In the
electricity sector in Japan, the standard voltage is 100 V, with both 50 and 60 Hz AC frequencies being used. Parts of the country use 50 Hz, while other parts use 60 Hz.
[20] This is a relic from the 1890s. Some local providers in
Tokyo imported 50 Hz German equipment, while the local power providers in
Osaka brought in 60 Hz generators from the United States. The grids grew until eventually the entire country was wired. Today the frequency is 50 Hz in Eastern Japan (including Tokyo,
Yokohama,
Tohoku, and
Hokkaido) and 60 Hz in Western Japan (including
Nagoya,
Osaka,
Kyoto,
Hiroshima,
Shikoku, and
Kyushu).
[21]
Most household appliances are made to work on either frequency. The problem of incompatibility came into the public eye when the
2011 Tōhoku earthquake and tsunami knocked out about a third of the east's capacity, and power in the west could not be fully shared with the east, since the country does not have a common frequency.
[20]
There are four
high-voltage direct current (HVDC) converter stations that move power across Japan's AC frequency border.
Shin Shinano is a
back-to-back HVDC facility in
Japan which forms one of four
frequency changer stations that link Japan's western and eastern power grids. The other three are at
Higashi-Shimizu,
Minami-Fukumitsu and
Sakuma Dam. Together they can move up to 1.2 GW of power east or west.
[22]
