# Progress in Improving Photovoltaics Longevity
## 5 Discussion  
The present paper's objective is, on the one hand, to summarize the current knowledge on key degradation mechanisms affecting PV modules and remote and on-field monitoring methods for identifying failures and, on the other hand, to present a series of mitigation strategies employed to prolong their sustainability and life expectancy. The first step toward this direction is an in-depth understanding of the degradation modes and their correlation with the different climatic and environmental conditions across the globe. Regional and geographic characteristics of the location of PV systems deployment pose multiple challenges to their performance, efficiency, and longevity, as the overall degradation effect is climate-dependent. A thorough insight into the intricate relationship between environmental stress factors and PV module reliability presupposes a correlation among degradation mechanisms, climate patterns, and weather conditions. Table 12 below provides a detailed overview of the association between the dominant degradation mechanism and the climate and regional factors. In the vast majority of cases, the occurrence of degradation emerges as a complex combination of multiple stresses and not due to the effect of a single mechanism. During real-world operation, PV systems are susceptible to the effect of the superposition of all the aforementioned degradation mechanisms, depending on the climate and region of installation. A promising mitigation strategy aiming at enhancing the longevity of PV modules is the development of new, hybrid accelerated test setups and the establishment of protocols, the so-called agnostic tests, which will simulate this complex interaction. This approach was examined by [PERSON] and [PERSON] et al. (2008,2009) in their work, who achieved an accurate replicate of a combined stress situation by exposing the module to combined or sequential stress factors and evaluating their durability. \begin{table}
\begin{tabular}{c c c c} \hline
**BIPV Longevity** & **Description** & **Key Features** & **References** \\
**Entance** & **Description** & & **Key Features** & **References** \\ \hline \multirow{6}{*}{Operational practices} & \multirow{6}{*}{Proper operation and maintenance (O\&M)} & \multirow{6}{*}{*} & Routine inspections should focus on \\  & & & moisture ingress, delamination, and thermal \\  & & management effectiveness & \\  & Proper operation and maintenance (O\&M) & *} & Preventive maintenance includes cleaning \\  & & practices are vital for ensuring long-term & & modules regularly to maintain performance \\  & & reliability of BIPV systems. & *} & Addressing installation-related crack issues \\  & & & is critical for preserving module longevity, \\  & & & as damage can lead to significant output \\  & & & reductions & \\ \hline \multirow{6}{*}{Future directions} & \multirow{6}{*}{Future improvements should focus on innovative designs that mitigate heat transmission, noise, and corrosion while enhancing overall reliability of BIPV systems.} & \multirow{6}{*}{
\begin{tabular}{c} Ongoing research should explore the impact of temperature on electrical properties of BIPV modules \\ \end{tabular} } \\  & & & & Comparison with conventional building \\  & & & materials will help refine design approaches \\  & & & for better performance in various \\  & & & environments \\  & & & Emphasis on developing predictive models \\  & & & for estimating lifespan and degradation \\  & & & rates will enhance economic viability of \\  & & BIPV solutions & \\ \hline \end{tabular}
\end{table} 
Table 11: _Cont._After focusing on the different degradation mechanisms that strongly impact PV modules installed in various climates and regions across the globe, it is worth discussing the different degradation challenges faced by different PV technologies and several subsequent mitigation strategies that have been developed. Different PV technologies are prone to specific degradation challenges that significantly impact their long-term effectiveness and durability.