Kashiwazaki-Kariwa Nuclear Plant: Significant Contribution to Stable Power Supply

Editorial

14:26 JST, April 30, 2026

For the first time in 14 years, following the 2011 Great East Japan Earthquake, electricity from a nuclear power plant has reached the Tokyo metropolitan area. Amid ongoing turmoil in the situation in Iran, the plant plays a significant role in ensuring a stable power supply.

Tokyo Electric Power Company Holdings, Inc. began commercial operation of the No. 6 reactor at its Kashiwazaki-Kariwa nuclear power plant in Niigata Prefecture on April 16. This marks the first time TEPCO has fully restarted a nuclear reactor since the 2011 accident at the Fukushima No. 1 nuclear power plant.

The No. 6 reactor was restarted in January this year with the consent of the Niigata prefectural government, but experienced a series of problems, including equipment malfunctions. As a result, the start of commercial operation, originally scheduled for Feb. 26, was delayed by about two months.

This likely reflects TEPCO’s commitment to thorough safety checks in light of the immense damage caused by the nuclear accident following the earthquake. TEPCO must continue to work to prioritize safety above all else so as not to undermine the trust of local residents.

With the restart of nuclear reactors stalling, supply and demand for electricity in the Tokyo metropolitan area has remained precarious in recent years.

The situation was particularly severe in 2022. This was due to increased household electricity demand resulting from the widespread adoption of telecommuting and other factors during the COVID-19 pandemic, as well as energy shortages caused by Russia’s aggression against Ukraine.

At the time, in response to the reduced power supply, the government issued a warning for the first time regarding the tight electricity supply-demand balance in March 2022 to prevent large-scale power failures. It also issued a request for power conservation that summer — the first instance in seven years — and repeated the request the following year.

This summer, with the restart of the reactor at the Kashiwazaki-Kariwa nuclear power plant, it is expected that a request for power conservation will not be issued. It can be said that this indicates the significant contribution that high-output nuclear power plants make to a stable power supply. TEPCO must take every possible precaution to ensure that no problems arise that could stop the operation.

Japan is facing heightened geopolitical risks, such as Iran’s de facto blockade of the Strait of Hormuz, a vital artery for crude oil transport. As energy security becomes an increasingly critical issue, nuclear power is vital as a “quasi-domestic energy source” that can help with decarbonization efforts.

The use of nuclear power also offers significant benefits in terms of conserving fossil fuels.

Although the share of renewable energy sources such as solar power has increased in Japan’s power mix, thermal power generation — primarily using liquefied natural gas — accounts for about 70% of the total. It is estimated that the restart of the reactor at the Kashiwazaki-Kariwa nuclear power plant would reduce LNG imports via the Strait of Hormuz by about 30%.

The outlook for the situation in Iran remains uncertain, and the difficult circumstances are likely to persist for Japan, which relies on imports for the majority of its energy. With LNG prices soaring, it is likely inevitable that electricity rates will rise this summer or later.

In light of the risk of continued instability in the Middle East, it is also important for both the public and private sectors to raise awareness about energy conservation.

(From The Yomiuri Shimbun, April 30, 2026)