The solar photovoltaic (PV) industry is confronting escalating financial losses from hail damage and a concerning increase in broader module reliability issues, as revealed by recent industry reports and expert analyses. While hail incidents account for only 6% of total loss events for U.S. solar PV projects, they are responsible for a staggering 73% of financial losses, totaling over $600 million in Texas alone since 2018, according to climate insurance provider kWh Analytics. This trend is exacerbated by the growing prevalence of larger, thinner PV modules and the increasing scale of utility-scale projects, where a single hailstorm can decimate 50% of a project, leading to losses of $40 million to $100 million.

Jon Previtali, Senior Principal Engineer at VDE Americas, emphasizes the critical need for data-driven risk assessment, cautioning against relying on anecdotal evidence or population-biased weather maps, such as those from the Federal Emergency Management Agency (FEMA). Previtali notes that the U.S. possesses the world's largest and most intense hail risk area, particularly east of the Rocky Mountains and in Arizona, due to unique atmospheric conditions. Accurate, radar-based forecasting, weighted to specific project locations, is paramount to understanding true hail exposure, avoiding distortions from population density in spotter data.

Mitigation strategies are proving effective. Hail-hardened modules, featuring thicker glass (e.g., 2.5mm/2.5mm or 3.2mm/2.0mm), have demonstrated significantly lower glass breakage rates in testing by Kiwa PVEL. Furthermore, advanced solar tracker stow strategies, which position modules at steep angles (e.g., 75-77 degrees), can reduce hail loss from an average of 50% to virtually 0%. Previtali advocates for early and frequent stowing based on regional alerts, noting that hailstorms typically occur during overcast conditions, minimizing energy production losses. However, the ability of trackers to maintain these high-tilt positions under co-occurring high wind speeds remains a critical design consideration, with less expensive trackers often failing to meet the necessary strength requirements.

Beyond hail, the latest PV module testing reveals a widening gap in overall reliability. Kiwa PVEL's 2025 Scorecard indicates that 83% of module manufacturers experienced at least one test failure, a significant increase from 66% in 2024. Mechanical stress testing and glass breakage were leading failure types, with 20% of Bills of Materials (BOMs) failing these tests. Issues such as delamination, power loss, and junction box problems persist. RETC's PV Module Index Report echoes these concerns, highlighting structural deficiencies in newer module technologies.

Underlying these issues is the industry's rapid transition to n-type solar cells, such as TOPCon and Heterojunction (HJT), which, while offering higher power output, are more susceptible to degradation modes like moisture-related corrosion. Kiwa PVEL's Tristan Erion-Lorico notes that material selection and lamination quality have become more critical, as even minor BOM changes can significantly impact performance. New findings, such as 'dark storage degradation' where modules lose performance when stored in dark conditions, further underscore the evolving challenges. While light exposure can reverse this specific issue, it highlights the complex and sometimes unforeseen vulnerabilities of modern PV module designs. Industry stakeholders must remain vigilant, prioritizing rigorous testing and quality assurance to ensure the long-term performance and financial viability of solar assets.