A variety of new products, such as photovoltaic (PV) systems and electric vehicles (EVs), have been introduced to electricity systems targeting an energy-saving and low-carbon society. However, it is still unclear that, when these energy-saving products will be disseminated in our society, the dissemination will influence future electricity systems. To explore how future electricity systems might unfold, this paper describes scenarios by analyzing the influence of the diffusion of energy-saving products; e.g., PV systems and EVs. We compose the scenarios of regional electricity networks by combining scenario texts and simulations. The simulations estimate products diffusion and electricity demand based on the assumptions described in the scenario texts. We analyze the influences of introducing especially PV systems and EVs into electricity networks using the simulation models that we developed. As a case study, we described the scenario of a suburb city in Osaka, Japan.