A technology for electricity power diversification has been developing in the individual equipments by using power conversion technology, however, is fal ling behind in this process of diversification in the energy supply. The diversification in electricity power must be also investigated from the supplier's viewpoints. The theme we will take up is the basic problem seen in every from of supply - the importance of its diversification, especially that of A.C. frequency. It is the aim of our study to make it clear how a new system for an electricity power supply should be, which enables to cope with various demands of consumers appropriately.We will survey the actual circumstances of type of power supply and util ization in general load and special load. Further we will investigate applications of frequency conversion technologies in various fields.Then, we will design a model of a system of varied power supply and uti I ization. The structure of the new system will be a hierachical type and the introduction of artificial intell igence will be discussed for higher level controller. In this system, we will be able to plan the power supplying schedule and to operate optimal Iy from the total system's viewpoints based on the knowledge base about past experiences, for example, of emergencies or the fluctuation of energy consumption in every situation.