Economic value of the inverter in residence-use PV system applied for electricity storage at night

In order to efficiently utilize the inverter in residence-use photovoltaic power generation system (PV system), the economic feasibility of introducing batteries for electricity storage at night was studied. Two investment schemes were analyzed. (1) The private owner of PV system makes an investment in the battery, and recovers it by the difference in electricity rates between daytime and nighttime. (2) The electric power company makes an investment in the batteries to be installed in the PV system of a private owner, and recovers it by reducing the capacity of peak generators. The results showed that the latter scheme was feasible. The relation between the capacities of batteries and the total battery-PV combined systems was studied.