Paper MS-ThA8
Establish Degradation Rates of Photovoltaic Modules and Systems Trough Comprehensive Electrical and Mechanical Analysis

Thursday, November 12, 2009, 4:20 pm, Room C3

Performance degradation of photovoltaic modules and systems follows a progression that is dependent on multiple factors. Many of the mechanisms responsible for degradation are difficult to simulate in a laboratory setting. While accelerated aging tests are a valuable tool in evaluating photovoltaic components and systems, long-term monitoring of systems installed in the field is the true test of reliability. A comparison of the original and weathered power output of several different photovoltaic technologies dating back to 1998 is presented here, along with an analytical description of the degradation and weathering effects responsible for reduced power production over extended periods of time. Experimental data has been collected on diverse generations of photovoltaic modules installed throughout the state of Florida, where the systems have been subjected to long-term exposure in a hot, humid climate. Some of the module degradation mechanisms may be attributed to optoelectronic effects, while others are more mechanical in nature (e.g. encapsulation and delamination issues). The effect of performance degradation on the system’s economics and life-cycle energy costs has been presented in order to better quantify the impact of the different degradation mechanisms. While working to reduce the initial degradation effects is of vital importance and has received considerable interest in the past, a better understanding of the long-term degradation mechanisms inherent in this technology is also fundamental in the effort to improve the reliability of photovoltaic modules and systems.