The electric power industry in Japan covers the generation, transmission, distribution, and sale of electric energy in Japan. Japan's electricity demand was approximately 805.9 terawatt-hours (TWh) in 2024. Before the 2011 Fukushima Daiichi nuclear disaster, about a quarter of electricity in the country was generated by nuclear power. In the following years, most nuclear power plants have been on hold, being replaced mostly by coal and natural gas. Solar power is a growing source of electricity, and Japan has the third largest solar installed capacity with about 50 GW as of 2017. Japan's electricity production is characterized by a diverse energy mix, including nuclear, fossil fuels, renewable energy, and hydroelectric power. Japan has the second largest pumped-hydro storage installed capacity in the world after China.

The electrical grid in Japan is isolated, with no international connections, and consists of four wide area synchronous grids. Unusually, the Eastern and Western grids run at different frequencies (50 and 60 Hz respectively) and are connected by HVDC connections. This considerably limits the amount of electricity that can be transmitted between the north and south of the country.

Consumption

In 2008, Japan consumed an average of 8507 kWh/person of electricity. That was 115% of the EU15 average of 7409 kWh/person and 95% of the OECD average of 8991 kWh/person.Energy in Sweden, Facts and figures, The Swedish Energy Agency, (in Swedish: Energiläget i siffror), Table: Specific electricity production per inhabitant with breakdown by power source (kWh/person), Source: IEA/OECD 2006 T23 , 2007 T25 , 2008 T26 , 2009 T25 and 2010 T49 .

+ Electricity per person in Japan (kWh/ hab.) Use Production Import Imp. % Fossil Nuclear Nuc. % Other RE Bio+waste* Wind Non RE use* RE % 2004 8,459 8,459 0 5,257 2,212 26.1% 844 146 7,469 11.7% 2005 8,633 8,633 0 5,378 2,387 27.6% 715 153 7,765 10.1% 2006 9,042 9,042 0 6,105 2,066 22.8% 716 154 8,171 9.6% 2008 8,507 8,507 0 5,669 2 010 23.6% 682 147 7,679 9.7% 2009 8,169 8,169 0 5,178 2,198 26.9% 637* 128 27* 7,377 9.7% * Other RE is waterpower, solar and geothermal electricity and wind power until 2008* Non RE use = use – production of renewable electricity * RE % = (production of RE / use) * 100% Note: European Union calculates the share of renewable energies in gross electrical consumption.

Compared with other nations, electricity in Japan is relatively expensive.Nagata, Kazuaki, "Utilities have monopoly on power ", Japan Times, 6 September 2011, p. 3.

History Beginnings Japan was a pioneer in electrification. Japan's first electric utility, Tokyo Electric Light, started 1883, about the same time as western countries such as Britain, Germany, and the USA. The first transmission line went into service between Komabashi and Tokyo with a voltage of 55 kV in 1907 and a 115 kV transmission line from Inawashiro to Tokyo in 1913. In 1935 Japan was one of the most electrified countries with 89% of households connected to electricity. Though rivalry of concurrent power operators and a lack of frequency standardization hampered the creation of a national transmission grid. In 1929, most regions had parallel grids, one for 50 Hz and one for 60 Hz, served by various private companies.https://www.tandfonline.com/doi/full/10.1080/18752160.2024.2334546#d1e886

Second world war During the Second Sino-Japanese War and the succeeding Pacific War, the entirety of Japan's electricity sector was state-owned; the system at the time consisted of a and several electricity distributors. At the behest of the Supreme Commander for the Allied Powers, Nippon Hassōden became the Electric Power Development Co., Limited in the fifties; and almost all of the electricity sector that are not under the control by EPDC was privatized into nine government-granted monopolies. The Ryukyu Islands electricity provider was, during the USCAR era, publicly owned; it was privatized shortly after the islands' admission into Japan.

Liberalization of the electricity market Since the Fukushima Daiichi nuclear disaster, and the subsequent large scale shutdown on the nuclear power industry, Japan's ten regional electricity operators have been making very large financial losses, larger than US$15 billion in both 2012 and 2013.

Since then steps have been made to liberalize the electricity supply market. In April 2016 domestic and small business mains voltage customers became able to select from over 250 supplier companies competitively selling electricity, but many of them sell only locally, mainly in large cities. Also wholesale electricity trading on the Japan Electric Power Exchange (JEPX), which previously traded only 1.5% of power generation, was encouraged. By June 2016 more than 1 million consumers had changed supplier. However total costs of liberalization to that point were around ¥80 billion, so it is unclear if consumers had benefited financially.

In 2020 transmission and distribution infrastructure access will be made more open, which will help competitive suppliers cut costs.

Transmission

Electricity transmission in Japan is unusual because the country is divided for historical reasons into two regions each running at a different mains frequency. Eastern Japan has 50 Hz networks while western Japan has 60 Hz networks. Limitations of conversion capacity causes a bottleneck to transfer electricity and shift imbalances between the networks.

Eastern Japan (consisting of Hokkaido, Tohoku, Kanto, and eastern parts of Chubu) runs at 50 Hz; Western Japan (including most of Chubu, Kansai, Chugoku, Shikoku, and Kyushu) runs at 60 Hz. That originates from the first purchases of generators from AEG for Tokyo in 1895 and from General Electric for Osaka in 1896.Gordenker, Alice, "Japan's incompatible power grids ," Japan Times, 19 July 2011, p. 9.

The frequency difference partitions Japan's national grid and so power can be moved only between the two parts of the grid using frequency converters, or HVDC transmission lines. The boundary between the two regions has four back-to-back HVDC substations, which convert the frequency: Shin Shinano, Sakuma Dam, Minami-Fukumitsu, and the Higashi-Shimizu Frequency Converter. The total transmission capacity between the two grids is 1.2 GW.

The limitations of these links have been a major problem in providing power to the areas of Japan affected by the Fukushima Daiichi nuclear disaster. During the 2011 Tōhoku earthquake and tsunami, there were blackouts in some areas of the country because of the insufficient ability of the three HVDC converter stations to transfer energy between the two networks.

A few projects are underway to increase the electricity transfer between the 50 Hz (eastern Japan) and 60 Hz networks (western Japan) which will improve power reliability in Japan. In April 2019, Hitachi ABB HVDC Technologies secured an HVDC order for the Higashi Shimizu project to increase the interconnection capacity between the 60 Hz area of Chubu Electric and the 50 Hz area of TEPCO from 1.2 GW to 3 GW. Chubu Electric will increase the interconnection capacity of the Higashi Shimizu Substation from 300 MW to 900 MW which should be operational by 2027. OCCTO (Organization for Cross-regional Coordination of Transmission Operators) supervises the power interchange among electric power companies.

Mode of production + Gross production of electricity by source in Japan (TWh) Year Total Coal Gas Oil Nuclear Hydro Solar Wind GeothermalBiofuels2004 1,121294 26.2% 256 22.9% 169 15.0% 282 25.2% 103 9.2% 2008 1,108300 27.1% 292 26.3%154 13.9% 258 23.3% 84 7.5% 2009 1,075290 27.0% 302 28.1% 98 9.1% 280 26.0% 84 7.8% 20101,148310 27.0% 319 27.8% 100 8.7% 288 25.1% 91 7.9% 3.800 0.33%3.962 0.35%2.647 0.23%20111,082291 26.9% 388 35.8% 166 15.4% 102 9.4% 92 8.5% 5.160 0.48%4.559 0.42%2.676 0.25%20121,064314 29.5%409 38.4% 195 18.3% 16 1.5% 84 7.9% 6.963 0.65%4.722 0.44%2.609 0.24%20131,066349 32.7% 408 38.2% 160 15.0% 9 0.9% 85 8.0% 14.279 1.34%4.286 0.4%0.296 0.03%20141,041349 33.5% 421 40.4% 116 11.2% 0 0%87 8.4% 24.506 2.35%5.038 0.48%2.577 0.25%20151,009342 34.0%396 39.2%91 9.0%9 0.9%85 8.4%35.858 3.55%5.16 0.51%2.582 0.26%20181,06733231.1%40638.0%44.64.2%64.96.1%88.48.3%62.6675.87%7.4810.7%2.5240.23%19.21.80%20191,03932731.5%20201,01731130.6%20211,05032130.6%20221,01830830.3%20231,00328428.3%33133.0%30.23.0%84.08.38%858.5%96.4599.62%10.4911.05%3.3990.34%39.093.90%202498229530.1%29329.9%22.42.3%93.59.5%85.38.7%97.89410%11.9841.22%3.8700.39%38.283.90% According to the International Energy Agency, Japanese gross production of electricity was 1,041 TWh in 2009, making it the world's third largest producer of electricity with 5.2% of the world's electricity.IEA Key World Energy Statistics 2011 , 2010 , 2009 , 2006 IEA October, pages electricity 27 gas 13,25 fossil 25 nuclear 17Bird, Winifred, "Powering Japan's future ", Japan Times, 24 July 2011, p. 7. After Fukushima, Japan imported an additional 10 million short tons of coal and liquefied natural gas imports rose 24% between 2010 and 2012. In 2012 Japan used most of its natural gas (64%) in the power sector.

Nuclear power

Nuclear power was a national strategic priority in Japan. Following the 2011 Fukushima nuclear accidents, the national nuclear strategy is in doubt due to increasing public opposition to nuclear power. An energy white paper, approved by the Japanese Cabinet in October 2011, reported that "public confidence in safety of nuclear power was greatly damaged" by the Fukushima disaster, and it calls for a reduction in the nation's reliance on nuclear power.

Following the 2011 accident, many reactors were shut down for inspection and for upgrades to more stringent safety standards. By October 2011, only 11 nuclear power plants were operating in Japan, and all 50 nuclear reactors were offline by 15 September 2013. That left Japan without nuclear energy for only the second time in almost 50 years.Fukushima: Japan promises swift action on nuclear cleanup Prime minister Shinzo Abe makes pledge amid growing concern at scale and complexity of operation The Guardian 2 September 2013 Carbon dioxide emissions from the electricity industry rose in 2012, reaching levels 39% more than when the reactors were in operation.

Sendai 1 reactor was restarted on 11 August 2015, the first reactor to meet new safety standards and be restarted after the shutdown. As of July 2018, there are nine reactors that have been restarted.

Hydro power

Hydroelectricity is Japan's main renewable energy source, with an installed capacity of about 27 GW, or 16% of the total generation capacity, of which about half is pumped-storage. The production was 73 TWh in 2010.EIA Country Analysis Briefs – Japan | 2012| As of September 2011, Japan had 1,198 small hydropower plants with a total capacity of 3,225 MW. The smaller plants accounted for 6.6 percent of Japan's total hydropower capacity. The remaining capacity was filled by large and medium hydropower stations, typically sited at large dams.

Other renewables

Benjamin K. Sovacool estimated that Japan has a total of "324 GW of achievable potential in the form of onshore and offshore wind turbines (222 GW), geothermal power plants (70  GW), additional hydroelectric capacity (26.5 GW), solar energy (4.8 GW) and agricultural residue (1.1 GW)."Benjamin K. Sovacool | 2011| . Contesting the Future of Nuclear Power: A Critical Global Assessment of Atomic Energy, World Scientific, p. 287.