The solar industry’s explosive growth to 2TW by 2024 coincides with a worrying trend: the increase in record-breaking weather events and their potential impact on PV infrastructure worldwide. The Intergovernmental Panel on Climate Change (IPCC) has confirmed that human-induced climate change is increasing the intensity and frequency of most extreme weather categories, with widespread impacts beyond natural climate variability.
A recently released IEA PVPS Task 13 report, with input from PV researchers from five continents, examines seven major weather threats and provides evidence-based guidance for designing more robust systems tailored to specific climate risks. While the report states that “most PV systems are robust when properly sited, designed and maintained,” the shortcomings described in the report, along with lessons learned, provide a roadmap to greater resilience.
Two categories of damage
Weather-related damage to PV systems falls into two different categories: catastrophic damage involving visible destruction of modules, strings, or entire systems, such as parts torn from supports, collapsed racks, and broken glass; and sub-catastrophic damage, which is subtle and has no visible indicators. The latter category is important because solar cells and internal module components exposed to extreme wind loads and intense humidity can experience accelerated degradation, resulting in a faster-than-expected drop in performance.
The hail threat: an insurance challenge
The weather event that draws the most attention in the solar community is the hail-producing convective storm, which is responsible for more economic damage than any other weather category. According to GCUbe Insurance data from 2018-2023, hail is responsible for only 1.4% of solar claims by volume, but represents 54.2% of total losses incurred. The four largest insurance claims, totaling more than $224 million, were all caused by hail events.
For example, hail-producing thunderstorms in West Texas in May 2019 damaged more than 400,000 modules (two-thirds of a 182 MW solar power plant), resulting in insured losses of $70-$80 million and an increase in regional insurance premiums by as much as 400%.
The 2022 Texas hail season was also damaging, with more than 1,700 MW in three counties affected by tennis ball-sized hail and cumulative damage estimated at $300 million.
Meanwhile, widespread hailstorms in Switzerland in June and July 2021 caused some of the most expensive hail-related losses in recent decades. About 15% of all PV systems in the country were located in areas with hailstones larger than 5 cm. EL imaging of approximately 6,000 modules from 411 affected systems revealed significant cell tears in 57% of the modules.
Tropical cyclones: wind and water
Tropical cyclones, including hurricanes and typhoons, occur along the coasts of North America and throughout Asia. While its frequency may decrease or remain unchanged, IPCC projections indicate that its intensity is expected to increase, providing opportunities to strengthen PV systems currently being developed in fast-growing regions, especially the coastal regions of North America and Asia.
Most damage results from poorly designed and installed racking systems, with bolts and fasteners being the major points of failure. Fasteners that are inadequately torqued or not designed for high-stress conditions can loosen during wind events and, if wind loads are severe enough, fail completely, causing cascading effects ranging from collapsed scaffolding to modules being torn from their fasteners.
In tracking systems, strong winds can cause torsional galloping, escalating stress on modules and single-point attachments, which can lead to runaway failures. This can happen when modules at the end of the row are left to rotate until the fasteners fail, leading to a domino effect where an entire row of modules can tear away.
The double challenge of snow and ice
In northern latitudes, extreme snow events pose a double threat: first, scaffolding can collapse under the heavy snow load; and second, snow covering the modules can block irradiation for extended periods. Fresh snow and ice have a density of 30-50 kg/m³ and 800-900 kg/m³ respectively, but as the snow ages and temperatures rise, compaction reduces permeability and increases weight. The load increases as new snow arrives before the older snow sheds.
In Japan, a study showed that snow pressure was greatest for 10° tilt arrays, with frontal loads along the leading edge reaching 6-8 kN/m. The load increased significantly when the snow cover on modules was connected to ground snow.
Japan’s National Institute of Technology and Evaluation found damage from heavy snowfall to 43 PV systems in the Tohoku and Hokkaido regions during 2018-2021, affecting about 30 MW of combined capacity. A subsequent 2021-2023 study covered 65 arrays, recommending budget allocation for snow removal, surveillance cameras for detection and regular site visits.
Dust storms and heat waves
Dust and sand storms (DSS) can reduce global horizontal irradiance and direct normal irradiance during events by 40-50% and 80-90%, respectively. Additionally, dust can persist on module surfaces when skies are clear, with reported losses as high as 7% in Portugal and 20% in Saudi Arabia after DSS events.
In Qatar, average daily PM₁₀ ranged from 115 to 339 μg/m³ on dust storm days, compared to 89 μg/m³ on clear days. Pollution rates increased dramatically to 1.23%/day during DSS days versus 0.42%/day on clear days – a more than twenty-fold increase in pollution losses from dust storms.
Meanwhile, heat waves pose multiple threats. For every 1°C increase above 25°C, the efficiency of the crystalline silicon cells is reduced relatively by 0.2-0.5%. Research shows that degradation rates could be as high as 0.8% per year in the hottest areas of Europe and up to 1.4% per year in regions near the equator.
Floods and forest fires
Flood damage also falls into two categories: physical damage caused by fast-flowing water and electrical faults caused by immersion of electrical components. In southern India, a south-facing factory with a fixed slope experienced catastrophic damage from fast-moving floodwaters that uprooted foundations and destroyed modules, while a nearby canal top system with a slope of only 6° showed minimal structural damage as the low tilt angle reduced resistance.
The number of forest fires worldwide is expected to increase by 14% by 2030 and by 50% by 2100. Fires generate more insurance claims than hail, although damage losses are much smaller. Like snow, wildfire can affect PV installations in two ways: fire can be physically destructive; and smoke blocks the radiation, which depresses the generation. For example, the 2019-2020 Australian bushfire season caused an estimated total energy loss of 175 ± 35 GWh, with an observed average power reduction of 13 ± 2% per 100 μg/m³ PM₂.₅ concentration.
Designing and planning for resilience
With proper planning and design decisions based on specific weather threats, most PV systems can survive high-intensity storms. An important first step is to integrate historical and forecast weather patterns into the site selection process to determine site suitability and enable risk calculations as a basis for purchasing decisions. A next step is to design the system based on the risk at that location, taking into account the choice of well-designed tracking systems that can withstand intensive loads, modules with the right specifications (such as thicker front glass in hail-prone areas), fixed tilt and tracking systems with sufficient ground clearance (for snowy climates) and waterproof electrical enclosures (for areas at risk of flooding). A third step is to ensure that rapid and effective response protocols, including pre- and post-event strategies, are in place and that field personnel are trained to implement them. And a fourth step is to have an O&M strategy that supports regular inspections of modules, fasteners and the electrical system balance components to check for signs of accelerated degradation or likely failure (as in the case of overheated connectors or loose bolts).
Conclusion
The report’s message is clear: by adhering to proper site assessment, appropriate material selection, rigorous installation practices and ongoing monitoring, PV systems in most of the world can be made resilient to most severe weather threats and remain a robust and reliable source of electricity generation.
Author: Ignacio Landivar
To access the full Operational and economic consequences of extreme weather on PV power plantsyou can download it here.
IEA PVPS Task 13 focuses on international cooperation to improve the reliability of photovoltaic systems and subsystems. This is achieved by collecting, analyzing and disseminating information about their technical performance and sustainability. This creates a basis for their technical evaluation and develops practical recommendations to increase their electrical and economic efficiency in different climatic regions.
The views and opinions expressed in this article are those of the author and do not necessarily reflect those of the author pv magazine.
This content is copyrighted and may not be reused. If you would like to collaborate with us and reuse some of our content, please contact: editors@pv-magazine.com.
