抄録
This paper describes that electric power systems in the world are transforming to “decentralized” and “democratized” systems and that, under such systems, aggregation of various distributed energy resources including renewable energy sources and a grid code, which is a set of rules and requirements for some characteristics applied to all generatorsand resources, are crucially important. The precedent examples of the grid code issues and current situation in Japan are reviewed to remind the stakeholders of the importance of aforementioned two elements.