Performance and reliability of crystalline-silicon photovoltaics in desert climate

Abstract

Performance and reliability of photovoltaic (PV) systems are important for the deployment of PV in desert climate. In this study, we investigate the performance and reliability of multi-crystalline, mono-crystalline and silicon heterojunction PV arrays operating in the field for 5-years from 2014 to 2018 under desert climate. From data monitoring and performing visual inspection at the field, a drop in the energy yield and the presence of various visual defects were observed and therefore further in-depth analysis was required to identify the potential of main cause of the performance losses. For the (Multi_D), (Multi_E), (Multi_F), (Mono_G), and (SHJ_H) arrays a degradation rate of −2.65 %/year, −1.91 %/year, − 0.14 %/year, − 1.59 %/year and − 0.62 %/year, respectively, was calculated using the RdTool. From each array, all modules returned from the field to perform indoor current–voltage (IV) measurements at Standard Testing Condition (STC) and at different irradiance and temperature operating conditions. The electrical parameters of these modules were analyzed and the degradation rate was estimated by comparing the STC values provided by the manufacturer with the STC values measured after 5-years exposure in desert climate. From the seven difference manufacturers, multi-crystalline silicon (Multi_A), (Multi_B) and (Multi_E) showed the lowest annual degradation rate below 1 %/year. Multi-crystalline silicon (Multi_D) and mono-crystalline silicon (Mono_G) showed the highest PV module power degradation of −3.0%/year and 6.3 %/year, respectively. Further, Encapsulant yellowing, back sheet cracking and cell cracking were the most prominent failure modes observed during the first 5-years of operation in the field.