Understanding Annual and Yearly Degradation in Solar Panels
When evaluating solar panels, initial rated wattage and efficiency are often the primary focus, but what truly defines performance is their temperature coefficient (which we delved into in the last blog) and degradation (first year as well as annual thereafter) from the product side. In this blog, let’s understand how and why degradation impacts the generation of a solar power system.
Solar panel degradation comprises a series of mechanisms through which a PV module degrades and reduces its performance. Ageing is one of the primary factors, others include Light Induced degradation (LID), Potential Induced Degradation (PID), Outdoor exposure and environmental factors.
Ageing: it’s the main degradation mechanism affecting PV modules throughout their life and is a direct consequence of modules being exposed to years of rainfall, snowfall, extreme temperature conditions, hail, dust, etc.
Light-Induced Degradation: This is a phenomenon causing an acceleration in the degradation, mainly in the first year of operation, which is a consequence of sunlight accelerating the oxidation process between the boron used to dope PV material and oxygen and mainly seen in P-type wafers. Science behind this loss is boron, which is used to dope cells, acts as a trap for electron hole pairs, impacting power generation.
Back Sheet Failure: Back sheet failure is the most dominant reason for degradation. Back sheet is the first line of defence that isolates and protects the inner components from external agents like moisture, wind, dust and UV light. Delamination and cracks in the back sheet material are the major reasons for its failure, exposing inner components to external agents and reducing the lifespan of modules.
The only way to reduce and control degradation is to use high-quality materials for module assembly, strict manufacturing processes, adhering to these processes and last but not least, proper installation and taking good care post installation of solar modules.
