In December 2019 the Irish Department of Housing, Planning, Community and Local Government (DHPLG) published the Draft Revised Wind Energy Development Guidelines (WEDG). The draft is a proposed update to the 2006 Wind Energy Planning Guidelines, approximately double the size and covering a range of topics including:

• Noise,
• Visual Amenity,
• Shadow Flicker,
• Consultation Obligations,
• Community Dividends, and
• Grid Connections.

Wind Farm Noise Assessments

With regard to Wind Farm noise the Draft Guidelines stated objective is ‘to achieve a balance between the protection of the amenity of communities in the vicinity of wind energy developments and meeting Ireland’s renewable energy targets in a cost-effective manner while providing security of future supply for the country’. The Draft Guidelines endeavour to achieve this by providing significantly more detail on the wind farm noise compared to the 2006 version, and by incorporating international best practice including the Institute of Acoustics Good Practice Guide on Wind Turbine Noise and Environmental Noise Guidelines for the European Region (2018).

Wind Farm Noise Limits and Special Audible Characteristics

Changes in the Draft Guidelines to the 2006 version include new noise limits which are more onerous particularly in areas of existing low background noise. The noise limits are now proposed on the rated noise level of the wind energy development which is noise attributable to the wind turbines plus ‘penalties’ for special audible characteristics. The Draft guidelines identifies three categories of special audible characteristics that may arise from wind turbines:

Tonal Noise

Amplitude Modulation

Low Frequency Noise

Notably, the new more stringent limits would also apply to existing wind energy sites that may be due for repowering or planning renewal!

Study Area and Cumulative Impact

Another significant change in the Draft Guidelines includes specific detail on the extent of the study area i.e. the potential area of noise impact. This now also includes a specific requirement to consider the cumulative impact of the noise from the Wind Farm and that from all the adjacent proposed, consented and existing wind turbines.

Wind Farm Noise Monitoring

The Draft Guidelines outlines requirements for noise monitoring of the completed Wind Farms to ensure compliance with the planning conditions and to identify if special audible characteristics are present. The Draft Guidelines expects a minimum of four locations for noise verification monitoring, with the results 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.

In addition, the Draft Guidelines specifies that compliance monitoring at the locations be conducted at least quarterly for smaller windfarms (<25 turbines), and continuously for larger developments (>25 turbines).

Foreseeable Challenges

The Draft Revised Wind Energy Development Guidelines are significantly more detailed than the original 2006 version and many of the topics it endeavours to cover are valid considerations for most wind farm developments. However, the Draft Guidelines attempts be an all-inclusive standalone document specifying both the site noise limits as well as condensing the robust technical methodology outline in existing standards and guidance such as the Institute of Acoustics Good Practice Guide on Wind Turbine Noise. In doing so it introduces some vagaries, conflicts and inconsistencies. As it the Draft Guidelines states its’ Technical Appendix ‘will take precedence over these publications where any conflicts arise’, this also introduces potential inconsistencies in noise impact assessments and future disputes.

This is particulary relevant for existing wind energy sites that may subject to repowering or planning renewal, which under the Draft Guideline may be expected to achieve substantially lower limits despite operating for more than a decade in the same location.

As the Draft Revised Guidelines have been published for almost a year, and an extensive public consultation has been completed, it is hoped that the final Guidelines will be a well refined document clearly setting out the requirements for wind energy development and achieving its’ objective of balance between the protection of amenity of communities and meeting Ireland’s renewable energy targets.