The Electric Power Development Co., Ltd., operating under the brand name J-POWER, is the largest electric utility in Japan. I ... t mainly produces Electricity from Coal and Hydroelectric Power Stations. It also has a few wind farms and is currently building a nuclear plant in Ohma, Aomori prefecture, that is scheduled to begin operations in November 2014. J-Power is the sole operator of the transmission lines connecting the four main islands of Japan. read more