Brief Synopsis of the Japanese MOE Sponsored Evaluation of Wind Turbine Noise

Brief Synopsis of the Japanese MOE Sponsored Evaluation of Wind Turbine Noise Principal Investigator: Dr. Hideki Tachibana Presented by Mark Bastasch, PE, INCE Slides Courtesy of Dr. Tachibana

Research on the Evaluation of Human Impact of Low Frequency Noise from Wind Turbine Generators (sponsored by the Ministry of the Environment, Japan) The Ministry of the Environment, Japan Research Committee WG for Field Measurement WG for Social Survey Executive Groups West-Japan Middle-Japan East-Japan Secretariat: Chiba Institute of Technology and INCE/J WG for Auditory Experiments WG for Material Survey Acoust. Lab., I.I.S.,Tokyo Univ. Research group for the study program on wind turbine noise

Double wind-screen wind-screen 2 cm wind-screen 7 cm Naked Mic. 8 Hz in 1/3 octave band 16 Hz in 1/3 octave band Experiments on the performances of the wind-screen

Table 1 Wind farms under the field measurements ID W1 Scale of the wind farms and geographical features 1 turbine of 1.98 MW on a hill of a peninsula Measurement Dec. 21 W2 W3 7 turbines of 2.5 MW in mountainous area 1 turbines of 2 MW in mountainous area Jan. 211 Feb. 211 W4 W5 1 turbines of 1,3 MW in mountainous area 9 turbines of 1.5 MW on a tableland Mar. 211 Feb. 211 W6 W7 6 turbines of 1.5 MW on a tableland 9 turbines of 2.3 MW along the ridge of a mountain Feb. 211 Aug. 211 W8 W9 21 turbines of 2.4 MW in mountainous area 9 turbines of 1.5 MW along a coast Oct. 211 Dec. 211 W1 W11 1 turbine of 1.5 MW in the skirts of a mountain 1 turbine of 1.98 MW on a mountaintop along a coast Dec. 211 Jan. 212 W12 5 turbine s of 1.99 MW in a hilly area Aug. 211 W13 1 turbine of 1 MW in a plain Nov. 211 29 W14 17 wind turbine s of farms 2 MW along the across ridge of a mountainjapan Dec. 211 W15 15 turbines of 2.5 MW along the ridge Jan. 212 W16 5 turbines of 3 MW along a coast Jan. 212 (164 W2 2 turbine measurement s of 4 kw, 4 turbines of 6 kw points and 2 Oct. in 211 turbines of 1.5 MW in flat farmlands W22 1 turbine of 1.95 MW a mountaintop Aug. 212 total W23 1 turbine in of immission 1.955 MW in a plain along areas) a coast Aug. 212 W24 1 turbines of 1.3 MW on a mountaintop Sep.-Oct. 212 W25 W27 8 turbines of 1.3 MW along the ridge of a mountain 2 turbines of 1 MW, 5 turbines of 1.5 MW and 14 Oct. 212 Sep. 212 turbines of 1.65 MW in a vast grassland W28 5 turbines of 1.5 MW and 1 turbine of 2.5 MW (not operated) on a hill along a coast Oct. 212 W29 1 turbine of 1.5 MW in gently sloping mountainous area Oct. 212 W3 1 turbines of 2 MW around a gently sloping mountainous area Nov. 212 W31 W32 1 turbine of 6 kw on a hill 1 turbine of 1 MW between harbor facilities and a Jan. 213 Sep. 212 coastal park W33 1 turbine of 4 kw in a hilly park Sep. 212 W34 1 turbines of 1.95 MW in farmlands Sep. 212

1/3 octave band sound pressure level [db] 1 9 8 7 6 5 4 3 2 1 Frequency [Hz] Hearing threshold levels in DIN 4568 Hearing threshold levels in NSG guideline Criterion curve by Moorhouse et al. Hearing thresholds for pure tones (ISO 389-7) 1 2 4 8 16 31.5 63 125 25 5 1k 2k 4k Measurement results of WTN at 164 points around 29 wind farms

4.21 m 4.4 m Sound absorptive finishing (3 cm) 6.72 m Sound absorbing material 16 woofers + full range LS. 3.5 m Listening position Expanded metal + carpet (.9 m height) 6.86 m Power Amplifier (SONY, SRP-P45) Power Amplifiers (Accuphase, Pro-3 4) Multi-channel Interface (RME, Multiface AE) PC (hp) Listener s response Acoustic Lab., IIS, The University of Tokyo Hearing-thresholds for pure-tones at low frequencies (1 Hz 25 Hz) Audibility of low frequency components in WTN Hearing-thresholds for band-limited noise in low frequency range Effect of Amplitude Modulation in WTN Loudness sensation for various kinds of environmental sounds Auditory experiments

1/3-octave-band sound pressure level [db] 9 8 7 6 5 4 3 2 1 Test sounds No.1: WTN near a wind turbine (56 dba) No.2: WTN outside a residence (44 dba) No.3: WTN inside a residence(27 dba) 4 8 16 31.5 63 125 25 5 1k 2k 4k Frequency [Hz] Audibility of low frequency components in WTN

1/3-octave-band sound pressure level [db] 9 8 7 6 5 4 3 2 1 Audible/sensible? No.1: WTN near a wind turbine (56 dba) 4 8 16 31.5 63 125 25 5 1k 2k 4k Frequency [Hz] Over all Audibility of low frequency components in WTN

Test sound No.1, cut-off: 125 Hz on off on Modulation of the test sound subject s response off Time [s] 124 (a) on/off of the test sound and the subject s response Correlation coefficient 1..8.6.4.2. -.2-8 38 ms.979-6 -4-2 2 4 6 8 Time delay [s] (b) Cross-correlation between the two binary signals shown in figure (a) Audibility test by applying the MLS modulation technique

Test sound No.1, cut-off: 2 Hz on Modulation of the test sound off on subject s response off Time [s] 124 (a) on/off of the test sound and the subject s response Correlation coefficient 1..8.6.4.2. -.2-8.31-6 -4-2 2 4 6 8 Time delay [s] (b) Cross-correlation between the two binary signals shown in figure (a) Audibility test by applying the MLS modulation technique

1/3-octave-band sound pressure level [db] 9 8 7 6 5 4 3 2 1 7/1 4 8 16 31.5 63 125 25 5 1k 2k 4k Frequency [Hz] Over all Audibility of low frequency components in WTN

1/3-octave-band sound pressure level [db] 9 8 7 6 5 4 3 2 1 3/1 4 8 16 31.5 63 125 25 5 1k 2k 4k Frequency [Hz] Over all Audibility of low frequency components in WTN

1/3-octave-band sound pressure level [db] 9 8 7 6 5 4 3 2 1 /1 Over all 4 8 16 31.5 63 125 25 5 1k 2k 4k Frequency [Hz] Audibility of low frequency components in WTN

1/3-octave-band sound pressure level [db] 9 8 7 6 5 4 2 1 /1 /1 1/1 /1 3/1 1/1 7/1 1/1 1/1 1/1 1/1 Background noise in the test room Frequency [Hz] Cutoff frequency 125 Hz 63 Hz 5 Hz 4 Hz 31.5 Hz Over all 25 Hz 2 Hz 16 Hz 12.5 Hz 1 Hz Conclusion: 3 Infrasound in this WTN is not audible/sensible. 4 8 16 31.5 63 125 25 5 1k 2k 4k Audibility of low frequency components in WTN

Relative response [db] +1-1 -2-3 -4-5 -6-7 C A 16 31.5 63 125 25 5 1k 2k 4k 8k 16k 31.5k Frequency [Hz] A-weighted SPL : L A Applicable? Various kinds of environmental noises Wind turbine noise

Categories No. Contents L Aeq,1s [db] (a) Environmental sounds (1) (a) Environmental sounds (1) (b) Transportation noises (5) (b) Transportation noises (5) (c) Cabin noises (7) (c) Cabin noises (7) (d) Other environmental sounds (6) noises(6) (d) Other environmental (e) Wind turbine noises (5) (e) Wind turbine noises (5) (f) Model noises for wind turbine noise (5) (f) Model noises for WTN (4) 1 Environmental sound in a forest 31 2 Sound of soughing through pine trees 61 3 Environmental sound on a seashore : A 61 4 Environmental sound on a seashore : B 54 5 Environmental noise in residential area : A 43 6 Environmental noise in residential area : B 32 7 Environmental noise in residential area : C 38 8 Noise in an industrial estate 49 9 Chirp of cicada in summer 54 1 Chirp of insects in autumn 38 11 Railway noise 76 12 Road traffic noise (distance: 22 m) 76 13 Road traffic noise (distance: 85 m) 63 14 Road traffic noise (distance: 85 m, in house) 43 15 Aircraft noise 65 16 Cabin noise in a jet-plane A 73 17 Cabin noise in a jet-plane B 81 18 Cabin noise in a super-express train 68 19 Cabin noise in a super-express train in a tunnel 71 2 Cabin noise in a conventional train 7 21 Cabin noise in (31 a conventional to train 81 running db on a steel inbridge L 7 22 Cabin noise in a car running on a highway Aeq ) 72 23 Air-conditioning equipment : A 4 24 Air-conditioning equipment : B 61 25 Air-conditioning equipment : C 66 26 Structure-borne sound from a subway truck 45 27 Concourse of a railway station 64 28 Construction noise (concrete breaker) 79 29 Wind turbine noise (near a wind turbine) 56 3 Wind turbine noise (residential area: outside) 43 31 Wind turbine noise (residential area: inside) 27 32 Wind turbine noise (with insects sounds) 41 33 Wind turbine noise (insects sounds were cut off) 37 34 35 35 Artificial noises with a spectrum characteristic of 45 36-4dB/octave in band spectrum modeling general wind 55 37 turbine noises 65 38 75 38 kinds of environmental sounds 38 sounds used in the experiment on the loudness for environmental sounds

(a) Environmental sounds (b) Transportation noises (c) Cabin noises (d) Other environmental noises (e) Wind turbine noises (f) Model noises for WTN 38 sounds used in the experiment on the loudness for environmental sounds

The loudness scores obtained in the experiment were arranged by using four kinds of noise indicators: (i) L Aeq : time-averaged A-weighted SPL (IEC 61672-1) (ii) L Ceq : time-averaged C-weighted SPL (IEC 61672-1) (iii) LL Z : Zwicker loudness level (ISO 532B) (from the time-averaged 1/3-octave-band SPLs from 25 Hz to 12.5 khz) (iv) LL MG : Moore-Glasberg loudness level (ANSI S3.4-27) (from the time-averaged 1/3-octave-band SPLs from 5 Hz to 16 khz) Loudness test by 7-step category

Loudness score (7-step category) 7 6 5 4 3 2 (i) L Aeq (i) L Aeq r=.993 1 2 3 4 5 6 7 8 9 1 11 L Aeq [db] 7 Loudness score (7-step category) 7 6 5 4 3 2 (ii) L Ceq (ii) L Ceq r=.934 1 2 3 4 5 6 7 8 9 1 11 L Ceq [db] 7 Loudness score (7-step category) 6 5 4 3 2 (iii) LL ZZ r=.991 1 2 3 4 5 6 7 8 9 1 11 LL Z [phon] Loudness score (7-step category) 6 5 (iv) LL MG MG 4 3 2 r=.988 1 2 3 4 5 6 7 8 9 1 11 LL MG [phon] Loudness test by 7-step category

Relative response [db] +1-1 -2-3 -4-5 -6-7 C A 16 31.5 63 125 25 5 1k 2k 4k 8k 16k 31.5k Frequency [Hz] A-weighted SPL : L A Applicable Various kinds of environmental noises Wind turbine noise

CONCLUSIONS (1) Acoustical characteristics of WTN: The frequency components in infrasound region contained in WTN are generally much below the hearing thresholds and hardly audible/sensible. However, most of the frequency components in audible frequency range are above the hearing thresholds and can cause annoyance when the background noise is low. Therefore, WTN should be discussed as an audible environmental noise. 1 8 1/3 octave band sound pressure level [db] 9 8 7 6 5 4 3 2 1 Not Audible/ sensible Frequency [Hz] Hearing threshold levels in DIN 4568 Hearing threshold levels in NSG guideline Criterion curve by Moorhouse et al. Hearing thresholds for pure tones (ISO 389-7) - 4 db/octave Audible 1 2 4 8 16 31.5 63 125 25 5 1k 2k 4k Sound Pressure Level [db] 7 6 5 4 3 2 1 /1 /1 1/1 /1 1/1 3/1 1/1 7/1 1/1 1/1 1/1 8 16 32 63 125 25 5 1k 1/3 octave band center frequency [Hz] Auditory experiment on low frequency components in WTN

CONCLUSIONS (2) Noise indicator: WTN can be assessed by the A-weighted SPL as a primary indicator, in common with general environmental noises. Relative response [db] +1-1 -2-3 -4-5 -6-7 C A 16 31.5 63 125 25 5 1k 2k 4k 8k 16k 31.5k Frequency [Hz] A-weighting Loudness score (7-step category) 7 6 5 4 3 2 (a) L Aeq r=.993 1 2 3 4 5 6 7 8 9 1 11 L Aeq [db] Loudness test on various noises

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