Japan’s energy sector, Tohoku Electric Power Company announced that Unit 2 at the Onagawa Nuclear Power Plant in northeastern Japan’s Miyagi region, adjacent to the Fukushima prefecture, has resumed operations after years of extensive upgrades. The unit became the first boiling water reactor (BWR) to restart since the 2011 Fukushima Daiichi disaster. This marks a pivotal moment in Japan’s energy policy as the country seeks to balance decarbonization goals with energy security amid a pressing need to reduce fossil fuel imports and bolster sustainable energy.
The plant’s operator, Tohoku Electric, has emphasized the importance of safety and preparedness in its decision, highlighting new structural measures—including a 29-meter-high tsunami wall, one of the tallest in Japan, designed to protect the plant from similar natural disasters that previously led to the Fukushima Daiichi catastrophe. The restart, expected to bolster energy production in Japan’s northeastern region, reflects the nation’s ongoing strategy to revive nuclear energy, an area of complex and often controversial policy focus since the 2011 disaster.
Following the Fukushima Daiichi disaster in March 2011, Japan made the historic decision to shutter all of its 54 nuclear reactors as a precaution. Since then, only 12 of the 33 reactors deemed operable have been reactivated, largely due to public concern over safety and the strict regulatory standards imposed by the Nuclear Regulation Authority (NRA). The Onagawa plant’s restart brings the tally of operational reactors to 13, underscoring Japan’s cautious but determined effort to reintegrate nuclear power as a cornerstone of its energy strategy.
The Japanese government has underscored nuclear energy’s importance in achieving its ambitious climate goals, including cutting greenhouse gas emissions by 46 percent by 2030, compared to 2013 levels. Nuclear energy, together with renewable sources such as wind and solar, forms a critical component of this strategy. Top government spokesman Yoshimasa Hayashi reiterated this priority during a press conference, stating, “Nuclear power, along with renewable energy, is an important decarbonized power source, and our policy is to make maximum use of it on condition that safety is ensured.”
Japan’s energy strategy calls for nuclear power to account for 20-22 percent of its energy mix by 2030, a significant increase from its current contribution, which remains below 10 percent. The plan also envisions boosting renewable energy’s share from approximately 20 percent today to between 36 and 38 percent, while reducing reliance on fossil fuels from two-thirds to 41 percent.
The Fukushima Daiichi disaster remains one of the most devastating nuclear incidents in modern history, triggered by a 9.0-magnitude earthquake and a subsequent tsunami that destroyed backup generators, leading to three reactor meltdowns. The incident resulted in widespread contamination, mass evacuations, and a prolonged cleanup effort, which continues to this day.
Following the disaster, Japan’s regulatory standards underwent significant reforms aimed at preventing similar occurrences. Safety measures, especially against natural disasters, became paramount, with rigorous checks introduced at all nuclear facilities. In 2020, the NRA gave Onagawa clearance to resume operations, contingent on enhancements designed to withstand extreme seismic and hydrological events. The plant now boasts a tsunami wall towering 29 meters above sea level, along with other structural reinforcements to bolster its resilience against natural calamities.
According to Tohoku Electric, these new protective measures represent some of the most comprehensive in Japan, designed to address and mitigate risks posed by tsunamis and earthquakes in the region. Onagawa’s restart is a litmus test for Japan’s nuclear industry, especially given the plant’s proximity to Fukushima and the public’s sensitivity to nuclear risks in the area.
Japan’s economic outlook has been impacted in recent years by its reliance on imported fossil fuels, particularly liquefied natural gas (LNG), to meet energy demands after the 2011 nuclear shutdowns. This reliance has not only escalated Japan’s energy expenses but has also complicated efforts to reduce greenhouse gas emissions.
To tackle these challenges, the Japanese government is seeking to decarbonize its power grid while ensuring a stable energy supply. Nuclear energy, less carbon-intensive than fossil fuels, offers an appealing alternative, and its revival is seen as a necessary step toward meeting Japan’s climate commitments under the Paris Agreement. The reactivation of the Onagawa plant aligns with a broader global trend, as many nations pivot back to nuclear energy to meet climate targets and provide reliable power for emerging sectors like data centers and AI.
Yoshimasa Hayashi, the government spokesperson, emphasized that decarbonized power sources, including nuclear, are essential for sustainable economic growth and meeting increasing energy demands. He stated, “The importance of restarting nuclear reactors is growing from the perspective of our nation’s economic growth driven by decarbonized power sources.”
While the government and industry stakeholders advocate for nuclear energy, public opinion in Japan remains divided. The memories of Fukushima linger, especially for residents of the Tōhoku region, who experienced firsthand the catastrophic effects of a nuclear meltdown. Local opposition has often emerged in response to plans for reactor restarts, with many citizens expressing concerns over the adequacy of safety measures and the potential for future accidents.
Environmental groups have also voiced criticism, urging the government to focus more on expanding renewable energy sources rather than relying on nuclear power. The E3G think tank recently ranked Japan last among the Group of Seven (G7) nations in terms of decarbonizing its energy sector. According to E3G, Japan’s dependence on nuclear and fossil fuels, combined with what they view as slower progress on renewables, puts the country behind its counterparts in adopting a fully sustainable energy mix.
However, advocates argue that nuclear energy can act as a bridge solution, filling energy gaps while Japan accelerates the development and adoption of renewable technologies. The increased presence of renewables, while promising, currently faces challenges related to scalability, storage, and consistent supply, particularly in a country that experiences frequent natural disasters.
Japan’s renewed nuclear ambitions reflect a larger global resurgence of interest in nuclear power as countries grapple with climate targets and energy security. Nations including the United Kingdom, the United States, and South Korea are revisiting nuclear energy as part of their decarbonization strategies, citing its ability to produce stable, low-carbon energy. Japan’s nuclear restarts are closely watched internationally, with energy policy experts pointing to the country’s stringent safety measures as a model for nuclear resilience.
The restart of the Onagawa reactor, particularly given its status as a BWR, will likely be examined for its operational performance and safety benchmarks. Lessons learned from Onagawa’s operations could guide future reactor restarts, both in Japan and globally, offering insights into how to safely manage nuclear energy in regions prone to natural disasters.
The Japanese government’s energy blueprint sees nuclear and renewables as complementary sources capable of fulfilling the country’s energy needs sustainably. By 2030, renewables are expected to account for up to 38 percent of Japan’s energy production, primarily through solar, wind, and hydroelectric sources. Nuclear energy’s anticipated share of around 22 percent would position it as a reliable backup, especially during times when renewable production dips due to unfavorable weather conditions or other disruptions.
Japan’s path forward, however, is not without challenges. Increasing renewable capacity necessitates substantial investment in grid modernization and energy storage solutions, particularly if the country aims to decrease its reliance on fossil fuels substantially. Achieving this balance between nuclear and renewables will require continued commitment from both the government and the energy sector, alongside consistent public engagement to build trust in the safety and sustainability of these solutions.
