Acoustic Noise Generated by Wind Turbines

Transcription

1 Acoustic Noise Generated by Wind Turbines Presented at the Lycoming County, PA Zoning Board Hearing on 12/14/25 Oguz A. Soysal, Ph.D. Frostburg State University Department of Physics and Engineering Frostburg, MD

2 Overview Measurements at distance of.55 miles from wind farm in Meyersdale, PA Sound level measurements Sound recordings Analysis of the frequency composition of the noise generated by wind turbines Analysis of the ambient noise level as a function of wind speed Discussion of the wind turbine noise characteristics (C) O. A. Soysal Lycoming County Hearing 2

3 Meyersdale Wind Generation Facility Located in Somerset County near Meyersdale, in southwestern Pennsylvania Consists of 2 wind turbines, Rated power of turbines: 1.5-MW Tower height: 375 (C) O. A. Soysal Lycoming County Hearing 3

4 Test Equipment Extech Datalogging sound level meter (Model#47764) Marantz Professional portable solid state recorder (Model PMD67) Omni-Directional microphone with frequency response 6Hz 12kHz and sensitivity 7 db (C) O. A. Soysal Lycoming County Hearing 4

5 Meyersdale, PA Sound recordings Time (s) Distance to windmills:.55 miles Recording date: October 29, 25 Time: 11: Frequency (Hz) (C) O. A. Soysal Lycoming County Hearing 5

6 Meyersdale, PA Frostburg, MD Time (s) Time (s) (C) O. A. Soysal Lycoming County Hearing Frequency (Hz) Frequency (Hz)

7 Sound recording and sound level measurements at Meyersdale, PA Recording date: November 2, 25 Time: 4:2PM Time (s) Frequency (Hz) Sound Level [db(a)] Time [s] Time [s] (C) O. A. Soysal Lycoming County Hearing 7 Sound Level [db(c)]

8 Ambient Noise versus Wind Speed No windmill.55 miles from Meyersdale wind farm Sound level db(a) Wind speed (miles/hr) Noise Level (dba) Wind speed (mi/hr) Wind speed measured in ground level, at the same location as the sound level measurement (C) O. A. Soysal Lycoming County Hearing 8

9 Lycoming County Zoning Ordinance Frequency Band (Cycles/second) ,2 1,2 2,4 2,4 4,8 Above 4,8 Noise Protection Levels Maximum Permitted Sound- Pressure Level (db) Corrected max. level as per Table 513.B due to periodic character of noise (db) (C) O. A. Soysal Lycoming County Hearing

10 IEC 614-Wind Turbine Generator Systems Part 11 Acoustic Noise Measurement Techniques Annex A Other possible characteristics of wind turbine noise emission and their quantification (page 35) (C) O. A. Soysal Lycoming County Hearing 1

11 db Weighing (C) O. A. Soysal Lycoming County Hearing 11

12 Sound Level Measurements in Meyersdale, PA; Distance to wind farm:.55 miles 1/22/25-4:13 PM 1/22/25-4:15PM Sound Level (dba) Sound Level (dbc) Time (seconds) Time (seconds) 1/22/25-1:9PM 1/22/25-1:12PM Sound Level (dba) (C) O. A. Soysal Lycoming County Hearing 12 Time (seconds) Sound Level (dbc) Time (seconds)

13 One-day Noise Measurements 11/27/25 - Meyersdale PA Sound Lavel (dbc) Hours 11/27/25 - Ground level wind speed Wind speed (miles/hr) Hours (C) O. A. Soysal Lycoming County Hearing 13

14 Subjective Issues A listener s ability to hear noises depend on many subjective factors The turbine noise is distinguished from the random background noise because of its periodic characteristic Wind speed in the ground level usually do not correlate to the wind speed at the height of the turbine A lower level masking noise in the ground level affect the listener s ability to hear the turbine noise (C) O. A. Soysal Lycoming County Hearing 14

15 Conclusions Recorded wind mill noise contains dominant low frequency components below 1 Hz Recordings clearly show the noise is distinguished from the background noise due to its periodic characteristic The noise level difference between A and C weighing is approximately 2 db A weighing does not represent adequately the wind turbine noise C weighing noise level measurements indicate that the noise level at.55 mile distance exceeds the Lycoming County Zoning ordinance (C) O. A. Soysal Lycoming County Hearing 15