An experimental cum computational economical approach for evaluation of performance loss rate or degradation rate for realistic roof-top PV plant in south India

Energy Institute Bengaluru, Centre of Rajiv Gandhi Institute of Petroleum Technology, Karnataka 562157, India.

^* Corresponding author: ssundaram@rgipt.ac.in; sivasankari66@gmail.com

Abstract

Degradation rate in Solar photovoltaic systems is truly an important factor affecting economic feasibility. A linear drop in performance is typically assumed during the operational life-time of the PV system. However, the operational ground performance data reveal that the degradation rate for PVmodule based systems is often non-linear similar to the present investigation. This, if neglected, can cause financial uncertainty. So, this paper presents an experimental field estimation coupled with an analytical model-based approach for prediction of degradation of Solar PV systems. A section of 380 kWp PV system is considered for the present work. Furthermore, comparison of regressors encompassing non-linearities like random forest and decision tree-based are attempted for model formulation. The work is also supported with a comprehensive review on modelling approaches for assessment of degradation-based failure modes in Solar PV system. The experimental average value of degradation rate of the 380 kWp PV system is 7.78% or 0.0778. The reported analytical models possess a close match with the experimental results which are quantified by MPE whose value ranges from a minimum of 1.79% to a maximum of 10.4%. The annual performance ratio of the considered system for study is as less as 0.4 indicating and justifying the occurrence of failure effects in the system.