Nuclear Energy by Country

Nuclear power has reentered the mainstream for energy security, climate goals, and dependable electricity as demand rises. Global output is at a new high, but trajectories diverge—America extends a vast fleet while adding capacity, France rebounds and plans standardized builds, China rolls out reactors steadily, and others restart, slow, or exit. This report ranks countries by actual TWh and explains shifts via concise looks at reactor fleets, policy choices, financing models, and supply chains—showing who leads, who’s catching up, and what it means for reliability, decarbonization, and industrial strategy.

The Quick Take

Worldwide nuclear output reached a record 2,667 TWh in 2024, topping the previous high set in 2006. That record came from a mix of U.S. steadiness (with two new reactors finally online), a strong rebound in France after a difficult maintenance year, and China’s relentless build-out. The big surprise: several countries once ambivalent about nuclear—South Korea, Sweden, Canada, and Japan—are moving from “maybe” to “more,” while Spain and Germany are heading toward zero.

The 2024 Nuclear Leaderboard (by TWh)

Latest full-year country totals (net output, terawatt-hours). Figures below are for 2024 and come from the World Nuclear Association’s consolidated country data.

Note: Germany is now at 0 TWh after shutting its last three reactors in April 2023—a pivotal political decision with system-wide consequences.

How We Ranked & Why These Numbers Matter

We used the World Nuclear Association’s (WNA) 2024 country-level nuclear generation table—the most comprehensive open roll-up of national TWh figures—as the authoritative basis for ranking. Country-specific insights and time-series context are cross-checked against primary sources such as the IEA/IAEA (PRIS), the U.S. EIA, national grid operators, and major newswires (Reuters/FT/Bloomberg) to track policy turns, capacity changes, and large one-off events (e.g., France’s corrosion repairs; Ukraine’s wartime constraints).

The Big Picture: A New Nuclear Peak

2024 set a new global nuclear record—2,667 TWh. That tops the 2006 high (around 2,660 TWh), reflecting both plant life-extensions in mature fleets and new builds (especially in China and, after many delays, the United States’ Vogtle 3 & 4). The World Nuclear Association notes 70 reactors under construction, with 2024 seeing ground-breakings in China, Pakistan, Egypt, and Russia—signs of momentum after a decade dominated by renewables headlines.

At the same time, nuclear is highly country-specific: capacities, policies, and public attitudes diverge sharply. That’s why the rankings above don’t just reflect megawatts—they map national strategy.

Country Storylines: What’s Driving Leaders Up—or Down

1) United States: Scale, Stability, and a Long-Awaited Expansion

The U.S. remains the world’s nuclear heavyweight by output, clearing 782 TWh in 2024. After a long build drought, Vogtle-3 and Vogtle-4—the first large U.S. reactors in decades—entered commercial operation in July 2023 and April 2024, respectively. Those units nudged generation higher and, more importantly, broke a psychological barrier: new large reactors can still be built in advanced economies, even if they’re expensive and slow.

Policy is also leaning supportive. The U.S. introduced a Zero-Emission Nuclear PTC (Section 45U) to help existing reactors stay competitive, while a separate clean-energy PTC for new assets under the Inflation Reduction Act underpins life-extensions and uprates. Meanwhile, 94 U.S. reactors (about 97 GW) gave the country the world’s largest fleet in 2024. Rising data-center loads, onshored manufacturing, and grid reliability concerns are rekindling interest in nuclear’s 24/7, carbon-free output.

Reality check: Vogtle was costly—estimates exceed $30–35 billion—and delayed by years, underscoring execution risk for gigawatt-scale projects. That’s why much of the new-build conversation now includes SMRs and advanced reactors, even as the proven workhorse remains the life-extension of the existing fleet.

2) China: Relentless Build-Out

China’s output hit ~418 TWh in 2024, firmly in second place and closing the gap with France on an all-time basis. The trend is unmistakable: an expanding fleet (dozens operating, many more under construction and planned) with serialized builds of Hualong One and other designs. International analysis regularly flags China’s accelerating approvals and starts, making it the center of gravity for new gigawatt-scale reactors—part of a broader push to decarbonize while meeting surging electricity demand from heavy industry and digital infrastructure.

China’s national planners emphasize energy security alongside climate goals, keeping nuclear’s role growing even as wind and solar scale dramatically. Independent trackers like Ember and others have documented China’s rapid clean-power growth; nuclear is a smaller slice than in France or the U.S., but the absolute TWh are advancing fast from a low base.

3) France: Back From Maintenance Hell

France is still the most nuclear-reliant large economy: 67% of its electricity came from reactors in 2024. After corrosion-related repairs and extensive inspections depressed 2022 output (to ~282 TWh), production rebounded to ~364 TWh in 2024 as units returned to service. Paris has also signaled long-term commitment: plans to build at least six EPR2 reactors and prepare for more, while keeping the existing fleet running safely for longer where feasible.

The combination of fleet-level maintenance recovery and new-build policy anchors France in the global top three for the foreseeable future, though execution remains the watchword—European megaprojects have struggled with cost and schedule discipline.

4) Russia: Exporter-in-Chief, Solid at Home

Russia generated ~202 TWh in 2024, placing fourth. Domestically, newer VVER-1200 units have helped offset retirements. Internationally, Rosatom remains the most active exporter of nuclear technology, building or supplying major projects in Turkey (Akkuyu), Egypt (El Dabaa), and Bangladesh (Rooppur)—even as geopolitical sanctions complicate financing and supply chains. That export pipeline gives Russia unique influence over nuclear standards, fuel services, and long-term customer ties in emerging markets.

5) South Korea: From Phase-Out to Push-Ahead

South Korea’s ~179 TWh in 2024 reflects a policy reset. The 10th Basic Plan (2022–2036) and subsequent updates aim to lift nuclear’s contribution to ~35% by the late 2030s, supported by life-extensions and new builds (Shin Hanul and Saeul units) and a strong export agenda (the APR-1400 design proved itself at the UAE’s Barakah). Output rose with Shin Hanul-2 coming online and streamlined outages, while Seoul laid out targets for more reactors and carbon-free power dominance.

6) Japan: Careful Restarts, Tangible Output

Japan’s nuclear generation reached ~85 TWh in 2024 as a dozen-plus reactors cleared safety retrofits and court challenges. The Onagawa-2 restart in late 2024 was symbolically significant—the plant closest to the 2011 quake and tsunami zone. With LNG prices volatile and data-center demand rising, Tokyo has pivoted to “maximize” nuclear within strict safety constraints. The political and regulatory trajectory now favors more restarts—gradual, but steady.

7) Canada: Refurbish First, Build Small Next

Canada posted ~81 TWh in 2024. The strategy blends life-extension of its big CANDU fleet—especially Bruce Power’s multi-unit refurbishment program, now marching through Units 3–8—with a first-mover push into SMRs. Ontario authorized construction of a BWRX-300 at Darlington in 2025 (the first SMR in the “Western world,” slated in the 2030 timeframe), with four units planned. Refurbishments secure large, low-carbon baseload for decades, while SMRs are a hedge for future growth and industrial loads.

The Next Tier: Europe’s Cross-Currents and Two Giant Wildcards

Spain (52 TWh) has confirmed a full nuclear phase-out by 2035, though recent system stress events reignited debate over whether some units should run longer to stabilize the grid through the 2030s. For now, the calendar stands. Sweden (49 TWh), by contrast, has pivoted hard toward nuclear, passing enabling laws and financing tools for new large reactors and/or SMRs, with ambitions equivalent to ten new full-size units by 2045.

The United Kingdom (37 TWh) is in a bridging decade: aging AGR units are retiring faster than Hinkley Point C can arrive (now delayed toward 2029–2031 with escalating costs). The government has pushed Sizewell C to a final investment decision and committed further public funding under a RAB model to de-risk financing, but consumer-bill impacts are controversial.

Two critical wildcards:

• Ukraine (50 TWh): Despite war, Ukraine’s non-occupied reactors continue generating; the huge Zaporizhzhya plant has been in cold shutdown and not producing power since 2022 due to safety and security concerns under occupation. Output could change substantially post-war, in either direction depending on asset condition and reinvestment.

• India (50 TWh): Today’s nuclear share is small, but New Delhi intends to triple capacity by 2031–32 (to ~22.5 GW) and is exploring policy changes to unlock private/foreign participation. Ambitions stretch even further—to 100 GW by 2047—though that would require unprecedented build rates and enabling reforms.

Add in Finland (31 TWh), where Olkiluoto-3 has stabilized after commissioning, Belgium (30 TWh) extending Doel-4 and Tihange-3 by a decade, and a cluster of 10–25 TWh markets (Czechia, Switzerland, Pakistan, Bulgaria, Hungary, Romania, Brazil, Belarus, Mexico). Europe’s map is a checkerboard of phase-outs, extensions, and new-build green lights.

And in the Middle East, the UAE (36.5 TWh) has quickly become a top-20 nuclear generator thanks to the four-unit Barakah plant, the world’s first complete export of South Korea’s APR-1400 design. The UAE now has one of the most modern civilian fleets anywhere.

Why Output Is Shifting: Four Forces to Watch

1) Energy Security Aftershocks

Russia’s invasion of Ukraine refocused Europe on security-of-supply. Nuclear’s value as domestic, weather-independent baseload rose in policymaking—helping nuclear win a “sustainable” label in the EU Taxonomy (with conditions). That classification may lower financing costs and ease green-bond participation for qualifying projects.

2) Climate Targets & System Reliability

Nuclear’s 2024 record came with an estimated 2.1 billion tonnes of CO₂ avoided vs. fossil alternatives, according to industry tallies. For grids wrestling with dunkelflaute (low wind + low sun) and peak demand spikes from data centers and electrification, dispatchable, zero-carbon gigawatts are scarce. This is where life-extended GW-scale units and firm SMR pilots enter the strategy set.

3) Economics of New Builds

New gigawatt-reactors face capital cost and schedule risk. The U.K.’s Hinkley C (EPR) delays and budget creep and America’s Vogtle overruns are cautionary. Hence policy innovation: regulated asset base (RAB) models (U.K.), long-term CfDs, and production tax credits (U.S.) designed to crowd in capital and stabilize revenue. Canada’s staged SMR program shows a different path: serial small units plus refurbish-what-you-have.

4) Domestic Industrial Strategy

Countries see nuclear as a supply-chain and export play. Rosatom and EDF market turnkey offerings; Korea pitches APR-1400 with Barakah credentials; Japan seeks to regain engineering leadership via restarts and uprates; China is validating designs at home before expanding exports. These industrial strategies, not just climate math, shape who climbs the TWh rankings next.

Country Case Studies (Deeper Dives)

United States: Life Extension + Two New Reactors = Record-Adjacent Stability

What changed: After decades of no large new builds, Vogtle 3 & 4 flipped on—first in July 2023, then April 2024—adding firm, zero-carbon output to the Southeast. The U.S. also created a production tax credit for existing nuclear (Sec. 45U) to keep plants profitable during low wholesale price periods. Result: A slight uptick in nuclear TWh in 2024 and a stronger base to meet rising data-center loads.

Why it matters: With 94 reactors still operating (the largest fleet), the U.S. can drive gigawatt-scale decarbonization by simply running what it has and selectively uprating and relicensing. The economics of new large reactors remain challenging, so SMRs and advanced designs may prove more bankable for fresh capacity—if first-of-a-kind projects demonstrate on-time, on-budget delivery.

China: From Catch-Up to Pacesetter

What changed: An approval-and-start cadence that few countries can match. Standardized builds, domestic supply chains, and long-horizon planning deliver reliable annual capacity additions. The state treats nuclear as a strategic complement to massive wind and solar—firming the system while curbing coal growth.

Why it matters: China will likely move closer to 500 TWh and beyond this decade, almost certainly solidifying second place and occasionally challenging France on annual output if French maintenance seasons are heavy. If exports of Chinese designs (e.g., Hualong One) scale, Beijing’s influence over global nuclear standards and fuel cycles could expand.

France: Fleet Healing and EPR2 Ambitions

What changed: After an extraordinary 2022 maintenance year, EDF restored output and is planning EPR2 builds. France’s nuclear share (about two-thirds of power) still underpins Europe’s lowest-carbon grids, but execution on new projects is under intense scrutiny after EPR experiences in Finland, France, and the U.K.

Why it matters: A successfully executed EPR2 program would anchor French supply for mid-century and reassert Europe’s homegrown nuclear engineering—counterweight to Russian and Asian suppliers.

Russia: Domestic Output, Global Footprint

What changed: At home, Russia’s new VVER-1200 units keep output steady above 200 TWh. Abroad, Rosatom remains the go-to EPC for countries starting nuclear from scratch—Akkuyu (Turkey), El Dabaa (Egypt), Rooppur (Bangladesh). Sanctions complexity hasn’t stopped contracts, highlighting how capability + financing wins greenfield deals.

Why it matters: The TWh scoreboard underestimates Russia’s strategic position—decades-long fuel and service agreements embed Moscow in client grids. That creates geopolitical interdependencies far beyond any one year’s generation.

South Korea: Output Rising with an Export Mindset

What changed: Policy reversal away from phase-out; Shin Hanul 2 online; outage management improved. The 10th Electricity Plan points to ~35% nuclear by 2036; a further draft aims for 70% carbon-free generation by 2038 with nuclear as a bedrock. Korea also seeks to export whole plants (APR-1400) and components/services.

Why it matters: Korea blends engineering reliability with export zeal, making it the most credible Western-aligned builder of big reactors today—see Barakah in the UAE as reference case.

Japan: The Long Climb Back

What changed: Court rulings, safety retrofits, and local politics slowly aligned to allow more restarts. The Onagawa-2 return in 2024 was a milestone; the government now plans to maximize nuclear’s role within a strict safety envelope to cut fossil imports and backstop new digital/electronics manufacturing.

Why it matters: Every restart meaningfully reduces Japan’s LNG exposure, benefiting both the trade balance and Asia’s gas market dynamics—especially in high-demand summers and cold snaps.

Canada: Refurbish to 2060s; Pilot SMRs for the 2030s

What changed: Bruce Power’s rolling refurbishments extend multiple CANDU units to 2064; Ontario granted a license and greenlit construction for the first BWRX-300 SMR at Darlington—the first in the West if timelines hold.

Why it matters: Canada’s playbook—sweat the big fleet and layer in small modular—could become the model for advanced economies that want low-carbon firmness without taking on a Hinkley/Vogtle-scale risk all at once.

Spain, Sweden, UK, India, UAE (and Ukraine)

• Spain: Output is still significant (~52 TWh), but policy is to close by 2035. Blackouts and system events periodically rekindle debate, yet the calendar hasn’t changed.

• Sweden: Quietly one of Europe’s most consequential policy pivots—laws now enable new reactors, with state loans/CfD-style support and an ambition equivalent to ten full-size units by 2045.

• United Kingdom: Output continues to slide with AGR retirements; Hinkley C delays to 2029–2031 and Sizewell C’s financing mean the 2030s will determine whether the U.K. re-enters the nuclear top-10 by TWh.

• India: Output (~50 TWh) belies massive ambition: ~22.5 GW by 2031–32 and explorations to allow up to 49% foreign stakes in projects. The government is also floating much larger 2040s targets, but policy execution will be the decider.

• UAE: Barakah (four APR-1400s) vaulted the UAE into the top tier (~36.5 TWh), offering a turnkey case study in on-time delivery by a non-Western builder (Korean consortium).

• Ukraine: Wartime operations continue away from occupied zones; Zaporizhzhya remains in cold shutdown. The country’s nuclear share is still high, but absolute output is constrained until assets are secure and fully restored.

Historical Arcs That Explain Today’s Map

• From 2006 to 2024: Global output’s new record reflects Asia’s rise (China, South Korea, India) offsetting OECD declines and retirements, then a French rebound. 2024 finally surpassed the 2006 peak.

• Japan’s long climb back: From pre-Fukushima highs (near 300 TWh in 2010) to single digits by mid-decade, now ~85 TWh and rising—slow, politically careful, grid-critical.

• Germany’s exit: One of the world’s top producers in the 2000s has exited entirely since April 2023; coal and gas, plus accelerated renewables and cross-border flows, now carry the slack.

• France’s maintenance saga: 2022’s corrosion inspections drove a generational low; 2023–2024’s recovery shows fleet effects—when many units return, TWh surges back.

Nuclear’s Role in the Transition: Complement, Not Competitor

The 2024 record doesn’t imply nuclear “outcompeted” renewables. In fact, wind and solar set records in many regions and, in the U.S., actually overtook nuclear output for the first half of 2024. What it shows is systems thinking: grids need firm, low-carbon generation to complement variable renewables. Where countries can refurbish, extend, or add reactors, total clean TWh climb faster—and fossil reliance falls faster.

What to Watch (2025–2035)

1. China’s cadence: Annual starts/approvals will determine when China crosses 500 TWh and how quickly it narrows the gap to the U.S. in the 2030s.

2. U.S. SMRs and uprates: Will SMR first-of-a-kind projects (and IRA tax credits) establish a replicable cost curve—and can life-extensions keep 90%+ capacity factors?

3. France EPR2 execution: If France delivers its EPR2 program on schedule and budget, it rewrites Europe’s nuclear narrative.

4. UK megaprojects: Hinkley and Sizewell timelines—and the politics of consumer levies—will shape investor confidence for European big-nuclear.

5. South Korea’s export pipeline: Watch Czechia and other tenders; APR-1400 could become the default Western-aligned option for first-time nuclear countries.

6. Spain’s calendar vs. system needs: Will 2035 hold, or will reliability/price concerns prompt extensions?

7. India’s reforms: Allowing foreign stakes and resolving liability hurdles could unlock a long-delayed scale-up—and move India up the TWh table.

8. Ukraine’s post-war rebuild: The pace and scope of nuclear asset restoration could swing Europe’s nuclear map again.

Bottom Line

Nuclear is having a systems moment. Not because it’s cheap or fast in every country, but because no single technology can decarbonize large, complex grids at the speed demanded by climate physics and industrial policy. The 2024 TWh leaderboard reveals the strategies nations are betting on:

• U.S.: Keep the massive fleet running; add select new capacity; explore SMRs; ride IRA incentives.

• China: Build, build, build—standard designs at scale.

• France: Heal the fleet; commit to next-gen EPR2; remain Europe’s low-carbon backbone.

• South Korea: Extend at home, export abroad.

• Russia: Use exports to entrench long-term influence.

• Japan/Canada/Sweden/UK: Each has found its own lane—restart + safety, refurbish + SMR, new-build push, megaproject slog—all contributing to the global record.

If the next decade turns today’s policy talk into on-time steel, the 2024 record will look like a waypoint, not a peak—especially as electrification, AI/data centers, green industry, and hydrogen create a voracious appetite for clean, round-the-clock power.