Especially with regards to the building of wind turbines, the sound immissions arising in the soundings of the selected locations must be evaluated with regards to whether the standard values set forth by the Sixth General Administrative Regulation to the Federal Immission Control Act (technical instructions for safety against noise – “TA Lärm”) can be observed:
This evaluation is done in a sound immission prognosis. Among other things, this takes into consideration the guidelines of the technical instructions for safety against noise, the DIN/ISO 9613-2, DIN EN 50376 and if necessary, special state-specific regulations and enactments.
The calculation of sound propagation is done using appropriate software; the submitted report entails the following key points:
During operation of wind turbines, periodical shadow flickers occur in the surroundings of a wind turbine due to the revolving rotor. Studies have shown that prolonged exposure to this strong light change can evoke stress situations.
This should therefore be considered in the planning phase and a prognosis calculation for the expected impact determined. Recommendations of the Federal Committee for Immission Control consider the following values acceptable:
The shadow flicker prognosis allows conclusions to be drawn about the times when periodical shadow flicker can be determined for selected living or working locations in the surroundings (shadow receptors). Generally, the calculation may be based on two different approaches:
Determination of the astronomically maximally possible shadowing – the worst case is calculated.
Determination of the meteorologically likely shadowing – the meteorologically most likely shadow duration based on statistical values with regards to sunlight and wind is calculated.
Calculation of the times with periodical shadow flicker takes place using special software; the submitted report contains statements regarding the following key points: