A long-term predictor circuit predicts a long-term predicted power indicating temporal variations in consumed power of a customer, using a long-term prediction model indicating the variations for each moment of clock times. A short-term predictor circuit predicts a short-term predicted power using a short-term prediction model indicating the variations over a time interval before and after a change in a consumed power of each load apparatus, based on the variations over a time interval immediately before a current time, the short-term predicted power indicating the variations over a time interval immediately after the current time. A controller circuit controls charging and discharging of a battery apparatus by setting a charging power or a discharging power based on the long-term predicted power, and controls discharging of the battery apparatus by setting a discharging power based on the short-term predicted power.