Hokkaido Expected to Restart Reactor at Tomari Nuclear Plant, Which Could Cut Electricity Costs by 11%

The Yomiuri Shimbun

20:00 JST, November 26, 2025

Hokkaido Gov. Naomichi Suzuki plans to indicate that he will approve the restart of the No. 3 reactor at the Tomari nuclear power plant run by Hokkaido Electric Power Co. (HEPCO), according to informed sources. HEPCO aims to restart the reactor in early 2027.

The governor is expected to announce a final decision that takes into consideration deliberations at the prefectural assembly.

Vice Gov. Tsuyoshi Mitsuhashi told the parliamentary group holding a majority in the assembly, which includes the Liberal Democratic Party, that the governor thinks “the restart will be unavoidable given what options are realistic,” according to the sources. The group’s members reportedly said they would agree to the restart in consideration of the governor’s opinion.

Suzuki is expected to explain his thoughts at a plenary session of the prefectural assembly as early as Friday. He is likely to announce his final decision as early as December after listening to assembly members’ views on the issue.

The governor has avoided making any clear-cut statements and has said that he will make a comprehensive decision after hearing from the prefecture’s residents, the prefectural assembly and municipalities.

Advanced semiconductor manufacturing plant and data center project are underway, and electricity demand is expected to increase in Hokkaido.

The Hokkaido prefectural government has finished explaining safety measures at the plant to residents in the area. While consent from local governments will also be needed for the restart, Tetsunori Takahashi, the mayor of Tomari, where the plant is located, gave the OK on Nov. 17.

The Tomari plant houses three reactors, and the No. 3 reactor was shut down in May 2012. HEPCO applied to the Nuclear Regulation Authority for a safety screening of the reactor in July 2013. However, the screening process took a long time as the firm had to explain that there is no fault below the plant site.

In July this year, the reactor passed its safety screening. HEPCO indicated that it aims to restart the plant’s No. 1 and 2 reactors, which were shut down shortly after the 2011 Great East Japan Earthquake, in the early 2030s.

The power company plans to reduce electricity fees for households by about 11% after the restart of the No. 3 reactor.

A seawall is currently under construction at the Tomari plant to protect it from tsunami. If it is not completed by March 2027 as scheduled, it may delay the restart of the No. 3 reactor.