Why was the assessment undertaken?
A Wind Farm can create noise due to mechanical noise produced by the wind turbine generators, movement of the rotor blades and general construction.
An Environmental Noise Assessment (ENA) (contained at Appendix G.3 of the Modification Application Report) was prepared by Sonus to assess the increase in tip height, removal of 12 wind turbines and changes to onsite ancillary infrastructure. The ENA assessed the change in potential construction and operational noise from the Approved Project to the Modified Project.
What was the approach?
The ENA was prepared considering the relevant conditions of the Development Consent and in accordance with the relevant Guidelines including:
- For Operational noise, the South Australian Environment Protection Authority’s Wind Farms – Environmental Noise Guidelines (SA EPA Guidelines)
- For Construction noise, Interim Construction Noise Guideline (ICN Guideline)
Noise predictions were based on an indicative wind turbine model being the GE 158 5.5MW wind turbine that has one of the highest noise emissions of those currently on the market. This was done to provide a conservative ‘worst case’ scenario.
What did we find and how does it compare to the approved project?
The ENA found that the noise generated from the indicative wind turbines is predicted to achieve the operational noise criteria at all residences in the vicinity of the Project, with the exception of four non-associated residences.
A curtailment regime (operating selected wind turbines in a noise reduced mode) was determined to ensure noise from the Modified Project can achieve the criteria at all residences.
The need for a curtailment strategy will be further evaluated once the final wind turbine model (which could be quieter) has been selected, the layout finalised and as part of a pre-construction noise assessment to ensure compliance with the relevant criteria.
Based on the predicted noise levels, it is expected that construction noise from wind turbine construction will be greater than 40 dB(A) at a distance of 1.2km. This noise limit is significantly less than the 75 dB(A) limit provided in the ICN Guidelines.
Against the ICN Guidelines, residences within this radius will be ‘noise affected’, meaning there may be some community reaction to noise. Construction of the internal access tracks will be 61 dB(A) at 330m from the closest non-associated residence. Again, this is below the ICN Guidelines.
What are the proposed mitigation strategies?
In accordance with the Development Consent, background noise monitoring is currently being undertaken and the preparation of a noise compliance testing plan is being progressed. The noise compliance testing plan will ensure the Project is compliant with the operational noise criteria.
Where residences are classed as ‘noise affected’, Tilt Renewables will apply all feasible and reasonable work practices and will inform residents of the proposed construction work. Strategies to be incorporated into a Construction Noise Management Plan could include:
- Scheduling construction work, including heavy vehicle movements, to between 7am and 6pm Monday to Friday, and between 8am and 1pm on Saturdays
- Locating fixed noise sources as far as reasonably practicable from residences
- Installing acoustic screens around fixed noise sources
- Enclosing generators and compressors
- Implementing alternative processes (where feasible and reasonable)
- Ensuring effective site, equipment and vehicle management and maintenance
Assessment against Development Consent
The Modified Project can comply with the existing conditions of the Development Consent relating to noise.