Draft Wind Energy Guidelines 2019 (Noise) Published

The long-awaited draft Wind Energy Development Guidelines (WEGs) for public consultation were published today by Eoghan Murphy T.D., Minister for Housing, Planning and Local Government (DHPCLG) and Richard Bruton T.D., Minister for Communications, Climate Action and the Environment (DCCAE). The consultation will run for ten weeks and it will have a deadline of the 19^th of February 2020.

These guidelines “offer advice to planning authorities on planning for wind energy through the development plan process and in determining applications for planning permission. The guidelines are also intended to ensure a consistency of approach throughout the country in the identification of suitable locations for wind energy development and the treatment of planning applications for wind energy developments. They should also be of assistance to developers and the wider public in considering wind energy development.”

 The document states that “The draft guidelines are based on best international practice on wind turbine noise control including the Institute of Acoustics Good Practice Guides[1], WHO Guidelines[2] and a procedure for the assessment of low frequency noise complaints[3].

The draft guidelines propose a noise limit, referred to as a Relative Rated Noise Limit (RRNL) in the range of 35 – 43 dB(A), while not exceeding the background noise level by more than 5dB(A) with an upper limit of 43 dB(A). This is in line with the “preferred draft approach” announced by DHPCLG and DCCAE on 13th June 2017. The noise limits in the draft guidelines are more onerous that the 2006 WEGs and afford a higher level of protection to people who live in the vicinity of any future wind farm development.

The rated wind turbine noise level (LA rated, 10 min) is determined by the measured noise level attributable to or related to the wind energy development plus any rating penalties for special audible characteristics. The guidelines impose penalties of up to 11 dB(A) on noise with tonal and amplitude modulation characteristics, in addition to a fixed threshold for low frequency noise. A penalty for special audible characteristics was identified in the “preferred draft approach”. However, the nature and extent of the maximum penalty of 11 dB is higher than was expected. The penalty is so significant that it is unlikely that most wind farms development would not be able to operate with special audible characteristics and mitigation measures will be  required to ensure that such special audible characteristics do not occur.

Apart from the headline noise limits and penalty scheme there are lots of other important detail contained in the document and some of the key items are outlined below:

• Wind energy developments can include electrical equipment such as transformers in sub-stations and other ancillary equipment within the boundary of the wind energy development site which can also contribute to noise emissions. These components have the potential to generate tonal noise in particular and must be considered in combination with the wind turbine noise.
• A noise sensitive location definition may include ‘protected wildlife areas, areas of particular scenic quality or special recreational amenity importance designated in the Development Plan.’
• Planning authorities will require that noise modelling of the wind energy development project carried out by the applicant in advance of and submitted with the planning application will test and demonstrate compliance with these limits including any presence of such special audible characteristics.
• Applicants shall submit documentary evidence that the type(s) of turbines proposed will use Best Available Technology (BAT)[4] and current engineering practice in terms of avoidance of noise generation and suppression of any noise nuisance.
• In order to be able to directly compare background noise levels to wind turbine operation noise levels it is necessary to measure background noise levels at night and set evening and daytime noise limits based on these levels.
• For the avoidance of doubt RRNL curves will be based on the background noise level curve developed from night time noise data. The evening and day time curves are extrapolated from the night time curve using the 5 dB(A) and 10 dB(A) differentials set out in the Environmental Noise Directive. It is necessary to control noise emissions during the day and evening periods in this way to ensure annual noise emissions remain within WHO conditional recommendation.
• The study area as part of the pre-planning noise assessment includes an area within which the wind turbine noise level is estimated to be equal to or greater than a level of 30dB LA90 at up to 12 m/s wind speed or an area contained within a perimeter line offset by 3,000 metres (3 km) from the outermost wind turbines in the proposed development or an adjacent existing or permitted wind energy developments.
• The developer shall incorporate noise verification locations into the plans for the wind energy development. A minimum of four locations are to be identified for verification monitoring and are to be clearly identified on a drawing submitted at planning application stage. The noise verification locations are to be used to compare the results of the pre-construction wind energy development noise modelling with the actual noise levels at those locations during the full operation of the wind energy development operating at maximum output.
• The results from the noise verification monitoring locations will be used as part of the compliance check with planning conditions.
• Applicants shall also submit the following with the application:

1. A proposed noise monitoring and control procedure for the construction phase.
2. A clear statement that the wind energy development shall not exceed the predicted LA rated levels stated in the noise report.
3. A proposed detailed methodology for a post completion noise survey in accordance with the IoA GPG Supplementary Guidance Notes
4. Post Completion Measurements for each turbine to be commenced within four weeks of commissioning of any turbine or group of turbines.
5. A map showing the noise monitoring locations for the ongoing operation phase of the wind energy development along with a detailed proposed noise monitoring and reporting procedure.
6. A proposal for a documented complaints handling procedure.

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[1] Institute of Acoustics, A Good Practice Guide to the Application of ETSU-R-97 for the Assessment and Rating of Wind Turbine Noise, May 2013 including Supplementary Guidance Note 1 to 6.

[2] World Health Organization, Environmental Noise Guidelines for the European Union, 2018.

[3] Moorhouse, A., Waddington D. and Adams, M., Procedure for the assessment of low frequency noise complaints, February 2005, Contract no NANR45 to the UK Department for Environment, Food and Rural Affairs (DEFRA)

[4] BAT is defined in Section 5(1) of the EPA Act 1992 as amended http://www.epa.ie/licensing/info/bref/