Comment Period: 30 days: submissions may be made between June 03, 2008 and July 03, 2008. Description of Policy: The ministry is proposing some clarifications to its “
Interpretation for Applying MOE NPC Technical Publications to Wind Turbine Generators” (Interpretation Document). The current Interpretation Document was developed in 2004 to provide interpretation of existing ministry Noise Pollution Control (NPC) Publications to wind turbine generators. Although the Document has proved to be a valuable tool in helping proponents determine what information should be submitted when applying for noise approvals for wind farms, a number of clarifications are required to ensure that proponents’ assessments reflect the principle of the “predictable worst case” noise impact. Because of the lack of clarity in some areas, submissions can vary widely. In some cases, proponents’ submissions make quite conservative assumptions, and in other cases, assumptions are less conservative. The ministry has been providing guidance to proponents on a project-by-project basis to ensure that project assessments reflect the predictable worst case emission scenario. To ensure that these clarifications are communicated consistently to all proponents, and to provide opportunity for input, the ministry has reflected this guidance in the
revised Interpretation Document and is posting it on the Environmental Registry for comment.
It is important to note that changes to the ministry’s noise limits are not being considered at this time. See “Other Information” for further details on the ministry’s broader wind turbine noise policy review.
Changes proposed in the attached Interpretation Document are set out below in the order in which they appear in the document. Please see the attached proposed revised Interpretation Document for further details.
Structure of Document A Table of Contents and numbered sections have been added to improve the layout and structure of the document and to improve consistency with other ministry noise publications.
Changes to Table 1 and Figure 1 Table 1 and Figure 1 set out the sound level limits. The limits in both the table and figure relating to the wind speed at 11 metres per second (m/s) have been removed because the International Electrochemical Commission (IEC) standard referenced in the Interpretation Document does not require assessment of noise emissions at wind speeds above 10 m/s . The “wind-induced background sound level”, which was represented by a solid line in the 2004 document, is now a dashed line, and the text relating to the figure and table clarify that the line is not a limit, but is presented for information purposes.
Transformer SubstationsThe 2004 document did not provide guidance regarding the assessment of noise from transformer substations associated with a wind farm. The ministry is proposing to clarify that noise from transformer substations must be considered with noise from the wind turbines. See sections 4.2, 4.3 and 5.4.4 of the proposed revised document. The guidance regarding transformer substation noise indicates that a tonal penalty must be applied, in accordance with Publication NPC-104.
Noise Assessment Report (Section 5) Additional guidance is provided in proposed section 5 of the document regarding the information that proponents are to submit to the ministry when seeking approval for a wind farm. The document indicates that proponents of wind farms are to prepare a Noise Assessment Report and sets out the information to be included in this report (details set out below).
Project Layout (Section 5.1)
Clarification is provided regarding what information proponents are required to provide about the project layout. This section would require that proponents include available information about other existing or planned wind farms within 5 kilometre (km) of the proposed Wind Farm.
Adjustment to Wind Turbine Acoustic Emissions for Wind Profile (Section 5.2.3) The ministry is proposing in the document to require proponents to indicate adjustments to the manufacturer’s data for the site-specific wind profile conditions. Some acoustical professionals are currently indicating such adjustments and using the adjusted emissions data in their noise impact assessments, and the ministry proposes that all proponents be required to include and use such information in their submissions. This will ensure consistency and fairness in submissions and in the assessment of expected noise emissions.
Noise Sources and Locations (Section 5.2.5) This section provides clearer direction regarding the information required by the ministry on noise sources.
Points of Reception – Location for Assessment (Section 5.3.1) This section provides guidance on how proponents are to identify for Points of Reception the specific location for assessment purposes. Separate guidance is provided for single, two storey and multiple storey dwellings. The intent is to allow proponents to choose a less complex assessment location as long as that location represents the predictable worst case scenario.
For single-storey dwellings, the ministry proposes that the proponent be able to choose a location at either 4.5 metres (m) above grade at the centre of the dwelling, or 1.5 m above grade and 30 m horizontally from the dwelling. The 4.5 m location is much less complex for modelling and assessment purposes and thus is the ministry’s preference. However, if a proponent wishes to perform the assessment at locations 1.5 m above grade and 30 m from the dwelling in the direction of each wind turbine location this will be acceptable to the ministry.
For two storey dwellings, the ministry proposes that proponents identify locations for assessment at 4.5 m above grade at the centre of the dwelling, or at 1.5 m above grade and 30 m horizontally from the dwelling in the direction of each wind turbine location. In this case the proponent must choose the location that results in the higher noise impact, and it is expected that this would be the location at 4.5 m. The intent is to allow proponents to choose a less complex location for assessment as long as that location represents the worst case scenario. A similar approach to identifying locations for assessment for three or more storey dwellings is proposed in the attached document.
The ministry is considering whether to further simplify the identification of assessment locations by directing proponents to simply use the location at 4.5 m above grade at the centre of the dwelling (for single or two storey dwellings, or for three or more storey dwellings, at the centre of the highest storey). This would significantly simplify the calculations, as proponents would not need to consider assessing the 1.5 m above grade and 30 m from dwelling locations, and in almost all cases would represent the predicable worst case emission scenario. The ministry would like to hear feedback from stakeholders on the identification of assessment locations.
Points of Reception - Vacant Lots (Section 5.3.1) The document clarifies that proponents are required to include vacant lots as Points of Reception. This is consistent with the ministry’s guidance applicable to other noise sources, unrelated to wind farms. Proposed direction regarding how to define the location of the Point of Reception on a vacant lot is provided in the text at the end of section 5.3.1
Participating Receptors (Section 5.3.2) The document clarifies that, consistent with current practice that the sound level limits set out in the document do not apply to participating receptors (those where the property of the receptor is associated with the wind farm). Although the limits do not apply, proponents would be required to include information in their Noise Assessment Reports on the predicted noise impacts on participating receptors.
Noise Impact Assessment (Section 5.4)
The introduction to this section clarifies that a detailed noise impact assessment is required only in the event that points of reception are located within a 1000 m distance from any wind turbine.
Noise Impacts from Other Existing or Planned Wind Farms (Section 5.4.1) In some cases, noise impacts at a particular Point of Reception may be affected by not only the noise emissions from turbines within the wind farm seeking approval, but also by noise emissions from other existing or planned wind farms. The ministry is proposing that the combined noise impact of both the turbines being assessed and other existing or planned wind turbines be included in the noise assessment for the wind farm. The ministry recognizes that there may be limitations in the availability of information about other wind farms that are in the process of being planned, and is interested in hearing from stakeholders about how noise contributions from such projects should be addressed.
Specific Parameters – Atmospheric Attenuation (Section 5.4.2 (
)
One aspect of the analysis of noise impacts is the assessment of atmospheric attenuation. In order to maintain a consistent approach in the planning of wind farms, the ministry has identified atmospheric absorption coefficients to be used by proponents. The values selected (10 degrees Celcius and 70 percent relative humidity) were selected as they represent typical conditions in spring/summer/fall in Ontario when people are most likely to be exposed to sound (through open windows or by being outdoors). These values are commonly used in assessing impacts from industrial noise sources.
Specific Parameters - Ground Attenuation (Section 5.4.2©)
Another aspect of the analysis of noise impacts is the assessment of ground attenuation (the ability for the ground to reduce the impact of noise). Hard ground provides less attenuation of sound than does ground covered with vegetation. During ministry review of noise assessment reports, the ministry has identified situations where the ground attenuation has been overestimated by selection of a ground attenuation factor that was not conservative. Ministry reviews have also found cases where the ground attenuation has been underestimated. In order to provide consistency in the noise reports, the ministry is clarifying the maximum values that proponents may select for ground attenuation. See the attached document for the maximum values established.
Sound Level Contributions from Distant Sources (Section 5.4.5) The standard on which the noise impact prediction method is based is designed for source/receiver distance of up to about 1000 m. Although the use of the standard may be extended to larger distances, other factors affecting sound level contributions from the distant sources may need to be considered. In practice, sound level contributions from sources such as wind turbines located at very large distances from Points of Reception are affected by additional attenuation effects.
To address this in a prediction method the ministry proposes that contributions from sources located at very large distances from Points of Reception, larger than approximately 5 km, should not be included in the calculations. The ministry is interested in hearing comments from stakeholders on this proposal.
Summary Tables (Section 5.6)
The ministry has included in the revised document sample tables to be used by proponents to present information and results of their evaluations. The inclusion of such tables will ensure consistency in the submission of project information, and will facilitate efficient review by ministry staff.
Purpose of Policy: The purpose of the clarifications to the Interpretation Document is to ensure that proponents are provided with guidance to assess the predictable worst case noise impact. The clarifications will promote consistency in submissions, which in turn will help to expedite the ministry’s review and approval process. The clarifications will also ensure that noise impacts from wind turbines are accurately assessed, and ensure that the public is not adversely affected by wind turbine noise.
Other Information: The clarifications to the Interpretation Document are part of a broader wind turbine noise policy review being undertaken by the ministry. Through a review of a report prepared by a noise expert on wind turbine facilities noise issues (see Registry posting 010-2525), and through an internal review, the ministry decided in April 2008 to proceed with its wind turbine noise policy review in two stages
During the first phase, the ministry will proceed with clarifications to the Interpretation Document (the subject of this proposal posting).
During the second phase, over the coming year the ministry will continue its review of emerging science in the field of wind turbine noise impacts. If this review concludes that changes to the ministry’s wind turbine noise policies are required, these changes would also be posted on the Environmental Registry for comment.
The ministry’s current noise limits for wind turbines, which are based on existing ministry Noise Guidelines with allowances for wind-induced background noise, will remain in place as the ministry makes clarifications to the existing Interpretation document and continues its review of emerging science.
The field of noise impacts relating to wind turbines is one that is expected to continue evolving and the ministry is committed to ensuring that its noise policies for wind turbines continue to reflect current science.
Public Consultation: This proposal has been posted for a 30 day public review and comment period starting June 03, 2008. If you have any questions, or would like to submit your comments, please do so by July 03, 2008 to the individual listed under "Contact". Additionally, you may submit your comments on-line.
All comments received prior to July 03, 2008 will be considered as part of the decision-making process by the Ministry of the Environment if they are submitted in writing or electronically using the form provided in this notice and reference EBR Registry number 010-3595.
Please Note: All comments and submissions received will become part of the public record. You will not receive a formal response to your comment, however, your comment will be reflected in the Decision Notice associated with this proposal.
Other Public Consultation Opportunities: The ministry held a focus group session with selected stakeholders in October 2007. The purpose of the session was to allow a noise expert retained by the ministry to review current literature regarding wind turbine noise impacts to present his draft findings. Although the focus of this session was the noise expert’s draft findings, some stakeholders at the meeting also provided comments on the Interpretation Document. These and other unsolicited comments from stakeholders regarding the current Interpretation Document have been considered in the development of the proposed clarifications.
Contact: All comments on this proposal must be directed to:
Elaine Hardy
Senior Program Support Coordinator
Ministry of the Environment
Operations Division
Environmental Assessment and Approvals Branch
2 St. Clair Avenue West
Floor 12A
Toronto Ontario
M4V 1L5
Phone: (416) 314-8350
To submit a comment online, click the submit button below:
Additional Information: The following government offices have additional information regarding this Proposal. To arrange a viewing of these documents please call the Ministry Contact or the Office listed below.
Environmental Assessment and Approvals Branch
2 St. Clair Avenue West
Floor 12A
Toronto Ontario
M4V 1L5
Phone: (416) 314-8001
The documents linked below are provided for the purposes of enhancing public consultation.
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1.
Current Document
2.
Proposed Document