Japan’s long-paused nuclear power sector took a meaningful step forward in early 2026 with the restart of Unit 6 at the Kashiwazaki-Kariwa Nuclear Power Station, marking the return to service of one of the country’s largest reactors more than a decade after the Fukushima disaster. The restart is expected to boost nuclear generation, displace fossil fuel-fired electricity — particularly natural gas — and influence Japan’s broader energy mix at a time of evolving climate, energy security and decarbonization priorities.
On February 9, 2026, Tokyo Electric Power Company Holdings (TEPCO) confirmed the restart of the 1,356-megawatt Unit 6 at Kashiwazaki-Kariwa in Niigata Prefecture, with full commercial operations expected by mid-March. The reactor — offline since the 2011 Fukushima Daiichi accident for safety enhancements and regulatory review — will be the first TEPCO unit to resume service in nearly 14 years and is projected to generate about 9.5 terawatt-hours (TWh) annually once fully ramped up.
Japan now has 15 operating nuclear reactors with a combined capacity of about 33 gigawatts (GW), out of an operable fleet of 32. In 2024, this fleet produced roughly 83 TWh — about 9 per cent of total electricity generation — as nuclear capacity gradually returned after extensive safety reviews and public debate over nuclear energy’s role.
Impact on fossil fuel use and LNG imports
Analysts and government estimates suggest the added nuclear output from Unit 6 could displace about 1.3 million tonnes of LNG — equivalent to roughly 62 billion cubic feet of natural gas imports annually — if generation from nuclear substitutes for gas-fired power. That displacement figure reflects Japan’s ongoing effort to reduce reliance on imported fossil fuels for electricity, a legacy effect of all reactors shutting down following the 2011 tsunami and nuclear accident.
Natural gas previously accounted for about 33 per cent of Japan’s electricity mix in 2024, with LNG imports serving as a critical feedstock for gas-fired plants. Japan remains the second-largest LNG importer globally after China, though annual LNG demand has declined in recent years as nuclear and renewables have grown. Japanese companies imported roughly 9 billion cubic feet per day (Bcf/d) of LNG in 2025, down from about 11 Bcf/d in 2018, according to market data. Australia, Malaysia, Russia and the United States have been among Japan’s top LNG suppliers, with Australian volumes rising in recent years while U.S. shipments declined.
The increase in nuclear output also fits within Japan’s long-term energy strategy, which aims to raise nuclear’s share of electricity generation to around 20 per cent by 2040. Meeting that goal would require up to 30 reactors in operation, meaning some of the 17 currently non-operating reactors would need to clear regulatory and local hurdles before restarting. Three units have initial Nuclear Regulation Authority approval and six more are under review.
Renewables and policy context
Alongside nuclear, Japan’s power mix has seen renewable generation grow steadily. Solar capacity, in particular, expanded rapidly in the past decade, and preliminary statistics indicate that renewables accounted for more than 26 per cent of electricity generation in 2024, with solar alone contributing more than 11 per cent and hydro nearly 8 per cent. Fossil fuels, including coal and natural gas, still made up the majority of generation but have trended downward from levels exceeding 70 per cent earlier in the decade.
Japan’s evolving energy policies — including its 6th Strategic Energy Plan and the broader Green Transformation (GX) agenda — reinforce these shifts. The plans aim to nearly double renewable generation’s share and boost nuclear’s role by 2030 while reducing fossil fuel dependence significantly. Officials see nuclear as an essential part of ensuring energy security and reducing electricity price volatility, particularly in a country that imports roughly 90 per cent of its energy needs.
Historical and public sentiment backdrop
Japan’s reliance on nuclear power draws directly from its pre-2011 energy configuration, when reactors provided around 30 per cent of electricity. Following the Fukushima disaster, all reactors were taken offline for safety upgrades under new regulatory standards, and public opinion tilted sharply away from nuclear generation. That shift significantly increased fossil fuel use and raised energy import costs.
Efforts to restart large reactors like Kashiwazaki-Kariwa have often been met with local debate and scrutiny over safety and disaster preparedness. Approval from regional authorities has been essential for restarts, reflecting lingering public sensitivity to nuclear risks. Still, government policy revisions now emphasize maximizing both renewable and nuclear “carbon-free” power sources, signalling a broader acceptance of nuclear as part of Japan’s decarbonization trajectory.
Market and geopolitical implications
Bloomberg and Reuters reporting over recent years has underscored that Japan’s nuclear comeback is closely tied to broader energy security concerns, including volatile LNG markets and price spikes following global supply disruptions. Analysts have noted that a robust nuclear fleet could insulate Japan from some of these risks, particularly as competition for LNG supplies intensifies in Asia.
NPR highlighted the challenge Japan faces balancing safety, public sentiment and decarbonization goals, noting that nuclear restarts require meticulous regulatory oversight and clear communication to gain social license.
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