HOUSEHOLD ELECTRICITY STORAGE SYSTEM

A controller (46) includes: a data accumulation unit (62) that obtains data of an amount of electric power consumed in a residence (6) and accumulates the obtained data; a representative pattern creation unit (64) that creates a representative pattern based on the data accumulated in the data accumulation unit (62), the pattern representatively indicating how the electric power storage device (48) varies in state of charge for its discharging period; and a limit value determination unit (66) that determines a limit value to correspond to the pattern.