Maximizing aged photovoltaic array power: a computer modelling study

Abstract

Abstract Photovoltaic (PV) modules age with time for various reasons such as corroded joints and terminals and glass coating defects, and their ageing degrades the PV array power. With the help of the PV array numerical model, this paper explores the effects of PV module ageing on the PV array power, and the power gains and costs of rearranging and recabling aged PV modules in a PV array. The numerical PV array model is first revised to account for module ageing, rearrangement and recabling, with the relevant equations presented herein. The updated numerical model is then used to obtain the array powers for seven different PV arrays. The power results are then analysed in view of the attributes of the seven PV array examples. A guiding method to recommend recabling after rearranging aged modules is then proposed, leading to further significant power gains, while eliminating intra-row mismatches. When certain conditions are met, it was shown that recabling PV modules after rearranging them may lead to further significant power gains, reaching 57% and 98% in two considered PV array examples. Higher gains are possible in other arrays. A cost–benefit analysis weighing annual power gains versus estimated recabling costs is also given for the seven considered PV array examples to guide recabling decisions based on technical and economic merits. In the considered examples, recabling costs can be recovered in <4 years. Compared with the powers of the aged arrays, power gains due to our proposed rearranging and recabling the PV arrays ranged between 73% and 131% in the considered examples—well over the gains reported in the literature. Moreover, the cost of our static module rearrangement and recabling method outshines the costs of dynamic reconfiguration methods recently published in the literature.