Long-Term Reliability Analysis of ESS - Multicrystalline Silicon and Conventional Polysilicon Modules in a Grid-Connected Photovoltaic System

Abstract

This work provides a long term reliability evaluation according to the field degradation and early-life failure behaviour of a 6.72 kWp rooftop photovoltaic (PV) system deployed at B V Raju Institute of Technology (BVRIT), at Telangana, India (17.37° N, 78 489 m asl). The plants consist of 28 modules and are separated into 4 arrays (7 modules × 4) two arrays filled with Elkem Solar multicrystalline silicon (ESS®) and the other two with conventional polysilicon. Real time 1 min inputs of plane-of-array irradiance, module/ambient temperature and AC/DC electrical quantities were collected for 12 months. Rate of degradation was determined from standard condition peak powers (Pmax) and classical two-parameter Weibull model with maximum likelihood estimation (MLE) was applied to estimating B10, B50 and B80 lifetimes. The average first-year power degradation of ESS® modules stood at 0.42 % compared with 0.61 % for polysilicon and their B10 estimated life is 19 years in comparison to 16 years for polysilicon. This supports the make of ESS technology as being more long-term reliable under hot-humid Indian conditions.