Overview
Solar Panel Glare occurs even though it is not expected because solar panels are designed to absorb sunlight, rather than reflect it. Solar Panel Glare is greater than expected because panels are good at absorbing light perpendicular to them but much less effective when the light is at a low angle.
Pager Power’s assessments can predict the timing and intensity of solar glare for solar PV installations near airports, railways, highways and dwellings.
What is solar panel glare?
Solar Panel Glare occurs when an observer sees a direct reflection of the sun caused by a specular (mirror-like) reflection from the surface of one or more solar panels.
Figure 1: Solar Panel Glare
What information is required for assessments?
When assessing solar panel glare accurately it is important to know:
- Location of the solar panels
- Location of the observer
- Azimuth and elevation angle of the solar panels
- Optical characteristic of the panels
Do anti-reflective coatings stop solar panel glare?
Whilst it is often claimed that anti-reflective coatings prevent harmful glare in reality they reduce glare levels – but often not when the sun is at a low angle when direct solar reflections are most likely.
How does solar panel glare compare with glare from other sources?
Other sources of glare include:
- Direct exposure to the sun
- Reflections from water
- Reflections from windows and glass
- Reflections from highly polished steel
- Reflection from wet paved surfaces
The intensity of solar panel glare is often less than the intensity of the above – however the size of the solar development can mean that solar panel glare can be deemed unacceptable.
Can solar panel glare be mitigated?
The most effective ways of reducing solar panel glare are:
- Choosing a panel with a rougher surface
- Reorienting the panels
- Shielding the panels so they cannot be seen
- Changing the panel layout to reduce visibility
What is typically included in a Glint and Glare assessment?
Glint and Glare assessments typically determine the times at which solar panel glare will occur. They also predict the intensity of glare in accordance with US Federal Aviation Administration guidance.
Download our glint and glare guidance document which includes a standardised methodology for PV developers, planners and stakeholders to follow.
Conclusion
Solar panel glare is a common occurrence which is not fully mitigated by anti-reflective coatings. Pager Power can predict glint and glare effects on airports, railways, highways and dwellings. There are a number of mitigation options available to solar developers.
Image accreditation: “First Array” by Russ Ferriday / CCBY 2.0 / Resized from original
