Energy storage operation planning system and operation condition determination method

An internal information collecting unit obtains collection data obtained by measuring each electricity storage device. An internal state estimation unit estimates the degradation degree of each electricity storage device on the basis of the collection data. A lifetime estimation unit calculates an estimated lifetime obtained by estimating, based on a degradation behavior model indicating the degradation behavior of the electricity storage devices and the degradation degree, how long each electricity storage device can supply power. An output distribution unit generates a list including one or more combinations of the operation conditions of the respective electricity storage devices, in which the output distributions to the respective electricity storage devices are set for each predetermined period so that the combined output of the electricity storage devices follows an estimated input waveform and periods until the estimated lifetimes of the electricity storage devices become long. An optimization unit selects a combination of the operation conditions from the list, said combination maximizing the accumulated value of an index value until the estimated lifetime, said index value being used for evaluating the benefits of a power supply.