SANDY KNOWE WIND FARM i APPENDIX 8.2

Appendix 8.2 Collision Risk Modelling

Contents

Golden Plover (Pluvialis apricaria) – Random Model 1

Pink Footed Goose (Anser Brachyrhyus) – Linear Model 8

SANDY KNOWE WIND FARM ii APPENDIX 8.2

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SANDY KNOWE WIND FARM 1 APPENDIX 8.2

Appendix 8.2 - Collision Risk Modelling

Golden Plover (Pluvialis apricaria) – Random Model

Stage 1: Number of Birds Flying Through the Rotors per Year

Calculate the number of hours of observation expressed in hectare hours. Where simultaneous surveys at

vantage points with overlapping viewsheds have been undertaken, the area of overlap has been determined

through use of GIS and the hectare hours for this area has been determined and subtracted from the total of

the vantage points in order to remove double counting. Where three or more vantage points have been

undertaken simultaneously, the same approach has been undertaken with the exception of where one viewshed

covers the entirety of the other vantage points observed. In this instance the hectare hour for this one vantage

point has been used in the calculation to avoid double counting.

Hectare hours = viewshed (to 2 km) within the site boundary (ha) * survey duration (hrs)

Vantage Point Ha

1 98.99

2 170.42

3 86.51

4 298.18

5 198.18

Date VP Start Time Hours surveyed Ha hrs Overlap (Ha) Corrected Ha Hrs

05/04/2011 1 13:30 1.5 148.485 51 327.615

05/04/2011 2 13:30 1.5 255.63

05/04/2011 3 09:00 3 259.53 5 839.07

05/04/2011 5 09:05 3 594.54

20/04/2011 1 13:30 1.5 148.485 51 327.615

20/04/2011 1 18:35 3 296.97 51 146.97

20/04/2011 2 13:33 1.5 255.63

20/04/2011 2 18:36 3 511.26

21/04/2011 3 05:50 3 259.53 80 914.07

21/04/2011 4 05:50 3 894.54

21/04/2011 4 11:15 3 894.54 133 1090.08

21/04/2011 5 11:05 3 594.54

09/05/2011 3 18:50 3 259.53 5 839.07

09/05/2011 5 18:53 3 594.54

11/05/2011 1 09:00 3 296.97 51

11/05/2011 2 06:45 3 511.26

11/05/2011 3 12:30 3 259.53 2

SANDY KNOWE WIND FARM 2 APPENDIX 8.2

Date VP Start Time Hours surveyed Ha hrs Overlap (Ha) Corrected Ha Hrs

11/05/2011 5 10:20 3 594.54 55 1536.05

12/05/2011 1 04:50 3 296.97 92 915.51

12/05/2011 2 11:00 3 511.26 108 1081.8

12/05/2011 4 05:00 3 894.54

12/05/2011 4 10:45 3 894.54

30/05/2011 2 13:00 3 511.26 770.79

30/05/2011 3 13:05 3 259.53

30/05/2011 4 16:40 3 894.54 133 1090.08

30/05/2011 5 16:30 3 594.54

31/05/2011 1 11:50 3 296.97 296.97

06/06/2011 1 19:45 3 296.97 296.97

14/06/2011 2 19:55 3 511.26 511.26

14/06/2011 5 04:05 3 594.54 594.54

15/06/2011 3 20:00 3 259.53 259.53

15/06/2011 4 20:00 3 894.54 894.54

16/06/2011 2 10:20 3 511.26 511.26

16/06/2011 5 14:00 3 594.54 594.54

30/06/2011 3 04:50 3 259.53 259.53

30/06/2011 4 13:30 3 894.54 894.54

30/06/2011 5 19:15 3 594.54 594.54

01/07/2011 1 04:40 3 296.97 296.97

01/07/2011 2 13:00 3 511.26 511.26

01/07/2011 3 09:30 3 259.53 259.53

08/07/2011 1 12:15 3 296.97 296.97

08/07/2011 4 04:35 3 894.54 894.54

28/07/2011 1 12:05 3 296.97 2 550.5

28/07/2011 1 16:05 3 296.97 2

28/07/2011 3 12:00 3 259.53

28/07/2011 3 16:00 3 259.53

28/07/2011 5 13:00 3 594.54 55 484.54

28/07/2011 5 17:00 3 594.54 55 484.54

29/07/2011 4 15:30 3 894.54 894.54

29/07/2011 4 19:30 3 894.54 894.54

31/07/2011 2 09:30 3 511.26 511.26

31/07/2011 2 13:30 3 511.26 511.26

09/08/2011 1 15:35 3 296.97

09/08/2011 1 19:15 3 296.97

SANDY KNOWE WIND FARM 3 APPENDIX 8.2

Date VP Start Time Hours surveyed Ha hrs Overlap (Ha) Corrected Ha Hrs

09/08/2011 3 15:15 3 259.53

09/08/2011 3 19:15 3 259.53

09/08/2011 4 15:15 3 894.54

09/08/2011 4 19:15 3 894.54 1789.08

19/08/2011 2 04:55 3 511.26 511.26

19/08/2011 2 08:55 3 511.26 511.26

08/09/2011 3 12:55 3 259.53 80 914.07

08/09/2011 3 16:55 3 259.53 80 914.07

08/09/2011 4 12:55 3 894.54

08/09/2011 4 16:55 3 894.54

16/09/2011 1 08:15 3 296.97 55 726.51

16/09/2011 1 12:15 3 296.97 55 726.51

16/09/2011 5 08:40 3 594.54

16/09/2011 5 12:40 3 594.54

26/09/2011 2 08:34 3 511.26 511.26

26/09/2011 2 12:40 3 511.26 511.26

21/10/2011 1 12.05 3 296.97 55 1930.08

21/10/2011 1 16.05 3 296.97

21/10/2011 3 12:05 3 259.53 2

21/10/2011 3 16:05 3 259.53

21/10/2011 5 12:05 3 594.54 5

21/10/2011 5 16:05 3 594.54

27/10/2011 2 09:30 3 511.26 511.26

27/10/2011 2 13:30 3 511.26 511.26

31/10/2011 4 09:45 3 894.54 894.54

31/10/2011 4 13:45 3 894.54 894.54

11/11/2011 1 10:20 3 98.99 1074.54

11/11/2011 1 14:20 3 296.97 1074.54

11/11/2011 3 10:20 3 259.53

11/11/2011 3 14:20 3 259.53

11/11/2011 4 10:20 3 894.54

11/11/2011 4 14:20 3 894.54

11/11/2011 5 10:20 3 594.54

11/11/2011 5 14:20 3 594.54

21/11/2011 2 09:30 3 511.26 511.26

27/11/2011 2 13:00 3 511.26 511.26

20/12/2011 1 07:40 3 296.97 894.54

SANDY KNOWE WIND FARM 4 APPENDIX 8.2

Date VP Start Time Hours surveyed Ha hrs Overlap (Ha) Corrected Ha Hrs

20/12/2011 1 11:40 3 296.97 894.54

20/12/2011 3 07:45 3 259.53

20/12/2011 3 11:45 3 259.53

20/12/2011 4 07:40 3 894.54

20/12/2011 4 11:40 3 894.54

23/12/2011 2 07:40 3 511.26

23/12/2011 2 11:40 3 511.26

23/12/2011 5 07:40 3 594.54 170.42 594.54

23/12/2011 5 11:40 3 594.54 170.42 594.54

11/01/2012 1 10:10 3 296.97 5 541.5

11/01/2012 1 14:10 3 296.97 5 541.5

11/01/2012 3 10:10 3 259.53

11/01/2012 3 14:10 3 259.53

12/01/2012 2 15:15 3 511.26 511.26

13/01/2012 2 12:00 2 340.84 340.84

13/01/2012 2 14:30 2 340.84 340.84

15/02/2012 5 10:10 3 594.54 594.54

15/02/2012 5 14:00 3 594.54 594.54

17/02/2012 2 12:00 2 340.84 108 1073.38

17/02/2012 2 14:30 1.5 255.63 108 988.17

17/02/2012 4 10:35 3 894.54

17/02/2012 4 14:35 3 894.54

22/02/2012 1 11:00 3 296.97 296.97

22/02/2012 1 15:00 3 296.97 296.97

24/02/2012 3 11:40 3 259.53 259.53

24/02/2012 3 15:40 3 259.53 259.53

12/03/2012 1 12:05 3 296.97 1074.54

12/03/2012 1 16:05 3 296.97 1074.54

12/03/2012 3 12:05 3 259.53

12/03/2012 3 16:05 3 259.53

12/03/2012 4 12:05 3 894.54

12/03/2012 4 16:05 3 894.54

12/03/2012 5 12:15 3 594.54

12/03/2012 5 16:15 3 594.54

19/03/2012 2 07:00 2 340.84 340.84

19/03/2012 2 09:30 2 340.84 340.84

19/03/2012 2 12:00 2 340.84 340.84

SANDY KNOWE WIND FARM 5 APPENDIX 8.2

Date VP Start Time Hours surveyed Ha hrs Overlap (Ha) Corrected Ha Hrs

20/04/2012 3 16:30 3 259.53 259.53

21/04/2012 2 07:30 3 511.26 511.26

21/04/2012 2 16:30 3 511.26 511.26

22/04/2012 3 07:05 3 259.53 259.53

Total 51536.86

Calculate hectare seconds = hectare hrs *3600

= 51536.86 * 3600

= 185532696 Hectare seconds

Calculate the bird observation in all areas and percentage of time birds active in overall observed area.

Date No. VP HB1 HB2 HB3 (PCH) HB4 Total flight time (at PCH) in seconds

26/09/2011 12 2 0 30 0 0 360

21/04/2012 23 2 0 0 75 0 1725

21/04/2012 1 2 0 25 0 0 25

21/04/2012 14 2 45 85 0 0 1190

21/04/2012 14 2 45 75 140 0 3010

21/04/2012 2 2 5 30 0 0 60

21/04/2012 2 2 30 180 30 0 420

21/04/2012 53 2 0 0 210 0 11130

21/04/2012 29 2 15 35 0 0 1015

23/12/2011 20 5 0 120 0 0 2400

Total 21335

Bird Activity = Total bird flight time / hectare seconds

BA = 0.000114993

Overall Area covered by VPs (excluding overlap) = 363 Ha

SANDY KNOWE WIND FARM 6 APPENDIX 8.2

Calculate the number of hrs per day birds are potentially active over a year and the number of hrs of bird

occupancy in the airspace per year

hrs potentially active (12 months daylight hours plus 25% night time hours) = 5337.86

seconds potentially active = 5337.86*3600

= 19216296

no of seconds of bird occur in airspace = sec potentially active * bird activity

= 19216296 * 0.000114993

= 2209.740

Calculate flight risk volume (Vw)

Vw = 3631290 (m2) * rotor diameter (m)

Vw = 366760290

Calculate combined rotor swept volume

Vr = number of turbines (n) * pi * r2 * (max chord + bird length)

Vr = 24 * (pi * 2550.25) * (3.5 + 0.28)

Vr = 726466.255

Calculate bird occurrence in swept volume

Occurrence = no of sec of bird occ * combined rotor swept volume/flight risk volume

= 2209.7395 * (Vr/Vw)

= 2209.740* (726466.255 / 366760290)

= 4.375

Calculate bird transits time and potential number of transits per year

Transit time = (max chord + bird length) / bird speed (m2)

= (3.5 + 0.28) / 10

= 0.378

No. of transits = occurrence / transit time

= 4.375 / 0.378

= 11.574

SANDY KNOWE WIND FARM 7 APPENDIX 8.2

Stage 2: Collision Risk of Bird Passing through Rotor (Assuming No Avoidance)

Annual Collision Rate assuming no avoidance

= No. of transits * Ave prob of collision

= 11.574 x 6.2

= 0.718

Corrected for avoidance

= 0.718 – ((0.718 / 100) *98)

= 0.014

Corrected for downtime

= 0.014 * 0.85

= 0.012

Over lifetime of the scheme

= 0.012* 25

= 0.3

K: [1D or [3D] (0 or 1) 1 Calculation of alpha and p(collision) as a function of radius

NoBlades 3 Upw ind: Dow nw ind:

MaxChord 3.5 m r/R c/C a collide contribution collide contribution

Pitch (degrees) 6 radius chord alpha length p(collision) from radius r length p(collision) from radius r

BirdLength 0.28 m 0.025 0.575 5.92 16.34 1.00 0.00125 15.91 1.00 0.00125

Wingspan 0.72 m 0.075 0.575 1.97 5.59 0.36 0.00267 5.16 0.33 0.00247

F: Flapping (0) or gliding (+1) 0 0.125 0.702 1.18 4.00 0.26 0.00319 3.49 0.22 0.00278

0.175 0.860 0.85 3.46 0.22 0.00386 2.83 0.18 0.00316

Bird speed 10 m/sec 0.225 0.994 0.66 3.12 0.20 0.00448 2.39 0.15 0.00343

RotorDiam 101 m 0.275 0.947 0.54 2.51 0.16 0.00440 1.82 0.12 0.00319

RotationPeriod 4.70 sec 0.325 0.899 0.46 2.08 0.13 0.00432 1.43 0.09 0.00296

0.375 0.851 0.39 1.77 0.11 0.00423 1.14 0.07 0.00274

0.425 0.804 0.35 1.55 0.10 0.00420 0.96 0.06 0.00261

0.475 0.756 0.31 1.38 0.09 0.00417 0.82 0.05 0.00250

Bird aspect ratioo: b 0.39 0.525 0.708 0.28 1.23 0.08 0.00414 0.72 0.05 0.00240

0.575 0.660 0.26 1.11 0.07 0.00409 0.63 0.04 0.00231

0.625 0.613 0.24 1.01 0.06 0.00403 0.56 0.04 0.00224

0.675 0.565 0.22 0.92 0.06 0.00396 0.50 0.03 0.00218

0.725 0.517 0.20 0.84 0.05 0.00387 0.46 0.03 0.00212

0.775 0.470 0.19 0.76 0.05 0.00378 0.42 0.03 0.00208

0.825 0.422 0.18 0.70 0.04 0.00368 0.39 0.02 0.00205

0.875 0.374 0.17 0.64 0.04 0.00356 0.36 0.02 0.00203

0.925 0.327 0.16 0.58 0.04 0.00343 0.34 0.02 0.00202

0.975 0.279 0.15 0.53 0.03 0.00330 0.33 0.02 0.00203

Overall p(collision) = Upwind 7.5% Downwind 4.9%

Average 6.2%

SANDY KNOWE WIND FARM 8 APPENDIX 8.2

Pink Footed Goose (Anser Brachyrhyus) – Linear Model

Stage 1: Number of Birds Flying Through the Rotors per Year

1. Calculation of the ‘risk window’; Cross section area equal to the width of the wind farm across the

general direction of flight multiplied by the height of turbine to rotor tip. Width of wind farm was

determined using GIS.

Width of transit flight (Ws) = 2676m

Turbine height (th) = 125m

Risk Window (W) = Ws * th

= 2676m * 125m

= 334500m2

2. Calculate the area occupied by rotor blades (A)

Number of turbine (n) = 24

Rotor radius (r) = 50.5

A = n * π *r2

A = 24 * 3.14* 2550.250

A = 192186.840m2

3. Express the area occupied by rotor blades (A) as a proportion of the risk window (W)

Proportion (P) = A/W

= 192186.840/334500

= 0.575

4. Calculate the number of bird potentially flying through the site per year (N)

N = number of pink footed goose transits at PCH per year

= hourly rate of transit * available hours for flight

Hours surveyed between September 2011 and March 2012

= hectare hours (correcting for overlap) / hectares visible in Study

area

= 51536.860 / 363

= 141.975

Number of geese observed in the same period = 134

Hourly rate of transit = 134/141.975

= 0.944

Hours available for flight are equal to number of daylight hours in the same period plus 25% of night hours.

Daylight and night hours taken from time and date website and based on Glasgow

(www.timeanddate.com/worldclock/sunrise.html) accessed 21.03.11.

SANDY KNOWE WIND FARM 9 APPENDIX 8.2

Hours available = 2825.22

N = 2825.22 * 0.944

= 2667.008

5. Calculate the number of birds flights (Nf) to fly through the rotor (P)

Nf = N * P

= 2667.008 * 0.575

= 1533.530

Stage 2: Collision Risk of Bird Passing Through Rotor (Assuming No Avoidance)

Stage 2 was calculated using the prepopulated spreadsheet provided by Scottish Natural Heritage (SNH) for

calculating the probability of collision for any species (available at: http://www.snh.gov.uk/docs/C234672.xls)

Variable highlighted in blue where entered into the spreadsheet. Bird biometrics where determined using the

British Trust for Ornithology website (http://www.bto.org/about-birds/birdfacts) bird flight speeds were

assumed using the flight speeds characterised by Bruderer and Boldt (2001).

K: [1D or [3D] (0 or 1) 1 Calculation of alpha and p(collision) as a function of radius

NoBlades 3 Upw ind: Dow nw ind:

MaxChord 3.5 m r/R c/C a collide contribution collide contribution

Pitch (degrees) 6 radius chord alpha length p(collision) from radius r length p(collision) from radius r

BirdLength 0.68 m 0.025 0.575 6.52 23.16 1.00 0.00125 22.74 1.00 0.00125

Wingspan 1.52 m 0.075 0.575 2.17 7.86 0.46 0.00342 7.44 0.43 0.00324

F: Flapping (0) or gliding (+1) 0 0.125 0.702 1.30 5.42 0.31 0.00393 4.91 0.28 0.00356

0.175 0.860 0.93 4.52 0.26 0.00459 3.89 0.23 0.00395

Bird speed 11 m/sec 0.225 0.994 0.72 3.97 0.23 0.00518 3.24 0.19 0.00423

RotorDiam 101 m 0.275 0.947 0.59 3.20 0.19 0.00511 2.51 0.15 0.00400

RotationPeriod 4.70 sec 0.325 0.899 0.50 2.66 0.15 0.00502 2.00 0.12 0.00378

0.375 0.851 0.43 2.28 0.13 0.00496 1.66 0.10 0.00360

0.425 0.804 0.38 2.05 0.12 0.00505 1.46 0.08 0.00360

0.475 0.756 0.34 1.86 0.11 0.00512 1.31 0.08 0.00360

Bird aspect ratioo: b 0.45 0.525 0.708 0.31 1.70 0.10 0.00519 1.19 0.07 0.00361

0.575 0.660 0.28 1.57 0.09 0.00525 1.09 0.06 0.00364

0.625 0.613 0.26 1.46 0.08 0.00530 1.01 0.06 0.00367

0.675 0.565 0.24 1.36 0.08 0.00533 0.95 0.06 0.00371

0.725 0.517 0.22 1.27 0.07 0.00536 0.90 0.05 0.00377

0.775 0.470 0.21 1.20 0.07 0.00538 0.85 0.05 0.00383

0.825 0.422 0.20 1.12 0.07 0.00538 0.82 0.05 0.00390

0.875 0.374 0.19 1.06 0.06 0.00538 0.79 0.05 0.00399

0.925 0.327 0.18 1.00 0.06 0.00537 0.76 0.04 0.00408

0.975 0.279 0.17 0.94 0.05 0.00534 0.74 0.04 0.00419

Overall p(collision) = Upwind 9.7% Downwind 7.3%

Average 8.5%

SANDY KNOWE WIND FARM 10 APPENDIX 8.2

Calculation of collision rate

Collision rate = Nf * average probability of collision

= 1533.530*0.085

= 130.350

Calculation of collision rate applying 99.8% avoidance rate

= 130.350*0.002

= 0.261

1. Correct collision rate for down time (assuming wind farm operates at 85%)

= (0.261/ 100)*85

= 0.222

2. Calculate the number of year per collision

= 1 / 0.222

= 4.505

3. Calculate the number of collisions per lifetime of the scheme

= 0.22 * 25

= 5.55