Nuclear Energy Statistics (2026)

The United States runs the largest commercial nuclear fleet on Earth: 94 reactors at 54 power plants, each plant with one to four units, totaling nearly 97 gigawatts of net capacity in 2024 (see the table below). That fleet generated 781.9 terawatt-hours of electricity, a small increase over 2023 and near the all-time high.

Despite that scale, the fleet has shrunk in count. Twelve reactors have permanently closed since 2013, mostly older single units squeezed by cheap natural gas. Capacity held up because operators ran the remaining reactors harder and added the two new Vogtle units in Georgia.

Nuclear supplied about 19% of US electricity in 2024, a share it has held roughly steady for two decades even as total generation grew. That makes it the single largest source of firm, always-available low-carbon power in the country, ahead of hydro and comparable to wind and solar combined.

The share has drifted down slightly from a peak above 20% in the late 1990s, not because output fell but because gas, wind, and solar grew faster. In absolute terms, US nuclear generation is near its record, thanks to high utilization rather than new plants.

Nuclear's superpower is uptime. US reactors ran at a 92.3% capacity factor in 2024, meaning they produced near their maximum output more than nine-tenths of the year, the highest of any source (see the chart below). Geothermal was next at 65%, then gas combined-cycle near 60%.

By comparison, coal averaged about 42%, wind 34%, and solar 23%, because sun and wind are intermittent and fossil plants cycle with demand. The US fleet has topped a 90% capacity factor every year since 2012, helped by shorter refueling outages and better operations.

Nuclear punches above its weight on carbon. In 2023 it provided 19% of US electricity but about 47% of the country's carbon-free power, more than utility-scale wind and solar combined, because it runs around the clock rather than only when the weather cooperates (NEI).

That output avoids roughly 470 million metric tons of CO2 a year that fossil plants would otherwise emit. It is why many decarbonization studies treat keeping existing reactors open as one of the cheapest ways to cut emissions, and why several states now pay to preserve at-risk plants.

US plants range widely in size. Since its new AP1000 units came online, Georgia's Vogtle is the largest at about 4.5 GW across four reactors, passing Arizona's Palo Verde at 3.9 GW, long the biggest US power plant of any kind (see the table below). California's Diablo Canyon runs 2.2 GW.

At the small end, New York's single-unit R.E. Ginna is about 0.6 GW. A typical modern US reactor is around 1 GW, enough to power roughly 800,000 homes, which is why even one unit closing removes a large, steady block of low-carbon supply from the grid.

America's reactors are old. Roughly half of the operating units are more than 40 years past their original startup, and most were licensed for 40 years, so keeping them running requires renewals from the Nuclear Regulatory Commission. Standard renewals already stretch licenses to 60 years.

The frontier now is 80-year operation via subsequent license renewals. Six units have already been approved to run for 80 years, and about 14 more are under NRC review. Life extension is cheap capacity: it defers the need to build expensive new plants for decades.

Vogtle Units 3 and 4 are the first newly built US reactors since 2016 and the only US deployments of the Generation III+ AP1000 design. Unit 3 entered commercial operation in July 2023 and Unit 4 in March 2024, bringing the fleet back to 94 reactors.

The project is also a cautionary tale on cost. Originally budgeted near $14 billion with a 2016-2017 start, it ran years late and its total cost climbed above $30 billion, closer to $35 billion by some estimates. Those overruns are why much of the industry's hope has shifted to smaller, factory-built reactors.

Worldwide, about 440 reactors are operable (the World Nuclear Association count) or 417 in operation (the IAEA's stricter tally), together providing roughly 377 to 403 GW of capacity across 31 countries (see the table below). The gap between the two counts is mostly Japanese reactors that are licensed but idle.

The pipeline is substantial: 79 reactors are under construction (about 87 GW), another 120 are planned, and 326 are proposed. China dominates new construction, and much of the growth is concentrated in Asia and the Middle East rather than the West.

Nuclear supplies close to 9% of the world's electricity, but the national picture varies enormously. France leads at roughly 70%, followed by Slovakia at 64% and Ukraine at 52%, while the US sits at 19% and fast-growing China at only about 5% despite its huge build-out (see the table below).

Together with renewables, low-carbon sources crossed 40% of global generation for the first time in 2024. Nuclear's slice has slipped from its 1990s high as electricity demand and renewables grew faster, but in absolute terms nuclear output is now setting records.

The United States is the runaway leader, generating about 823 TWh in 2024, roughly 29% of all nuclear electricity worldwide (see the chart below). China is second at 451 TWh and rising fastest, followed by France at 381 TWh, Russia at 202 TWh, and South Korea at 179 TWh.

France posted the biggest jump among the top five in 2024, up more than 12% as its fleet recovered from earlier maintenance issues. Note that these are gross-generation figures from the World Nuclear Association; the EIA's net US figure of 782 TWh is lower because it excludes power the plants use themselves.

The construction pipeline is the clearest signal of where nuclear is headed. Some 79 reactors, about 87 GW, are being built right now, overwhelmingly in China, India, Russia's export projects, and the Middle East. The UAE's four-unit Barakah plant, finished in the 2020s, already makes it a top-20 generator.

Western new-build has been slower and pricier, as Vogtle showed. That is pushing utilities and governments toward standardized designs and small modular reactors, betting that repeatable factory production can finally bend the cost curve that large bespoke plants never could.

For the fifth year running, the IAEA raised its long-term outlook. From 377 GW of operational capacity at end-2024, its low case sees 561 GW by 2050 (a 50% rise) and its high case 992 GW, about 2.6 times today's level (see the chart and table below). Both require heavy life extension plus new build.

Small modular reactors carry much of the upside: they account for 24% of new capacity in the high case but just 5% in the low case, so how fast SMRs actually commercialize will largely decide whether nuclear doubles or merely grows steadily.

SMRs are the industry's big bet: factory-built units of roughly 50-300 MW that promise faster, cheaper, more standardized deployment than gigawatt-scale plants. Market-research estimates put the global SMR market between about $6 billion and $7.5 billion in 2024-2025, growing to anywhere from $8 billion to $16 billion by the mid-2030s.

Those forecasts vary widely and come from private market-research firms (secondary sources), so treat the exact dollar figures as directional. The common thread is fast growth, roughly 5% to 15% annual, driven by clean-energy targets, energy security, and, increasingly, data-center power demand.

The sharpest new driver is artificial intelligence. Data-center electricity use is projected to jump from about 460 TWh in 2024 toward 1,000-1,300 TWh by the early-to-mid 2030s, and operators want firm, 24/7 carbon-free power that nuclear can uniquely supply. Over the past year, Big Tech signed contracts for more than 10 GW of new US nuclear (see the table below).

The marquee deals include Microsoft's roughly $16 billion agreement to restart Three Mile Island (835 MW) by 2028, Amazon's commitment to up to 5 GW of SMRs by 2039, and Google's 500 MW SMR fleet deal with Kairos Power. This corporate demand, more than policy alone, is behind nuclear's sudden financial revival.