An electric energy storage system includes: an electric energy storage device; and a control device configured to perform charge and discharge control and temperature adjustment control of the electric energy storage device. The electric energy storage device is configured to be electrically connected to a power network. The control device is configured such that execution of the temperature adjustment control of the electric energy storage device is restricted when the control device performs the charge and discharge control so as to alleviate power shortage on the power network according to a request from a management computer for the power network.