This study has been done to make a practical suggestion in figuring out required size of electricity power facility in preparation for reunion of Korean Peninsula, estimated based on capacity increase and demand changes in the past. In making the suggestion, balanced development of South and North Korea Economy, recovery of existing power facilities, and construction of new power facilities were taken into consideration. As an alternatives, study result of power system interconnections in Korean Peninsula and/or in North-East Asia Region, PEACE Network, is suggested with a cooperation scheme of information and communications technology as an extra advantage. Concluded a cooperation of electric power system and information & communications technology in the peninsula is expected to be a great opportunity in developing electric power economy, maintaining clear environment, improving security of power supply in the region, and in reunion of Korean Peninsula and peace in the world.