Solar Panel Glare: Airport Safety Concern?

Solar panels are being installed at airports around the world, including in India, Australia, the UK, the US, and more. However, the potential glare from solar panels has raised safety concerns. The reflection of sunlight off the panels can cause flash blindness, retinal burn, and distraction for pilots and air traffic controllers, compromising the safety of the entire aircraft space. To address these concerns, the Federal Aviation Administration (FAA) has published a policy requiring airports to measure the visual impact of solar projects on aviation personnel. Airports are encouraged to conduct sufficient glare analysis before installing solar energy systems and may face compliance action if they fail to address glare-related safety hazards. While solar panels installed near airports must adhere to certain regulations, they can coexist safely if preventive measures, such as anti-glare coatings, are taken.

Does solar panel glare affect airports?

Solar panels can cause flash blindness and retinal burn

Solar panels can indeed cause flash blindness and retinal burn. Flash blindness is produced by the bleaching of the retinal visual (light-sensitive) pigments caused by bright light exposures. The sun's ultraviolet (UV) rays can damage the tissue of the retina, causing solar retinopathy, or retinal burn.

Solar panels can reflect light, causing discomfort, and in some cases, retinal burn. This reflection of light can cause flash blindness, which is a temporary and immediate loss of vision. Flash blindness is not usually considered a problem in daylight conditions, as the locations usually have bright surroundings and high global and diffuse radiation. However, in the context of airports, the reflection of light off solar panels can cause flash blindness for pilots and air traffic control (ATC) staff, which can lead to a major tragedy.

The glare or reflection of the sun from solar panels can cause flash blindness and retinal burn, affecting the vision of pilots and ATC staff. The top glass surface of solar panels can reflect light, and if the panels are facing the wrong direction, they can reflect sunlight directly into the path of pilots, causing a glare-related issue. The specific link between solar panels and glare also depends on other factors, such as the sun's position, the tilt angle, surface texture, colour, and location of the panels.

To prevent these issues, some airports have covered or rebuilt their solar panel systems. Software simulations are also available to assess the potential for glare, but these may not capture all dynamic conditions accurately. Anti-glare solar glass is another solution, as it diffuses the reflected light, reducing the risk of glare.

The sun's position, tilt angle, and location affect glare

The sun's position, tilt angle, and location significantly impact the glare produced by solar panels. The sun's rays can reflect off the top glass surface of solar panels, causing discomfort, retinal burn, and even flash blindness in pilots. This poses a significant safety concern for airports transitioning to clean energy sources.

In the Northern Hemisphere, solar panels typically face south to track the sun's path and maximize electricity generation. However, this orientation increases the potential for glare, as the reflected sunlight can align with flight paths and the line of sight of pilots. The likelihood and severity of glare depend on various factors, including the sun's position in the sky, the tilt angle of the panels, and the location of the panels relative to the ATC tower and runways.

The tilt angle of solar panels influences the direction and intensity of reflected sunlight. By adjusting the tilt angle, the reflected light can be directed away from sensitive areas, reducing the risk of glare. However, this must be carefully balanced with the need to optimize solar energy absorption, which is also affected by the tilt angle.

The sun's position in the sky varies throughout the day and year, impacting the angle and intensity of sunlight hitting the solar panels. During certain times of the day, such as midday when the sun is directly overhead, the potential for glare may be higher. Additionally, the changing seasons influence the sun's altitude and azimuth, which can affect the likelihood of glare occurring at specific locations.

To mitigate the impact of glare, some airports have implemented anti-glare measures, such as using solar panels with anti-glare glass. This specially designed texture diffuses the reflected light, reducing the intensity of glare. Additionally, airports can perform glare analysis simulations to identify potential issues and take preventive measures. These simulations consider factors such as tower and runway coordinates, solar installation height and tilt angles, and building heights.

Glare affects pilots and air traffic controllers

Solar panel glare can affect pilots and air traffic controllers, compromising the safety of an aircraft. The reflection of sunlight off the panels can cause pilot distraction, especially during crucial flight stages such as takeoff and landing. This can be hazardous, causing flash blindness, retinal burn, veiling, and after-image effects. Pilots are familiar with reflections from bodies of water, which have a higher level of reflectivity than glass or solar panels. However, the specific link between solar panel glare and pilot vision depends on factors such as the sun's position, tilt angle, surface texture, colour, and location of the PV modules.

To address these concerns, the Federal Aviation Administration (FAA) has implemented policies to ensure that airport solar projects do not create hazardous glare. Airports are required to assess the potential for glint and glare and determine any ocular impact on air traffic control towers. The FAA also encourages airports to conduct thorough analyses before installing solar energy systems to avoid creating aviation safety hazards.

While solar panels installed near airports can pose a safety risk, it is important to note that modern PV modules with anti-reflective coatings and low iron high transmission glass can mitigate glare issues. Additionally, installing solar panels in specific directions can reduce the risk of glare. A study by Seoul National University of Science and Technology, South Korea, found that if solar panels face away from runways and potential flight paths, they would reflect sunlight outside of aircraft routes.

Despite these concerns, there is no definitive evidence linking solar panel glare to accidents. Airports worldwide, such as Adelaide Airport, Alice Springs Airport, and Singapore's Changi Airport, have installed large solar arrays without any reported issues. With proper precautions and regulatory compliance, solar panels can coexist safely in airports, harnessing clean energy without compromising aviation safety.

Airports are turning to solar energy for environmental benefits

Airports are large energy consumers, and their operations contribute significantly to global carbon emissions. As governments and industries strive to achieve the Paris Agreement's climate goals and reduce carbon emissions, airports are increasingly turning to solar energy as a more environmentally friendly alternative.

Solar power is energy captured from sunlight and converted into electricity using solar panels. This form of energy production does not produce carbon dioxide emissions, making it an attractive option for airports aiming to reduce their carbon footprint. Airports in various parts of the world, including India, the United States, and Australia, have embraced solar power to meet their energy requirements and those of the surrounding communities.

One notable example is Cochin International Airport in Kerala, India, which became the first airport in the world to be entirely solar-powered in 2015. It achieved this feat by installing a 12-megawatt peak plant on 45 acres of land. Another Indian airport, the Ahmedabad Airport, also transitioned to solar energy in 2016. Additionally, the Airports Authority of India (AAI) has committed to using 100% renewable energy at all of its 137 airports by 2024.

Solar power offers multiple advantages for airports. Airports often have vast, open spaces, making them ideal for installing large-scale solar panels. This setup can generate significant amounts of energy to meet the high electricity demands of airports. Additionally, advancements in solar panel technology, such as thin-film solar panels and tandem solar cells, have made solar energy more affordable and efficient. These innovations increase panel efficiency, reduce space requirements, and improve overall economic potential, making solar power a viable option for even city airports located in built-up areas.

However, one significant concern with airport solarization is the issue of glare or reflection from the solar panels. The glass surface of solar panels can reflect sunlight, causing flash blindness, retinal burn, and discomfort for pilots and air traffic control staff. This safety hazard has led to incidents such as the Manchester Boston Airport briefly grounding its PV system in 2012 to address blinding glare affecting the control tower. To mitigate this issue, companies like Borosil Renewables Ltd. have developed anti-glare solar glass, and simulation software is being utilized to assess and minimize glare risks during the planning stages of solar installations.

Anti-glare glass diffuses reflected light

Solar panels are a significant source of renewable energy for airports, with many airports around the world adopting solar energy to meet their electricity demands. However, a major concern with installing solar panels near airports is the potential for glare, which can affect the vision of pilots and air traffic control (ATC) towers, leading to hazardous situations.

To address this issue, manufacturers have developed anti-glare glass that can be used in solar panels to reduce the impact of reflected light. Anti-glare glass is designed to diffuse reflected light, preventing it from causing discomfort, retinal burn, or flash blindness in individuals who may be affected by the glare. This diffusion is achieved through various methods, such as matte finishes, diffuse particles, or small etchings on the glass surface.

One example of anti-glare glass is "Selene," launched by Borosil Renewables Ltd. in 2019. Selene is specifically designed for photovoltaic (PV) installations near airports, diffusing reflected light through a specially designed texture. This innovation ensures that solar panels can be oriented in the most efficient direction for energy generation without causing glare-related issues for incoming and outgoing flights.

The use of anti-glare glass in airport solar panels offers a potential solution to the challenge of balancing the adoption of renewable energy sources with the priority of ensuring safe aviation operations. By diffusing reflected light, anti-glare glass can minimize the impact of glare on pilots and ATC towers, reducing the risk of accidents caused by impaired visibility.

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