US nuclear power plants achieved a fleet-wide capacity factor of 92.7% in 2023, the highest capacity factor of any electricity generation technology tracked by the US Energy Information Administration. Capacity factor measures how much electricity a plant actually produces relative to its maximum possible output, making it a key indicator of operational reliability.

By comparison, natural gas combined-cycle plants operated at a capacity factor of approximately 57%, coal plants at 40%, utility-scale solar at 25%, and onshore wind at 35% in the same period. Nuclear's advantage in capacity factor reflects its continuous baseload operation and the relatively infrequent scheduled outages for refueling, which typically last 20 to 40 days every 18 to 24 months.

The EIA reports that nuclear generation has remained remarkably stable over the past decade even as the fleet size has declined slightly. Improved efficiency and longer fuel cycles have offset the output reduction from plants that have retired, meaning total nuclear generation has held near 775 terawatt-hours annually despite the smaller fleet count.

Nuclear fuel costs are a minor component of overall plant operating costs. Uranium fuel represents roughly 25 to 30% of a nuclear plant's total generating cost, compared to fuel being 70 to 80% of the cost at natural gas plants. This cost structure makes nuclear generation largely insulated from fossil fuel price volatility.

The EIA projects that without significant new builds or restarts, the US nuclear fleet's generation share will decline gradually through the 2030s as older plants reach the end of their extended licenses, unless the current momentum in advanced reactor development produces commercial deployments at scale.

Source: US Energy Information Administration -- https://www.eia.gov/electricity/annual/