environmental statement - Rotherham's Online Application for ...

PREDICTED EFFECTS
15.10 Table 15.1 summarises the occurrence of shadow flicker at the most
affected window at each assessment location.
Table 15.1 Maximum Theoretical Shadow Flicker Occurrence at Each
Assessment Location
Assessment
Location
Theoretical
Frequency of
Shadow
Occurrence
(days/year)
Theoretical
Max Hours
Shadow
per Day
15.11 The instances of shadow flicker will always be less than that predicted by
the model as these are based on the worst case scenario. The
occurrence of shadow flicker is only possible during the operation of the
wind farm (i.e. when the rotor blades are turning) and when the sky is clear
enough to cast shadows.
15.12 It is important to consider the following facts when making an assessment:
climatic conditions dictate that the sun is not always shining. Regional
Met Office data gives actual sunshine hours for the „Midlands‟ region
(which includes South Yorkshire) to be 32% of total daylight hours 14 .
Cloud cover during other times may obscure the sun and prevent
shadow flicker occurrence. While some shadow may still be cast under
slightly overcast conditions, no shadow at all would be cast when
heavy cloud cover prevails. It is considered that weather conditions
will reduce actual occurrence of shadow flicker by at least half,
compared to calculated levels;
14 Met Office Data from http://www.metoffice.gov.uk/climate/uk/averages/19712000/
1408 actual sunshine hours per year/4380 daylight hours per year = 32%
296
Theoretical
Mean Hours of
Shadow per
Day
Theoretical
Total Hours
per Year
H1:Morthen 0 0 0 0
H2:Brampton-en-le
Morthen
99 0.62 0.45 45
H3:Ulley Beeches 179 1.15 0.71 126.9
H4:Penny Hill Lane 234 0.71 0.45 104.9
H5:Turnshaw Road 95 0.5 0.37 35.2
H6:Vassey Close
Farm
84 0.48 0.4 34
H7:Ulley 160 0.53 0.41 65.6
Penny Hill Wind Farm
Environmental Statement