A power management system includes a receiver, an estimator, an administrator and a determiner. The receiver acquires DR information that includes a reduction value and a target period for requesting a reduction of received power. The estimator estimates, as first power information, power that is consumed by an electric load during the target period. The administrator manages, as second power information, power that can be output from a power supplying apparatus including a power storage apparatus. The determiner determines that a condition for participating in a power trade market is met, when determining that the reduction value is achievable during the target period, based on the first power information and the second power information.