This paper proposes an application of mobile agent technique to power flow control of future power systems in competitive environments. " Open Electric Energy Network (OEEN)" which has been proposed by the authors is one of the future power networks . The major function of OEEN is to maintain energy balance with respect to bilateral transactions so as not to cause line overloading. In order to achieve the function, many storage devices are distributed in the network, and which are controlled by a management system named as Power Router. The Power Router acquires information about bilateral transactions and power flows through a communication system to make a charge-discharge schedule of storage devices. The mobile agent discussed in the paper supports the information acquisition and the charge-discharge scheduling of storage devices, and which is called Power Router Support Agent (PRSA). We also discussed about another mobile agent to manage many storage devices in OEEN, and which is called Storage Device Management Agent (SDMA). The mobile agent is a kind of computer program which can deal with some works ordered by its user and also move within computer networks such as Internet.