Currently, the ten privately-owned electric power companies are in charge of regional power supply services as General Electricity Utilities and are responsible for supplying electricity from power generation to distribution to the consumers in their respective service area. General Electricity Utilities must obtain approval from the Japanese Government by providing supply conditions such as electricity rates as general supply provisions to those consumers who are excluded from the retail liberalization. They are also responsible for supplying electricity to consumers subject to retail liberalization, based on the provisions for last resort service, if they cannot conclude contracts with power producers and suppliers (PPSs).
The electric power companies work closely with each other to enhance the stability of electricity supply to customers nationwide. For example, they exchange or provide electricity via extra-high voltage transmission lines linking the entire country from north to south, in order to cope with emergency situations resulting from accidents, breakdowns, or summer peak demand.
The Linchpins of East-West Grid Connection-Frequency Converter Facilities
The frequency of grid power differs between eastern Japan (50 Hz) and western Japan (60 Hz). This is due to historical reasons: the Tokyo area adopted German-made generators when starting the electricity business whereas Osaka chose those made in the US. Therefore, Frequency Converter Facilities (FCF) became necessary to connect eastern and western power grids.
Currently, three FCFs, Sakuma and Higashi-Shimizu in Shizuoka Prefecture and Shin-Shinano in Nagano Prefecture, are in operation with a total conversion capacity of 1130MW. Chubu EPCo now plans to increase the capacity of Higashi-Shimizu FCF from 135MW to 300MW by Autum 2014 in order to reinforce the east-west grid connection.