Nuclear energy remains the backbone of carbon-free electricity in the United States, supplying about 18 percent of the nation total generation from a fleet of 94 operating reactors, according to industry statistics from the Nuclear Energy Institute. Those reactors provide roughly 100 gigawatts of capacity that runs continuously, independent of weather or time of day.

The fleet punches above its size. While nuclear accounts for less than a tenth of installed U.S. generating capacity, it produces close to a fifth of the electricity because reactors operate at very high capacity factors, running above 90 percent of the time on an annual basis. That reliability makes nuclear the single largest source of firm, carbon-free power on the grid, ahead of wind and solar in total zero-emission output.

The plants are also long-lived assets. Many reactors first licensed decades ago have received or applied for extensions that allow operation for 60 or even 80 years, and the NRC recently completed its fastest-ever license renewal, signaling a regulatory push to keep existing units running. Extending the current fleet preserves large blocks of baseload capacity that would be expensive and slow to replace.

The statistics arrive as electricity demand rises for the first time in years, driven by data centers, electrified transport, and new manufacturing. With the existing fleet already running near full output, the numbers help explain why utilities are pursuing both plant life extensions and new reactor construction to keep nuclear share of the grid from slipping as total demand grows.

Source: Nuclear Energy Institute - https://www.nei.org/resources/statistics