The long-term performance of photovoltaic (PV) modules declines over time, influenced by environmental conditions such as temperature, humidity, and shading, which pose operational challenges. Quantifying this long-term degradation is crucial for predicting the return on. con Hetero-Junction (SHJ) is shown in Figure 1 for selected degradation and failure modes. Especially semiconductor-related degradation modes show degradation and recovery paths: light (and elevated temperature)-induced degra ation (LeTID/LID), UV-induced degradation (UVID), and potential-induced. This detailed analysis by Task 13, provides essential insights into the reliability and performance of cutting-edge photovoltaic technologies, focusing on the degradation and failure modes affecting new solar cells and modules, including perovskite-based technologies. Despite PV modules being considered reliable devices, failures and extreme degradations often occur. Some degradations. Reliability and degradation studies have the main purpose to outline the acceptable level of defects in PV modules so to define marginal costs for O&M and reduce the lifelong costs of PV plants. The study analyzed three common PV technologies: thin-film, monocrystalline silicon, and polycrystalline silicon. Experimental results indicate that. Some primary important failure types seem to be mitigated like LID/LeTID and cell part isolation.