Japan Approves Restart of World's Largest Nuclear Plant, Kashiwazaki-Kariwa: A Major Energy Policy Shift

A significant turning point in Japan's energy strategy was reached on December 22, 2025, when the Niigata Prefectural Assembly formally endorsed Governor Hideyo Hanazumi’s proposal to reactivate the Kashiwazaki-Kariwa Nuclear Power Station. This facility holds the distinction of being the world's largest nuclear power plant by installed capacity, yet it has remained dormant for nearly 15 years following the devastating 2011 Fukushima disaster. This assembly approval signals a critical pivot in national policy, driven by the urgent need to curb reliance on imported fossil fuels, which cost the nation a staggering 68 billion US dollars last year alone.

The operator of this massive complex is the Tokyo Electric Power Company (TEPCO), the same entity responsible for managing the Fukushima Daiichi site. Strategically situated in Niigata Prefecture, approximately 220 kilometers northwest of Tokyo, the plant boasts a combined net capacity of 7,965 MW across its seven reactors. While the timeline for bringing all units back online remains fluid, TEPCO has set its sights on restarting Reactor Unit No. 6 as early as January 20, 2026. Crucially, Units 6 and 7 have already successfully navigated rigorous post-Fukushima safety assessments. The revival of Kashiwazaki-Kariwa is integral to Japan’s broader national agenda: achieving carbon neutrality by 2050 and substantially increasing nuclear power’s contribution to the energy mix to 20% by 2040.

Despite gaining the necessary political clearance, the decision has not been met without considerable public dissent. Approximately 300 demonstrators gathered outside the Prefectural Assembly building, voicing deep-seated anxieties regarding operational safety. A local poll conducted in October revealed that a substantial 60% of residents felt the safety prerequisites had not been adequately met, with nearly 70% expressing reservations specifically about TEPCO continuing as the plant's operator. Critics within the assembly characterized the vote as little more than a political maneuver that disregarded the genuine concerns of Niigata’s populace. Governor Hanazumi, addressing the approval, acknowledged it as a vital milestone but stressed that the work toward ensuring absolute safety remains ongoing.

In a concerted effort to rebuild public trust, TEPCO has proactively showcased enhanced safety protocols to the press. These demonstrations included showcasing newly constructed seawalls and upgraded filtration systems, all designed based on hard-won lessons from the Fukushima accident. Furthermore, the company has committed to injecting 100 billion yen into the Niigata Prefecture economy over the course of the next decade. This restart is particularly noteworthy as it marks the first time a TEPCO-operated reactor will resume power generation since the Fukushima Daiichi incident.

Looking at the bigger picture, Japan is navigating a complex energy landscape, balancing decarbonization goals with surging energy demands, particularly from the burgeoning data center sector. The nation is seeking pragmatic solutions that involve not only bringing existing, reliable capacity back online but also actively pursuing the development of next-generation reactor designs. This measured approach underscores a commitment to energy security while striving for environmental sustainability in the coming decades.