Ear to the Ground

NPC-350: Proposed Changes to the Ontario MOECC Compliance Protocol for Wind Turbine Noise

The Ontario Ministry of the Environment and Climate Change (MOECC) has recently released  NPC-350: proposed changes to the Compliance Protocol for Wind Turbine Noise. Our review and commentary of the proposed changes are summarized in the charts below.


Acoustic Audit Immission


Proposed Language / Change

Our Comments

D 3

Auditor has option to complete to Section D or Section E 5.4

New option for data


D 3.4
(p. 37)

Wind measurement position within 15m of microphone

Fewer receptors now
suitable for Audit. Potential for interference from wind tower due to close


D 3.8.3
(p. 40)

Tonality assessment in accordance with CAN/CSA-C61400-11-07

Better definition of method for determining tonality.


D 5.2. 4.
(p. 42)

Only downwind data to be considered (+/- 45 degrees in direction to wind turbine with greatest noise impact)


Audits will take longer to complete. Increased possibility of non-compliance.

D 5.2. 5.
(p. 42)

Only data when turbine output is greater than 85%.


Audits will take longer to complete. Increased possibility of non-compliance.

In case of Incomplete submissions:


E 5.3
(p. 57)

Option 1: combine Spring and Fall data


Required to complete a minimum of 6 consecutive weeks of monitoring, and to submit an interim audit report.


E 5.4
(p. 58)

Option 2: Revised Assessment Methodology (RAM) I Audit


May shorten time required to complete I-Audit.

Less data required than Section D Audit (3 wind bins instead of 4).


< 60 OFF data points and/or OFF data from lower wind bins can be utilized


< 120 ON data points for each bin


10 second data points instead of 1 minute (although 60 minutes of data still required).


Revised wind gust criteria



Acoustic Audit Emission


Proposed Language / Change

Our Comments

E 3.1
(p. 48)

E-Audits are compliant if the sound power level of the turbine is less than the approved level +0.5 dBA

This provides increased clarity on what is acceptable. It is unclear how this will be interpreted in relation to measurement uncertainty which is often still higher than 0.5 dBA

E 3.1.5. b. (p. 50)


If there is a sound level excess there are two options:



E 3.1.1
(p. 48)

Option 1 – remodel with measured
sound power level. Revised Noise Impact Assessment to be submitted to the MOECC


Provides increased clarity on direction if E-Audit indicates a sound level excess

E 3.1.2
(p. 48)

Option 2 – Conduct an I Audit or RAM I Audit at the worst point of reception


E 3.1.4 ii. (p. 49)

If an excess, develop Noise Abatement Action Plan (NAAP) which could include de-rating turbines or curtailment under specific wind speed and direction.


Provides clarity and flexibility for the operator to work with the MOECC on the most productive NAAP.

E 3.2.1 b. (p. 51)

An alternate method for analysis under IEC 61400-11 is no longer permitted


Likely a minor change.

E 3.2.1 c. (p. 51)

All measurements for one E-Audit must be made in one season.


Likely a minor change.

E 3.2.1 a. (p. 51)

Utilization of 10 second measurement intervals

Some tests may be completed quicker



 For further clarifications on the proposed changes, please contact Ian Bonsma,PEng, INCE Sr. Associate at ibonsma@hgcengineering.com or 905-826-4044.