A power controller apparatus predicts demand power of a load apparatus, generated power of a power generator apparatus, and inherent stored energy of a battery apparatus. The power controller apparatus calculates excess electric energy and deficient electric energy achieved when the inherent stored energy reaches higher- and lower-limit stored energies, respectively. The power controller apparatus combines at least one first customer facility and at least one second customer facility having the excess electric energy and the deficient electric energy, respectively, and thus, forms at least one group including the first and second customer facilities. For each group, the power controller apparatus determines transmitting power from the first customer facility to the second customer facility, so that stored energy of each of the battery apparatuses of the first and second customer facilities is equal to or less than a first threshold, and equal to or more than a second threshold.