Climate change will impact how fast PV modules degrade: new study

“Large scale commercial PV modules have a typical lifespan of about 20 to 25 years, although they naturally degrade or lose their efficiency over time,” says Shukla Poddar, lead author of the study and a Postdoctoral Research Fellow at the UNSW School of Photovoltaics and Renewable Energy Engineering.

“However, we know that local weather and climate influence the degradation of PV modules and for the first time, this research aims to statistically model the weighted average degradation rate Australia-wide for the different degradation modes.”

Different climates around Australia

For the study, the researchers used regional climate model projections to study the forecasted levels of temperature and relative humidity around Australia – and track their impact on the degradation of PV modules around Australia.

The study looked at three degradation mechanisms that are typically observed in silicon modules: hydrolysis degradation , which considers temperature and relative humidity; thermal degradation, which takes into account changes in temperature of the module; and, photo degradation, which factors in UV radiation temperature and humidity.

The weighted average degradation rate was calculated using the probability of occurrence of each of these mechanisms under specific climate types including hot and humid, moderate, and desert conditions.

To assess the impact of climate change on module degradation, they estimated, then forecasted, changes in the weighted average module degradation rate under a low and high emission scenario.

Under both scenarios, they found module degradation rates were higher in regions with hot and humid climates, such as northern parts of Australia compared to central Australia where the degradation rate increase was smaller due to the drier weather conditions and lower humidity of the region.

Regions with high degradation rates are also expected to experience the greatest power loss – with the projected weighted average degradation rate almost doubling by the end of the century.

“PV module degradation is climate-dependant and very specific according to where they’re installed in Australia,” says Ms. Poddar.

“If you have a module, say in the middle of the desert, and you have the same module installed somewhere along the coast, while they may be identical, the degradation rate would vary because they are exposed to different climates.”

Climate-proofing PV modules

Dr Fiacre Rougieux, co-author of the study and lecturer in the School of Photovoltaic and Renewable Energy Engineering, says we need to have climate change front of mind when it comes to PV design.

"We can see that climate stressors are becoming more extreme and as a result PV modules are likely to be replaced more frequently in some regions,” he says.

“PV panel technology has gone through a complete revolution in the last 10 years, and this is a call for manufacturers to now focus their attention on how to make them more climate resilient.”

Gearing up for changing weather

As the world experiences more extreme weather climates, the researchers believe, this could play a part in the lifetime of PV modules.

“It’s important to understand how we can help manufacturers understand which modules or which types of technology will perform better, based on the degradation performance under specific types of climates,” says Associate Professor Merlinde Kay, co-author of the study and lecturer in the School of Photovoltaic and Renewable Energy Engineering.

While the researchers identified that thermal degradation is Australia’s main degradation precursor, further research should focus on reducing the extent of thermal cycling in modules.

“It is essential to focus on improving the module design to limit temperature rise of the modules. This would ensure higher power output and a better lifetime of the modules. This will benefit future industrial large-scale PV plants to choose the most cost-effective and climate resilient modules,” says A/Prof. Kay.