Exploring the impact of climate change on solar PV

With solar expected to become one of the largest sources of renewable energy worldwide by 2026, scientists from the University of New South Wales (UNSW) have investigated the impact of climate change on photovoltaic (PV) modules. Their findings have been published in the journal Progress in Photovoltaics: Research and Applications.

“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,” said Shukla Poddar, lead author of the study and a Postdoctoral Research Fellow at the UNSW School of Photovoltaic 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,” Poddar said.

The researchers used regional climate model projections to study the forecasted levels of temperature and relative humidity around Australia. They then calculated the impact of these estimated climate levels 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 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, the team 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 the northern parts of Australia. In contrast, the degradation rate increase was smaller in Central Australia due to the region’s drier weather conditions and lower humidity.

Regions with high degradation rates are also expected to experience the greatest power loss.

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

“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.”

Dr Fiacre Rougieux, co-author of the study and lecturer in the School of Photovoltaic and Renewable Energy Engineering, said climate change should be front of mind when designing PVs.

“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 said. “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.”

Now that the researchers have identified thermal degradation as being Australia’s main degradation precursor, the next step is 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 better lifetime of the modules. This will benefit future industrial large-scale PV plants to choose the most cost-effective and climate resilient modules,” said Associate Professor Merlinde Kay, co-author of the study and lecturer in the School of Photovoltaic and Renewable Energy Engineering.

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