Abstract
A new sizing method for stand-alone PV systems was developed and applied to a fictitious village with a population of 50 individuals, to which electric power is supplied only through the PV system. As in the case of previously developed numerical methods, the electric power balance was calculated day by day, with variable daily irradiation. In this study, variable electric demands were also employed and fluctuated with a trend (sine curve) and normal distribution. Based on a factorial design, amounts of daily power generation and consumption were calculated for a 1 year period and repeated for 100 years, under several conditions of given PV panel and battery capacities. A sizing function of two variables (PV panel and battery capacities) was obtained using repeated calculation averages and response surface methodology. This procedure provides an analytical solution for cost optimization of PV systems. By following the procedure, we demonstrated cost optimization of PV systems under a design condition of only one day of power failure per year. The construction specifications and costs for 20 years operation were estimated to be 448 kWp of PV panel capacity and 683 kWh of battery capacity, and 439 million yen, respectively.
