Environmental Noise Assessment
A Background Noise Monitoring Report and Environmental Noise Assessment have been undertaken for the Project by Marshall Day Acoustics. The MDA assessments have also been subject to peer review by Sonus and Environmental Audit by an EPA Appointed Environmental Auditor, in accordance with the requirements Clause 52.32-4 of the Planning Scheme.
The process for the noise assessment is:
- assess the background noise levels at residential properties (receivers) around the project;
- assessing the land zoning of the project site and surrounding areas;
- establishing the noise criteria accounting for background noise levels and land zoning;
- predict the level of noise expected to occur as a result of the proposed turbines and battery storage facility; and
- assess whether the development can achieve the requirements of Victorian policy and guidelines by comparing the predicted noise levels to the noise criteria.
Different turbines generate different noise outputs and the turbine to be installed in the wind farm will be selected via a tender process prior to construction. Three different turbine models that are likely to be among those to be selected for the project have been used to complete the Noise Impact Assessment:
- Vestas V162-5.6MW;
- GE Renewable Energy 5.5-158; and
- Siemens Gamesa SG 6.0-170
Provision has been made in the modelling for measurement uncertainties in manufacturer noise specifications to ensure the modelling provides a conservative assessment of ‘worst-case’ noise emissions.
Legislation and Policy
The relevant legislation and government policies required to be considered in the Assessment include:
- Development of Wind Energy Facilities in Victoria – Policy and Planning Guidelines (March 2019);
- New Zealand Standard 6808:2010 Acoustics – Wind farm noise (NZS 6808:2010) (the NZ Standard);
- EPA publication 1411 titled Noise from Industry in Regional Victoria – Recommended maximum noise levels from commerce, industry and trade premises in regional Victoria (NIRV);
- EPA Publication 1254 Noise Control Guidelines (EPA Publication 1254).
Background noise monitoring was undertaken at nine ‘receivers’ (dwellings identified as being in the vicinity of the Project) in the vicinity of the proposed wind farm between 6 March 2020 and 18 June 2020 to determine the existing conditions relevant to the site. The results of this monitoring which varies with wind speed was then used in the noise impact assessment.
All noise levels are expressed as decibels (dB), which is the standard unit used to describe sound levels. The NZ Standard, which is required to be used in Victoria requires the noise level from a wind turbine at a noise sensitive location to be no more than 5dB above the background noise level or 40dB, whichever is greater. Compliance with the NZ Standard does not mean that the wind farm will never be heard at all locations.
High Amenity Areas
The NZ Standard also requires lower limits in areas of ‘high amenity’ during evening and night-time periods of no more than 5dB above background or 35dB, whichever is greater. High amenity noise limits are not applicable during the daytime period.
Special Audible Characteristics
Wind turbine sound levels with special audible characteristics (such as tonality, impulsiveness and amplitude modulation) are addressed in the Standard by requiring them to adjusted by arithmetically adding up to +6dB to the measured level at the noise sensitive location.
Applicable Noise Limits
The background noise assessment is used to determine the applicable noise criteria at different wind speeds, being 40dB (or 35dB for High Amenity) or background LA90 plus 5dB (whichever is greater). The assessment concluded that the High Amenity limit under the NZ Standard does not apply to any of the dwellings surrounding the site.
Results of the noise modelling with the predicted 35dB and 40dB noise contours are shown in Figures 1 to 3 for each of the three turbines modelled, at the wind speeds that generate the highest predicted noise levels.
This noise modelling results demonstrate that the proposed wind turbines are predicted to comply with the operational noise requirements of the NZ Standard, as required by the Victorian Wind Energy Guidelines.
The peer review concludes that the Marshall Day assessment has been conducted in accordance with the Wind Energy Guidelines and the assessed layout will achieve the objective requirements of the Project.
EPA Auditor Findings
An environmental audit has been completed in accordance with Section 53V of the Environment Protection Act 1970 of the assessment undertaken by Marshall Day of the proposed wind farm.
The auditor agreed with the approach taken and the conclusions drawn in the noise assessment and included two recommendations for additional assessment works relating to tonality of selected turbines and post construction noise monitoring consistent with the recommendations of Marshall Day Acoustics.
Figure 1: Highest predicted noise level contours, dBLA90 for Turbine Model V162-5.6MW (Source: Environmental Noise Assessment, Marshall Day 2020)
Figure 2: Highest predicted noise level contours, dBLA90 for Turbine Model GE 5.5-158 (Source: Environmental Noise Assessment, Marshall Day 2020)
Construction of a wind farm project will generate noise and vibration from activities occurring both on and off the site of the proposed development. Off-site noise generating activities primarily relate to heavy goods vehicle movements to and from the site, whilst on-site works include a range of activities such as construction of access tracks, connection infrastructure, turbine foundations and erection of the turbines.
The construction activity that typically occurs nearest to receivers is access road construction. This activity involves a short period of elevated noise while work is carried out to improve existing roads in some locations, create new intersections at site access points, and construct site access tracks. During these initial works, construction noise levels of the order of 70 to 75 dB could be expected for brief periods when road and access work is carried out.
During minor public road upgrade works for the Delburn Wind Farm, three receivers along Golden Gully Road would be located less than 500 metres from this type of construction activities. These noise levels are comparable to, and typical of, noise levels produced by general road maintenance works and activity.
Once the initial work for road access is complete the majority of the work occurs in proximity to the turbine locations, related infrastructure and on-site cabling routes and therefore there is typically greater separation distances to receivers. However, depending on noise levels and wind directions, construction noise has the potential to be audible at surrounding receivers from time to time. To mitigate this the majority of work should be restricted to normal working hours.
There are some occasions when work will be required outside normal business hours such the delivery of oversized turbine components which need to occur at times that minimise traffic disruption associated with intersection closures, and potentially turbine installation activities that are sensitive to weather conditions (e.g. installation of rotors).
Controls around construction activities will be documented and agreed in a Construction Environmental Management Plan (CEMP) which is typically included as a planning permit condition.
On the basis of the operation and implementation of a CEMP the noise assessment concludes that it is expected that construction noise associated with the wind farm can be acceptably managed.
An updated assessment of the wind farm’s compliance with the New Zealand Standard will need to be completed for the final turbine layout and selected turbine. This assessment needs to be completed prior to construction commencing and should include information based on data for the turbine chosen to be installed.
A noise management plan should also be prepared which identifies how compliance with the wind farms’ operational noise limits will be demonstrated, including details of testing procedures and reporting time frames following the commencement of operation for the wind farm.
Consideration be given to conducting indicative on-site noise emission testing for a sample of the first turbines to start generating power at the site to determine whether the turbines’ noise emissions are consistent with expectations.