Engineers from UNSW have created a worldwide UV radiation map for solar panels, highlighting major differences in exposure depending on climate and mounting systems.
A new global study has revealed that ultraviolet (UV) radiation may be quietly shortening the lifespan of next-generation solar panels by up to 10 years - and current industry testing standards may not fully reflect real-world conditions.
Researchers from UNSW Sydney have developed a high-precision model to calculate how much UV radiation solar panels receive in different parts of the world, depending on climate, atmospheric conditions and mounting configuration.
The work provides the first global-scale comparison of UV exposure for fixed-tilt and sun-tracking solar systems, offering the solar industry a new way to predict long-term performance and durability.
While traditional silicon solar panels primarily rely on visible and infrared light to generate electricity, newer high-efficiency technologies are designed to capture a broader portion of the solar spectrum which includes UV light.
But that improvement may come with unintended consequences.
The work, led by Dr Shukla Poddar and supervised by Prof. Bram Hoex and A. Prof. Merlinde Kay, with contributions from Dr Phillip Hamer and Mr Shuo Liu, has been published in the IEEE Journal of Photovoltaics .
"Our results highlight that modules with similar technology and orientation can still exhibit region-specific degradation," the researchers say in the paper.
"This is due to the influence of local weather and climate when exposed to outdoor conditions. This underscores the need for climate-specific indoor testing and accelerated tests for reliability and better lifetime predictions.
"Notably, UV photodegradation alone can account for nearly a quarter of the total annual degradation in monocrystalline silicon modules in regions with high UV dose, potentially reducing system lifetime by 7-10 years."
Until now, there has been no comprehensive way to estimate how much UV radiation a solar panel will experience at a given location - particularly once panels are tilted or mounted on tracking systems.
Global map
Most global UV data is measured on horizontal surfaces, which does not reflect how panels are actually installed.
"We've basically developed a method to quantify the amount of ultraviolet radiation based on different spectral wavelengths, and we've produced a global map that shows what you could expect depending on your location," corresponding author Dr Poddar says.
"It gives a holistic overview for manufacturers or developers who want to install panels somewhere, without having to do all the background calculations themselves."
The modelling approach was validated using high-precision UV measuring instruments in Europe and compared against long-term climate datasets.
The model can also incorporate local atmospheric inputs such as clouds, water vapour and aerosols, allowing developers to tailor assessments to specific sites.
One of the study's key findings is that solar panels mounted on tracking systems - which move throughout the day to follow the sun - are exposed to significantly more UV radiation than fixed-tilt systems.
"For single-axis or double-axis trackers, it's worse," Dr Poddar says. "They're always trying to track the sun to catch the maximum amount of sunlight. That means they're also getting the maximum UV on top of them, which makes those panels more susceptible and vulnerable."
In high-irradiance regions, the research indicates that UV-related degradation for single-axis tracking systems could reach around 0.35 per cent per year from UV alone.
"That number might not sound dramatic at first," she says. "But when you quantify it over 20 years, it accumulates quite quickly."
Manufacturers typically quote overall degradation rates of around 0.5 per cent per year, often assuming a steady, linear decline. The study suggests degradation may not be strictly linear - and that UV could represent a significant fraction of total performance loss.
Improving testing standards
Current international standards require solar modules to pass a UV test equivalent to 15 kilowatt-hours per square metre. However, the study shows that in some high-irradiance environments like Alice Springs, Australia, panels may receive that amount of UV in little more than a month.
"It is a significant underestimation of the amount of UV radiation the panels may be exposed to," Dr Poddar says. "So a module can pass the UV test, but in reality, it could perform much worse because we don't have sufficiently stringent tests."
The findings are particularly relevant as modern high-efficiency technologies such as TOPCon and heterojunction cells become more widespread, with some recent industry reports already documenting notable UV sensitivity in certain designs.
"One of the key messages from our paper is that the UV testing standards need to be amplified or changed. With new high-efficiency PV technologies being rolled out so quickly, we need to ensure the standards reflect real-world conditions," she adds.
The researchers say the new modelling tool is designed to help manufacturers, developers and asset owners make better-informed decisions.
Before installation, developers could use the data to conduct more rigorous accelerated UV stress testing on candidate modules.
