Test results prove wind turbine noise modelling faulty

As a service to Ontarians concerned about the use of suspect noise modelling by engineers working on behalf of wind developers to get projects approved it appears concern is warranted. HCG were instrumental in developing the noise regulations for the Ontario government. Recently they conducted a Section D audit test on the Unifor turbine. Highlights of that test are below;

Unifor Wind Turbine (Page 2)

Acoustic Immission Audit January 8, 2018

Table 1: Predicted Sound Levels and UTM Coordinates of Selected Locations

Location Easting Northing Predicted Sound Level [dBA]

J Receptor 467256 4919594 42.7±
Monitoring Location M1 467348 4919607 43.9*

T Receptor 467416 4919124 40.1±
Monitoring Location M2 467474 4919119 39.2*

Q Receptor 467169 4919269 42.0±
Monitoring Location M3 467212 4919266 44.1*

 ± Sound level taken from ENIR [1]. ( Original CAW modelling )  * Sound level predicted by acoustic model created by HGC Engineering.

NOTE: 2 of the 3 test locations modelled higher by HCG than by CAW’s original engineering consultant.

Receptor location J is a single storey cottage located at 12 Globe Place. Turbine T1 is approximately 210 m to the southeast. The sound level meter was installed on a fence at the northwest side of the Unifor property, approximately 205 m from T1, designated Monitoring Location M1. The microphone was placed at a height of 4.5 m, consistent with the ENIR.

Table 4a: Monitoring Location M1 – Sound Level Summary

10 m Height Wind Speed [m/s]

LEQ Sound Level [dBA] 1 2 3 4 m/sec

Average Operating (ON) / Std Dev. –
1 –
1 47.9 1.5 48.7 1.4

Average Ambient (OFF) / Std Dev. 34.4 3.3 36.3 3.2 40.2 2.4 42.8 1.4

Wind Project Only – – 47 47

Criteria 45 45 45 45 ( our faulty 45 db semi urban classification – normally rural at 40 db )

Excess – – 2


Closest receptor the Groves home at 12 Gobles Place at 210 m. away from the Unifor turbine was modelled at 42.7 by CAW, predicted at 43.9 by HCG and HCG audit tested it at 47 and 48 dB. An unpublished MOECC approved Section D audit test by CAW engineer on April 27,28,29 2014 had measurements of 45 db at 4m/sec and 57 dB at 6 m/sec. It was later deemed incomplete after found by FOI as CAW called off the test each night as residents unaware of testing being done called in noise complaints.

The HCG 47 and 48 dB illegal noise levels were based on an alternate test track of less than half the normal amount of measuring supposedly due to lack of good data. We had never heard of this optional test track.

Only low wind speeds between 1 to 4 m/sec (max 14.4km/hr) were used in this reduced data testing track for 1 hour averaging. Meanwhile the MOECC chart shows wind speeds from 4 to 10 m/sec. and shows that all wind speeds from 4 to 8 m/sec shall not exceed the max limit of 45 dB.

Where are the noise test results for wind speeds from 5 to 10 m/sec? No good wind for the 3rd time?? Common sense says they would be much higher than the 48 dB HCG measured and could most likely be extrapolated by talented acousticians.

So we have learned that HCG, the architect of Ontario’s noise testing regulations, has just proven how faulty the wind turbine noise modelling scheme is that MOECC uses to approve wind projects in Ontario. And while using low max. wind speeds of 4 m/sec. HCG is off by 5 dB ( 48.7-43.9 ) and that is significant.

Any yet to be approved or built wind projects like those now launching legal challenges based on concern of the adverse effects faulty modelling will have on them appear to be well justified.

Greg Schmalz

2 thoughts on “Test results prove wind turbine noise modelling faulty

  1. Do the tip speed ratios increase during a wind gust? Are the increases in tip speed ratio sound levels recorded and published? Are the operations of the wind farm rotor speeds part of any study on noise level increases? These are questions that need to be answered by the developers.

  2. Would someone please provide an update on this situation? Is it possible that, despite the fact that this turbine was finally proven to be out of compliance after years of residents reporting harm, it’s still running?

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