Nowadays we can witness many mobile and IoT devices constituting intelligent environments. The physical status of the real world is obtained with many wirelessly-connected devices and it seems that we can create any arbitrary intelligent environments. However, these devices still have a problem of inflexibility of supplied power; wireless IoT devices tend to necessitate the batteries solely dedicated to them. Therefore, as the number of IoT devices increases, the cost of managing these batteries also increases. To cope with the problem, Ichikawa et al. has developed Virtual Grid Hub (VGHub), where USB-PD-connected devices can alternatively provide and receive electrical power. In this study, we show how to control VGHub connecting personal computers, mobile phones, and portable batteries to maximize the utilization of electrical power taking practical issues into consideration.