METHOD FOR OPERATING STORAGE BATTERY SYSTEM

A plurality of storage batteries are divided into a plurality of storage battery blocks. A useful life of each of the storage batteries is shorter than the project life. Total capacity of the plurality of storage batteries is equal to or greater than the product of capacity required for a project and a ratio of the project life to the useful life. The project life is divided into a plurality of periods. For each of the plurality of periods, a rest storage battery block is selected from the plurality of storage battery blocks in rotation, the rest storage battery block is rested, and an operational storage battery block is operated. The sum of actual operating time of each of the storage battery blocks and equivalent operating time of each of the storage battery blocks is prevented from exceeding the useful life during the project life.