As a result we believe that the current draft guidelines from the NWG reveal a fundamentally flawed, unsound scientific approach in all areas. The draft guidelines do not, therefore, in our view form a suitable starting point for wider consultation. Planks A–C Summaries Plank A: Background Noise Measurement Measurement Location Free field or facade? Common sense says ‘facade’ as this is where residents will experience the noise but the guidelines say ‘free field’. What’s the difference? Background can be around 3dB lower at the facade due to screening and turbine noise can be 3dB higher due to reflection. This yields up to a 6dB difference within the assessment. Why measure background noise at 1.2 to 1.5m height and not at ground level where we could minimise wind induced noise as is the case for measuring turbine noise? Where is the science to justify this measuring height? Microphone Wind-Induced Noise There is data contamination at wind speeds above around 5m/s No commercially available wind screens currently being used are suitable for measuring in windy conditions. Magnitude of the data contamination is unknown. ETSU report W/13/00386/REP has been used and quoted out of context. The letter from Ed Davey MP is totally wrong on this. Directional Screening The guidance fails to recognise the importance for this or to provide for a robust directional screening process. It is particularly important for sites near motorways and major roads. Poor Statistical Science We see widespread misuse of statistical regression analysis and a failure by decision makers to question or even understand the analysis. This allows a misuse of science providing developers the opportunity to steal 2 or 3dB extra to noise limits. This is ‘Bad Science’ being employed to confuse decision makers. Plank B: Turbine Noise Wind Shear Correction
As a result we believe that the current draft guidelines from the NWG reveal a fundamentally flawed, unsound scientific approach in all areas. The draft guidelines do not, therefore, in our view form a suitable starting point for wider consultation. Planks A–C Summaries Plank A: Background Noise Measurement Measurement Location Free field or facade? Common sense says ‘facade’ as this is where residents will experience the noise but the guidelines say ‘free field’. What’s the difference? Background can be around 3dB lower at the facade due to screening and turbine noise can be 3dB higher due to reflection. This yields up to a 6dB difference within the assessment. Why measure background noise at 1.2 to 1.5m height and not at ground level where we could minimise wind induced noise as is the case for measuring turbine noise? Where is the science to justify this measuring height? Microphone Wind-Induced Noise There is data contamination at wind speeds above around 5m/s No commercially available wind screens currently being used are suitable for measuring in windy conditions. Magnitude of the data contamination is unknown. ETSU report W/13/00386/REP has been used and quoted out of context. The letter from Ed Davey MP is totally wrong on this. Directional Screening The guidance fails to recognise the importance for this or to provide for a robust directional screening process. It is particularly important for sites near motorways and major roads. Poor Statistical Science We see widespread misuse of statistical regression analysis and a failure by decision makers to question or even understand the analysis. This allows a misuse of science providing developers the opportunity to steal 2 or 3dB extra to noise limits. This is ‘Bad Science’ being employed to confuse decision makers. Plank B: Turbine Noise Wind Shear Correction
submission_to_environment_committee.docx