Unlike most other industrial countries , Japan does n't have a single national grid but instead has separate eastern and western grids . The standard voltage at power outlets is 100 V , but the grids operate at different frequencies : 50 Hz in Eastern Japan and 60 Hz in Western Japan . The grids are connected together by 3 frequency converter stations ( Higashi-Shimizu , Shin Shinano and Sakuma ) , but these can only handle 1 GW in total . A converter station also exists at Minami-Fukumitsu . The 2011 Tōhoku earthquake and tsunami resulted in 11 reactors being taken offline with a loss of 9.7 GW . The 3 converter stations did not have the capacity to transfer enough power from Japan 's western power grid to significantly help the eastern grid
2011 Tōhoku earthquake and tsunami
2011 Tōhoku earthquake and tsunami
Energy in Japan