More data and studies are required to justify the deployment of photovoltaic systems in regions with harsher climates worldwide, according to a new IEA-PVPS report.
The CMI Report 13, “Optimisation of Photovoltaic Systems for Different Climates”, includes best practices for optimizing the performance and reliability of solar systems for cold, snowy climates; hot, dry climates; and tropical climates.
As the installation of PV globally accelerates, an increasing number of installations are being deployed in harsher climates. Such installations pose new risks to system durability, which can only be mitigated through climate-based strategies and specialized design.
To date, the application of climate-optimized solar modules is relatively rare. In the article, most applications so far have been achieved through the utilization of standard products in extreme climates. A global trend towards large modules, utilizing thin glass as a step towards cheaper modules, has proved inappropriate for extreme temperatures.
The IEA-PVPS finds that cold and snowy weather lowers temperatures, which helps promote a module’s efficiency and reduces chemical material degradation reactions. Temperatures, however, can subject system components and modules to additional physical and thermomechanical degradation, ultimately resulting in system failure. Snow may also cause module overloading.
The report recommends high-tilt systems with proper ground clearance and fences as measures to mitigate snow drift and reduce losses. It also recommends optimizing modules for snow by employing thicker glass, micro-crack-resistant cells, special encapsulants, and frames.
Though studies on encapsulant characteristics, UV durability, and new snow-removal techniques have been promising thus far, as this article observes, experience with climate-optimized PV modules and mounting systems under real-field conditions “is still very limited.”
Under hot and dry climatic conditions, the IEA-PVPS identifies thermal cycling, high temperatures, and soiling as the primary stressors for PV plants. Furthermore, salty mists, high UV irradiance, and wind conditions also affect certain sites.
Low-temperature coefficient modules using different encapsulants and UV-and heat-stable materials are also suggested to increase system longevity when deployed in hot and dry climate areas. IEA-PVPS also suggests that cooling technologies, such as heat-spreading plates, air-cooled fins, and phase change materials, are restricted in commercialization. “Monitoring performance and environment by a combination of manual and automatic methods is necessary to reduce age-related inefficiencies,” the report went on.
At high temperatures and humidity, the IEA-PVPS acknowledges that prolonged exposure to these conditions can lead to corrosion and deterioration of PV components and modules. Even high moisture can be induced by high dust adherence and biological infestation, with significant effects on energy yields.
It states that module designs for tropical regions require moisture-proof encapsulants, corrosion-resistant frames, and UV-resistant materials. It states that frequent cleaning frequencies, especially in arid climates and areas with high rain-induced caked soiling or biological fouling, reduce soiling loss while also extending the material’s lifespan.
The report concludes that whether you are where you are or somewhere else, climate-specific stressor mitigation begins on-site and continues throughout the system’s life. It also reiterates that the identification of stressors and their impacts would have had to have been accomplished as quickly as possible.
Other hindrances to the uptake of climate-specific PV modules that are already available include cost, availability, and existing work contracts. The IEA PVPS has recently introduced SolarStations.org, a global directory of solar irradiance observation stations, as a tool to aid researchers, developers, and policymakers.
