Energy yield optimization for micro-inverter photovoltaic systems with spare parts inventory

To further enhance energy production and reduce the Levelized cost of energy (LCOE) it is essential to plan spare parts to reduce the downtime of the photovoltaic (PV) systems with micro-inverter (MI) caused by the failure. The present investigations only consider the deterministic effects of spare parts of PV products on energy yield. The spares optimization, especially considering the stochastic inventory policy, for the PV system has not been reported yet. In this paper, an optimization model of generating capacity incorporating inventory policies of spare parts is constructed for the MI PV system combining the Continuous time Markov chain (CTMC) with stochastic inventory theory. The range of the installation scale from 100 to 2000 is investigated to analyze the effect of spare parts on the energy yield. We find that the installation scale being more than 200 for a 500 W PV system should reserve spare parts. At the installation scale approaching 2000 PV systems, the LCOE decreases by 0.0063 $/kWh, about 15 %. Compared to not stocking the spare parts of policy (-1,1), the cost saves 8.3 x 10 boolean AND 5 $, more than 14 %. The optimal profits deduced by the proposed methodology can enhance the competitiveness of the utilities and the PV manufacturer.