Understanding local planning policy and processes is paramount when conducting impact assessments to support planning applications. As part of our day-to-day, we need to be knowledgeable in this area to ensure our reports are fit for purpose. We also need to be technically proficient so that we can adapt our analysis when a technical conundrum comes our way that requires a different approach.
As authors of publicly available guidance on the impacts of glint and glare, we regularly read and review new documentation on the topic so that we can continue to lead the glint and glare conversation in a comprehensive manner. In this article we present a review of the planning policies and guidance across Australia with specific reference to glint and glare for solar photovoltaic developments.
National Policy
To Pager Power’s knowledge, there is no specific national policy on assessing glint and glare from solar developments in Australia. There are wider policies regarding the deployment of renewable energy, such as the Future Made in Australia Act and Renewable Energy Target scheme, however the impacts of solar and how they are assessed are considered more so at the state level or as a matter of best practice.
State Policy
New South Wales Government
The New South Wales (NSW) Government produced the document titled ‘Large-Scale Solar Energy Guideline’ from their Department of Planning and Environment in August 2022. In section 5.6, the guidance document specifically references glint and glare alongside a high-level methodology detailing the impact assessment process.
The definition of glint and glare aligns with our own, and it states the principles of glint and glare effects are as follows:
- Solar panels should be sited to reduce the likely impacts of glint and glare.
- Solar panels and other infrastructure should be constructed of materials and/or treated to minimise glint and glare.
- If a large scale-solar energy development is likely to exceed the relevant criteria for glare and standards for glint, mitigation strategies must be adopted to reduce impacts.
The criteria that define the overall impact are presented in Figure 1 below.
Figure 1: NSW glint and glare impact criteria.
The glare criteria that signify a high impact align with those that are typically set for shadow flicker effects from wind turbines (30 minutes/30 hours) [1]. This similarity of effect significance is also referenced within Pager Power’s Glint and Glare Guidance document, which was originally published in 2017. The comparison between the two has merit, however glint and glare effects are less invasive than shadow flicker effects because an observer needs to directly observe glint and glare for an impact to occur, whereas for shadow flicker effects to materialise, an observer does not necessarily need to have a direct view of a wind turbine i.e. a person could just be present in a room with a window that has a view of a wind turbine for shadow flicker effects to be experienced in the room.
Appendix C of NSW guidance also gives a more detailed overview of the assessment process for varying receptors, including dwellings, roads, rail and aviation. The key criterion that sticks out is the requirement to assess dwellings out to 3km (as opposed to 1km, which is recommended by Pager Power). This vastly expands the assessment area and, given the typical low-lying nature of solar developments, is probably too conservative. There remains little justification for their choice of criteria for roads, rail and aviation however they seem reasonable based on project experience.
The overall impact criteria are therefore deemed to be more conservative than those Pager Power would typically consider, however the methodology (30 minutes/30 hours) is grounded in planning precedence for environmental effects concerning exposure to sunlight. Based on Pager Power’s experience of assessing Australian solar developments, the levels of glare that need to be met to have an acceptable level of impact can be routinely met by detailed assessment and implementation of typical mitigation options.
Victoria State Government
The Victoria State Government published solar guidance in October 2022 titled ‘Solar Energy Facilities Design and Development Guideline’. This document has been a source of reference for many of Pager Power’s Australian solar glint and glare assessments. Under the section titled ‘Glint and Glare Management’ on page 23, the definition of glint and glare is provided, which again, agrees with that of Pager Power. Whereas the NSW solar guidance gives specific criteria that need to be avoided (30 minutes/30 hours), the Victoria guidance is not as specific.
The guidance also states that dwellings need to be assessed within 1km, as opposed to 3km for dwellings in the NSW guidance. There is also no specific distance given for aviation receptors, though the term ‘close to’ is used (the NSW guidance limits the distance to ‘all air traffic control towers and take off/landing approaches to any runway or landing strip within 5km of the proposed solar array’).
Lastly, there is no specific reference to railway receptors, though the guidance does mention that there may be the need to assess ‘any other receptor to which a responsible authority considers solar reflection may be a hazard’.
The key difference between the two guidance documents lies within the overall criteria which determine the impact. Specifically, the Victoria guidance states:
- No impact: a solar reflection is not geometrically possible, or it will not be visible from the assessed receptor. No mitigation is required.
- Low impact: a solar reflection is geometrically possible, but the intensity and duration of an impact is considered to be small and can be mitigated with screening or other measure.
- Moderate impact: a solar reflection is geometrically possible and visible, but the intensity and duration of an impact varies according to conditions. Mitigation measures (such as through design, orientation, landscaping or other screening method) to reduce impacts to an acceptable level will be required.
- Major impact: a solar reflection is geometrically possible and visible under a range of conditions that will produce impacts with significant intensity and duration. Significant mitigation measures are required if the proposed development is to proceed.
There are no specific timeframes given with respect to the duration of glint and glare and overall impact. This is a significant variation from the NSW guidance (and Pager Power’s), which states this explicitly. This could lead to varying standards being applied for solar developments across the two states.
Queensland State Government
The Queensland State Government released its guidance titled ‘Queensland: Solar Farm Guidelines: Practical guidance for communities, landowners and project proponents’ from the Department of Natural Resources, Mines and Energy in 2018. There are only two references to glint and glare within the document, with the first stating that a glint and glare assessment might be required, and that community engagement could help identify their specific concerns.
The second reference is as follows:
‘Impact assessments, such as glint and glare assessments or visual amenity assessments, to properly understand the potential impacts and propose an appropriate design response or mitigation measures. These assessments are not required for all development applications as they are determined based on proximity to surrounding sensitive receptors, such as urban areas or airports.’
There is no definitive assessment methodology provided, with this guidance being the least comprehensive in terms of the methodology and impact classification for glint and glare effects. It is possible that developers would refer to the guidance provided by NSW or Victoria States for more detailed information when considering glint and glare effects for their solar development.
The Remaining States
There appears to be no solar guidance relating specifically to glint and glare in the remaining Australian States.
Aviation Policy
Whilst there is no Australian Civil Aviation Safety Authority (CASA) guidance with respect to glint and glare, it is understood that the CASA follow the Federal Aviation Authorities’ (FAA) position from the USA. The latest FAA guidance can be found here.
Conclusions
Upon review of three state policies on glint and glare, it is clear there is variation in how the issue is assessed across Australia. The identified policies offer varying levels of detail, and this could lead to developments of differing environmental impacts being permitted on neighbouring sides of a state boundary. A consolidated, uniform and comprehensive national approach should therefore be considered. This would not only assist developers but also stakeholders (such as residents, highway authorities, airports, and railway operators), and it would guarantee that solar developments are being developed to the highest standard.
The position of CASA is fairly typical of a country that does not have its own specific policy on glint and glare. Many countries refer to the FAA standard when determining the impact of solar development on its operations. The FAA standards are fairly clear, and it is something that Pager Power referred to in the development of its own glint and glare guidance document.
Additional Pager Power Content on Australia
Further information from Pager Power regarding Australian renewables, aviation and the built environment can be found in the following articles:
- Australia Focus – Part 1 – Renewable Energy and First Nations
- Australia: A Clean Energy Superpower
- Comet Solar Farm, Australia
- Are the Australian Bushfires caused by Climate Change?
- Australian Wind and Solar Forced Shutdowns
- Australia’s bright renewable energy expansion
- Renewable Energy Prospects in Australia – Solar, Wind and Batteries
- Australian wind project may affect radar and airstrips more than planned report shows
- Tall buildings in Brisbane, Australia, could lead to a revision of airspace rules
- Australia’s supertall skyscraper plans scrapped
References
[1] Best Practice Guidance to Planning Policy Statement 18 ‘Renewable Energy’, Northern Ireland Department of the Environment (2009, and guidance note added in 2019). The shadow flicker recommendations are based on research by Predac, a European Union sponsored organisation promoting best practice in energy use and supply which draws on experience from Belgium, Denmark, France, the Netherlands and Germany. Last accessed 29/05/2024.
Thumbnail image accreditation: Wandoan South Solar Farm, Woleebee, Queensland, 2023 on WikiCommons. Last accessed on 30.05.2024. Available at: https://commons.wikimedia.org/wiki/File:Wandoan_South_Solar_Farm,_Woleebee,_Queensland,_2023,_02.jpg
