Mt Piper Power Station Extension Noise Impact Assessment Peer Review
27 October 2009
NSW Government Department of Planning Major Infrastructure Assessments
23-33 Bridge Street
SYDNEY NSW 2001
HEGGIES PTY LTD
Delta Electricity (Delta) seeks Concept Plan Approval for the proposed Mt Piper Power Station Extension (the Project) which is state declared critical infrastructure. Heggies Pty Ltd has been engaged by the Department of Planning (DoP) to conduct an independent peer review of the noise impact assessment undertaken for the Project, including review and comment on:
- The technical adequacy and completeness of the Proponent’s noise impact assessment including methodology and modelling assumptions;
- The adequacy of mitigation measures identified for the respective projects considering reasonable and feasible criteria; and
- Recommended conditions that may be applied to the projects to minimise, mitigate and/or manage noise amenity impacts to achieve regulatory and best practice standards.
The documents examined as part of this independent peer review include (but not limited to):
- Chapter 8 Noise Impacts – Mt Piper Power Station Extension Environmental Assessment (EA), Main Report dated September 2009, prepared for Delta by Sinclair Knight Merz (SKM).
- Appendix D – Mt Piper Power Station Extension Operational and Construction Impact Assessment (NIA) dated September 2009, prepared for Delta by SKM
The scope of the review did not involve site inspection or vetting the Project noise model (or the like) but solely on the information presented in the Project EA.
1.1 Technical Completeness and Mitigation Adequacy Assessment
Technical completeness and mitigation adequacy has been generally determined by comparison to the Director General Environmental Assessment Requirements dated 4 July 2009 Noise Impacts as presented in EA Chapter 8 and reproduced as Table 1.
Table 1 Environmental Assessment Requirements – Noise Impacts
The Environmental Assessment must include a comprehensive operational noise impact assessment for the project, prepared in accordance with NSW Industrial Noise Policy (EPA,2000) considering worst case operating scenarios and meteorological conditions and cumulative impacts from surrounding power stations (including Mount Piper and Wallerawang) and the Western Rail Coal Unloader.
The assessment must consider the potential for low frequency noise generation and peak noise events with the potential to cause sleep disturbance. The Environmental Assessment must also consider the potential for:
Construction noise impacts considering potential cumulative impacts from the concurrent construction works (eg Western Rail Coal Unloader) consistent with the DECC’s “construction noise existing guidelines” available electronically at http://www.environment.nsw.gov.au/noise/constructnoise/htm.
Vibration impacts during construction and operation consistent with Assessing Vibration: A Technical Guideline (DECC, 2006); and
Traffic generated noise during construction and operation consistent with Environmental Criteria for Road Traffic Noise (EPA, 1999)
The Environmental Assessment must include a framework for the mitigation, management and monitoring of noise impacts, particularly with respect to sensitive receptors likely to be significantly impacted by cumulative noise impacts in the local area.
In addition, the DECCW has specifically requested the following assessment requirements:
- Assessment requirements for potential noise from increased rail movements on the NSW Rail Network can be provided if rail transport is proposed as part of the application.
- Levels of operational noise and vibration from any existing power station on the licensed premises needs to be presented, together with predicted levels for any new power station; and,
- The combined operational noise and vibration from both existing and proposed power stations on the licensed premises, not just solely from the proposed power stations alone, needs to be compared against the relevant criteria.
- Cumulative noise and vibration impacts are to be assessed by consideration of noise from other premises.
2.1 Operating Activities
The Proponent has endeavoured to assess both the Coal Fired and Gas Fired power station alternatives. Nominated plant and equipment details for the Coal Fired station together the allocated Sound Power Levels (SWLs) are presented in Table 8. (see downloadable document at bottom of page for Table 8)
Comment: The Proponent has not identified any specific noise mitigation requirements for the proposed Coal Fired station and has determined a total SWL of 121 dBA. However, based on a similar proposal in the Hunter Valley for a 2000MW Coal Fired station it is reasonable to anticipate the source noise potential for the Mt Piper extension to be approximately 140 dBA (without mitigation) and approximately 125 dBA to 130 dBA (with mitigation). It appears the Proponent has potentially understated the Coal Fired station source noise SWL by at least 4 dBA (assuming full mitigation).
The Nominated plant and equipment details for the Gas Fired station together the allocated (SWLs) are presented in Table 9. (see downloadable document at bottom of page for Table 9)
Comment: Similarly, it appears the Proponent has not identified any specific noise mitigation requirements for the proposed Gas fired station and has determined a total SWL of 108 dBA (ie equivalent to the only single item of construction equipment such an excavator). Again based on a similar proposal in the Hunter Valley for a 2000MW Gas Fired station its is reasonable to anticipate the source noise potential of a 2000MW power station to approximately 140 dBA (without mitigation) and approximately 125 dBA to 130 dBA (with mitigation). It appears the Proponent has potentially understated the Gas fired station source noise SWL by at least 17 dBA (assuming full mitigation).
2.1 Operating Noise Assessment
The NIA Section 5 (Coal) and Section 6 (Gas) presents the predicted operating noise levels at assessment Locations A to D under neutral and noise enhancing weather conditions. The predicted (cumulative) operating noise levels included the existing Mt Piper station, the proposed extension and the Western Rail Coal Unloader however individual project noise contributions are not provided.
The Proponent notes the INP requirements with regard to modifying factor adjustments and the predicted levels include a 5 dBA penalty due to potential low frequency noise. (Note, this should not deter the Proponent from undertaking to address any potential low frequency noise during the preferred station project approval and detailed engineering design phase).
Comment: The INP requires an assessment of prevailing wind, temperature inversion (and combinations as appropriate) that have the potential to enhance noise emissions from the Project.
The noise assessment relies on the meteorological analysis reported at the Mt Piper station in 2001 with regard to frequency of occurrence of seasonal winds and atmospheric stability. The Proponent’s wind analysis does not appear to be in accordance with the INP’s requirements (perhaps) leading to the inappropriate conclusion that prevailing winds are not a feature of the area. However, moderate temperature inversions (F-class atmospheric stability 1.5oC/100 m to 4oC/100 m) and associated west southwest 1.5 m/s drainage flow are determined to be feature of the site.
In any case, the Proponent also includes INP’s default meteorological parameters applicable to non-arid areas and applied the following noise enhancing weather conditions:
- Source to receiver winds 3 m/s; and
- F-class stability plus source to receiver winds 2 m/s