Due to the problems of global warming and energy disruption in the event of a disaster, it is required to reduce the carbon content of energy systems and strengthen their resilience. Therefore, the attention is being paid to a system called "regional smart grid" in which power is interchanged between a plurality of facilities having distributed power sources according to the power demand. By exchanging power between facilities that have distributed power sources, the power generated in the area can be used without waste, and power can be supplied even in the event of a disaster. Thus, it is possible to improve the low carbon performance and resilience of the regional energy system. In this study, we have assumed multiple facilities where power interchange is possible, and tried to optimize the amount of PV / storage batteries installed and the amount of power interchange. Then, the difference in low carbon performance and resilience depending on the presence or absence of power interchange has been quantitatively evaluated.