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NORTH MEATH WIND FARM LTD.

ENVIRONMENTAL IMPACT STATEMENT FOR THE

PROPOSED CASTLETOWNMOOR WIND FARM, COUNTY

MEATH

VOLUME 2 – MAIN EIS

CHAPTER 11 – SHADOW FLICKER

JULY 2016

P0177 i/ii

TABLE OF CONTENTS

PAGE

11 SHADOW FLICKER ........................................................................................... 1

11.1 Introduction .................................................................................................... 1

11.1.1 Study Area .......................................................................................... 1

11.1.2 What is Shadow Flicker? ........................................................................ 1

11.2 Methodology ................................................................................................... 1

11.2.1 Relevant Guidance ................................................................................ 2

11.2.2 Consultation ........................................................................................ 2

11.2.3 Field Assessment .................................................................................. 2

11.2.4 Desk Study .......................................................................................... 2

11.3 Existing Environment ....................................................................................... 3

11.4 Potential Impacts ............................................................................................ 5

11.5 Mitigation Measures ....................................................................................... 12

11.6 Residual Impacts ........................................................................................... 12

11.7 References ................................................................................................... 12

P0177 ii/ii

LIST OF FIGURES

FIGURE 11.1: LOCATION OF BUILDINGS CONSIDERED IN THE SHADOW FLICKER ASSESSMENT ...................... 4

LIST OF TABLES

TABLE 11.1: AVERAGE MONTHLY SUNSHINE HOURS AT DUBLIN AIRPORT (1981 – 2010) ......................... 3

TABLE 11.2: SHADOW FLICKER RESULTS FOR PROPOSED CASTLETOWNMOOR WIND FARM ......................... 5

Chapter 11 – Shadow Flicker North Meath Wind Farm Ltd.

Castletownmoor Wind Farm Environmental Impact Statement

Volume 2 – Main EIS

P0177 Chapter 11 Page 1 of 12

11 SHADOW FLICKER

11.1 Introduction

This chapter has been prepared to examine the potential impact of shadow flicker from the proposed Castletownmoor Wind Farm, County Meath, on local residences. The layout of the proposed development is considered, taking account of mitigation measures to reduce or eliminate any potential impacts caused by

shadow flicker.

11.1.1 Study Area The proposed Castletownmoor wind farm comprises up to 25 no. wind turbines with a tip height of up to 169

m, access tracks, a sub-station, borrow pits and associated works, as well as minor alterations to the public road for the delivery of turbines to the site (turbine delivery route) and the laying of an underground cable from the wind farm site to the existing Gorman sub-station. The layout of the proposed wind farm is as

shown in Figure 2.1.0 which is included in the Figures and Drawings Volume 2a.

11.1.2 What is Shadow Flicker? In times of direct sunshine, and at certain times of the year, wind turbine blades could occasionally cast

moving shadows on residences in close proximity to the turbines. These moving shadows of the turbine blades can periodically reduce light to a room causing the light to appear to flicker. For shadow flicker to occur at a dwelling certain conditions must exist concurrently:

The sun is shining at a low angle i.e. after dawn or before sunset.

There is sufficient sunlight to cast shadows i.e. no significant fog, mist or cloud cover.

The turbine is directly between the sun and the dwelling. The dwelling has a window facing in the direction of the wind turbine. The wind direction is parallel with the line between the sun, the turbine and the window in question

(a condition which means the turbine will be facing the dwelling). There is sufficient wind speed that the turbines are operating. The dwelling has a direct view of the turbine i.e. no screening (trees, hedges, etc.) or no obscuring

features around the receivers which would minimise views of the development, and hence reduce or

eliminate the potential for shadow flicker.

All seven conditions outlined above must exist simultaneously for shadow flicker to occur at a dwelling. Shadow flicker does not generally have any effect on health or safety, but could on limited occasions present a brief nuisance effect for some neighbours.

11.2 Methodology

This section presents the methodology used in assessing the potential impact of shadow flicker from the wind farm on the receiving environment. The following sources of information were considered in this assessment:

The design layout of the proposed development.

• Published literature as described below.

Field assessment of the dwellings in the vicinity of the proposed development.

A desk-based assessment of the dwellings with planning permission in the vicinity of the proposed

development that are not yet constructed.





11.2.1 Relevant Guidance The scope and methodology for the shadow flicker assessment has been devised in consideration of the

following planning, policy and guidance documents:

Department of the Environment, Heritage and Local Government (DoEHLG) (2006) “Wind Energy

Development Planning Guidelines” Irish Wind Energy Association (2012) “Best Practice Guidelines for the Irish Wind Energy Industry” Environmental Protection Agency (2002) “Guidelines on the Information to be Contained in

Environmental Impact Statements” Environmental Protection Agency (2003) “Advice Notes on Current Practice in the preparation of

Environmental Impact Statements”

A number of these guidelines are addressed in further detail in Chapter 3 of the EIS.

We are aware that the Department of the Environment, of Heritage and Local Government (DoEHLG) Wind Energy Development Planning Guidelines are currently being revised. The turbine layout as presented can comply with the proposed draft Guidelines with respect to proposed shadow flicker limits.

11.2.2 Consultation This chapter considers the responses, with particular regard to concerns relating to shadow flicker, which were received following consultations with the statutory authorities and other relevant bodies, as summarised

in Chapter 4. During the public consultation process held prior to the submission of the application, some individuals who attended the event raised concerns in relation to the potential impacts of shadow flicker and the guidelines and limits were discussed with these individuals.

11.2.3 Field Assessment For the purposes of carrying out the shadow flicker assessment, a rotor diameter of 131 m has been utilised as the size of the candidate turbine. This may not be the final rotor diameter, however it is considered to

represent the worst case scenario for shadow flicker. The exact turbine will be dictated by the final selection of the turbine make and model post planning and the turbine shadow flicker control system will be programmed to ensure that the shadow flicker limits will be in accordance with the relevant guidance. A building survey was undertaken in April 2016 by North Meath Wind Farm Ltd. All buildings within 1,310 m

(10 rotor diameters) of a proposed turbine were recorded. These buildings are included in the shadow flicker assessment for the proposed development.

11.2.4 Desk Study

11.2.4.1 Planning Search In addition to considering all constructed buildings, a search was undertaken of Meath County Councils’ online

planning database of all dwellings with valid planning permission and which went through the planning process, within 1,310 m (10 rotor diameters) of a proposed turbine.

11.2.4.2 Extent of Shadow Flicker Appraisal

A shadow flicker appraisal was carried out for all buildings within 10 rotor diameters of a proposed turbine in

accordance with the Irish Wind Energy Association (IWEA) “Best Practice Guidelines for the Irish Wind Energy Industry” (2012)i.

The closest meteorological station to the proposed Castletownmoor Wind Farm with historical measurements compiled by Met Éireann is located at Dublin Airport. This data, presented in Table 11.1 below, represents

the average sunshine per day as recorded in Dublin Airport over a 30 year period (1981 – 2010).





The actual sunshine (daylight) hours at the proposed development site and therefore the percentage of time

shadow flicker could actually occur is 32 %. A factor of 32 % was applied to the predicted maximum amount of annual shadow flicker.

Table 11.1: Average Monthly Sunshine Hours at Dublin Airport (1981 – 2010)

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Annual

Mean

Daily Duration 1

1.9 2.7 3.5 5.3 6.2 5.8 5.3 5.1 4.3 3.3 2.4 1.7 3.9

Daylight hours 1

8.1 9.8 11.9 13.3 15.4 15.9 15.6 14.2 12.4 10.2 8.8 7.3 11.9

% Sunshine

23 28 29 40 40 36 34 36 35 32 27 23 32.0

1 Based on climatic data for Dublin Airport 1981‐2010 (http://www.met.ie/climate‐Ireland/1981‐2010/dublin.html)

Although this methodology is considered a more likely scenario, it has not been considered here that the wind turbine will not always be yawed such that the rotor is in the worst case orientation (i.e. perpendicular to the sun-turbine vector). In order to include the probability of rotor being orientated within the sun-turbine vector,

a wind directionality factor has also been applied. Wind direction frequency distribution was collected on-site between 03 August 2013 and 08 May 2016. Using

this data, it is possible to estimate the probability of a rotor being orientated within 30 degrees (30o) of a vector perpendicular to the turbine. This maximum probability of the rotor being orientated within 30o of sun (turbine vector) is estimated at a reduction of 40.8 % based on the most onerous wind direction.

The IWEA Guidelines recommend that any existing and/or permitted wind farm developments within 2 km of the proposed development should be considered in a cumulative shadow flicker assessment. As there are no neighbouring wind farms within 2 km of the proposed development footprint, a cumulative shadow flicker

assessment is not considered necessary.

11.3 Existing Environment There is currently no shadow flicker resulting from activities within the site of the proposed wind farm development. Potential shadow flicker levels arising from the proposed wind farm development have been

modelled and are discussed further in Section 11.4. There are 293 buildings, including occupied, unoccupied and permitted are located within 10 rotor diameters (1,310 m) and these are included in the shadow flicker assessment. Of these buildings, 9 buildings are derelict,

25 are non-residential and there are 8 buildings that have been considered in the planning process but not yet built. The locations of these buildings can be identified on Figure 11.1.

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22/07/2016DateClient Name

Project Title

Figure Title

Scale 1:25,000

Figure No.11.1

Rev.

Map: R:\Map Production\Projects\P0177\Workspace\MXDs\EIS\Chapter 11 Shadow Flicker\P0177_Fig11-1_ShadowFlickerAnalysisArea_A3.mxd Mapping Reproduced Under Licence from the Ordnance Survey Ireland Licence No. EN 0001215 © Government of Ireland

A

Legend!( Proposed Turbine Location#* Existing Met Mast Location

Wind Farm Site BoundaryProposed Onsite Substation FootprintExisting Gorman SubstationProposed Compound FootprintProposed Borrow Pit FootprintExisting Access TrackProposed Access TrackIndicative HV Cable Route

(( (( (( (( Indicative MV Cable Route500m Buffer of Turbines1310m Buffer of Turbines

House Survey and Planning Applications!( Dwelling!( Dwelling/Commercial!( Commercial!( Planning Application!( Derelict!( Church!( Church Ruin!( Mobile Home!( Sporting Facility

@ A3

Co. Meath

CONSULTANTS IN ENGINEERING & ENVIRONMENTAL SCIENCES

Core House, Pouladuff Road, Cork, T12 D773, IrelandT: +353-21-4964133, F: +353-21-4464Unit 16, J5 Plaza, North Park Business Park, Dublin 11, D11 PXT0, IrelandT: +353-1-6583500, F: +353-1-6583501

W: www.fehilytimoney.ie E: [email protected]

0 1 20.5Kilometers

«1

North Meath Wind Farm Ltd.

Castletownmoor Wind Farm

Location of Buildings Considered in the Shadow Flicker Assessment

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293 buildings surrounding 25 turbines represents approximately 12 buildings per turbine. This figure is not untypical of other Irish wind farm sites, both operational and planned. There are 2 buildings of the 293 buildings located less than 500m from a proposed turbine. They are both

commercial buildings (sheds).

11.4 Potential Impacts The locations of the 293 buildings considered in the shadow flicker model are shown in Figure 11.1.

The model calculates times throughout the year when a turbine, viewed from the window of a building, is in line with the sun, and therefore the potential exists for shadow flicker to occur.

Existing screening has not been taken into consideration, and it has been assumed that each building has windows at 2 m high throughout 360 degrees (‘glass house’ model). This approach means that the model simulates potential shadow flicker impact on a ‘glass house’. The maximum daily shadow flicker modelled is based on the assumption that daylight hours consist of 100 % sunshine. This is a conservative assumption

which represents a worst case scenario. Following the discussion on sunshine hours presented in Section 11.1.4.2 of this document, a sunshine factor of 32 % will be applied.

Based on the potential shadow flicker calculations for Castletownmoor Wind Farm, there are 45 buildings where the potential annual shadow flicker guideline limit (30 hours) is exceeded when the 32 % sunshine assumption is applied. Taken into account the wind directionality on the site, the probability of rotor being orientated within 30 degrees of the sun-turbine vector is estimated at a 40.8% of the most onerous wind direction. This factor will

also be accounted for estimating the shadow flicker occurrence.

Combining these two probabilities of sunshine and wind direction, an approximation of the ‘estimated actual’ shadow flicker occurrence has been calculated and it is outlined in Table 11.2 below. These results have been

illustrated in the map in Appendix J1. Properties which have no predicted shadow flicker are not tabulated.

Table 11.2: Shadow Flicker Results for Proposed Castletownmoor Wind Farm

Building No

Easting (ITM)

Northing (ITM)

Nearest turbine

Nearest Distance

from Nearest Turbine

(m)

Length of Time Affected by Shadow

Flicker Assuming 32% sunshine and 40.8%

Wind Direction Comment

Maximum

Minutes per Day on Day

Affected

Hours per Year

1 679235 777310 T5 525 5 4 Residential

2 679166 777186 T5 589 4 5 Residential

3 679133 777122 T5 632 4 5 Derelict

4 678668 776933 T5 803 2 1 Residential

5 678676 776913 T5 821 2 0 Residential

10 678613 776962 T5 793 1 0 Residential

11 678739 777099 T5 625 4 4 Residential

20 678077 777127 T4 689 4 4 Residential





Building

No

Easting

(ITM)

Northing

(ITM)

Nearest

Turbines

Nearest Distance

from

Nearest Turbine

(m)




Maximum

Minutes per Day

on Day Affected

Hours per

Year

21 678117 777176 T4 672 5 4 Residential

22 678132 777092 T4 749 3 2 Residential

23 677914 777114 T4 630 4 5 Residential

27 678176 777386 T4 568 8 11 Residential

28 677129 777415 T4 652 7 10 Residential

29 677212 777396 T4 589 7 7 Residential

30 677051 777498 T4 692 6 7 Residential

31 677228 777373 T4 588 6 5 Residential

33 676793 778294 T3 924 4 7 Derelict

34 676689 778785 T3 1190 4 4 Residential

35 676739 778736 T3 1122 4 6 Residential

36 676758 778710 T3 1093 4 6 Residential

37 676776 778690 T3 1067 4 6 Residential

38 676809 778642 T3 1015 4 11 Residential

39 676853 778571 T3 944 4 13 Residential

40 676785 778481 T3 974 4 11 Residential

41 676771 778420 T3 970 4 10 Residential

42 676813 778238 T3 899 5 7 Residential

43 676834 777936 T4 904 5 6 Residential

44 676833 777892 T4 895 5 6 Residential

45 676775 778342 T3 950 4 6 Residential

46 676731 778376 T3 999 4 6 Residential

47 676700 778411 T3 1037 4 4 Residential

48 676767 778571 T3 1023 4 10 Residential

49 677200 778447 T3 578 7 15 Residential

50 676860 778144 T3 850 5 8 Residential

51 676789 778458 T3 964 4 11 Residential

52 676718 778344 T3 1006 4 4 Residential

53 676760 778134 T3 950 4 5 PA KA140183.

Old app

KA802504

54 677222 778504 T3 589 7 14 Non-residential

55 676645 778772 T3 1222 4 4 Residential


57 676985 779868 T1 1151 4 3 Residential

58 676994 779793 T1 1097 4 3 Residential





Building

No

Easting

(ITM)

Northing

(ITM)

Nearest

Turbines

Nearest Distance

from

Nearest Turbine

(m)




Maximum Minutes

per Day on Day

Affected

Hours per Year

59 676821 779628 T1 1158 4 2 Residential

60 676809 779606 T1 1160 4 2 Residential


62 676715 779623 T1 1254 3 2 Derelict

63 676739 779618 T1 1230 4 2 Residential

64 677141 780093 T1 1208 4 2 Residential

65 676613 779448 T1 1295 3 1 Residential

66 676593 779414 T1 1306 3 1 Residential



69 676672 779505 T1 1253 3 2 Residential

70 676630 779459 T1 1281 3 1 Residential

71 676668 779578 T1 1281 3 2 Residential

72 676687 779579 T1 1263 3 2 Residential

73 676699 779580 T1 1252 3 2 Residential

74 676719 779581 T1 1234 4 2 Residential

75 676730 779581 T1 1224 4 2 Residential

76 676686 779556 T1 1257 3 2 Residential

77 676686 779544 T1 1252 3 2 Residential

78 676686 779521 T1 1245 3 2 Residential

79 676678 779512 T1 1249 3 2 Residential

80 676665 779498 T1 1257 3 2 Residential

81 676659 779490 T1 1261 3 2 Residential

82 676652 779484 T1 1266 3 2 Residential

83 676636 779467 T1 1277 3 1 Residential

91 678218 779956 T1 900 4 3 Residential

92 678242 780017 T1 966 3 2 Residential

94 678351 780139 T1 1122 4 2 Residential

96 678301 780081 T1 1048 3 2 Residential-Mobile Home

102 678226 779549 T1 554 7 11 Residential

103 678269 779523 T1 565 7 10 Residential

104 678482 779238 T1 625 7 17 Residential

105 678507 779206 T1 645 8 18 Residential

106 678533 779171 T1 668 8 19 Residential





Building

No

Easting

(ITM)

Northing

(ITM)

Nearest

Turbines

Nearest Distance

from

Nearest Turbine

(m)




Maximum Minutes per Day

on Day Affected

Hours per

Year

107 678282 779413 T1 504 8 9 Residential

108 678021 779693 T1 586 7 7 Residential

109 678073 779636 T1 549 7 10 Residential

110 678305 779475 T1 560 7 10 PA KA100088

111 678909 779738 T17 619 7 13 Residential

112 678896 779780 T17 623 7 12 Residential

113 678869 779908 T17 641 7 11 Residential

114 678913 779982 T17 604 7 9 Residential

115 678851 780015 T17 670 6 8 Residential

116 678836 780066 T17 696 6 8 Residential

117 678844 780233 T17 749 6 9 Residential

118 678758 780351 T17 882 5 7 Residential

119 678792 780422 T17 893 5 7 Residential

120 678775 780461 T17 930 5 4 Residential


122 678741 780845 T17 1226 4 3 Residential

128 680134 780244 T17 717 8 15 Residential

132 679753 780707 T17 852 2 0 Residential

133 679757 780679 T17 826 3 1 Residential

134 679781 780633 T17 790 4 2 Residential

135 679794 780538 T17 707 8 9 Residential

136 679847 780458 T17 660 10 12 Residential

137 679857 780417 T17 630 10 13 Residential

138 679930 780427 T17 681 10 14 Residential

139 679950 780158 T17 515 11 15 Residential

140 680104 780260 T17 699 7 14 Residential

141 680070 780575 T17 884 8 9 Residential

142 680153 780599 T17 957 6 7 Residential

143 680430 780645 T19 999 4 2 Residential

144 680417 780739 T19 1093 4 3 Residential

145 680441 780743 T19 1092 4 3 Residential

146 680454 780748 T19 1094 4 3 Residential

149 679862 780533 T17 733 9 10 Residential





Building

No

Easting

(ITM)

Northing

(ITM)

Nearest

Turbines

Nearest Distance

from

Nearest Turbine

(m)





on Day Affected

Hours per

Year

151 680005 780711 T17 958

7 5 PA KA100845 - Open file since

2010



155 680192 780996 T17 1298 2 0 Residential

156 680146 779737 T19 540 11 24 Residential

157 680155 779713 T19 529 11 26 Residential

158 680159 779670 T19 524

11 30 Residential – Not

conf

159 680156 779642 T19 528 11 31 Residential

160 680155 779606 T19 532 11 33 Residential

161 67692 777623 T4 795 5 8 Residential

162 678653 778774 T2 669 9 22 Residential


164 681361 780397 T20 776 8 21 Residential

165 681378 780352 T20 731 8 18 Residential

166 681331 780209 T20 590 6 17 Residential

167 681066 780017 T20 509 15 30 Residential

168 681151 780173 T20 600 11 23 Residential

169 681182 781138 T23 906 5 7 Residential

170 681137 780733 T23 904 5 9 Residential

171 681194 780687 T23 854 7 12 Residential

172 681296 780507 T23 809 8 21 Residential

173 681128 780682 T23 920 5 8 Residential

174 681199 780548 T23 884 5 12 Residential

175 681170 781274 T23 971 4 4 Residential

177 680841 780902 T23 1196 4 2 Residential

178 680910 780917 T23 1129 4 2 Residential

179 681290 781595 T23 1065 4 6 Residential

180 681162 781704 T23 1233 4 4 Residential

181 680874 780862 T23 1162 4 2 Planning ref no.

KA70630 - Open

file - 7 years old

182 680772 780883 T19 1208 3 1 Residential

183 681103 781689 T23 1265 4 4 Residential





Building

No

Easting

(ITM)

Northing

(ITM)

Nearest

Turbines

Nearest Distance

from

Nearest Turbine

(m)




Maximum Minutes

per Day on Day

Affected

Hours per Year

184 681186 781749 T23 1249 4 4 Residential

187 682636 781825 T25 709 7 4 Residential

188 682564 781868 T25 732 2 1 Residential

189 682057 781507 T25 508 8 16 Residential

190 682741 781709 T25 645 10 12 Residential

191 682748 781695 T25 636 10 13 Residential

192 682816 781613 T25 609 9 13 Residential

193 682838 781569 T25 592 8 10 Residential

194 682831 781642 T25 641 8 13 Residential

204 683228 780582 T24 618 7 13 Residential

205 683238 780803 T24 628 9 14 Residential

206 683881 780646 T24 1262 3 2 Residential


208 683139 780796 T24 530 11 19 Residential

209 683667 780391 T24 1090 4 2 Residential

210 683872 780374 T24 1292 3 2 Residential

211 683553 779910 T24 1218 2 0 Residential

212 683581 779876 T24 1261 1 0 Residential

213 683875 780344 T24 1303 3 2 Residential

214 683871 780406 T24 1284 3 2 Residential

216 683057 778376 T11 1271 3 4 Residential

217 682351 778330 T11 607 8 16 Residential

218 682533 777698 T12 506 8 28 Residential

219 682595 777894 T12 637 10 19 Residential

220 683046 777861 T12 1044 4 6 Residential

221 682994 777393 T13 858 5 9 Residential



224 682650 777086 T13 521 10 16 Derelict

225 682735 777032 T13 619 8 13 Residential

226 682728 776975 T13 633 7 10 Residential

227 682697 776946 T13 618 7 9 Residential

257 682636 777106 T13 1249 11 17 Residential

262 681314 777025 T10 709 5 6 Derelict





Building

No

Easting

(ITM)

Northing

(ITM)

Nearest

Turbines

Nearest Distance

from

Nearest Turbine

(m)





on Day Affected

Hours per

Year

263 681520 776857 T10 649 6 7 Residential

264 681402 776986 T10 548 5 6 Residential

265 681442 776982 T10 540 6 8 Residential

266 681509 776987 T10 521 8 13 Residential

267 681615 776932 T10 573 11 12 Residential

268 681713 776944 T13 525 10 10 Residential

269 681315 777010 T10 561 5 6 Residential

270 681539 776952 T10 553 10 13 Derelict




293 683123 778155 T12 1226 4 3 Residential


295 682855 781598 T25 625 8 11 Residential

296 680150 779612 T16 532 11 32 Residential


Note 1: potential length of time figures in bold exceed guidelines

Note 2: for building number locations please refer to Figure 11.1.1.

A further 5 properties are described in Table 11.2 as being derelict.

This ‘estimated actual’ shadow flicker is still considered conservative as the following items are not considered:

Receivers may be screened by cloud cast and/or vegetation. The extent of screening by vegetation (evergreen/deciduous) or built form such as adjacent dwellings, outbuildings, garages or barns is

outlined in the Residential Amenity Assessment in Appendix I7.

Each receiver will not have windows facing in all directions onto the wind farm.

At distances greater than about 500 – 1,000 m, ‘the rotor blade of a wind turbine will not appear to be chopping the light, but the turbine will be regarded as an object with the sun behind it. Therefore,

it is generally not necessary to consider shadow casting at such distances’ii.

The hours when the wind is blowing in a line between the turbine and the house may not coincide

with sunny hours.

When the 32 % sunshine and the 40.8 % wind direction assumptions are applied to the annual shadow flicker results, in none of the buildings the potential shadow flicker occurrences exceed the daily limit of 30 minutes

per day. The number of buildings where potential shadow flicker occurrences slightly exceed the guideline limit of 30 hours per year, is three (buildings no. 159,160 and 296). The potential annual shadow flicker occurrences at these three buildings are 31, 32 and 32 hours per year.





11.5 Mitigation Measures As outlined in Section 11.4, all buildings within 10 rotor diameters of one or more proposed turbines were

appraised for potential impacts due to shadow flicker. The model does not account for the percentage of time during which the wind is blowing parallel to a line between the turbine and the houses being considerably less

than 100 %. The model also does not account for the likelihood of this percentage of time coinciding with

sunshine hours. As such, the predicted shadow flicker at the buildings is a conservative estimate of the actual shadow flicker likely to occur. However, as outlined in Section 11.4, the shadow flicker modelling undertaken predicts that three buildings,

located at a distance of over 500 m from the nearest turbine, will experience shadow flicker slightly greater than the guideline limit of 30 hours per year. Given the conservative nature of the shadow flicker model and considering that no building is predicted to experience shadow flicker exceeding the guideline limit of 30 min

per day limit, the likelihood of any actual shadow flicker exceedances occurring is considered to be low. However, should shadow flicker exceedances be experienced at any buildings, site visits will be undertaken to determine the level of occurrence and if annoyance is found, suitable mitigation measures (such as

screening or turbine shut-down) will be employed. In an event of an exceedance, the procedure for logging public complaints is outlined in Appendix 5 of the CEMP (Appendix D of this report). We are aware that the DoEHLG Wind Energy Development Planning Guidelines are currently being revised

and should these guidelines be finalised in advance of the Board’s decision on the application for permission for this proposed development, the turbine shadow flicker control system will be modified to meet the planning requirements and guidelines in place.

In order to ensure that no exceedance of the guideline limits for shadow flicker occur, a procedure of evaluating the existing screening, window orientation and the periods of actual shadow flicker occurrence will

be undertaken in consultation with the relevant building owner.

11.6 Residual Impacts

Results of a shadow flicker model predict that the proposed wind farm has the potential to introduce shadow flicker impacts at buildings surrounding the wind farm. When the 32 % sunshine and the 40.8 % wind direction assumptions are applied to the predicted annual shadow flicker, there are three buildings where

potential shadow flicker occurrences slightly exceed the guideline limit of 30 hours per year. The daily guideline limit of 30 minutes per day is not exceeded for any building. Due to the conservative assumptions and methodology used in the shadow flicker appraisal, actual exceedances of the guideline limits are not

anticipated. In any event should exceedances of the guideline limits be experienced at any building, suitable mitigation measures will be employed to ensure no dwelling experiences any shadow flicker above the guideline limits.

11.7 References

i Irish Wind Energy Association “Best Practice Guidelines for the Irish Wind Energy Industry” (2012),

http://www.iwea.com/contentFiles/Documents%20for%20Download/Publications/IWEA%20Policy%20Documents/IWEA%

20best%20practise%20guidelines.pdf ii Danish Wind Energy Association, 2003; http://guidedtour.windpower.org/en/tour/env/shadow/shadow2.htm

http://www.iwea.com/contentFiles/Documents%20for%20Download/Publications/IWEA%20Policy%20Documents/IWEA%20best%20practise%20guidelines.pdf

http://www.iwea.com/contentFiles/Documents%20for%20Download/Publications/IWEA%20Policy%20Documents/IWEA%20best%20practise%20guidelines.pdf

http://guidedtour.windpower.org/en/tour/env/shadow/shadow2.htm