Glint and Glare Assessment

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What is this assessment?

The assessment determines the impact of solar panel installations on surrounding environments. It's essential for making sure that solar projects do not:

  • Pose hazards to aviation operations or nearby receptors
  • Create nuisances for nearby residents

Legal basis: Planning and Development Act 2000

What is the process?

Glint and glare assessments in Ireland are conducted to evaluate the potential impacts of solar reflections from photovoltaic (PV) panels on surrounding receptors, particularly for aviation safety.

Methodology and tools

The primary tool used for glint and glare assessments in Ireland is the Solar Glare Hazard Analysis Tool (SGHAT). The SGHAT is considered the industry standard for measuring the ocular impact of proposed solar energy systems on airports and other aviation-related receptors.

Another model used in Ireland is the Macro Works Glint and Glare analysis model, developed in conjunction with the Physics Department of the National University of Ireland, Maynooth. This model has been used to assess glint and glare effects for over 80 solar development sites throughout Ireland.

Assessment process

The glint and glare assessment typically involves the following steps:

  • Identifying relevant receptors, such as airports, aerodromes, roads, railways, and residential areas
  • Analysing the potential for glare using SGHAT or similar tools
  • Determining the intensity and frequency of potential glare occurrences
  • Evaluating the results against established thresholds and guidelines
  • Considering mitigating factors such as terrain, vegetation, or buildings that may block glare

Regulatory context

While Ireland does not have specific statutory policies on glint and glare, assessments are typically conducted based on international guidance and best practices. The Irish Aviation Authority (IAA) requests consultation on all applications for PV solar arrays within 10km of an airport or aerodrome. The Dublin Airport Authority (DAA) requests referral for projects within 15km of Dublin or Cork Airports.

Key considerations

  • Aviation safety: Potential impact on air traffic control towers and runway approaches
  • Road and rail safety: Potential glare effects on drivers and train operators
  • Residential impacts: Nearby residential properties are evaluated for potential nuisance glare
  • Intensity classification: Glare is typically classified as green (low potential for after-image), yellow (potential for after-image) or red (potential for retinal burn).
  • Acceptable levels: For aviation, green glare is generally acceptable, while any glare at air traffic control towers is typically unacceptable

Mitigation measures

If significant glare is predicted, mitigation measures may be required. These can include adjusting the tilt angle of panels, implementing screening measures or modifying the layout of the solar installation.

By conducting thorough glint and glare assessments, developers and planners in Ireland can minimise impacts on aviation safety and surrounding receptors. They can ensure that solar PV installations are designed and implemented in a way that minimises any potential negative impacts.

Submitting your assessment

The results of this assessment should be included with your submission to the relevant planning authority.

Supporting information