Experimental study of degradation modes and their effects on reliability of photovoltaic modules after 12 years of field operation in the steppe region

This paper presents an evaluation of the performance degradation of photovoltaic modules after twelve operation years in a steppe region environment in Algeria. The objective is to understand the different degradation modes of the photovoltaic modules and associated factors and their impact on the electrical properties (V_{oc}, I_{sc}, V_{max}, I_{max}, P_{max} and FF) using the degradation tests of IEC 61215 qualification standard and the electroluminescence test. The experimental results show that yearly degradation rates of the maximum power output P_{max} present the highest possible loss, ranging from 2.08% to 5.2%. Additionally, the results show that the short-circuit current I_{sc} comes second with yearly degradation rates spanning from 2.75% to 2.84%. Finally the open-circuit voltage V_{oc} is the least affected, with yearly degradation occurring from 0.01% to 4.25%