A novel estimation method for controllable demand achieved by numerous-electric-vehicle charging management

The penetration of renewable energies is likely to cause serious problems in supply-demand balancing, because the generation of renewable energies is unstable and unpredictable. To solve these problems, integration technologies have been proposed for demand-side resources in power systems. We have been focusing on the future penetration of electric vehicles (EVs) and developing an EV-charging control technology. By controlling multiple EVs´ charging time, the demand curves can be shaped as planned during any period, for example, to mitigate of generation fluctuation. However, the controllable charging curves are limited by EVs´ behaviors. In this paper, we propose a practical method to define the limitation of the available total EV demand curves by the preferable form of curve. Using the method, we are able to comprehend the range of demand curve as region enclosed by upper- and lower- demand curves. This method finds a part of available curves, which is practically sufficient for power system application. We also demonstrate the flexibility of total EV demand curve with this method.