Design and Access Statement Site: Lyng Farm, NR20 4JE

Design and Access Statement 

Site: Lyng Farm, NR20 4JE 

Agent Details 

Name: 

Windcrop Limited 

Contact: 

Tracey Dorling 

Address: 

The Granary, Honingham Thorpe, Norwich NR9 5BZ 

Telephone: 01603 882152 

Email: 

tracey@windcrop.co.uk 

Reference: Design and access statement 

Date: 26 th January 2012 

Contents 

This supplementary information document contains; 

 

 

 

Summary details on the location and proposed renewable energy system. 

Supporting Planning Statement – National Policy Context. 

Local Validation Requirements – including the following subheadings as laid out in the 

Breckland District Council Local Validation Requirements: 

Biodiversity Survey and Report 

Economic Statement 

Environmental impact statement 

Flood risk, Foul Sewage, Utilities and surface water drainage Assessment 

Heritage statement 

Land Contamination Statement 

Landscaping Details 

Lighting Assessment 

Noise impact assessment 

Transport Assessment/Travel Plan 

Schematic views and photos of the turbine – Appendix A. 

Noise report – Appendix B. 

Site photographs – Appendix C. 

Photo visualisation – Appendix D. 

If planning officers would like to visit a similar installed turbine locally to take readings on 

sound levels or to gain a good firsthand appreciation of the scale of the turbine, it would be 

possible to arrange this. 

Page | 1



Project Overview 

The project will provide Lyng Farm with a suitable method of generating a renewable, 

sustainable and efficient electrical energy supply using a single Evance R9000 x 5.5 small wind 

turbine. The turbine to be installed is economically viable, robust and quiet by design and 

extremely efficient. The turbine will be mounted on a 15m tower and will be grid connected to 

a Single Phase supply. 

Site Description 

Installation location: 

Lyng Farm 

Whissonett Road 

Stanfield 

Norfolk 

NR20 4JE 

OS grid reference: Turbine 1, X – 593333, Y – 321222 

Estimated Annual Mean Wind Speed: 

Expected annual energy: 

Expected annual carbon saving: 

5.6 m/s 

11.66 MWh 

6.26 tonnes 

Nearest neighbour: 

163m approximately from proposed location – ‘Lyng 

Bungalow’ 

Nearest public road: 275m approximately from proposed location – 

Whissonett Road 

Description: 

The turbine will be located in a rough grassed field to 

the north east of the farm yard. 

The development comprises a single small scale wind turbine. The proposed sites have been 

chosen to minimise any visual impact and/or noise disturbance. Crime prevention measures do 

not appear to be relevant to this development. 

The height of the tower has been selected to ensure that it is the required height to capture 

the wind energy on this site whilst keeping any impact to a minimum. The turbine has been 

designed for low noise operation and minimal visual impact. 

The tower is a pale grey colour, the turbine housing and blades are Dark Squirrel Grey 

(RAL7000). These characteristics will help it blend in with both the sky and the rural 

background at the location. 

Wind energy is an abundant natural resource. It is non-polluting, clean and sustainable. The UK 

has one of Europe‘s windiest climates and wind energy will be an important element in 

achieving the targets contained in the government’s UK Low Carbon Transition Plan published 

in Summer 2009. The overall target is to reduce carbon dioxide emissions to 34% below 1990 

levels by 2020. More specifically, it is Government policy to achieve 30% of the nation’s 

electricity requirements from renewable sources by 2020. 

Page | 2



The Evance R9000 wind turbine is Micro generation Certification Scheme (MCS) approved. The 

turbine is CE marked and approved for sale in the UK. 

System Specification 

Wind turbine: 

Rated power: 

Hub height (ground to 

centre of hub): 

Rotor diameter: 

Tower type: 

Turbine finish: 

Blade finish: 

Tower finish: 

Rotor speed: 

Tip speed: 

Rotor orientation: 

Evance R9000 

5kW @ 12m/s (26.0mph), continuous to 60m/s (134mph) 

14.97 m 

5.5 m 

Rotor swept area: 23.75 m 2 

Number of blades: 3 

Power regulation: 

Electrical connection: 

14.97 m, to centre of hub, steel on patented tripod & helical pile 

foundation 

Glass Fibre Reinforced Composite, low reflection, UV and antierosion 

coating in RAL7000 Dark Squirrel Grey 

Glass Fibre Reinforced Composite, low reflection, UV and antierosion 

coating in RAL7000 Dark Squirrel Grey 

Matt grey galvanised to BSEN1461 

200 rpm nominal – maximum 230 rpm 

57 m/sec nominal – maximum 65 m/sec 

Upwind, self-regulating 

G83 compliant inverter 

Single phase 

Page | 3



Supporting Planning Statement – National Policy considerations. 

Wind energy is an abundant natural resource. It is non-polluting, clean and sustainable. The UK 

has one of Europe‘s windiest climates and wind energy is expected to be an important element 

in achieving the targets contained in the government’s UK Low Carbon Transition Plan 

published in Summer 2009. The overall target is to reduce carbon dioxide emissions to 34% 

below 1990 levels by 2020. In 2008 the UK agreed to achieve 15% of our national energy 

consumption from renewable energy by 2020, from a starting point of just 1.3% in 2005. More 

specifically, it is Government policy to achieve 30% of the nation’s electricity requirements 

from renewable sources by 2020. The Committee on Climate Change were asked by the new 

Coalition Government to review these targets and concluded in September 2010 that they 

should remain at their previously agreed levels. 

Planning Policy Statement 22 (PPS22), Renewable Energy (August 2004) and the accompanying 

Companion Guide, cover all aspects of renewable energy including considerations for the siting 

of wind turbines and encourages favourable views towards small scale renewable power 

sources. The PPS, Companion Guide and Technical Annex identify a number of specific issues 

that need to be considered when determining an application for planning permission: 

 

 

 

 

Noise: paragraph 41 of the Technical Annex states that noise levels from wind turbines 

are generally low and, under most operating conditions, it is likely that turbine noise 

would be completely masked by wind-generated background noise. The report, ‘The 

Assessment and rating of noise from Wind Farms (ETSU-R-97), describes a framework 

for the measurement of wind farm noise and gives indicative noise levels calculated to 

offer a reasonable degree of protection to windfarm neighbours, without placing 

unreasonable restrictions on wind farm development or adding unduly to the costs 

and administrative burdens on wind farm developers or planning authorities. The 

report can be regarded as relevant guidance on good practice. This methodology 

overcomes some of the disadvantages of BS1412 when assessing the noise effects of 

windfarms, and should be used by planning authorities when assessing and rating 

noise from wind energy developments (PSS22, paragraph 22). 

Visual and Landscape Impact: Of all renewable technologies, wind turbines are likely 

to have the greatest visual and landscape effects. However, the impact of turbines on 

the landscape will vary according to the size and number of turbines and the type of 

landscape involved, and these impacts may be temporary if conditions are attached to 

planning permissions which require the future decommissioning of turbines. 

Safety: the Technical Annex identifies little or no risk arising to the public and states 

that properly designed and maintained generators are a safe technology. 

Ecology: PPS22 (paragraph 15) states that local nature conservation designations 

should not be used in themselves to refuse planning permissions for renewable energy 

developments. The Technical Annex states that the impact of a wind farm on local 

ecology should be minimal. A common concern has been the risk of bird strike; more 

recently, an additional concern around the risk of harm to bats has emerged. 

Electro-magnetic Production and Interference: the Technical Annex (paragraph 64) 

states that provided careful attention is paid to siting, wind turbines should not cause 

any significant problems of electrical interference. Scattering of signal is a 

phenomenon that arises very occasionally and effects on radio or television 

Page | 4



transmitters can usually be resolved through careful siting, in consultation with the 

relevant bodies. 

 

 

 

Specialist Consultation: It may be necessary to consult specialist bodies, including 

users of telecommunications systems, local utility companies, or emergency services 

on occasions. 

Shadow Flicker: PPS22. Shadow flicker is a rare event which sometimes can occur 

when the shadow of the turbines blades play on nearby buildings at certain times of 

day and days of the year. It most commonly would affect nearby buildings to the East 

or West of the turbine at dusk and dawn. However this is not a problem normally 

found with small wind turbines and the siting of this installation eliminates any risk of 

shadow flicker on neighbouring buildings. Planning for Renewable Energy A 

Companion Guide to PPS22 advises that turbines should be positioned at least 10x the 

diameter of the rotor blades away from the nearest dwelling to prevent the possibility 

of shadow flicker. 

Icing: The Companion Guide states that the build-up of ice on turbine blades is unlikely 

to be a problem. For ice to build up on wind turbines particular weather conditions 

are required that in England occur for less than one day per year 

Page | 5



Siting and scale 

It has been normal practice to site utility scale wind turbines on elevated and exposed ground 

in order to achieve the highest possible energy capture and optimise the economics of the 

project. This has led to considerable opposition to wind power projects wherever they have 

been proposed. It is important to appreciate that the proposed turbine is of a completely 

different scale to the now familiar utility scale giants, which may have tower heights of 100m 

and rotor diameters of 80m or more. 

By way of comparison, the proposed installation sits on a 15 metre mast with a rotor diameter 

of 5.5 metres and is closer in scale to a typical telegraph or power transmission pole, which 

forms a familiar aspect of our rural landscape. The diagram below demonstrates this contrast. 

120m 

110m 

100m 

90m 

80m 

70m 

60m 

50m 

40m 

30m 

20m 

10m 

Typical Wind Farm Turbine 

compared with proposed 5kW turbine 

Rotor Dia (m) 82 5.4 

Hub Height (m) 78 15 

Power(kW): 1,650 5 

Output(MWh/yr)4,300 7.4 

CO2(t/yr) 1,900 4.0 

Eq households 970 1.7 

Views on Small Wind Turbines 

 

The Royal Society for the Protection of Birds (RSPB): 

The RSPB has in the past been a strong opponent of many large wind farms, however they 

have recently expressed their support for renewable energy, including wind farms and locally 

generated energy. 

“We particularly support solutions that enable individuals and communities to generate their 

own power close their homes and businesses. 

Page | 6



Wind power is the most advanced renewable technology available at a large scale during this 

time period. For this reason, the RSPB supports a significant growth in offshore and onshore 

wind power generation in the UK. 

We believe that this growth can be achieved in harmony with, rather than at the expense of, 

the natural environment. We will therefore continue to require that wind farms are sited, 

designed and managed so that there are no significant adverse impacts on important bird 

populations or their habitats.” 

http://www.rspb.org.uk/ourwork/policy/windfarms/index.asp 

 

The National Trust: 

"We are committed to investing in small-scale renewables, greater energy efficiency, and using 

low carbon materials and products to reduce our use of fossil fuels." 

“From our practical experience, we believe that small-scale renewable energy has huge 

potential to be a cost effective and sustainable means of providing affordable heat and 

electricity to homes and businesses.” 

http://209.85.229.132/u/nationaltrust?q=cache:CDXpfDxCiYwJ:www.nationaltrust.org.uk/mai 

n/w-microgen-policy_from_practice.pdf+microgen&cd=1&hl=en&ct=clnk&ie=UTF-8 

 

English Nature: 

English Nature’s response to renewable energy: "We welcome the government’s commitment 

towards greater energy efficiency, as reducing energy consumption is environmentally benign 

and will help make the target achievable. We welcome the scaling up of wind energy both 

onshore and offshore, and want to work with government and industry to find the right places 

for new wind energy development. 

We recognise that biomass driven heat and electricity generation could have a positive impact 

on the management, and replanting, of England’s woodlands and provide an effective market 

for agricultural and wood waste. It will also provide farmers with a valuable market for 

biomass materials. 

We believe that the target will need to be delivered at all scales. Small scale community energy 

production has an important role to play in making rapid progress toward the UK renewables 

target while larger scale projects, with a much longer lead-in time, are developed." 

http://www.naturalengland.org.uk/about_us/news/2008/260608.aspx 

Page | 7



Local Validation Requirements 

In preparing this section of the documentation, the Breckland District Council Local Validation 

Requirements have been reviewed and information is provided in all relevant categories. 

Economic Statement: 

The wind turbine is expected to generate an average of 11.66 MWh of electricity each year, 

equivalent to a saving of 6.26 tonnes of carbon dioxide. This yield data has been calculated 

from the Small Wind Turbine Yield Calculator, jointly developed by the Carbon Trust and 

Renewable UK (formerly BWEA) and which is widely recognised as the most accurate yield 

forecast tool available. In particular it has addressed many of the issues of overoptimistic yield 

forecasts from earlier tools which did not take account of local geographic conditions. 

This installed capacity will also help to contribute towards regional targets for renewable 

energy generation included in the UK Low Carbon Transition Plan. 

Biodiversity: 

A site check has been made using the Multi Agency Geographic Information for the 

Countryside Interactive Map (MAGIC), managed by Natural England on behalf of DEFRA. The 

site is not situated in a protected habitat area, nor is it located close to one. 

In addition, the proposed site has been assessed in accordance with guidelines for the siting of 

small wind turbines, prepared by an established independent ecological consultant, so as to 

minimise risks to protected species. The site assessment considers features which may be 

used by bats or birds, and takes account of the available guidance in relation to the siting of 

small wind turbines. These features comprise trees, hedgerows, ponds and waterways, 

including permanently wet ditches. A micro turbine on or close to any hedgerow or linear 

feature may increase the likelihood of an effect on bat populations. The relationship to 

connective habitat is also taken into consideration, as many species of bats follow linear 

features when travelling between foraging sites and a roost. Isolated or fragmented habitat 

features are less likely to be used by bats as they provide little cover or foraging potential. 

Bats roost in a wide range of buildings and all buildings except those constructed from nontraditional, 

modern or pre-fabricated materials, are considered as potential bat roosts. Large 

mature trees (girth greater than 300cm) are also potentially suitable as roost sites. 

Particular attention has been paid to ensuring that the site is an appropriate distance from 

potential bat habitats and roost sites. There are no known bat roosts or buildings that could 

potentially become bat roosts within 50 metres of the site, and the closest potential foraging 

feature is located over 25m from the turbine. No trees, hedgerows or scrub will be affected by 

the installation and the turbine is not expected to disturb any ground dwelling fauna. Hence 

the risk of harm to protected species is considered minimal. 

Landscape and visual impact: 

The site is not situated in an Area of Outstanding Natural Beauty. Care has been taken to 

minimise the landscape and visual impact, and views from adjacent receptors have been 

considered. Images of the site and surrounding area are provided at Appendix C and a 

visualisation of the turbine viewed from approximately 100 m is provided at Appendix D. No 

significant landscape or visual issues have been identified. 

Page | 8



Heritage Statement: 

A site check has been made using the MAGIC interactive map to identify any relevant 

archaeological sites, scheduled ancient monuments, conservation areas and historic parks and 

gardens, a copy of which is enclosed. The proposed location is not in the vicinity of any known 

conservation areas. 

Three Ancient Woodlands (AW) have been identified as follows; 

Normans Wood (AW) is located approximately 826 metres to the north west of the proposed 

development with various fields, hedging, trees, existing buildings and Whissonett Road in the 

intervening area between the two locations. 

Sandholes Wood (AW) is situated approximately 1.93Km to the west of the site with various 

fields, hedging, trees, existing buildings, Whissonett Road and Tittleshall Road in the 

intervening area between the two locations. 

Hurdle Wood (AW) is located approximately 1.01Km to the west northwest of the site with 

various fields, hedging, trees, existing buildings and Whissonett Road in the intervening area 

between the two locations. 

The intervening landscape of various field types and other features together with the small 

scale of the development will have no impact on the woodlands. 

A listed building search has been conducted using the online search engine maintained by 

English Heritage, with the following results; 

Page | 9



The search identified one listed buildings within a 1Km radius of the proposed installation. 

The Church of St Margaret (LB) is situated approximately 778 metres to the south west of the 

proposed development with various fields, hedging, tall trees and Church Lane in the 

intervening area between the two locations. A brief description of the church is provided 

below; 

TF 92 SW STANFIELD CHURCH LANE. 

3/50 Church of 30.5.60 St. Margaret. G- I 

Parish church. Medieval and later. Flint with ashlar dressings and slate roofs. West tower, 

aisleless nave with south porch and chancel. Early C14 west tower with one pair of diagonal 

buttresses. 2-light cusped Y-traceried west window and 2-light plain Y-traceried bell-openings. 

C14 porch consisting of arched entrance with dying moulding and carved label stops and 

kneeler finials of mutilated kneeling figures. C14 nave doorways. 6 late Perpendicular, flatheaded, 

3-light panel-traceried nave windows with straight hood moulds displaying finely 

carved stops. C13 chancel with 3 remodelled lancets to north, one 3-light C19 east window in 

Decorated style and 2 original lancets with one 2-light Y-traceried window to south. These 

south windows have hood moulds. C14 chancel arch of 2 plain-chamfered orders on polygonal 

responds with bell capitals. Chancel windows with nook shafts and deeply moulded scoinson 

arches. Double piscina with trefoil arches. C17 communion rail with shaped board balusters 

and patterned rails. C15 5-bay chancel screen with tracery and spandrel carvings. 2-deck pulpit 

with an elaborately carved C17 polygonal box, an C18 tester and a later clerk's desk. 19 late 

medieval poppy-head bench ends with animal arm rests. Plain octagonal font with a Jacobean 

cover on turned balusters. Cock's-head hinges to-opening sides and simple scrolls above 

supporting a ball finial. Fragments of medieval glass. 

We conclude that the proposed development does not present a risk to biodiversity. 

Noise Impact Assessment: 

The turbine manufacturer has commissioned an independent noise report as part of the 

accreditation procedures required to enable the equipment to qualify for the Feed-In Tariff 

(FiT) scheme introduced on 1 April 2010. Appendix B details the noise impact assessment. The 

distance to the garden boundary of the nearest neighbour is approximately 161 metres to the 

west northwest of the installation. Various fields, tall trees and hedging are situated between 

the turbine location and the neighbour and lead us to conclude that the neighbouring property 

will not be adversely affected. 

Environmental Impact: 

The helical piles do minimal damage to the ground and any (under)ground dwelling animals, as 

well as being easily retracted on decommissioning of the turbine. The mast is mounted on a 

tripod which is located by three helical piles. These are inserted by rotation and can be 

removed by the same method, leaving no residual structure. Disturbance to ground 

vegetation is minimal and temporary in nature as a helical pile foundation system is used in 

place of traditional concrete foundations. As a result, restoration of the site following decommissioning 

is very low impact and existing flora in the area adjoining the site will be 

retained. 

Page | 10



No ancillary structures or buildings are required to house electrical equipment or controllers, 

which will be mounted to the mast base. The cable to feed the generated power to the nearest 

building will be buried in accordance with BS7671:2008. 

Shadow Flicker: 

The nearest dwelling is approximately 163 metres from the proposed installation, which is 

outside the recommended calculation of 55 metres for the selected turbine. 

Flood Risk Assessment, Foul Sewage and Utilities Assessment, Surface Water Drainage: 

Considering each of these and the nature of the proposal, it is concluded that these are not 

applicable to the project because the turbine will not create or use any extra water. No sewage 

will be generated from the site and surface water drainage will be unaffected. 

Land Contamination Statement: 

The proposed site is a small area of rough grass on the north eastern periphery of the farm 

yard and is not known to be contaminated. The installation will not result in contamination 

and on decommissioning the helical piles will simply be unscrewed leaving no residual 

material. 

Lighting Assessment: 

No external lighting is to be installed on or around the turbine. 

Parking Provision: 

No dedicated parking or other access provision will be required for the turbine. 

Photographs: 

Please see appendix C. 

Transport Assessment/Travel plan: 

The installation process will generate minimal traffic, involving one day on site to insert the 

foundation helical piles and erect the turbine. 

Following installation, access will be required for routine maintenance only. Access will be via 

the existing entrance to the field, which would also provide good access for any emergency 

services in the unlikely event they were required. 

The remaining items which appear on the local list have been considered and determined to 

be not relevant to this application. 

Page | 11



Appendix A - Schematics 

The diagrams below are representative of the system proposed to be installed. 

The 15m tower is supported by a patented tripod system which is located on three helical 

piles, each of 4m depth. This type of foundation system has the advantage of being more 

environmentally sensitive than a large concrete block and easier to remove to reinstate the 

site in future. 

The works will be completed by our own installation team – we are a Microgeneration 

Certified Scheme (MCS) accredited installer and an ISO9001 certified organisation. 

Page | 12



Appendix B - Noise Report: Evance R9000 

Acoustic Impact Assessment of Small Wind System Installation 

In considering the noise generation of small wind systems and the impact of this noise level on 

neighbouring properties, Windcrop has been working with local Environmental Health Officers 

to develop a practicable and clear method of presenting the expected impact. This makes use 

of the ETSU-R-97 assessment approach which takes into account not only the noise levels at 

noise sensitive locations but also sets these against the expected background noise levels for 

the normally experience range of site wind speeds. 

Under the ETSU-R-97 methodology, the site background noise is measured against wind speed 

and this is then compared against the expected noise immission from the wind system(s). To 

undertake this type of testing for a small system is completely uneconomic and as such the 

approach being developed is that tests are being carried out on a range of typical site types to 

generate a reliable empirical generic forecast of background noise for a range of site types. 

Whilst this work is in progress, and to enable safe assessment to be made of the impact of 

small wind systems on noise today, a low level assumed background noise curve has been 

agreed as shown on the attached graph. This is based on data taken on open, treeless sites and 

so represents a lowest expected background noise. It is also based on a base level of 

background noise with no wind of only 28dB. It is therefore expected that any typical rural site 

will have actual background above this level. 

The noise immission from the wind system(s) is then overlaid onto this background noise curve 

to enable an assessment to be made of the wind system noise compared with the background 

noise across the wind speed range. This shows that a worst case at a wind speed of around 

7.5m/s wind speed. A decision is then needed on the relative level of the wind system to 

background. To date the approach has focussed on the nigh time levels at the façade of a 

neighbouring property and set the limit as 3dB above background. A secondary level has also 

been reviewed based on amenity use of a garden taking 5dB above background at the 

boundary of a neighbouring garden. At present only the façade level is being assessed on the 

basis that the typical boundary immission at the worst case of 7.5m/s wind speed is under 

40dB and is considered well inside acceptable daytime amenity levels. 

Page | 13



Wind System Noise Emission 

The Evance R9000 wind system has been tested under certification conditions (reference 

Certificate Number MCS WT0039). The graph below gives the test data which in turn generates 

a Sound power level (dB) - based on LA,90 at 8m/s wind speed of 89.0dB and a noise slope of 

2.095dB per m/s wind speed. 

Immission Level against Background Noise Levels 

Taking the sound power emitted against wind speed and comparing it with typical background 

noise minimum levels for a very low noise, rural site provides a clear indication of the relative 

noise levels. However the background noise data used is taken at 10m height and the Evance 

system used is at 15m height. This means that the effective wind speed at 15m will be higher 

than that used at 10m for the background noise data by an amount equivalent to 

factor of 1.0845. Correcting the data provides a revised table of background noise against wind 

speed at 15m as follows: 

or a 

Page | 14



Having established the acceptability criteria, the actual noise immission for each site can be 

assessed at the worst case wind speed of 7m/s (at 15m). (This analysis actually takes simply 

the distance between the system location and the noise sensitive site which underestimates 

distance by about 4% at 50m and 1% at 100m.) 

This calculation can be carried out for a specific site to give a value for each turbine’s 

contribution and the contributions summed. The calculation for this is as follows: 

Sound Power Emitted at 7m/s: Lw=87 dBA 

SPL at distance R = Lw-10log 10 (2πr 2 ) 

And the contribution for multiple sites summed as follows: 

SPL sum =10log 10 (10 SPL1/10 +10 SPL2/10 ) 

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Taking these calculations for a single installation and multiple installations and comparing the 

immission against the noise limit of 39dB at 7m/s wind speed, it can be shown that the 

minimum distances before further investigation of noise sensitivity for a particular site are as 

follows: 

Single Installation: 70m 

Double Installation: 100m 

Triple Installation: 120m 

Noise Propagation Theory 

The sound energy in the propagation direction of the sound is inversely proportional to the increasing 

surface area the sound propagates through and can be expressed as: 

L p = L w + 10 log[(Q/4π)(1/r 1 2 + 1/r 2 2 + ...+1/r n 2 ) + 4/R] (1) 

or modified for a single source: 

L p = L w + 10 log(Q/(4π r 2 ) + 4/R) (1b) 

where 

L p = sound pressure level (dB) 

L w = sound power level source in decibel (dB) 

Q = directivity coefficient (1 uniform spherical, 2 uniform half spherical (single reflecting surface), 4 

uniform radiation over 1/4 sphere (two reflecting surfaces, corner) 

r = distance from source (m) 

R = room constant (m 2 ) 

Single Sound Source - Spherical Propagation 

With uniform spherical radiation (1) can be modified to express the sound pressure level from a 

single sound source as: 

L p = L w + 10 log(1/(4π r 2 ) 

= L w - 10 log( 4 π r 2 ) (2) 

since 

Q = 1 

R ≈ ∞ 

(2) can also be expressed as: 

Page | 16



L p = L w - 20 log( r) + K' 

(2b) 

where 

K' = -11 (single sound source and spherical radiation) 

Recommended Good Practice on Controlling Noise from Wind Turbines 

From ‘The Assessment and Rating of Noise from Wind Farms’ (ETSU-R-97). 

The current practice on controlling wind farm noise by the application of noise limits at the 

nearest noise-sensitive properties is the most appropriate approach. 

Noise limits should be applied to external locations and should apply only to those areas 

frequently used for relaxation or activities for which a quiet environment is highly desirable. 

Noise limits set relative to the background noise are more appropriate in the majority of cases. 

Generally, the noise limits should be set relative to the existing background noise at the 

nearest noise-sensitive properties and the limits should reflect the variation in both turbine 

source noise and background noise with wind speed. 

It is not necessary to use a margin above background noise levels in particularly quiet areas. 

This would unduly restrict developments that are recognised as having wider national and 

global benefits. Such low limits are, in any event, not necessary in order to offer a reasonable 

degree of protection to wind farm neighbours. 

Separate noise limits should apply for day-time and for night-time as during the night the 

protection of external amenity becomes less important and the emphasis should be on 

preventing sleep disturbance. 

Absolute noise limits and margins above background should relate to the cumulative effect of 

all wind turbines in the area contributing to the noise received at the properties in question. 

Any existing turbines should not be considered as part of the prevailing background noise. 

Noise from the wind farm should be limited to 5 dB(A) above background for both day- and 

night-time, remembering that the background level of each period may be different. 

The L A90,10min descriptor should be used for both the background noise and the wind farm noise, 

and when setting limits it should be borne in mind that the L A90,10min of the wind farm is likely to 

be about 1.5-2.5 dB(A) less than the L Aeq measured over the same period. The use of the 

L A90,10min descriptor for wind farm noise allows reliable measurements to be made without 

corruption from relatively loud, transitory noise events from other sources. 

A fixed limit of 43 dB(A) is recommended for night-time. This is based on a sleep disturbance 

criteria of 35 dB(A) with an allowance of 10 dB(A) for attenuation through an open window 

(free field to internal) and 2 dB(A) subtracted to account for the use of L A90,10min rather than 

L Aeq,10min . 

Page | 17



Both day- and night-time lower fixed limits can be increased to 45 dB(A) to increase the 

permissible margin above background where the occupier of the property has some financial 

interest in the wind farm. 

In low noise environments the day-time level of the L A90,10min of the wind farm noise should be 

limited to an absolute level within the range of 35-40 dB(A). The actual value chosen within 

this range should depend upon: the number of dwellings in the neighbourhood of the wind 

farm, the effect of noise limits on the number of kWh generated, and the duration of the level 

of exposure. 

For single turbines or wind farms with very large separation distances between the turbines 

and the nearest properties, a simplified noise condition may be suitable. If the noise is limited 

to a L A90,10min of 35 dB(A) up to wind speeds of 10 m/s at 10 m height, then this condition alone 

would offer sufficient protection of amenity, and background noise surveys would be 

unnecessary. 

Assessment under BWEA Standard 

As a comparison, the standard BWEA assessment method is given below for the Evance R9000 

Wind System. 

This approach is currently being revised to bring it into line with the now more accepted ETSU- 

R-97 approach used in the main body of this assessment. 

Acoustic Performance Estimate for typical 4.7m/s site 

Calculation 

Result 

Windspeed at 10 metre altitude mean 

speed from NOABL database 

4.7 

Using Rayleigh wind distribution to 

calculate the 90% windspeed at 10 

metres height. 

=1.72* 

= 8.08 

Using wind correction factor from 10m 

height using a power law (in accordance 

with IEC 61400-2) to estimate wind at 

installation rotor centre height, H 

(H=15m) 

= * = 8.76 

Turbine distance Noise Immission Point 



Page | 19



Appendix C - Site photographs 

View north from turbine. 

View east from turbine. 

Page | 20



View south from turbine. 

View west from turbine. 

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Panoramic view north east south from turbine. 

Panoramic view south west north from turbine. 

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Appendix D – Visualisation 

Viewpoint 

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Design and Access Statement Site: Lyng Farm, NR20 4JE

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