Degradation effects in photovoltaic modules
Smith, Kieren (2016) Degradation effects in photovoltaic modules. Honours thesis, Murdoch University.
This thesis focuses on the inspection of a set of photovoltaic (PV) modules for visual defects that may cause degradation in the modules performance, as well as analysing a module’s output characteristic through the use of a solar simulator such as the Spire 5600SLP. These modules were installed between 1996 and 1998 as part of a collaborative project. The study was conducted by the Japanese Quality Assurance Organisation (JQA) and the Murdoch University Energy Research Institute (MUERI) team, with the aim to evaluate the long-term performance of photovoltaic modules in various climatic conditions, with this particular set of modules having been exposed to the hot and dry climate of Perth.
Since production of the first PV modules decades ago, researchers and manufacturers have been striving to improve the efficiency and long term reliability of this renewable energy technology. The aim to become a reliable and practical source of alternative energy to that generated from the burning of fossil fuels has inspired the technological advances that the photovoltaic industry has undergone.
Through the use of new PV module designs, materials and manufacturing methods, PV modules have come a long way in terms of power output and long term performance. These days most modules are seeing manufacturer warranty periods of at least 20 years, ensuring that the power output remains above 80% of its original rated power within this time period [1,2,3]. To remain operating within warranty specifications, a module warranted with a 20 year, 20% maximum reduction in output power would be expected to see an average yearly degradation rate ( of less than 1%. A module that sees a reduction in power output of more than 20% of the rated power may be considered a failure and be up for warranty if it meets all manufacturer warranty conditions.
Three different photovoltaic cell technologies have been selected to be analysed for this thesis, with 3 monocrystalline silicon, 2 polycrystalline silicon and 4 amorphous silicon modules. It was found that the monocrystalline modules suffered from the lowest rate of degradation, experiencing a low median rate of 0.18% reduction in the modules power output per year of exposure. This rate of degradation was found to be under half the of 0.47% that Jordan & Kurtz found in their study and analysis of monocrystalline modules manufactured prior to 2000 . The polycrystalline modules were the next best in terms of long term reliability, revealing a median of 0.41% per year. This value was again lower than that found in the Jordan & Kurtz study, with the Pre 2000 polycrystalline modules experiencing a rate of 0.61%/year. The amorphous silicon modules studied in this thesis were found to differ in their comparison to the J&K results, with the JQA modules revealing a high median of 1.94%/year, to that of 0.96%/year from J&K .
These rates of degradation mentioned above were then linked to observed defects experienced by the modules, providing reason for high degradation rates found occurring in the amorphous modules, as well as cause for the other two technologies to experience their . It was observed that two of the amorphous modules suffered from delamination of the PV cell and glass front, which lead to these modules experiencing the highest of 3.17% and 2.48%. This effect of delamination on the is likely a result of a combination of types of degradation and not just the delamination itself. The effect of degradation types on the performance degradation of a module is the key aspect in the objective for this thesis topic, and the reason behind many studies conducted on PV modules worldwide. There is a lot to learn from the performance of past technologies to help improve the future generations of PV modules in their pursuit of long term reliability as a renewable energy source.
|Publication Type:||Thesis (Honours)|
|Murdoch Affiliation:||School of Engineering and Information Technology|
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