Container terminal acts as an important intermodal node that connects cargo sea and land transportation mode. It is an important infrastructure supporting Japan's socioeconomic activities. Maritime container logistics faces many challenges environmental issues such as reduction of CO2 at ports and operational costs for international competition. A solution of introducing electric RTG system is effective to suppress greenhouse gas emission, but there are some problems such as the increase in total amount of electrical consumption and a peak of electric consumption especially during summer. In this study, we construct a detail simulation model of seaside operation of container terminal with consideration of restriction of electric usage and examine the influence of electric RTG deployment system to suppress the power peak in Hakata Island City Container Terminal.