Japan has made a decisive course correction. The Seventh Strategic Energy Plan, approved by the government on February 18, 2025, dropped the language — carried in every energy plan since 2014 — calling for a gradual reduction of nuclear dependence. The new directive is straightforward: maximize. The goal is to raise nuclear power’s share from 8.5% in 2023 to roughly 20% by 2040, while cutting fossil fuels from today’s 70% to a range of 30–40%.
The most telling symbol of this shift is the Kashiwazaki-Kariwa plant, owned by TEPCO and the largest nuclear facility in the world by installed capacity. Shut down for over a decade following the 2011 Fukushima disaster, it restarted reactor 6 on February 9, 2026, reaching commercial operation in April. With 1,356 MW of installed capacity, that single reactor could replace approximately 1.3 million tonnes of imported LNG per year — equivalent to 62 billion cubic feet of natural gas — according to Japanese government estimates. With this restart, Japan now has 15 nuclear reactors in operation, with a combined capacity of 33 GW.
The drive to return to nuclear is not motivated solely by climate goals. Japan relies on imports for more than 90% of its primary energy needs. Before Fukushima, nuclear covered around 30% of national electricity generation. After 2011, that share collapsed, and natural gas — entirely imported — filled the gap, accounting for 33% of power generation in 2024. LNG imports have declined from 11 billion cubic feet per day in 2018 to 9 billion in 2025, thanks to progressive nuclear restarts, but Japan remains the world’s second-largest LNG importer after China. The war in Ukraine and tensions in the Strait of Hormuz have made the cost of this dependency even more apparent. The plan also calls for the development of next-generation advanced reactors to replace aging units: the Ministry of Economy estimates that between 2 and 5 new plants will be needed by the 2040s, and between 11 and 14 by the 2050s.
Industrial demand is also pushing electricity consumption higher. The rapid expansion of AI data centers and semiconductor manufacturing facilities is driving up power needs significantly. The plan explicitly states that a shortage of clean energy sources could undermine Japan’s industrial competitiveness. The government is therefore committed to maximizing both renewables — expected to reach 40–50% of the mix by 2040 — and nuclear, abandoning any either/or framing between the two. Restarted reactors achieved a capacity factor of 80.5% in 2024, confirming the operational reliability of units brought back into service. Reaching the 20% target by 2040 will nonetheless require up to 30 reactors to be online: 15 are currently operating, 3 have received initial approval from the Nuclear Regulation Authority, and 6 are under review.
The regulatory framework also underwent a significant change in June 2025, when new rules came into force excluding from a reactor’s operational lifespan the periods when units were idled for post-Fukushima regulatory reviews. This effectively extends the economic horizon of existing plants and makes them more attractive to investors. Japan is betting on a technology it knows well — nuclear — to reduce its longstanding energy vulnerability. If the pace of restarts maintains the momentum built over recent months, Tokyo could approach its 20% target by the 2040 deadline, and durably reshape its energy posture across the Pacific.
