Solar module degradation

Solar modules lose output capacity over time. 2026 Tier 1 TOPCon and HJT modules typically warranty 87–90% of nameplate at 25 years (equivalent to 0.4–0.5% annual linear degradation). Real-world fleet data shows median degradation closer to 0.5%/year, with outliers driven by hot climates, PID (potential-induced degradation), and manufacturing defects. Degradation is the single biggest assumption in 25-year solar LCOE calculations.