US nuclear power plants operated at an average capacity factor of about 92.3 percent in 2024, the highest reliability figure of any electricity source in the country, according to data tracked by the Energy Information Administration and the Nuclear Energy Institute. Capacity factor measures how much electricity a plant actually generates compared with its theoretical maximum output if it ran at full power every hour of the year.

Nuclear's performance has remained close to that level for more than two decades. US reactors have posted capacity factors near 90 percent since the early 2000s, after averaging well below 70 percent in the 1970s and 1980s. Utilities credit the improvement to longer intervals between refueling outages, better predictive maintenance and operational upgrades made across the fleet as reactors have aged.

By comparison, natural gas plants, coal plants, wind and solar all post lower average capacity factors, reflecting scheduled maintenance, fuel costs, weather dependence or grid dispatch decisions that curtail output. Because nuclear plants run at high output nearly continuously, a single reactor can supply a steady, predictable share of a region's electricity around the clock, a characteristic utilities increasingly cite when planning for growing power demand from data centers and industrial customers.

The roughly 92 US commercial reactors currently operating supply about a fifth of the nation's electricity generation, a share that has held steady even as overall generation capacity from other sources has expanded, underscoring nuclear's consistent output relative to its installed capacity.

Source: U.S. Energy Information Administration -- https://www.eia.gov/nuclear/generation/