about house prices. Some 7% of them said that they
had anticipated that house prices would be reduced by the

wind farm; when asked about the actual effect, the
number who said house prices had fallen dropped to 2%.

Further studies have been carried out on sites in Cornwall
using actual selling prices. A preliminary study by the Royal
Institute of Chartered Surveyors (RICS) in 2004 reported
60% of property professionals found new wind farm
developments had a detrimental effect on residential
property values.3 These effects were stated by the
respondents to occur overwhelming at the planning and
construction stage, somewhat echoing the findings of
earlier polls (discussed above). Since then, more rigorous
research has been carried out.

In these later studies, the statistical samples are controlled
so that other factors that may influence house prices (e.g.,
waterfront views, which can disproportionately enhance a
property’s market value) do not affect the relationship
between the presence of a wind farm and house prices —
this is generally known as the ‘hedonic pricing method’.
Initial data from these areas in Cornwall show no linear
correlation between the presence of a wind farm on house
prices in the immediate surroundings (within 5 miles).4
Further statistical analysis of the same area demonstrates
that there was no causal relationship between distance to
the wind farm and house price, or even visibility of the
turbines themselves.5 The largest statistical analysis to date
uses data from almost 7500 sales across nine states in the
USA.6 This is an extremely thorough and rigorous study
which summarises its main findings thus:

“Specifically, neither the view of the wind facilities nor

the distance of the home to those facilities is found to

have any consistent, measurable, and statistically

significant effect on home sales prices.”

Conclusion

The installation of infrastructure relating to power
generation and distribution is not a new issue. High voltage
overhead transmission lines (HVOTLs, commonly known as
electricity pylons) have also been the subject of extensive
studies over the years, employing the same techniques of
hedonic pricing.7

Increasingly, the installation of wind turbines at sites across
the UK has prompted many surveys and studies to
determine if nearby residents’ property values are adversely
affected.2,3,4,5 There is no evidence that a causal links exists
between house prices and the proximity of wind turbines,
and this is borne out by larger studies carried out on
transaction data in the USA.6 What many of these studies
have shown is an anticipation “stigma”, whereby the
perceived negative impact of wind turbines being
constructed nearby causes a transitory drop in house prices,
which quickly reverses when these negative affects fail to
materialise post-construction.6,8 This inflated anticipatory
effect is also evident in the attitudes of local residents near
large wind farms surveyed in Scotland.2

www.cse.org.uk Centre for Sustainable Energy

Common concerns about wind power

In many cases, the stigma is reinforced by the opinions of
real estate agents when planning for wind farms begins,
but this viewpoint is found to be misguided when post-
construction data is available.3,4 It is accepted that
predictions by estate agents are found to be inaccurate
(negative predictions in particular often being significantly
inflated) when compared with actual transaction data and
the views of the buyers themselves.3 to 9

Furthermore, the actions of groups inherently opposed to
the construction of wind turbines can distort popular
perceptions of how a community integrates a new
installation – in the case of wind farms in Cornwall, 95% of
objections raised during the planning stage originated from
non-locals4. In recent years, estate agents and surveyors
have begun to accept that data on house purchases clearly
show there is no lowering of house prices caused by wind
turbines.10,11

1
National Statistics, 2010. Digest of United Kingdom Energy Statistics 2010. London:TSO. Published with permission of Department of Energy and Climate
Change. www.decc.gov.uk/assets/decc/statistics/publications/dukes/348-dukes-2010... (accessed 23 Nov 2010)

2
Braunholtz, S. 2003. Public Attitudes to windfarms: a survey of local residents in Scotland. Edinburgh: MORI Scotland. On behalf of Scottish Executive Social
Research. www.scotland.gov.uk/Publications/2003/08/18049/25579 (accessed 24 Nov 2010)

3
Impact of wind farms on the value of residential property and agricultural land: a RICS survey. London: Royal Institute of Chartered Surveyors; 2004.
www.savethebluffs.ca/archives/files/Windfarmsandpropertyprices.pdf (accessed 27 Nov 2010)

4
Sims, S., Dent, P. 2007. Property stigma: wind farms are just the latest fashion. Journal of Property Investment & Finance; 25(6): 626–51.

5
Sims, S., Dent, P., Oskrochi, G.R. 2008. Modeling the impact of wind farms on house prices in the UK. International Journal of Strategic Property Management. 12:
251—69.

6
Hoen, B., Wiser, R., Cappers, P., Thayer, M., and Sethi, G. 2009. The Impact of Wind Power Projects on Residential Property Values in the United States: A
Multi-Site Hedonic Analysis. Berkeley, CA: Ernest Orlando Lawrence Berkeley National Laboratory. Report No.: LBNL-2829E. Contract No.: DEAC0205CH1123.
Prepared for the Office of Energy Efficiency and Renewable Energy, Wind and Hydropower Technologies Program, U.S. Dept. of Energy.
http://eetd.lbl.gov/ea/ems/reports/lbnl-2829e.pdf (accessed 27 Nov 2010)

7
Sims, S., Dent, P. 2005. High-voltage overhead power lines and property values: a residential study in the UK. Urban Studies; 42(4): 665–94.

8
Sims, E.N. (Springfield-Sangamon County Regional Planning Commission). 2010. Effect of wind farms on property values: a brief review of the literature.
SSCRPC InformationBrief. Springfield, IL: Springfield-Sangamon County Regional Planning Commission.
www.co.sangamon.il.us/Departments/RegionalPlanning/planning.asp (accessed 27 Nov 2010)

9
Bond, S., Hopkins, J. 2000. The impact of transmission lines on residential property values: results of a case study in a suburb of Wellington, NZ. Pacific Rim
Property ResearchJournal; 6(2): 52–60.

10 Sims, S., Dent, P. 2007. What is the impact of wind farms on house prices? London: RICS; 2007 March. Findings in Built and Rural Environments (FiBRE) series
report sponsoredby the Royal Institute of Chartered Surveyors. www.rics.org/site/download_feed.aspx?fileID=3524&fieExtension=PDF (accessed 27 Nov 2010)

11 National Association of Realtors [Internet]. 2009. Field guide to wind farms and their effect on property values. Chicago: National Association of Realtors.
www.realtor.org/library/library/fg509 (accessed 29 Nov 2010)

Centre for Sustainable Energy
www.cse.org.uk

Common concerns about wind power
--------------------------------------------------------------------
9. Wind turbines and safety

Summary

All sources of energy supply, wind power included, can
present a hazard to human health: fuel extraction and
transport; construction and maintenance of plant and
distribution networks associated with energy production;
and the operation of such facilities; present a risk to human
health, both to industry workers and, in rare instances, the
public. In the energy industry, fatalities are measured in
such a way as to show the cost/benefit for the energy
produced, i.e. deaths per unit energy generated. This is
usually given as deaths per gigawatt year (GWey). Wind
energy enjoys one of the lowest fatality rates per GWey of
any energy source, considerably lower than that for fossil
fuels.

However, there is no escaping the fact that deaths occur
due to the installation and use of wind turbines. These are
almost overwhelming related to industry workers, although
there are rare incidences of members of the public being
killed: as with any industry, wind energy must strive to
minimise or eliminate any fatalities where possible. When
appraising wind energy, it must be remembered that wind
continues to provide one of the safest forms of electricity
generation available, without the additional environmental
burdens that can impinge on public health, such as
pollution or hazardous by-products.

What is this based on?

Despite having no requirement for large sources of fuel to
be extracted (as with fossil fuels) or dangerous reactions to
be controlled (as with nuclear reactors), wind turbines
create hazards of their own. A typical commercial 2–3 MW
turbine will have a hub height anywhere from 65–100m
(roughly 215–330 ft) with blades around 45m (150 ft) in
length. The risks of working on such high structures are
readily apparent, not to mention the potential hazards
created when transporting the component parts.
Worldwide between 1975 and 2010, 23 workers have
been killed while installing or removing turbines, and a
further 16 people have been killed during operation and
maintenance procedures (this does not include three
recorded deaths that occurred on offshore installations).

In addition, there have also been four members of the
public reported killed in accidents between 2000 and 2010.
A parachutist in Denmark, a crop duster pilot in the US, a
traffic accident in the UK involving a turbine transporter,
and a child in Canada who was killed whilst playing around
a residential turbine that was under repair.1

During operation a major hazard is also presented by the
phenomenon known as ‘blade throw’, whereby a blade or
piece of a blade becomes detached and is thrown clear of

the turbine. Related to this, and a reported problem in
areas prone to hard winters with icy conditions (e.g.,
Switzerland, Germany and Canada) is the occurrence of ‘ice
throw’ – as the name implies ice accretes on the blade
edge and is thrown through the air in chunks of varying
sizes. These operational hazards are of particular concern as
the distances travelled by blade parts or large pieces of ice
can be considerable. There are concerns that the
phenomenon of blade throw in particular is not being
sufficiently addressed, with oversensitivity by the industry
resulting in incidents not being openly reported.2

Perhaps partly due to this attitude of secrecy, the issue is
further complicated by reports of blade throw that are
difficult to corroborate. For instance, an extreme incidence
of blade throw that occurred in 1993 is regularly cited as
indicative of the large distances damaged blade parts can
travel – up to 400m.2 This figure should be treated with
some scepticism: the mechanical failure was caused by a
storm effecting an installation of small turbines (each 300
kW) and is referred to on a prominent anti-wind website.3
Although the website carries a citation from an industry
publication, the 400m distance is not mentioned anywhere
in this reference cited,4 nor is it mentioned in any related
articles (in fact, no distances are mentioned at all). The
website citation includes the fact that “An independent
witness estimated the blade piece to weigh 1 tonne and
travel almost 500m” but fails to mention any source for
this additional statement. Care must be taken to ensure
incidences such as these are not repeated without some
basis in fact.

What is the evidence?

Modern societies have enormous and diverse energy needs.
For instance, in the case of electricity, daily demand in the
UK regularly fluctuates between 15–24kWh per person per
day: taking the whole population this equates to some 40–
60GWe of demand every day (the highest demand of the
last decade occurred on 10th December 2002 and reached
60.12GWe).5 Society derives its energy needs from a
mixture of fossil fuels, nuclear and renewables, each with a
cost to society through impacts on the environment or
directly on human health6. In the dry language of
economics these are termed ‘negative externalities’, but are
more broadly known as social costs. The salient fact is that
with all the above methods of delivering energy there is
injury and loss of life involved. It is generally accepted that
society strives to minimise these as much as possible, but
such social costs are unavoidable.

There has been a considerable amount of data collected on
the safety of conventional energy industries and
hydroelectricity.7,8,9 Taking figures from the start of the
commercial wind energy industry in 1975 up to 2010, there
have been 44 recorded fatalities (this includes a technician
who reportedly committed suicide by hanging), an average
of 0.054 deaths/GWey.1 Conventional fossil fuel industries
have considerably higher rates, ranging from 0.197/GWey
for natural gas, to 6.921/GWey for coal and 15.058/GWey

www.cse.org.uk Centre for Sustainable Energy

Common concerns about wind power

for liquified petroleum gas.7 The outlier is nuclear energy,
with just 0.048 deaths/GWey due to accidents – although it
should be remembered that the hazards associated with
nuclear energy are much greater in the event that
something goes wrong, with ‘latent mortality’ difficult to
quantify (see also section 6).9 The data is summarised in the
chart on the following page.

It is clear that maintaining an energy supply carries a
human cost, but the superior safety profile of wind energy
is evident. Going back to the UK’s typical supply any one
year: in 2009 natural gas was used to deliver some 19GWy
of electricity5 at a supposed rate of 17 fatalities, if taking
the average accident risk calculated between 1965 and
20007. An equivalent supply generated by wind power
would, on average, result in one death.

But what of nuclear? It is, indeed, an impressively safe
industry when the above figures are analysed. In fact, some
recommend the risk element for modern nuclear reactors
used in the OECD nations should be closer to 0.02
deaths/GWey.9 The risk is low, but the hazard that nuclear
power plants pose should something go wrong is
considerable. A similar situation is demonstrated by the
chart (next page), which shows the catastrophic effects of
the Banqiao Dam disaster and how the safety profile of
hydroelectricity has been distorted by this single incident.7

Finally, additional negative externalities exist that are not
adequately captured by the data above, which simply focus
on immediate fatalities. As well as being comparatively
safe, wind power does not create air pollution or
radioactive emissions, and has a significantly lower carbon
footprint that any conventional thermal power source.6

Conclusions

As with other features of modern life (e.g. air, rail or motor
transport), society makes the decision to accept certain risks
in exchange for the benefits that this development brings.
Measuring one against the other is of paramount
importance, as is a continual effort to minimise the risks
along with any detrimental outcomes. This also implies that
we should regularly re-evaluate the costs and benefits, so
that we can be sure that what was once an acceptable cost
is still the case and meets the increasing standards of safety
expected in modern society.

Great care should be exercised when attempting to show
wind-generated electricity is a benign source of energy.10
There have been at least 44 recorded fatalities involving
wind power since 1975 – very low by the industry
standards, but the fact that lives are lost should not be
ignored.

Analysing these statistics again reveals that the mortality
rate per GWey has dropped ten-fold since the first
commercial expansion of the wind industry in the 1980s.1
However, wind turbines continue to suffer from faults
which pose potential hazards to workers and the public.
The problem of blade throw has been around for some
time, and efforts by the industry to downplay this issue can
only be detrimental.2 It is telling that even very recent
guidelines by pro-wind groups mention ice throw, but fail
to address the much broader problem of blade throw.11

Much has been learnt in the last two decades as the wind
energy industry has grown: more rigorous safety standards
are being implemented in manufacturing, and work is
being carried out to adequately model for risks such as
blade throw to incorporate them into planning.12,13
Although it could tackle some issues more openly, overall
the wind energy industry has one of the best safety records
of any energy industry, and has seen fatality rates decrease
in the face of a rapidly expanding capacity. Wind continues
to offer a clean, safe form of electricity supply, with
considerably less cost and risk to society than either fossil
fuels or nuclear energy.

Centre for Sustainable Energy www.cse.org.uk

Common concerns about wind power

Fig 9.1
Number of fatalities per GWey*

Coal
Oil
LPG
Gas
Nuclear
Hydro
Hydro (inc Banqiao)†
Wind‡

0 2 4 6 8 10 12 14 16

*
Data for all energy types except wind taken from Burgherr & Hirschberg (2008)7: note that these data cover the period 1969–2000 and only include severe
accidents with five or more fatalities (see note below for wind). Figures for wind cover the period 1975–2010 and are taken from Gipe (2010).1

Figures for hydro are listed a second time to include the Banqiao Dam failure of 1975, which killed 26,000 people due to immediate flooding alone.

Unlike data from Burgherr & Hirschberg (2008), data shown here for wind includes all recorded fatalities, not just severe accidents. In fact, each of the 44
accidents recorded resulted in a single fatality in each case1.
1
Gipe, P. Contemporary mortality (death) rates in wind energy [Online database]. 2010. Paul Gipe; c.2010 [cited 2010 Dec 15]. Avaliable www.windworks.
org/LargeTurbines/WindMortalityStatisticsNeedUpdates.html

2
Larwood, S., van Dam, C.P. (California Wind Energy Collaborative). 2006. Permitting setback requirements for wind turbines in California. California Energy
Commission, PIERRenewable Energy Technologies. CEC-500-2005-184. www.energy.ca.gov/2005publications/CEC-500-2005-184/CEC-500-2005-184.pdf
(accessed 24 Jan 2011)

3
Wind turbine accident compilation [Internet]. Caithness Windfarm Information Forum; c.2011 [cited 2011 Jan 24]. Available
www.caithnesswindfarms.co.uk/fullaccidents.pdf

4
Storm takes its toll on turbines. Windpower Monthly. 1994 Jan 1. www.windpowermonthly.com/news/953141/Storm-takes-its-toll-turbines/ (accessed 2 Feb
2011)

5
National Statistics, 2010. Digest of United Kingdom Energy Statistics 2010. London:TSO. Published with permission of Department of Energy and Climate
Change. www.decc.gov.uk/assets/decc/statistics/publications/dukes/348-dukes-2010... (accessed 23 Nov 2010)

6
Energy, sustainable development and health. Copenhagen: WHO Regional Office for Europe, Global Change and Health Programme; 2004 June 3.
Background document published for Fourth Ministerial Conference on Environment and Health, Budapest, Hungary, 23–25 June 2004.
EUR/04/5046267/BD/8. www.canwea.ca/pdf/talkwind/WHO%20-%20Energy,%20sustainable%20development... (accessed 7
December 2010)

7
Burgherr, P., Hirschberg, S. 2008. A Comparative Analysis of Accident Risks in Fossil, Hydro, and Nuclear Energy Chains. Human and Ecological Risk
Assessment; 14: 947–73.

8
Hirschberg, S., Spiekerman, G., Dones, R. Severe accidents in the energy sector. Villigen: Paul Scherrer Institut; 1998 November. Report no. 98-16.
http://gabe.web.psi.ch/pdfs/PSI_Report/ENSAD98.pdf (accessed 15 Jan 2011)

9
Severe Accidents in the Energy Sector. Villigen: Paul Scherrer Institut; 2005 May. Energie-Spiegel no.13. http://gabe.web.psi.ch/pdfs/Energiespiegel_13e.pdf
(accessed 16 Jan2011)

10 Gipe, P. [Internet] Wind Energy – The breath of life or the kiss of death: contemporary wind mortality rates. Paul Gipe; c.2003 [cited 2010 Dec 15]. Available
www.wind-works.org/articles/BreathLife.html

11 Guidelines for onshore and offshore wind farms. London: RenewableUK; 2010 August. 2010 update on Health & Safety in the Wind Energy Industry Sector.
www.bwea.com/pdf/HSGuidelines.pdf (accessed 24 Jan 2011)

12 International Standard IEC 61400-1: Wind turbines – Part 1: Design requirements. Geneva: International Electrotechnical Commission; 2005 Aug. Published
standard IEC61400-1. 3ed.

13 LeBlanc, M.P. (Garrad Hassan). Recommendations for risk assessments of ice throw and blade failure in Ontario. Garrad Hassan Canada Inc.; 2007. Report for
the CanadianWind Energy Association. 38079/OR/01. www.canwea.ca/images/uploads/File/GH-RiskAssessment-38079or01a(1).pdf (accessed 24 Jan 2011)

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Common concerns about wind power
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10. Wind turbines, shadow flicker and epilepsy

Summary

An effect known as ‘shadow flicker’ is caused when the
rotating blades of a wind turbine cast a shadow on an
observer. As the blades move they cause shadows on the
ground or nearby dwellings to move too, giving rise to a
flicker effect through windows and doors where the
contrast between light and shade is most noticeable. An
observer oriented so as to be looking in the direction of the
sun’s disc through the wind turbine’s open face will also see
a flicker effect as each blade transits the sun.

Because of the geometries involved, shadow flicker is an
easily modelled property and can be accounted for during
planning and development of a wind farm; indeed, UK
government planning regulations stipulate that this must
be considered. Due to the size and speed of modern
commercial wind turbines, there is no risk of shadow flicker
causing photo-epileptic seizures in vulnerable persons.

What is this based on?

Wind turbines are tall structures, and present an open disc
in the form of rotating blades. Depending on the sun’s
bearing in relation to observers (this is the sun’s azimuth)
and the sun’s altitude in the sky, wind turbines will cast a
shadow over nearby ground – this can be a significant
length at certain times of the day and at certain times of
the year. An important factor in the case of wind turbines is
that the rotating blades will pass in front of the sun’s
azimuth, giving rise to moving shadows that are particularly
noticeable through windows and doors where the contrast
between light and shade is most apparent. This shadow
flicker effect would certainly present an annoyance to
exposed residents, and some critics have predicted
(wrongly) that sufferers of photosensitive epilepsy would be
prone to seizures as a result.

What is the evidence?

The position of the wind turbine in relation to the observer
is critical, both in terms of the sun’s bearing and it’s
altitude, factors dependent upon the longitude and latitude
of the location in question. In the UK, only dwellings sitting
within 130° either side of north relative to the turbines can
be affected (going clockwise, that is 230° to 130° from true
north).

Research carried out at various wind farm installations
across the UK has found that shadow flicker only occurs
when the shadow is sufficiently in focus and lasts a certain
duration, both properties that diminish rapidly with
distance from the rotating blades. Thus, it has been

calculated that distances up to ten times the rotor diameter
can create the right circumstances to give rise to shadow
flicker.1,2 For example, a rotor diameter of 80m will
potentially give rise to shadow flicker up to 800m away, if
at the correct orientation. This ratio is used as part of the
planning regulation guidelines for the siting of wind turbines
in the UK.3

Since shadow flicker does occur, the optimum site for a
wind farm may create the circumstances whereby nearby
dwellings are affected. However, shadow flicker doesn’t
occur all the time; on many days the intensity of sunlight is
diminished due to cloud cover or the time of year. For
example, in winter months in the UK, the sun is lower in
the sky and casts longer shadows, but 80% of the time the
sun does not shine brightly enough to create the necessary
contrast; even in summertime, the sunlight is not bright
enough 60% of the time. The sun must also be at the
correct bearing in relation to the turbine rotor face to cast a
shadow across an exposed dwelling. Due to this
combination of sunlight and bearing, these circumstances
in reality only occur together for a fraction of the
theoretical maximum – 15% in winter and 30% in summer.

Since it is possible to accurately model this phenomenon it
is relatively simple to predict. In addition to re-siting, there
are a number of other mitigation measures the developer
can employ to protect residents. For example, it is possible
to plant a screen of trees between the turbines and the
affected properties to disperse the light. In addition, wind
turbines are controlled remotely and can be easily
programmed to stop operation in the brief window of time
during which shadow flicker has been predicted to affect
certain dwellings.

It has also been suggested that shadow flicker poses a
threat to the small percentage of epileptics who suffer from
photosensitive epilepsy in which seizures are triggered by
flashing lights or contrasting patterns of light and dark.4 In
the UK, the National Society for Epilepsy states that 1 in
131 people suffer from epilepsy during their lifetime, and
about 5% of this group will have photosensitive epilepsy.
Flashing or flickering at frequencies between 3–30 Hz are
the most common form of photic stimuli known to cause
photo-epileptic seizures – note that large commercial
turbines have rotation speeds that result in frequencies
below 2 Hz.3

Potential triggers for photo-epileptic seizures are well-
understood and are commonly found in everyday life.
Well-publicised instances of photo-epilepsy involving
television broadcasts have led to stringent guidelines which
have shown substantial success in reducing episodes in the
vulnerable population.5,6 Similarly, there has been recent
research into the effect shadow flicker from wind turbines
might have on photosensitive individuals.

There are some concerns that flicker can be apparent at
greater distances than currently taken into account by
planners and engineers; including flicker caused by sunlight

www.cse.org.uk Centre for Sustainable Energy

Common concerns about wind power

reflecting off the blades (as opposed to the shadow cast by
the blades). However, the parameters involved are
applicable to the flicker rate produced by smaller turbines
not found in wind farms. These smaller turbines have the
compounded problem of greater number of blades and
faster rotation speeds that create flicker above the critical
frequency.7

The photo-epileptogenic potential of smaller turbines is still
an important consideration, but it should be remembered
that modern commercial turbines rotate more slowly
(roughly 35 r.p.m.) producing a frequency of no more than

1.75 Hz, well below the threshold known to trigger photo-
epileptic seizures.8,9 In fact, largely due to atmospheric
conditions, the contrast threshold between light and dark is
significantly reduced with the end result that observed
flicker will not have the capacity to induce epileptic seizures
at distances greater than 1.2 times the turbine height8.
Even for smaller turbines the hub height and rotor diameter
will be less (typically hub height is < 45m), meaning their
potential reach is not as great.
Government guidelines advise developers to minimise the
specular properties of turbine blades to avoid light
reflecting off the blades unduly; indeed minimising
reflectiveness of the blades is something the industry been
carrying out for several decades already.3,10

Conclusion

Shadow flicker from the rotating blades of a wind turbine is
a known, quantifiable effect. Large commercial turbines
can create a flicker effect at frequencies up to 2 Hz, safely
below the threshold that can cause photo-epileptic
seizures.3,4,10 While flicker can be annoying, there is no
evidence that the operating characteristics of commercial
wind turbines can induce seizures in the vulnerable
population of epilepsy sufferers.4,8

Due to the precipitating factors, which involve turbine
position in relation to the solar azimuth and sun’s altitude
above the horizon relative to an observer, this phenomenon
can be accurately modelled and predicted. In practice,
shadow flicker occurs within narrow spatio-temporal limits.
This means that even if it is predicted to affect certain
dwellings, shadow flicker is only apparent when the
intensity of sunlight and angle of the blades to an observer
combine with the sun’s position in the sky to create a
noticeable effect – this is effectively for short periods in any
single day affecting those particular dwellings that are
vulnerable during such periods.

The predictability and infrequency makes shadow flicker an
eminently manageable problem: it can be curtailed by the
introduction of various mitigation measures, among them
re-siting of individual turbines, creating screening features
such as treelines (or using existing ones), and programming
the turbines to cease operation for the short time during
which dwellings are affected.

1
Clarke, A.D. A Case of shadowflicker/flashing: assessment and solution. Milton Keynes, UK: Open University; 1991.

2
Taylor, D. and Rand, M. Planning for wind energy in Dyfed. Milton Keynes, UK: Open University; 1991. Report by Energy and Environment Research Unit,
Open University, UK.Report EERU 065.

3
Planning for Renewable Energy: a Companion Guide to PPS22. Office of the Deputy Prime Minister, 2004. 04PD02691.
www.communities.gov.uk/documents/planningandbuilding/pdf/147447.pdf (accessed 14 Nov 2010)

4
Epilepsy factsheet 1: Photosensitive epilepsy. Chalfont St Peter, Bucks., UK: National Society for Epilepsy; 2010, August.
www.epilepsysociety.org.uk/FileStorage/main_content/Photosensitiveepilep... (accessed 31 January 2011)

5
Binnie C.D., Emmett J., Gardiner P., Harding, G.F.A., Harrison, D., Wilkins, A.J. 2002. Characterising the flashing television images that precipitate seizures.

SMPTE J; 111: 32–39.

6
Takahashi Y., Fujiwara T. 2004. Effectiveness of broadcasting guidelines for photosensitive seizures prevention. Neurology; 62: 990–3.

7
Harding G.F.A., Harding P., Wilkins A. 2008. Wind turbines, flicker, and photosensitive epilepsy: characterizing the flashing that may precipitate seizures and

optimizing guidelines to prevent them. Epilepsia; 49:1095–98.

8
Smedley, A., Webb, A., Wilkins, A. 2010. Potential of wind turbines to elicit seizures under various meteorological conditions. Epilepsia; 51: 1146–51.

9
Wilkins A.J., Emmett J., Harding G.F.A. 2005. Characterizing the patterned images that precipitate seizures and optimizing guidelines to prevent them. Epilepsia; 46: 1212–

18.
10 Burton, A., Sharpe, D., Jenkins, N., Bossanyi, E., editors. Wind Turbine Installations and Wind Farms. In: Wind Energy Handbook. Chichester: John Wiley &
Sons Ltd; 2001. p.511–58.

Centre for Sustainable Energy
www.cse.org.uk

Common concerns about wind power
-----------------------------------------------------------------------------------------------------
11. Wind turbines and noise

Summary

Wind turbines rely on mechanical operations to generate
electricity. The movement of the blades through the air
inevitably creates noise, and the increasing size of mediumto-
large turbines (typically 2.3–3.6 MW rating, standing
65–105m tall) has prompted concern that they will generate
an unacceptable level of noise for nearby residents.

In the UK, this phenomenon has been studied by a
government working group, and detailed guidelines form
part of UK planning regulations to prevent undue noise
pollution. These, coupled with the quieter design of modern
turbines, mean that the noise levels generated by wind
farms are comparable to outdoor background noise. Studies
have found topography and changing wind patterns at
night can accentuate this noise in specific locations, but
understanding this process means it can be correctly
assessed during planning to ensure that properties that
might be prone to these effects are not affected.

Experience of wind farms in Europe has shown that
residents’ negative perceptions of noise are reduced when
they enjoy a direct financial benefit from the turbines, and
also diminishes with time post-construction.

What is this based on?

Any large device that has moving parts will create some
noise, and wind turbines of any size are no exception. Many
people’s idea of wind turbine noise is derived from small
turbines mounted on houses (around 2.5–6.0 kW range)
that cause vibrational disturbance, or from standing up
close to a large megawatt turbine. Medium-to-large
turbines (0.5–3.6 MW) commonly in use will generate
significant levels of noise during operation if one is stood at
the base, with typical noise output ranging between 97 and
107 dB(A) at 10m.1

It is apparent from this that wind turbines cannot be sited
too close to residential dwellings. Excessive ‘community
noise’, defined as traffic, industries, construction works, and
the urban environment, can create a host of adverse effects
on human health according to World Health Organization
(WHO) guidelines.2

As the wind energy sector began to expand in the early
1990s the UK planning authorities recognised that the
existing guidelines (BS 4142:1990) did not adequately cover
the use of increasingly larger wind turbines in the megawatt
range. A Noise Working Group set up to advise the
government carried out detailed research to define the lower
limits for noise emissions from wind farms, after which these
recommendations were laid down in the ETSU-R-97 report
and incorporated into national planning guidelines.3

Noise levels encountered in everyday situations are given in
the table below. Note that noise levels are measured using
an ‘A-weighting’ that emphasises those frequencies to
which the human ear is most sensitive, hence sound
pressure levels are given in dB(A). The A-weighting helps
ensure measured sound levels are close to the perceived
sound levels of the human subject. The dynamic range of
human hearing is discussed in more depth in the section on
low-frequency sounds (section 12).

Despite revised guidelines in the UK and other European
countries with a high penetration of wind power (e.g. The
Netherlands, Denmark and Germany), some researchers
have reported that noise continues to be an annoyance
factor for a significant number of residents living near wind
farms.4,5 At certain sites, noise emissions were found to be
unexpectedly high at night time, but in other surveys many
complainants stated various degrees of annoyance at sound
levels no greater than ambient background noise caused by
other factors, such as passing traffic.6,7 Noise emissions from
wind turbines can be problematic even when planning
guidelines are adhered to, and there is some evidence that
particular acoustic characteristics of turbines are more
intrusive than previously thought.7,8

Table 11.1 Indicative noise
level in dB(A)
Threshold of pain 140
Jet aircraft at 150m 105
Pneumatic drill at 150m 95
Truck at 30mph at 100m 65
Busy general office 60
Car at 40mph at 100m 55
Wind farm at 350m 35-45
Rural night-time background 20-40
Quiet bedroom 20

What is the current evidence?

Modern designs have seen the gear mechanisms and their
housings producing progressively quieter wind turbines, and
the latest generation of ‘direct drive’, or gearless turbines
create even less mechanical noise.7,9 In addition, blade
design has constantly been refined to reduce the noise
generated, which also creates a more efficient turbine as
less energy is lost to acoustic energy.9,10,11 However, one
acknowledged feature of a wind turbine sound that is
independent of mechanical noise are the broadband
emissions caused by the rotating blades, particularly as they
pass the turbine mast itself. This rhythmic ‘amplitude
modulation’ is generally described onomatopoeically as a
“swish”, “swoosh”, “whistle” or, at times of high activity, a
“thumping” sound.6,7,8 The phenomena associated with
these aerodynamic sounds were discussed in detail by the
UK working group in ETSU-R-97. They concluded that
equating blade noise to background noises like wind
blowing through trees is “perhaps an oversimplification”.12

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Common concerns about wind power

The discovery that a small but significant proportion of
residents find audible emissions annoying and intrusive is
surprising, as levels of noise have been repeatedly measured
as falling inside accepted limits for ambient background
noise (30–40 dB[A]).5,7 It is thought that the characteristics
of aerodynamic noise from wind turbines may be perceived
differently depending on the sensitivity of individual
residents8.

After visual impact, noise is most frequently cited as the
reason for complaints by nearby residents relating to wind
farms, and a feature common to most studies into intrusive
noise is that negative attitudes toward the siting of wind
farms plays a large part in any individual subject’s response
to noise.4,5,7,13

Researchers into the peculiar noise characteristics of wind
turbines and their affect on annoyance and disturbance
have pointed out that if residents feel disconnected from
decisions made by local government, or are generally
unhappy with changes to their community space, then they
are much more likely to be affected once a wind farm is
installed. Profound changes brought about by the
installation of wind farms in rural areas correlates with
increasing sensitivity to noise-related disturbance.7,13
Tellingly, a further field study in The Netherlands has shown
that residents who enjoy a direct benefit from a
neighbouring wind farm do not experience the same
feelings of annoyance despite being exposed to the same
level of noise.14

Conclusion

Renewables are essential for the move toward low-carbon
energy sources and public attitudes on the whole are strongly
in favour of their implementation. However, there is a striking
divergence between overall support and more local
opposition to the installation of renewable technologies.15
Although wind energy is not the only renewable energy that
produces divisive opinion, it is best placed to achieve the CO2
emission targets set by the UK government and take on a
significant proportion of the country’s electricity needs by
2020.16 An increasing number of installations will see an
increasing number of challenges from concerned residents
unless the causes of negative opinion are understood.

In spite of continual improvements made to turbine design,
there is a significant body of evidence showing that the
characteristics of noise emissions from wind turbines can
affect a small proportion of the communities that are
exposed.4,5,7 Evidence also suggests that failure to take into
account the topography of individual sites and the increased
size of modern turbines can lead to unexpectedly high noise
emissions.6

Accordingly, the issue of noise should be treated with due
consideration, and guidelines must be strictly adhered to, or
efforts made to revise them if necessary. There are some
critics who point out the existing UK planning guidelines are
in need of updating, and there is some justification for this

when current planning regulations in 2011 continue to refer
to a working group report released in 1996; indeed, the
original reporters presciently aired much the same wish in
the ETSU-R-97 document itself.12 However, the report is still
a well-grounded and thoroughly researched reference and it
is clear that the recommendations on which planning
regulations rely clearly stipulate that sound pressure levels,
not distance, should determine the minimum setback from
nearby dwellings:

“The difference in noise emissions between different

types of machine, the increase in scale of turbines and

wind farms seen today and topographical effects

described...all dictate that separation distances of 350–

400 metres cannot be relied upon to give adequate

protection to neighbours of wind farms.”12

Day- and night-time levels should be set at 5 dB(A) above
background ambient noise, with a fixed limit of 43 dB(A) for
night-time use; an upper limit of 45 dB(A) is acceptable for
a dwelling which derives a direct economic benefit.
Guidelines also takes into account areas that might
experience low levels of background noise and that absolute
noise limits need to be set relative to this if necessary.3,12

It is important to note that the literature on the small but
significant number of residents who are continually
disturbed by perceived noise from wind farms almost
invariably reveals that the propagated sound is not any
higher than normal community background levels. Visibility
plays a significant part in exacerbating disturbance due to
sound, with affected respondents frequently already
unhappy that their local setting has been marred by the
introduction of wind farms, and the overall perception of
intrusive sound is intimately associated with the feeling that
the visible structures have been forced on the landscape
without any say from them.5,7,13 This lies at the heart of the
divergence mentioned above (section 7).

Alienated residents (i.e. those not involved in decision-
making, with no direct economic benefit, without a
knowledge of how wind energy operates and suspicious of
wind farms thrust upon them) will ultimately perceive any
wind farm development negatively, regardless of public
support in general.15

Accusations of nimbyism are unhelpful and irrelevant: it is
up to the wind energy industry and its supporters to be
honest about any noise concerns local residents might have,
and to work with them to minimise these affects within the
framework of the planning regulations (designed for exactly
this purpose).17 It is evident that residents who feel
installations are forced upon their local setting will judge any
subsequent noise accordingly, and it is cogent that clearly
realised benefits for residents (direct financial benefit and a
better understanding of how wind power contributes to a
low-carbon economy) significantly mitigate this negative

bias.14,15

Centre for Sustainable Energy www.cse.org.uk

Common concerns about wind power

1
V90-3.0 MW [Product brochure]. Vestas WInd Systems A/S; c.2010 [cited 24 Jan 2011]. Available
http://nozebra.ipapercms.dk/Vestas/Communication/Productbrochure/V9030MW...

2
Berglund, B., Lindvall, T., Schwela, D.H. 1999. Guidelines for Community Noise. Geneva: World Health Organization (outcome of WHO expert task force
meeting: London, April1999). http://whqlibdoc.who.int/hq/1999/a68672.pdf (accessed 03 Dec. 2010)

3
Planning for Renewable Energy: a Companion Guide to PPS22. Office of the Deputy Prime Minister, 2004. 04PD02691.
www.communities.gov.uk/documents/planningandbuilding/pdf/147447.pdf (accessed 14 Nov 2010)

4
Wolsink, M., Sprengers, M., Keuper, A., Pedersen, T.H., and Westra, C.A. 1993. Annoyance from wind turbine noise on sixteen sites in three countries.
European Community WindEnergy Conference, 8–12 March, Lübeck, Travemünde, Germany, pp. 273–76.

5
Pedersen, E., Waye, K.P. 2007. Wind turbine noise, annoyance and self-reported health and well-being in different living environments. Occup Environ Med; 64:480–
86

6
Van den Berg, G.P. 2004. Effects of the wind profile at night on wind turbine sound. J Sound Vib; 277: 955–70.

7
Pedersen, E., Waye, K.P. 2004. Perception and annoyance due to wind turbine noise: a dose–response relationship. J Acoust Soc Am; 116: 3460–70.

8
Waye, K.P., Öhrström, E. 2002. Psycho-acoustic characters of relevance for annoyance of wind turbine noise. J Sound Vib; 250: 65–73.

9
Enercon wind energy converters: technology and service [Brochure]. Aurich (Germany): Enercon GmbH. July 2010.
www.enercon.de/p/downloads/EN_Eng_TandS_0710.pdf (accessed 29 Nov 2010)

10 Tangler, J.L. The evolution of rotor and blade design. Golden (CO): National Renewable Energy Laboratory, July 2000. Report no. NRELCP50028410. Contract
no.DEAC3699GO10337. Sponsored by US Department of Energy.

11 Leloudas, G., Zhu, W.J., Sørensen, J.N., Shen, W.Z., Hjort, S. 2007. Prediction and reduction of noise from a 2.3 MW wind turbine. J Phys Conf Ser; 75
012083. http://iopscience.iop.org/1742-6596/75/1/012083 (accessed 15 Nov 2010)

12 The assessment and rating on noise from wind turbines. ETSU-R-97. The Working Group on Noise from Wind Turbines. Final Report, September 1996. On
behalf of the Department of Trade and Industry.

13 Pedersen, E., Hallberg, LR-M., Waye, K.P. 2007. Living in the vicinity of wind turbines – a grounded theory study. Qual Res Psychol; 4: 49–63.

14 Pedersen E, van den Berg F, Bakker R, Bouma J. 2009. Response to noise from modern wind farms in The Netherlands. J Acoust Soc Am;126(2): 634-43

15 Devine-Wright, P. 2005. Beyond NIMBYism: towards an integrated framework for understanding public perceptions of wind energy. Wind Energy; 8: 125–39.
16 The UK low carbon transition plan: national strategy for climate and energy. London: HMSO; 2009 July 20. URN 09D/716. http://tinyurl.com/6z5p6yv
(accessed 16 Jan 2011)

17 Wolsink, M. 2007. Wind power implementation: The nature of public attitudes – equity and fairness instead of .backyard motives'. Renewable Sustainable
Energy Rev; 11: 1188– 1207.

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Centre for Sustainable Energy

Common concerns about wind power
----------------------------------------------------------------------------------------------------------------------------------------------------
12. Infrasound from wind turbines and ‘Wind Turbine Syndrome’

Summary

The subject of low-frequency sounds typically inaudible to
the human ear (infrasound) has been posited as a hidden
causative agent behind reported ill-health suffered by some
individuals living near wind farms. This is based largely on
the promotion of a small number of biased case studies by
one self-published lobbyist which has garnered significant
media attention, despite the overwhelming consensus in
the peer-reviewed literature that there is no evidence such
a thing as “wind turbine syndrome” exists. Repeated
efforts have been made to measure the perceived effects of
infrasound from wind turbines, with no positive results.
Guidelines for environmental noise already exist both
nationally and internationally. They take low-frequency
noise into account, and are based on robust evidence from
decades of research, and these continue to be refined.

The continuing coverage that “wind turbine syndrome”
receives, obscures the much-better understood issues
surrounding environmental noise, and the continued
distraction hinders treatment for the small number of
individuals who genuinely suffer from anxiety, stress and
attendant health problems brought on by the perceived
existence of negative environmental agents with no
discernible physical cause.

What is this based on?

In 2009, drawing on a series of case studies from 10
families with a total of 37 subjects, a paediatrician in New
York state attributed the following symptoms to low-
frequency sound emissions from wind turbines: sleep
disturbance, headache, tinnitus, other ear and hearing
sensations, balance and equilibrium disturbances, anxiety,
nausea, irritability, energy loss, motivation loss, memory
and concentration disturbances. The author of this case
series grouped these symptoms together under the
umbrella of “wind turbine syndrome”. These findings have
been self-published in a book marketed by the author.1

What is current evidence?

Sound propagates as a pressure wave through vibrations in
the air, and the number of vibrations – the frequency – is
given in Hertz (Hz). The intensity of the pressure wave
emitted is measured in decibels (dB), which is usually
recorded as a logarithmic scale to account for the
enormous range of frequencies at which sound is audible
to the human ear, i.e. 20–20,000 Hz. Below the 20 Hz
threshold is ‘infrasound’ – this low frequency sound outside

the normal range of human hearing; however, it is
accepted that frequencies below 20 Hz can be detected at
high levels (>79 dB), although as the frequency decreases
the level of sound required for auditory perception
becomes very high; for instance, frequencies below 8 Hz
must be at levels above 120 dB to be heard (akin to
standing within 60m of a jet aircraft taking off).2,3

The effects of noise on human health and activities have
been studied for many decades. Outdoor noise in modern
society originates primarily from traffic (road, rail and air),
industries, construction works, and the urban environment
or neighbourhood: these sources of noise are commonly
grouped under the term ‘community noise’.4 The World
Health Organization (WHO) acknowledges that community
noise guidelines should take into account the presence of a
strong low-frequency component when assessing noise
emissions,4 but when dealing with very low-frequency
sound emissions it should be remembered that in many
cases these sounds, although low-frequency, still fall outside
what can be correctly termed infrasound.3

Overall, the case series presents very weak evidence for
anything akin to a definable syndrome. Following several
years of campaigning after a wind farm was proposed next
to her town in Malone, NY, the author asked for
respondents who already believed they were suffering
symptoms caused by nearby wind turbines. This self-
selection bias makes it difficult to identify a causative
agent. Many of the subjects suffered from pre-existing
conditions including: mental health disorders, persistent
migraines, continuous tinnitus and motion sensitivity, and
several had a history of significant exposure to loud noise in
the workplace. A similar report authored in the UK,
published exclusively on lobby group websites, exhibits
many of the same methodology flaws.5

To understand the recent accusation that infrasound can
cause detrimental effects to health to residents living near
wind turbines, it is useful to break down the hypothesis of
“wind turbine syndrome” into its two main parts.1

1. Infrasound at 1–2 Hz from wind turbines propagating
through the air directly affects the vestibular system of the
ear. The vestibular system within the inner ear plays an
important part in balance, and also works in combination
with the visual system to maintain focus when moving. To
do this, specialised hair cells suspended in fluid in the
cochlea transmit mechanical fluid movement caused by
sound waves to the brain via nerve cells. These inner hair
cells, are responsible for almost all of the auditory capability
of human hearing (i.e. sounds generally above 20 Hz), but
are insensitive to frequencies in the infrasound range. A
recent review suggests a possible link between the
mechanical movement of other sensory hair cells that are
more sensitive to infrasound, inferring that some
physiological effect can be elicited by infrasound at levels
below normal auditory perception.6 Tellingly, the reviewers
propose that these effects are only likely to appear in
subjects who are susceptible to infrasound, i.e. people who
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Common concerns about wind power

suffer from rare conditions affecting the inner ear. It should
be remembered that the non-pathological inner ear is a
poor detector of low frequency sound. In studies on normal
subjects that aimed to produce ill effects from infrasound,
the participants had to be subjected to very high levels of
sound, considerably higher than those produced by wind
turbines.7,8

2. Infrasound at the 4–8 Hz range enters the lungs via the
mouth and then vibrates the diaphragm, which transmits
vibration to the internal organs of the body. This internal
vibration conflicts with auditory and visual signals received
by the brain, causing agitation, anxiety, nausea and
irritability. The author coins this phenomenon “visceral
vibratory vestibular disturbance” (VVVD).
In addition to the vestibular system mentioned above, the
internal organs (generally termed the viscera) can transmit
information to the brain based on the body’s position and
motion. This sense is called proprioception, and is initiated
by the balance organs in the inner ear and by
‘proprioreceptors‘ found in the muscles and supporting
ligaments; it is also thought to involve contact and vibration
receptors in the skin, although these receptors are not
sensitive to sound waves at infrasound frequencies. It is the
effect of infrasonic vibrations on this visceral system that
supposedly forms the basis of VVVD.1 However, this
hypothesis ignores several salient facts.

Transmission directly through the head does not occur, for
the skull has to resonate at frequencies much higher than
20Hz to transmit the energy from a sound wave to
vibrations within the body. Vestibular disturbance can occur
at inaudible levels through bone conductance, but only at
frequencies much higher than infrasonic sounds (around
100Hz)9; this independent research was misinterpreted by
the creator of wind turbine syndrome to provide a “direct
link” to VVVD – a fact later openly criticised in a public
refutation by the lead researcher.10 In addition, the natural
resonant frequency of the viscera is around 4 Hz: infrasonic,
but the wavelength at this frequency is so long (85m) that
the sound pressure behaves as a compression wave of
negligible force, acting on the body equally from all points
and thus preventing any resonant vibrations in the
viscera.8,11 To cause noticeable sensation and unpleasant
effects, infrasound must be at levels far exceeding the
emissions measured from wind turbines.7,8,11

Conclusion

The evidence sited above does not confirm the existence of
a “syndrome”. The propagation and effects of low-
frequency sound are well understood, and adverse effects
on humans are only evident at infrasound levels far
exceeding that generated by operating wind turbines.3,7,11

The UK Health Protection Agency welcomes additional
research in the field of environmental infrasound, while
acknowledging the lack of evidence supporting wind
turbine-generated infrasound as a health risk.8 Research

into the effects of infrasound is ongoing to refine what is
already known. Guidelines in the UK and internationally are
clear that sounds at all frequencies must be taken into
account when assessing the impact of environmental
noise.4,8 It is recognised that weighting should also be given
to low-frequency noise, and government and industry
continually incorporate this information into accepted
guidelines for measuring the acoustic emissions from wind

turbines.3,4,12,13

Claims that infrasound is “wind energy’s dirty little secret”14
are unfounded and ignore the existing body of evidence
that states the opposite. An advisory expert panel goes as
far to state that:

“Wind turbine syndrome,” not a recognized medical

diagnosis, is essentially reflective of symptoms

associated with noise annoyance and is an unnecessary

and confusing addition to the vocabulary on noise.”11

A 2006 report investigating complaints about nearby wind
farms in the UK found that of the 126 operational wind
farms, five complaints were made regarding low-frequency
noise. At one location, a resident was found to have
sensitivity to infrasound that made some emissions by the
nearby wind farm audible, although the same resident was
actually found to be awoken by the low-frequency noise
from traffic, not the wind turbines themselves. In all the
locations studied, infrasound was found not to play a part
in disturbance to residents.15 The confusion between
audible sound and infrasound may have supported the
argument for the “hidden effects” of wind turbines.3,11

The reporting of ‘health scares’ in the national media also
perpetuates these myths, and may reinforce the preexisting
belief that wind turbines are the cause of
underlying pathologies and contributing somatoform
disorders brought on by negative anticipation.11 This is
unhelpful, and distracts from those truly susceptible to
stress and anxiety, exacerbating the frustration at not being
able to control their external environment and creating
misguided fixation on the ‘cause’ of their suffering (i.e.
wind turbines).16

Centre for Sustainable Energy www.cse.org.uk

Common concerns about wind power

1
Pierpont, N. Wind Turbine Syndrome: A Report on a Natural Experiment. 1st ed. Santa Fe: K-Selected Books; 2009.

2
Acoustics – Normal equal-loudness-level contours. Geneva: International Organization for Standardization. 2003 Aug. International Standards Classification
ICS 13.140: Noise withrespect to human beings. Published standard ISO 226:2003.

3
Leventhall, G. A review of published research on low frequency noise and its effects. Ashtead, UK: Dr Geoff Levanthall, Consultant in Noise, Vibration and
Acoustics; 2003 May.Contract no. EPG 1/2/50. Sponsored by Department for Environment, Food and Rural Affairs.

4
Berglund, B., Lindvall, T., Schwela, D.H. 1999. Guidelines for Community Noise. Geneva: World Health Organization (outcome of WHO expert task force
meeting: London, April 1999). http://whqlibdoc.who.int/hq/1999/a68672.pdf (accessed 03 Dec. 2010)

5
Harry, A.J. 2007. Wind turbines, noise and health [Internet]. Independent report by Dr Amanda Harry; 2007 February [cited 24 Jan 2011.]. Available at

www.wind-watch.org/documents/wp-content/uploads/wtnoise_health_2007_a_ha...

6
Salt, A.N., Hullar, T.E. 2010. Responses of the ear to low frequency sounds, infrasound and wind turbines. Hearing Research; 28: 12–21.

7
Berglund, B., Hassmén, P., Job, R.F.S. 1996. Sources and effects of low-frequency noise. J Acoust Soc Am; 99(5): 2985–3002.

8
Health effects of exposure to ultrasound and infrasound. Chilton, UK: Report of the Independent Advisory Group on Non-ionising Radiation; 2010 February.

Report no. RCE-14.Issued by Health Protection Agency. www.hpa.org.uk/web/HPAwebFile/HPAweb_C/1265028759369 (accessed 5 Nov. 2010)
9 Todd, N.P., Rosengren, S.M., Colebatch, J.G. 2008. Tuning and sensitivity of the human vestibular system to low-frequency vibration. Neurosci Lett; 444: 36–

41.
10 Todd, N. IoS letters, emails & online postings. Independent on Sunday; 2009 August 9th. www.independent.co.uk/opinion/letters/iiosi-letters-emails--onlinepostings-
9-august-2009-1769575.html (accessed 5 Dec. 2010)
11 Colby, W.D., Dobie, R., Leventhall, G., Lipscomb, D.M., McCunney, R.J., Seilo, M.T., Søndergaard, B. Wind turbine sound and health effects: an expert panel
review. WashingtonDC: Scientific Advisory Panel for AWEA and CanWEA; 2009 December. Advisory Expert Panel appointed by American Wind Energy
Association (AWEA) and Canadian Wind Energy Association (CanWEA).
12 Acoustics – Frequency-weighting characteristic for infrasound measurements. Geneva: International Organization for Standardization. 2007 Aug.
International Standards Classification ICS 17.140.01: Acoustic measurements and noise abatement in general. Published standard ISO 7196:1995
13 Wind turbine generator systems – Part 11: Acoustic noise measurement techniques. Geneva: International Electrotechnical Commission (IEC) technical
committee 88: Windturbine systems; 2002 December. International Standard IEC 61400-11.

14 Pierpont, N. Wind Turbine Syndrome [Internet]. Malone, NY: Nina Pierpont c.2010 - [cited 5 December 2010]. Available at www.windturbinesyndrome.com.

15 The measurement of low-frequency noise at three UK wind farms. London: Department of Trade and Industry (DTi); 2006. Report by Hayes and MacKenzie

Partnership Ltd onbehalf of DTi under contract W/45/00656/00/00. URN 06/1412.
16 Leventhall, G., Benton, S., Robertson, D. 2008. Coping strategies for low frequency noise. Journal of Low Frequency Noise, Vibration and Active Control; 28(1): 35–

52.
www.cse.org.uk
Centre for Sustainable Energy

Common concerns about wind power
----------------------------------------------------
13. Bat and bird mortality in relation to wind turbines

Summary

Construction of large-scale wind farms first took place in
the 1980s in California, and other similar locations in the
USA and Europe. Unfortunately, the contemporary design
of the smaller commercial wind turbines (with open-lattice
towers), the greater number of such turbines required on a
single site, and their placement across areas used by
ecologically sensitive raptor populations have all conspired
to cause an elevated rate of avian mortality, particularly
affecting important populations of rare species. These
unfortunate events form the basis of the current
misconception that new wind farms will cause
disproportionate harm to bird populations.

In fact, wind turbines are responsible for less than 0.01%
of avian mortality caused by humans, with by far the
largest cause of deaths being standing buildings (more
precisely, the windows), power lines and domestic cats.
Considerable variation exists in the number of birds killed
annually across different wind farms worldwide, and the
industry now undertakes extensive surveying of avian
populations and migratory routes to further minimise any
detrimental effects before commercial turbines are sited.
Modern, large-scale megawatt turbines in use for the past
ten years have been found to result in a significantly lower
rate of fatalities in most areas where they have been
subsequently introduced. In terms of electricity generated,
wind is substantially safer than fossil fuel energy when
avian deaths per unit of electricity generated are compared.

Although avian mortality has received the greatest
attention by far over the preceding three decades, there is
increasing concern that bat fatalities may occur on a
proportionally larger scale, and are potentially more
damaging to the smaller number of species involved. The
migratory patterns of bats are not well understood, but
considerable variation in fatality rate also exists between
different wind generation sites, as found with birds. Bats
are typically adept at avoiding moving objects, and it is
thought that the unexpectedly high mortality at some sites
may be accounted for by altered behaviour during
migration, and by the occurrence of ‘barotrauma’ caused
by rapid air pressure reduction near the edge of the turbine
blade as it moves through the air. In any case, it is clear that
more data must be collected on bat populations if the wind
industry is to repeat its success with reducing avian deaths.

What is this based on?

Avian mortality due to all sorts of human activity
(anthropogenic causes) has been well-documented for
many decades, and is an ongoing area of research.1,2 Wind

turbines have earned a bad reputation thanks to several
large installations built in the early 1980s, most famously
Altamont Pass in California (the Altamont Pass Wind
Resource Area [APWRA]), and the Navarro and Tarifa
regions in Spain. Early wind turbines were sited with very
little consideration for the indigenous raptor populations in
the APWRA, causing excessive fatalities in six raptor
species. This effect is not observed to such a degree in
similar wind farms sited elsewhere in the USA leading to
the conclusion that poor planning and outmoded turbine
design is largely responsible.3

In southern Spain, two large installations in the mountains
of the Campo de Gibraltar region totalling more than
30 MW have also recorded a high proportion of raptor
deaths, including the griffon vultures, a vulnerable species.
In this case, the particular arrangement of turbines along
ridges used by migrating raptors to gain height in the
absence of thermals was thought to contribute to the high
rate of fatalities, as little difference was seen between
turbines of older and newer designs.4 Similarly, the Navarra
region was one of the earliest sites opened up in Spain for
large-scale wind farms. Large numbers of the griffon
vulture (63% of raptor fatalities) have been killed across
this region in collisions with turbines, from installations that
make up just 5% of the nation’s installed capacity at the
end of 2010.2,5

Even smaller installations in Belgium (Zeebrugge harbour)
and Norway (Smøla) have recorded large numbers of
deaths per turbine in sensitive breeding populations of
eagles and seabirds.2

Although a small but significant level of bat fatalities were
known at wind farms in the USA as part of studies on bird
mortality,6,7,8 there was a surge in deaths recorded at
several wind farms in the Appalachian Mountain region in
studies between 2002 and 2005.3 In particular, a small
installation in Tennessee and a much larger wind farm in
West Virginia both reported a worryingly high fatality rate
in excess of 20–30 bats per turbine.9,10 The figures for the
southeastern US are alarming, but lower numbers of
fatalities have also been reported at wind farms across
America.11

In Europe and the UK the problem has become apparent
with over 1,500 fatalities recorded as of April 2009 and up
to 21 species being affected. Some species on the
European mainland are known to migrate notable
distances, but data on UK migratory patterns is currently
scarce.12

The discovery that bats are being killed by wind turbines
has raised a number of questions as to why this should
occur, since bats are known to be excellent at avoiding
moving objects using their ability to navigate by
echolocation. A recent review of the problem put forward
no less than 11 hypotheses as to what might be
contributing to these fatalities.13 Clearly, a great deal of
research is still needed.

www.cse.org.uk Centre for Sustainable Energy

Common concerns about wind power

What is current evidence?

The existing body of research into avian deaths caused by
wind turbines over the last 20 years is extensive, and the
literature on bat fatalities is increasing.2,11,12 This increase in
awareness has provided the wind energy industry with vital
information that must be incorporated into planning and
developing existing and future wind farms14. Indeed,
planning regulations already exist in the UK to protect
natural habitats and prevent damaging development that
may harm protected species: these include the Natural
Environment and Rural Communities Act 2006, and the
Planning Policy Statement 9 on Biodiversity and Geological
Conservation.12

Fig 13.1
Estimated annual avian mortality per 10,000 deaths

(Data taken from Erickson 20051)

5820

1370

1060

850

710

50

<1 <1

There is little existing evidence for the UK that shows any
detrimental effects to sensitive bird populations (although
fatalities do occur);14 bats, however, are protected species,
and the government advisory body, Natural England, took
immediate steps to provide guidelines for the installation of
commercial wind turbines.15

It is clear that, while much research is still underway, there
is a great deal of data available on the overall effects of
wind turbines on bird and bat populations. Much of this
information is collected on a site-specific basis and requires
a great deal of assimilation to reach a perspective on the
ecological effects of wind power generation.

As avian mortality has been continually researched for
decades, it is worthwhile summarising this data. Doing this
shows that the contribution made by wind turbines to

AeroplanesWind turbinesCommunications towersPesticidesVehiclesCatsPower linesBuildings

avian mortality is negligible when compared to overall
mortality from anthropogenic sources. Figures collected
across the USA and Europe show that bird deaths caused
by collisions with wind turbines make up less than 1
incident out of every 10,000 deaths from all causes: that is
less than 0.0001%.1

The human activity estimated to cause by far the largest
number of avian deaths is the erection of buildings,
collisions involving birds accounting for over 58% of
fatalities (see figure). This is thought to be largely due to
windows, which birds seem poorly equipped to deal with,
and artificial lighting.2,16 Following this, transmission power
lines and domestic cats account for >13% and >10%
respectively.

In the context of overall human activity, the above statistics
are compelling.

However, since wind farms are being introduced as a
means to reduce CO2 emissions, a more meaningful way to
analyse avian deaths would be to compare wind power
with non-renewable sources. The concept of comparing
data by unit electricity produced is discussed above in
relation to the risks to human health posed by different
sources of energy (section 9). A preliminary study suggests
that when the same principle is applied to avian mortality,
existing fossil fuels are responsible for over 15 times the
number of deaths for every GWh produced: that is 5.2
fatalities/GWh for fossil fuels compared with just 0.3
fatalities/GWh for wind. Nuclear power had a similar
mortality rate to wind energy, with 0.4 deaths per GWh.17

Conclusion

Wind turbines represent an insignificant fraction of the
total number of bird deaths caused by man-made objects
or activities (e.g. building structures, transmission lines, and
keeping domestic cats). However, the industry is well aware
that fatalities do occur, and there is considerable interest in
refining monitoring techniques to inform developers when
planning wind farms. In the UK, wind farms are subject to
an Environmental Impact Assessment, which must take into
account any sensitive bird populations, including migratory
species. The planning regulations and advisory guidelines
ensure bird populations in areas affected are studied to
best predict the influence siting a wind farm might have –
and planning permission can be refused if the perceived
detrimental effects are unacceptable or cannot be
sufficiently mitigated.14,18

There are an increasing number of sophisticated models
used to measure and track migratory bird populations,
which are the most likely to suffer significant mortality from
wind turbine collisions.2,4,6,7 A great deal of data has been
derived from long-established sites in California, namely the
APWRA, and there is a consensus that replacement of older
turbines with a smaller number of larger modern turbines
(usually as part of ‘repowering’ the installation) is one way
in which mortality can be reduced.7,19 The excessive raptor

Centre for Sustainable Energy www.cse.org.uk

Common concerns about wind power

fatalities recorded at the APWRA have mostly involved the
5,400 turbines (<250kW each) originally installed, the
output of which could be theoretically achieved with a
tenth of that number of modern turbines. Although this is
an attractive idea, it should be remembered that raptor
deaths recorded in similar landscapes in Spain did not
appear to show any correlation with the turbine structure
itself, merely the presence of wind turbines along a
particular topographical bottleneck.4

It seems reasonable to assume that, while global mortality
rates have decreased as wind turbines have grown to
become taller, tubular structures, the impact of any wind
farm can be significantly reduced through careful siting in
response to data gathered on seasonal density in feeding
and nesting areas, and on flight paths.2,7,17 Meticulous
collection of information can aid flexibility when developing
sites for wind energy, using “micro-siting” so as not to
disrupt flight paths.2,20,21

The plight of bats has come to light in the last decade,
unfortunately due to a number of locations in the USA and
mainland Europe that have suffered unexpectedly high
fatality rates.3,11,12 Unlike bird populations, bat migratory
patterns are less well known, and in many cases it is not
clear what causes such excessive mortality in certain
areas.13

Although a great deal of monitoring is being done, there
are possibly several confounding factors that lead to bat
deaths at wind farm sites.11 As well as striking the turbines
blades directly, there is increasing evidence that barotrauma
is brought on by the dramatic changes in air pressure
around the moving blade edges.22 Of some concern is the
finding that the increased height of modern turbines
contributes to fatalities in migratory bat populations.23
There are theories that this effect is caused by the habit of
migrating bats to fly higher than their usual foraging
routine, and that some bats may not use echolocation when
following migration paths.13,23

Co-ordinating the needs of both local and migratory avian
and bat populations presents a challenge to the wind
energy industry, and one that will have to be tackled on a
site-by-site basis. The natural development of the
commercial wind sector that has brought about turbines
with taller, tubular designs that have slower rotating blades
has mitigated avian deaths to some extent, although there
is a risk this may actually increase the threat to vulnerable
bat populations. The steady refinement of data collection
methods, with regard to birds in particular, will help
generate the information needed to correctly plan future
sites for wind farms.

It is hoped increased research into bat populations will reap
similar rewards. Positive developments, such as the finding
that ‘feathering’ turbines to increase their start up wind
speed can reduce both bird and bat fatalities, illustrates
how the wind energy industry can respond (happily, the
adjustment results in a minimal loss of power equal to less
than 1% across a year).2,24 It can certainly be stated that,
for every unit of electricity generated, wind has a
considerably lower avian fatality rate than fossil fuels, and
this will only improve as planners and regulatory bodies
learn from the mistakes first made in the 1980s.

www.cse.org.uk Centre for Sustainable Energy

Common concerns about wind power

1
Erickson, W.P., G.D. Johnson & D.P. Young. 2005. A summary and comparison of bird mortality from anthropogenic causes with an emphasis on collision.
USDA Forest ServiceGen. Tech. Rep. PSWGTR-191: 1029–1042. www.fs.fed.us/psw/publications/documents/psw_gtr191/Asilomar/pdfs/1029-1... (last
accessed 12 Nov 2010)

2
Drewitt, A. & Langston, R. 2008. Collision effects of wind-power generators and other obstacles on birds. Ann NY Acad Sci; 1134: 233–66.

3
Wind Power: Impacts on Wildlife and Government Responsibilities for Regulating Development and Protecting Wildlife. Washington D.C.: United States
Government Accountability Office; 2005 September. Report to Congressional Requesters GAO-05-906. www.gao.gov/cgi-bin/getrpt?GAO-05-906 (accessed

25 Jan 2011)

4
Barrios, L., Rodríguez, A. 2004. Behavioural and environmental correlates of soaring-bird mortality at on-shore wind turbines. J Appl Ecology; 41: 72–81.

5
“Wind power installed capacity in Spain increased by 1,516 MW in 2010, the lowest in seven years” [Internet]. Madrid: Spanish Wind Energy Association

(AEE); c.2011 [cited 26Jan 2011]. Available at www.aeeolica.es/en/ [English]

6
Johnson, G., Erickson, W., Strickland, M.D., Shepherd, M., Shepherd, D., Sarappo, S. 2002. Collision mortality of local and migrant birds at a large-scale
wind-power developmenton Buffalo Ridge, Minnesota. Wildlife Bulletin; 30: 879–87.

7
Erickson, W., Johnson, G., Young, D., et al. Synthesis and comparison of baseline avian and bat use, raptor nesting and mortality information from proposed
and existing winddevelopments. Cheyenne (WY): WEST, Inc. December 2002. Sponsored by Bonneville Power Administration, Portland (OR).
www.bpa.gov/Power/pgc/wind/Avian_and_Bat_Study_12-2002.pdf (last accessed 12 Nov 2010).

8
Johnson, G., Perlik, M., Erickson, W., Strickland, M.D. 2004. Bat activity, composition,and collision mortality at a large wind plant in Minnesota. Wildlife
Bulletin; 32: 1278–88.

9
Nicholson, C., Tankersley, R., Fiedler, J., Nicholas, N. Assessment and prediction of bird and bat mortality at wind energy facilities in the Southeastern United
States. Knoxville:Tennessee Valley Authority; 2005. Final report. www.tva.gov/environment/bmw_report/bird_bat_mortality.pdf (accessed 26 Jan 2011)

10 Kerns, J., Kerlinger, P. (Curry & Kerlinger, LLC). A study of bird and bat collision fatalities at the Mountaineer Wind Energy Center, Tucker County, West
Virginia: Annual Report for 2003. Cape May Point, NJ: Curry & Kerlinger, LLC; 2004 February 14. Report prepared for FPL Energy and Mountaineer Wind
Energy Center Technical Review Committee. www.wvhighlands.org/Birds/MountaineerFinalAvianRpt-%203-15-04PKJK.pdf (accessed 26 Jan 2011)

11 Arnett, E.B. (technical editor). Relationships between bats and wind turbines in Pennsylvania and West Virginia: an assessment of bat fatality search protocols,
patterns of fatality,and behavioral interactions with wind turbines. Austin: Bat Conservation International; 2005 June. A final report submitted to the Bats and
Wind Energy Cooperative.

12 Jones, G., Cooper-Bohannon, R., Barlow, K., Parsons, K. Scoping and method development report – Determining the potential ecological impact of wind
turbines on batpopulations in Britain. Report by University of Bristol and Bat Conservation Trust commissioned by Defra; 2009 May. Phase 1 Final Report.
www.bats.org.uk/data/files/determining_the_impact_of_wind_turbines_on_br... (accessed 26 Jan 2010)

13 Kunz, T., Arnett, E., Erickson, W., Hoar, A., Johnson, G., Larkin, R., Strickland, M.D., Thresher, R., Tuttle, M. 2007. Ecological impacts of wind energy
development on bats:questions, research needs, and hypotheses. Front Ecol Environ; 5: 315–24.

14 Langston, R., Pullan, J. 2003 Windfarms and birds: an analysis of the effects of wind farms on birds, and guidance on environmental assessment criteria and
site selection issues.Report T-PVS/Inf (2003) 12, by BirdLife International to the Council of Europe, Bern Convention on the Conservation of European Wildlife

and Natural Habitats. RSPB/BirdLife in the UK.

15 Bats and onshore wind turbines: Interim guidance. Sheffield: Natural England; 2009 February 11. Technical Information Note TIN051.

16 Klem, D. 1990. Collisions between birds and windows: mortality and prevention. J Field Ornithol; 61:120–28.

17 Sovacool, B.K. 2009. Contextualizing avian mortality: A preliminary appraisal of bird and bat fatalities from wind, fossil-fuel, and nuclear electricity. Energy

Policy; 37: 2241–48.

18 Planning Policy Statement 9: Biodiversity and Geological Conservation. London: TSO; 2005 Aug. Published for the Office of the Deputy Prime Minster.
www.communities.gov.uk/documents/planningandbuilding/pdf/147408.pdf (accessed 25 Jan 2011)

19 Smallwood, K.S, Thelander, C.G. Bird Mortality at the Altamont Pass Wind Resource Area: August 2005 March 1998 — September 2001. Subcontract report
for NREL. Golden,Col.: National Renewable Energy Laboratory; 2005 Aug. Report NREL/SR-500-36973. Subcontract LAT-1-30222-01.
www.nrel.gov/wind/pdfs/36973.pdf (accessed 30 Nov 2010)

20 Bright, J., Langston, R., Bullman, R., Evans, R., Gardner, S., Pearce-Higgens, 2008. Map of bird sensitivities to wind farms in Scotland: a tool to aid planning
and conservation.Biological Conservation; 141: 2342–56.

21 Bright, J., Langston, R., Bullman, R., Evans, R., Gardner, S., Pearce-Higgens, Wilson, E. Bird Sensitivity Map to provide locational guidance for onshore wind
farms in Scotland. Sandy, Beds.: Royal Society for the Protection of Birds; 2006 Jun. RSPB Research Report No 20. Available from

www.rspb.org.uk/news/details.aspx?id=tcm:9-179628 (accessed 25 Jan 2010)

22 Baerwald, E.F., D.Amours, G.H., Klug, B.J., Barclay, R.M.R. 2008. Barotrauma is a significant cause of bat fatalities at wind turbines. Curr Biol; 18: R695–6.

23 Barclay, R.M.R., Baerwald, E.F., Gruver, J.C. 2007. Variation in bat and bird fatalities at wind energy facilities: assessing the effects of rotor size and tower

height. Can J Zool; 85:381–7.

24 Arnett, E., Huso, M., Schirmacher, M., Hayes, J. Altering turbine speed reduces bat mortality at wind-energy facilities [Online proof ahead of press]. Frontier
Ecol Environ; 2010doi:10.1890/100103

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