Wind Turbine Noise Assessment Ridgecombe Farm Lifton Devon PL16 0HD

Transcription

1 Wind Turbine Ridgecombe Farm Lifton Devon PL16 0HD Ref: 5285/P41/pja Revision: grid ref location E N EWT DirectWind kw on a 40m mast Date; Prepared by; Mr Peter Ashford BSc MIOA Acoustic Associates South West Ltd Bampfylde House Poltimore Exeter EX4 0AF Signed Viewed by; Mr John Hammond TechIOA Signed Client: Aardvark EM Ltd Higher Ford, Wiveliscombe, Somerset TA4 2RL

2 CONTENTS Contents 1.0 Executive Summary Noise Impact from Wind Farm Developments Noise Planning Guidance Site Location Noise Predictions Cumulative Impacts Noise Impact Assessment Planning conditions Appendix 1 References Appendix 2 Noise Calculations Application Turbine Appendix 3 Noise Calculations Cumulative Level at Lowley only Appendix 4 EWT54 sound data Appendix 5 EWT Warrantee Details Page 2 of 34

3 1.0 Executive Summary 1.1 It is proposed to erect a single 500 kw wind turbine on a 40m mast on farm land at Ridgecombe Farm, Lifton, Devon PL16 0HD (West Devon Borough Council planning reference No /2014). 1.2 The nearest non-finically involved residential dwellings are Lowley Farm & Crosstown at approximately 435m & 442m to the south and east respectively. Ridgecombe Farm House, which is deemed to be financially involved, is 520m to the north west of the turbine. 1.3 The Standard by which noise from wind turbines should be assessed is ETSU-R-97 (The assessment & rating of noise from wind farms published by DTI) and this has been confirmed in a number of wind farm appeal decisions, including recently at Batsworthy Cross (App/X1118/A/11/ ). 1.4 ETSU-R-97 recommends two levels of assessment. Where there are single turbines with no near neighbours and a predicted maximum noise level of 35 db L A90 10 minute or less no monitoring is required of background noise. 1.5 Turbine noise levels have been calculated using the latest manufacturer s noise data and in accordance with the ETSU-R-97, ISO9613 part 2 as well as the latest best practice guide published by the Institute of Acoustics on 20 th May The calculated maximum noise level at the nearest portion of garden of Lowley is 35 db L A90,10minute within the ETSU criteria for single turbines. 1.7 The next closest existing turbine is some 3 km to the north west at Lifton Farm Shop where there is a single 500 kw turbine. There are no other screening requests or planning applications for turbines in the vicinity of the application site. This turbine is sufficiently far away to make no impact on the predicted turbine noise levels at the neighbours with level remaining 35 db L A90,10minute or lower. 1.8 This report sets out all the technical noise data for the proposed wind turbine, its location and the noise levels predicted at each of the neighbours, demonstrating that noise from the proposed turbine and from the neighbouring wind farm is below ETSU absolute criterion of 35 db for non-financially involved properties and recommends that a planning condition should be applied to control noise from this application turbine to no more than 35 db L A90,10minute at the nearest non-financially involved dwelling. Page 3 of 34

4 2.0 Noise Impact from Wind Farm Developments 2.1 Noise Sources Noise is generated by wind turbines as they rotate to generate power. This only occurs above the cut-in wind speed and below the cut-out wind speed. Below the cut-in wind speed there is insufficient strength in the wind to generate efficiently and above the cutout wind speed the turbine is automatically shut down to prevent any malfunctions from occurring. The cut-in wind speed at turbine hub height is normally between 3 and 5 metres per second (m/s) and the cut out wind speed is normally around 25 m/s The principal sources of noise are from the blades rotating in the air (aerodynamic noise) and from internal machinery and to a lesser extent, the generator (mechanical noise). The blades are carefully designed to minimize noise whilst optimising power transfer from the wind. The tower also has an isolation system to prevent vibration from the blades, rotor and generator passing down the tower and into the ground. 2.2 Noise in the Environment Although the source noise levels are fairly low and of a benign nature, wind turbines are generally situated in rural environments where there are few other sources of noise. When wind speeds are high this is not a problem since any noise is masked by wind induced noise effects, particularly that of the trees being blown. At lower wind speeds, however, or in particularly sheltered locations, the wind induced background noise may not be sufficient to mask any noise from the turbines. However, under these conditions, the generated noise levels may be so low as to generate very little impact Noise levels are normally expressed in decibels. Noise in the environment is measured using the db(a) scale which includes a correction for the response of the human ear to noises with different frequency content. A 1dB change in noise level is just perceptible, a 3dB change in noise level is clearly perceptible and a 10dB change in noise level is heard as a doubling or halving of the perceived level. Table 1 shows noise from wind turbines in the general context of noise in the environment. Table 1 - Examples of Indicative Noise Levels Sound Level 0dB (A) Threshold of hearing 20 to 30 db (A) Quiet bedroom at night 30 to 40 db (A) Living room during the day 40 to 50 db (A) Typical office 50 to 60dB (A) Inside a car 60 to 70 db (A) Typical high street 70 to 90 db (A) Inside a factory 100 to 110 db (A) Burglar alarm at 1m away 110 db (A) to 130 db (A) Jet aircraft on take off 140 db (A) Threshold of pain Page 4 of 34

5 3.0 Noise Planning Guidance 3.1 National Planning Policy Framework The Department for Communities and Local Government published in March 2012 The National Planning Policy Framework (NPPF) and revokes the previous noise planning policy document PPG24, Planning and Noise, and the previous renewable energy planning policy document PPS22, Renewable Energy. The section on noise states that planning policies and decisions should aim to: - avoid noise from giving rise to significant adverse impacts on health and quality of life as a result of new development; - mitigate and reduce to a minimum other adverse impacts on health and quality of life arising from noise from new development, including through the use of conditions; - recognise that development will often create some noise and existing businesses wanting to develop in continuance of their business should not have unreasonable restrictions put on them because of changes in nearby land uses since they were established; - identify and protect areas of tranquillity which have remained relatively undisturbed by noise and are prized for their recreation and amenity The NPPF makes reference to the Noise Policy Statement for England (NPSE) and sets out the concepts of significant adverse impacts and other adverse impacts. It states that 'planning policies should sustain compliance with and contribute towards EU limit values or national objectives for pollutants' Paragraph 97 of the NPPF states that, 'in assessing the likely impacts of potential wind energy development when identifying suitable areas, and in determining planning applications for such development, planning authorities should follow the approach set out in the National Policy Statement for Renewable Energy Infrastructure (read with the relevant sections of the Overarching National Policy Statement for Energy Infrastructure, including that on aviation impacts) '. 3.2 Noise Policy Statement for England The Noise Policy Statement for England (NPSE) was published by the Department for Environment Food and Rural Affairs in March 2010 and sets out a Noise Policy Vision and Noise Policy Aims The Noise Policy Vision is to: 'promote good health and a good quality of life through the effective management of noise within the context of Government policy on sustainable development'. Page 5 of 34

6 3.2.3 The Noise Policy Aims are: - 'Through the effective management and control of environmental, neighbour and neighbourhood noise within the context of Government policy on sustainable development: - avoid significant adverse impacts on health and quality of life; - mitigate and minimise adverse impacts on health and quality of life; and - where possible, contribute to the improvement of health and quality of life' Three further concepts are then introduced comprising; - No Observed Effect Level (NOEL), - Lowest Observed Adverse Effect Level (LOAEL) - Significant Observed Adverse Effect Level (SOAEL) It is stated that 'it is not possible to have a single objective noise-based measure that defines SOAEL that is likely to be applicable to all sources of noise in all situations' and that 'not having specific SOAEL values in the NPSE provides the necessary policy flexibility until further evidence and suitable guidance is available'. 3.3 Overarching National Policy Statement for Energy (EN-l) The Overarching National Policy Statement for Energy (NPS), published by the Department of Energy and Climate Change (DECC) in July 2011, provides guidance on noise along with the relevant technology-specific NPS documents and national policy for energy infrastructure. Although this is aimed at applications which are submitted to the Infrastructure Planning Commission (IPC), it is stated that 'in England and Wales this NPS is likely to be a material consideration in decision making on applications that fall under the Town and Country Planning Act 1990 (as amended)' This contains a generic section on noise and vibration which, in turn refers to the NPSE, and states that: 'operational noise, with respect to human receptors, should be assessed using the principles of the relevant British Standards and other guidance. Further information on assessment of particular noise sources may be contained in the technologyspecific NPSs. In particular, for renewables (EN-3) and electricity networks (EN-5) there is assessment guidance for specific features of those technologies. For the prediction, assessment and management of construction noise, reference should be made to any relevant British Standards and other guidance which also give examples of mitigation strategies'. 3.4 National Policy Statement for Renewable Energy Infrastructure (EN-3) The DECC also published the National Policy Statement for Renewable Energy Infrastructure in July 2011 and together with EN-1, 'provides the primary basis for decisions by the IPC on applications it receives for nationally significant renewable energy Page 6 of 34

7 infrastructure'. Its significance in applications under the Town and Country Planning Act 1990 are as stated for EN In respect of Onshore Wind Farm Impacts, it states at Paragraph that: 'The method of assessing the impact of noise from a wind farm on nearby residents is described in the report, 'The Assessment and Rating of Noise from Wind Farms' (ETSU-R-97). This was produced by the Working Group on Noise from Wind Turbines Final Report, September 1996 and the report recommends noise limits that seek to protect the amenity of wind farm neighbours' The noise levels recommended by ETSU-R-97 are determined by a combination of absolute noise limits and noise limits relative to the existing background noise levels around the site at different wind speeds. Therefore noise limits will often influence the separation of wind turbines from residential properties' A footnote is included which states 'Notwithstanding the date of this report, the Government is satisfied on the balance of subsequent scientific research that it s key conclusions (and in particular the limits it recommends) remain a sound basis for planning decisions' It goes on to state that: The applicant's assessment of noise from the operation of the wind turbines should use ETSU- R-97, taking account of the latest industry good practice. This should include any guidance on best practice that the Government may from time to time publish. 3.5 ETSU-R-97 - The Assessment and Rating of Noise from Wind Farms The ETSU report presents the recommendations of the Working Group on Noise from Wind Turbines (WGNWT), set up in 1993 by the Department of Trade and Industry as a result of difficulties experienced in applying the noise guidelines existing at the time to wind farm noise assessments. The group comprised independent experts on wind turbine noise, wind farm developers, DTI personnel and local authority Environmental Health Officers. The findings of the group are summarised in PAN45 Figure It is recommended that noise limits should be applied to external locations used for relaxation or where a quiet environment is highly desirable. These limits should be set relative to background noise and should reflect the variation in both turbine source noise and background noise with wind speed. It is not, however, necessary to use a margin above background in particularly quiet areas as such low limits are not necessary in order to offer a reasonable degree of protection to wind farm neighbours Where predicted noise levels are low at the nearest residential properties, a simplified noise limit is suggested such that noise is restricted to an L A90 level of 35 db(a) for wind speeds up to 10 m/s at 10m height. This removes the need for extensive background noise measurements for smaller or more remote schemes. This condition is also recommended Page 7 of 34

8 for single turbines or wind farms with very large separation distances between turbines and the nearest sensitive properties It is stated that the L A90,10min noise descriptor should be adopted for both background and wind farm noise levels and that, for the wind farm noise, this is likely to be between 1.5 and 2.5 db less than the L Aeq measured over the same period. The L Aeq,t is the equivalent continuous 'A' weighted sound pressure level occurring over the measurement period t. It is often used as a description of the average noise level. Use of the L A90 descriptor for wind farm noise allows reliable measurements to be made without corruption from relatively loud, transitory noise events from other sources The suggested noise limits take into account the fact that all wind turbines exhibit the character of noise described as blade swish to a certain extent. The WGNWT recommends that a penalty should be added, however, to the predicted noise levels, where any tonal component is present. The level of this penalty is described and is related to the level by which any tonal components exceed audibility The noise limits prescribed in ETSU-R-97 take into account the fact that all wind turbines exhibit the character of noise described as blade swish, to a certain extent. DTI Report W/45/00656/QO/QO. The Measurement of Low Frequency Noise at Three UK Windfarms 4 concluded that "the common cause of complaints associated with noise at all three wind farms is not associated with low frequency noise, but is the audible modulation of the aerodynamic noise, especially at night ". It suggests that "it may be appropriate to re-visit the issue of aerodynamic modulation (AM) and the means by which it should be assessed" As a result, Salford University recently carried out a study, jointly commissioned by Defra, BERR (formerly the DTI) and the CLG, to investigate AM of wind turbine noise. The results were published by way of report NANR233. Research into Aerodynamic Modulation of Wind Turbine Noise 5, which concluded that AM was only considered to be a factor at four, and at a possible further eight, of the 133 sites (all the sites in the UK operational at the time of the study) considered. At these four sites, it was considered that conditions associated with AM might occur between about 7 and 15% of the time. In a statement accompanying the published report, the Government states that it continues to support the approach set out in Planning Policy Statement (PPS) 22 - Renewable Energy. This approach for local planning authorities to ensure that renewable energy developments have been located and designed in such a way to minimise increases in ambient noise levels, through the use of the 1997 report by ETSU to assess and rate noise from wind energy developments The Institute of Acoustic has recently published the Good Practice Guide to the application of ETSU-R-97 for the assessment and rating of wind turbine noise published on 20 th May 2013 [9] in which it recommends; 1). Warranted or specified manufacturer data can be used provided that a margin to account for uncertainty has been included. This is more likely the case for warranted data than for specifications. If not, a correction factor to allow for uncertainty needs to be added to the values provided, and this should clearly be explained in the assessment. The presence of such an uncertainty margin can be established through Page 8 of 34

9 comparison with at least one measurement report. - When comparing warranted/specified data with results of a representative test report, obtained in accordance with the IEC standard, with a reported test uncertainty σ, a margin of σ (between 1 and 2 db(a)) between the tested and stated values over the majority of wind speeds represents a clear indication that suitable uncertainties have been incorporated. - If the document prescribes a value of uncertainty or a correction factor applicable to the data then this can be added to the values stated, unless the above test is already satisfied; - If no data on uncertainty or test reports are available for the turbine then a factor of +2 db should be added. 2). The ground factors G a G m G r assumed. On the evidence available, we consider that ISO calculations using either G = 0 or G = 0.5 (G s = G m = G r ) will lead to appropriate prediction of noise emission levels at typical receptor locations, depending on the input values of other parameters. The use of either (a) G = 0 together with measured (IEC I (test) sound power levels or (b) G = 0.5 (with a 4 metres receptor height) together with vendor's warranted sound power levels (or measured turbine sound power levels plus an allowance for measurement uncertainty), will generally result in realistic estimates of noise emission levels at receptor locations downwind of wind turbines. Noise emission levels calculated using these combinations of parameters can generally be relied on for the purposes of noise assessment. The assumption of 'soft' ground (G = I) should not be made. 4). The effects of barriers. Barrier attenuation calculated using the method within ISO96I3-2 should not be included within predictions. Generally, no account should be taken of barrier attenuation by the landform unless there is no line-of-sight between the receptor and the highest point on the rotor, when a barrier attenuation of 2dB (A) should generally be assumed. A higher barrier attenuation may be appropriate in cases where a landform 'barrier' is very close to the receptor but the assumption of a barrier attenuation greater than 2dB(A) requires to be fully justified in the noise assessment. 5). A further correction of +3 db (or +1.5 db if using G=0.0) should be added to the calculated overall A- weighted noise level for propagation across a valley, i.e. a concave ground profile, or where the ground falls away significantly, between the turbine and the receiver location. The following criterion of application is recommended: H m 1.5 x (abs (h s h r ) /2) Where h m is the mean height above the ground of the direct line of sight from the receiver to the source (as defined in ISO , Figure 3), and h s and h r are the heights above local ground level of the source and receiver respectively. This may be calculated using standard topographic data with a resolution of 50 m or less. Care needs to be exercised when evaluating this condition, as small changes in distance Page 9 of 34

10 and height may trigger (or not) the criterion when the actual situation has not changed significantly. Examination of ground profiles between sources and receivers can assist in determining its application. 4.0 Site Location The site (NGR: , 83929) is situated on land currently in use for agricultural purposes, at Ridgecombe Farm, south of Lifton, West Devon The nearest residential dwelling non-financially involved with the applicant and the proposal lies approximately 450m south of the proposed wind turbine site at Lowley (435m to the closest portion of the garden). The site lies at approximately 177m AOD. The land slopes down to the east and the neighbours are lower in height than the proposed turbine site The turbine will have a 40m mast and give an approximate nacelle height of 217m AOD The table below details the names of the nearest neighbours and their separation distances (from turbine to the closest part of the gardens of each of the properties), all of which are lower in height than the turbine nacelle. Receiver point E N z Separation (m) Distance (m) Ridgecombe Farm Whitley Farm Crosstown Lowley Lake Farm Ashleigh financially invloved properties The map over page shows the location of these neighbours; Page 10 of 34

11 Ridgecombe Whitley Farm proposed turbine Cross Town Ashleigh Lowley Lake Farm 5.0 Noise Predictions Noise predictions were carried out using International Standard ISO 9613, Acoustics Attenuation of Sound During Propagation Outdoors 3. The propagation model described in Part 2 of this standard provides for the prediction of sound pressure levels based on either short-term downwind (ie. worst case) conditions or long term overall averages. We have only considered the former, which is for wind blowing from the proposed site towards the nearby houses. When the wind is blowing in the opposite direction noise levels will be significantly lower, especially if there is any shielding between the site and the houses The ISO propagation model calculates the predicted sound pressure level by taking the source sound power level for each turbine in separate octave bands and subtracting a number of attenuation factors according to the following: Predicted Octave Band Noise Level = L w + D A geo - A atm A gr A bar - A misc These factors are discussed in detail below (Sections 5.1 to 5.7). The predicted octave band levels from the turbine are summed together to give the overall A weighted predicted sound level. Page 11 of 34

12 5.1 L W - Source Sound Power Level The noise levels generated by wind turbines do vary depending on the power rating, blade length and the manufacturer. Noise levels do vary marginally between manufacturers however the following assessment has been carried out based on a candidate turbine the EWT DW54 (500 kw) turbine with a 40m mast. A photograph is shown below; Emergya Wind Technologies BV publish tested sound power data for their EWT54-500kW turbine in their report entitled Sound power levels DW54-500kW reference S docx (dated ) for wind speeds from 5 to 10m/s as well as Sound power warranty levels in their report reference S dated The table below compares these quoted levels; Wind speed at 10m height (m/s) Sound Power level db L Aw Tested L Aw db Tested Uncertainty Level db Overall Tested Level db Overall Tested Level including IoA 1.645σ EWT Warranty L Aw Copies of these documents are included in Appendix 4 & The IoA latest Good Practice Guide suggests care should be taken when considering tested sound power level data and warranted sound power values (levels which the manufacturer will guarantee not to be exceeded). Recommending that a check should be carried out to ensure that the quoted warranted level does include a reasonable level of uncertainty. Page 12 of 34

13 5.1.4 The IoA states in ; when comparing warranted/specified data with results of a representative test report, obtained in accordance with IEC standard, with a reported test uncertainty σ, a margin of σ (between 1 & 2 dba) between the tested and stated values over the majority of wind speeds represent a clear indication that suitable uncertainties have been incorporated. If the document prescribes a value of uncertainty or a correction factor applicable to the data then it can be added to the values stated, unless the above test is already satisfied. If no data on uncertainty or test reports are available for the turbine then a factor of +2dB should be added A 0.7 db uncertainty has been stated in EWT s report and therefore an assessment uncertainty of 1.2 db has been assumed and will be added to calculated turbine noise levels According to ETSU-R-97 a 2.5 db tonal penalty should be added at the receiver for 5 m/s wind speed only. 5.2 D Directivity Factor The directivity factor allows for an adjustment to be made where the sound radiated in the direction of interest is higher than that for which the sound power level is specified. In this case the sound power level is measured in a down wind direction, corresponding to the worst case propagation conditions considered here and needs no further adjustment. 5.3 A geo Geometrical Divergence The geometrical divergence accounts for spherical spreading in the free-field from a point sound source resulting in attenuation depending on distance according to: A geo = 20 x log(d) + 11 where d = distance from the turbine (m) The wind turbine may be considered as a point source beyond distances corresponding to one rotor diameter. 5.4 A atm - Atmospheric Absorption Sound propagation through the atmosphere is attenuated by the conversion of the sound energy into heat. This attenuation is dependent on the temperature and relative humidity of the air through which the sound is travelling and is frequency dependent with increasing attenuation towards higher frequencies. The attenuation depends on distance according to: Page 13 of 34

14 A atm = d x a where d = distance from the turbine (m) a = atmospheric absorption coefficient in db/m We have used published values of a from ISO9613 Part 1 5 corresponding to a temperature of 10ºC and a relative humidity of 70% which give relatively low levels of atmospheric attenuation, and subsequently worst case noise predictions as given over page. 5.5 A gr - Ground Effect Ground effect is the interference of sound reflected by the ground interfering with the sound propagating directly from source to receiver. The prediction of ground effects are inherently complex and depend on the source height, receiver height, propagation height between the source and receiver and the ground conditions. The ground conditions are described according to a variable G which varies between 0 for hard ground (includes paving, water, ice, concrete and any sites with low porosity) and 1 for soft ground (includes ground covered by grass, trees or other vegetation). Our predictions have been carried out using a source height corresponding to the proposed height of the turbine mast, a receiver height of 4m and an assumed ground factor G = 0.5. This ground factor falls half way between fully reflected ground such as lakes or large areas of concrete and fully absorptive ground and represents reasonable approximation of the open agricultural land that lies between the turbine and the neighbours. 5.6 A bar - Barrier Attenuation The effect of any barrier between the noise source and the receiver position is that noise will be reduced according to the relative heights of the source, receiver and barrier and the frequency spectrum of the noise. For the purposes of these calculations it is assumed that there will be a direct line of sight from all the neighbours to the turbine and therefore no screening allowances have been made. 5.7 A misc Miscellaneous Other Effects ISO9613 includes effects of propagation through foliage, industrial plants and housing as additional attenuation effects. These have not been included here and any such effects are unlikely to significantly reduce noise levels below those predicted. 5.8 Valley Correction A further correction of +3 db (or +1.5 db if using G=0.0) should be added to the calculated overall A- weighted noise level for propagation across a valley, i.e. a concave ground profile, or where the ground falls away significantly, between the turbine and the receiver location. The following criterion of application is recommended: h m 1.5 x (abs (h s - h r ) /2) Page 14 of 34

15 Where hm is the mean height above the ground of the direct line of sight from the receiver to the source (as defined in ISO , Figure 3), and hs and hr are the heights above local ground level of the source and receiver respectively Here there is no valley lying between the turbine and the near neighbours and therefore no correction has been applied as shown in the table below; Proposed turbine receiver low point distance intervening height 177m AOD AOD AOD from turbine valley m m m Ridgecombe Farm no Whitley Farm no Crosstown no Lowley no Lake Farm no Ashleigh no 5.9 Predicted Noise Levels Turbine noise levels have been calculated at the closest properties using IMMI noise modelling software. The predicted turbine noise L Aeq has been adjusted subtracting 2 db (A) to give the equivalent L A90 as suggested in the WGNWT report. Table 5.8a below sets out the noise levels at the closest receivers and is shown in detail in Appendix 2; Receiver point E N z Separation Turbine Noise Level (m) Distance Ridgecombe (m) only db LA90 Ridgecombe Farm Whitley Farm Crosstown Lowley Lake Farm Ashleigh Page 15 of 34

16 6.0 Cumulative Impacts There is one existing/proposed turbine within a 3km radius of the application turbine at Lifton Farm Shop as detailed below;; Planning Application No. Turbine type 00063/ x EWT kw on 50m mast Address Lifton Farm Shop, PL16 0DE Grid reference E N Lifton Farm Shop EWT kw proposed EWT 54 turbine The calculated noise impact of the application turbine and the turbines at the nearest sensitive receivers to this application site are shown in the table below and shown in detail in Appendix 3; Receiver point E N z Separation Turbine Noise Level (m) Distance Ridgecombe Cumulative (m) only db LA90 db LA90 Ridgecombe Farm Whitley Farm Crosstown Lowley Lake Farm Ashleigh Page 16 of 34

17 6.0.3 From this table it can be seen that the adjacent turbine has no impact on the noise levels at the near neighbours The calculation for the cumulative impact at Ridgecombe is set out in Appendix Noise Impact Assessment 7.1 Non-financially involved Residential Dwellings For single wind turbines where predicted noise levels are low, at the nearest residential properties, a simplified noise limit is specified in ETSU of 35 db L A The noise predictions show that the maximum turbine noise level at the closest nonfinancially involved neighbour Lowley is 35 db L A90 and therefore within the 35 db L A90 criterion When the cumulative impact of all the existing and proposed turbines is considered the combined noise level at the closest neighbour remains 35 db L A90, 10min. 7.2 Financially Involved Residential Dwellings Ridgecombe is the nearest financially involved dwelling at a distance of 520m from the application turbine for which ETSU provides a higher limit of 45 db L A90. The predicted cumulative noise level here is 33 db L A90 and therefore well inside this limit. 8.0 Planning conditions To protect residential amenity, planning conditions will be required to limit noise. There are likely to be at least two planning conditions required; 1.The wind turbine shall operate at all times (day and night) so as to ensure that the level of noise generated does not exceed an absolute level of 35dB (A)(LA90 (10min) when measured at a distance of 3.5 metres from the facade of any dwelling lawfully existing at the date of this permission save where the occupier of any such dwelling has a financial interest in the operation of the turbine an absolute level of 45dB (A) (LA90 (1Omin)) shall apply. 2. Following notification from the Local Planning Authority (LPA) that a justified noise complaint has been received, the wind turbine operator shall employ a suitably competent and qualified person (at their own expense) to measure and assess, by a method to be approved in writing by the LPA, whether noise from the turbine meets the specified level. The assessment shall be commenced within 21 days of the notification, or such longer time as approved by the LPA. A copy of the assessment report, together with all recorded data and audio files obtained as part of the assessment, shall be provided to the LPA (in electronic form) within 60 days of the notification. The operation of the turbine shall carry out mitigation works if the specified level is confirmed as being exceeded. Page 17 of 34

18 Appendix 1 References [1] National Planning Policy Framework (NPPF) published by The Department for Communities and Local Government, March 2012 [2] ETSU-R-97, The Assessment and Rating of Noise from Wind Farms ETSU for the Department of Trade and Industry, 1996 [3] ISO , Acoustics - Attenuation of Sound During Propagation Outdoors, Part 1: General Method of Calculation International Organization for Standardization, 1996 [4] British Standard IEC :1998 Wind turbine generator systems: Part 11: Acoustic noise measurement techniques [5] ISO , Acoustics - Attenuation of sound during propagation outdoors Part 2: Method of calculation of the attenuation of sound by atmospheric absorption. International Organization for Standardization, 1992 [6] ETSU W/13/00385/REP, A critical appraisal of wind farm noise propagation ETSU for the Department of Trade and Industry, 2000 [7] ETSU W/13/00392/REP Low frequency noise and vibrations measurement at a modern wind farm. ETSU for the Department of Trade and Industry 1997 [8] Community Noise - Document Prepared for the World Health Organization Eds. Bergland B. & Lindvall T. Archives of the Centre for Sensory Research Vol. 2(1) 1995 [9] Good Practice Guide to the application of ETSU-R-97 for the assessment and rating of wind turbine noise published on 20 th May 2013 Page 18 of 34

19 Appendix 2 Noise Calculations Application Turbine Point calculation Receiver point: Ridgecombe Farm X = Y = 2539 Z = 4.00 Variant: Variant 0 Elem. type: Single point source (ISO 9613) Noise prediction following ISO 9613 LfT = Lw + Dc - Adiv - Aatm - Agr - Afol - Ahous - Abar - Cmet Element Label Lw Dc DistanceAdiv Aatm Agr Afol Ahous Abar Cmet LfT LfT / db / db / m / db / db / db / db / db / db / db / db / db(a) EZQi004 EWt Hz Hz Hz Hz Hz Hz Hz Hz Hz Hz Hz Hz Hz Hz Hz Hz Hz Hz Hz Hz Hz Hz Overall level 33.9 Calculated turbine noise level Laeq 33.9 ETSU LA90.10min.Laeq reduction (1.5 to 2.5 dba) 2 used 2.0 Uncertainty at 9m/s 0.7 db x 1.645σ 1.2 "valley" correction 0.0 LA90.10min at nearest dwelling 33.1 Point calculation Receiver point: Whitley Farm X = Y = 2593 Z = 4.00 Variant: Variant 0 Elem. type: Single point source (ISO 9613) Noise prediction following ISO 9613 LfT = Lw + Dc - Adiv - Aatm - Agr - Afol - Ahous - Abar - Cmet Element Label Lw Dc DistanceAdiv Aatm Agr Afol Ahous Abar Cmet LfT LfT / db / db / m / db / db / db / db / db / db / db / db / db(a) EZQi004 EWt Hz Hz Hz Hz Hz Hz Hz Hz Hz Hz Hz Hz Hz Hz Hz Hz Hz Hz Hz Hz Hz Hz Overall level 34.6 Calculated turbine noise level Laeq 34.6 ETSU LA90.10min.Laeq reduction (1.5 to 2.5 dba) 2 used 2.0 Uncertainty at 9m/s 0.7 db x 1.645σ 1.2 "valley" correction 0.0 LA90.10min at nearest dwelling 33.8 Page 19 of 34

20 Point calculation Receiver point: Crosstown X = 4056 Y = 2117 Z = 4.00 Variant: Variant 0 Elem. type: Single point source (ISO 9613) Noise prediction following ISO 9613 LfT = Lw + Dc - Adiv - Aatm - Agr - Afol - Ahous - Abar - Cmet Element Label Lw Dc DistanceAdiv Aatm Agr Afol Ahous Abar Cmet LfT LfT / db / db / m / db / db / db / db / db / db / db / db / db(a) EZQi004 EWt Hz Hz Hz Hz Hz Hz Hz Hz Hz Hz Hz Hz Hz Hz Hz Hz Hz Hz Hz Hz Hz Hz Hz Overall level 35.5 Calculated turbine noise level Laeq 35.5 ETSU LA90.10min.Laeq reduction (1.5 to 2.5 dba) 2 used 2.0 Uncertainty at 9m/s 0.7 db x 1.645σ 1.2 "valley" correction 0.0 LA90.10min at nearest dwelling 34.7 Point calculation Receiver point: Lowley X = 3647 Y = 1739 Z = 4.00 Variant: Variant 0 Elem. type: Single point source (ISO 9613) Noise prediction following ISO 9613 LfT = Lw + Dc - Adiv - Aatm - Agr - Afol - Ahous - Abar - Cmet Element Label Lw Dc DistanceAdiv Aatm Agr Afol Ahous Abar Cmet LfT LfT / db / db / m / db / db / db / db / db / db / db / db / db(a) EZQi004 EWt Hz Hz Hz Hz Hz Hz Hz Hz Hz Hz Hz Hz Hz Hz Hz Hz Hz Hz Hz Hz Hz Hz Hz Overall level 35.7 Calculated turbine noise level Laeq 35.7 ETSU LA90.10min.Laeq reduction (1.5 to 2.5 dba) 2 used 2.0 Uncertainty at 9m/s 0.7 db x 1.645σ 1.2 "valley" correction 0.0 LA90.10min at nearest dwelling 34.9 Page 20 of 34

21 Point calculation Receiver point: Lake Farm X = Y = 1869 Z = 4.00 Variant: Variant 0 Elem. type: Single point source (ISO 9613) Noise prediction following ISO 9613 LfT = Lw + Dc - Adiv - Aatm - Agr - Afol - Ahous - Abar - Cmet Element Label Lw Dc DistanceAdiv Aatm Agr Afol Ahous Abar Cmet LfT LfT / db / db / m / db / db / db / db / db / db / db / db / db(a) EZQi004 EWt Hz Hz Hz Hz Hz Hz Hz Hz Hz Hz Hz Hz Hz Hz Hz Hz Hz Hz Hz Hz Hz Hz Overall level 31.7 Calculated turbine noise level Laeq 31.7 ETSU LA90.10min.Laeq reduction (1.5 to 2.5 dba) 2 used 2.0 Uncertainty at 9m/s 0.7 db x 1.645σ 1.2 "valley" correction 0.0 LA90.10min at nearest dwelling 30.9 Point calculation Receiver point: Ashleigh X = Y = 1821 Z = 4.00 Variant: Variant 0 Elem. type: Single point source (ISO 9613) Noise prediction following ISO 9613 LfT = Lw + Dc - Adiv - Aatm - Agr - Afol - Ahous - Abar - Cmet Element Label Lw Dc DistanceAdiv Aatm Agr Afol Ahous Abar Cmet LfT LfT / db / db / m / db / db / db / db / db / db / db / db / db(a) EZQi004 EWt Hz Hz Hz Hz Hz Hz Hz Hz Hz Hz Hz Hz Hz Hz Hz Hz Hz Hz Hz Hz Hz Overall level 29.4 Calculated turbine noise level Laeq 29.4 ETSU LA90.10min.Laeq reduction (1.5 to 2.5 dba) 2 used 2.0 Uncertainty at 9m/s 0.7 db x 1.645σ 1.2 "valley" correction 0.0 LA90.10min at nearest dwelling 28.6 Page 21 of 34

22 Appendix 3 Noise Calculations Cumulative Level at Lowley only Point calculation Receiver point: Lowley X = Y = 1740 Z = 4.00 Variant: Variant 0 Elem. type: Single point source (ISO 9613) Noise prediction following ISO 9613 LfT = Lw + Dc - Adiv - Aatm - Agr - Afol - Ahous - Abar - Cmet Element Label Lw Dc DistanceAdiv Aatm Agr Afol Ahous Abar Cmet LfT LfT LAT tot / db / db / m / db / db / db / db / db / db / db / db / db(a) / db(a) EZQi004 EWt Hz Hz Hz Hz Hz Hz Hz Hz Hz Hz Hz Hz Hz Hz Hz Hz Hz Hz Hz Hz Hz Hz Hz Overall level 35.7 EZQi005 EWT 54 Lifton Farm S 50 Hz Hz Hz Hz Hz Hz Hz Hz Hz Hz Hz Hz Hz Hz Hz Hz Hz Hz Overall level Calculated turbine noise level Laeq 35.8 ETSU LA90.10min.Laeq reduction (1.5 to 2.5 dba) 2 used 2.0 Uncertainty at 9m/s 0.7 db x 1.645σ 1.2 "valley" correction 0.0 LA90.10min at nearest dwelling 35.0 Page 22 of 34

23 Appendix 4 EWT54 sound data Page 23 of 34

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33 Appendix 5 EWT Warrantee Details Sound Power Level Warranty Contractor warrants for the duration of the Defects Notification Period that the sound power level of the WTG type DW54 will not exceed the levels set out in the following table, measured according to IEC ( Warranted Sound Power Levels ). Wind velocity at 10m height Warranted sound power level DW54 5 m/s 97.0 db(a) 6 m/s 98.0 db(a) 7 m/s 99.0 db(a) 8 m/s 100. db(a) 9 m/s db(a) 10 m/s db(a) Contractor acknowledges and agrees that the Warranted Sound Power Levels makes allowance for measurement uncertainty Contractor warrants for the duration of the Defects Notification Period that the WTG type DW54 does not produce any tone other than at a wind speed of 5 m/s, in which case the WTG may produce a tone resulting in a maximum tonal penalty of 2.5 db, measured and calculated according to ETSU-R-97 guidelines If the Warranted Sound Power Level is not achieved, Contractor shall be liable exclusively as set out in this Article If Employer demonstrates that: (a) the WTG sound level exceeds the Warranted Sound Power Level at 10 m/s; (b) the WTG sound level exceeds any maximum noise level conditions set out in the planning permission for the Works; and (c) there have been complaints with respect to the noise levels of the WTG, Contractor shall be entitled to attempt to rectify the breached Warranted Sound Power Level for an aggregate period not to exceed three (3) calendar months In the event that Contractor at the end of such three (3) calendar month period has not succeeded to achieve the higher of (i) the Warranted Sound Power Level or (ii) the sound power level required to comply with noise level requirements as set out in the planning permission, the Power Curve shall be reduced to meet such (higher) level and Contractor shall pay to Employer liquidated damages calculated as the energy loss that occurred due to the Power Curve reduction to meet the level as applicable. Such liquidated damages are limited to a maximum amount of 5% (five percent) of the Contract Price. Such liquidated damages shall be the sole remedy of Employer with respect to the sound level of the WTG. Page 33 of 34