One gigawatt (GW) of electricity from a nuclear power plant differs from 1 GW of coal power, natural gas, or renewable energy (Solar, Wind, Water). You cannot compare these 1:1 Capacity factors as a measure of the reliability of energy sources.
Capacity factor as a measure of the reliability of energy sources.
The capacity factor can measure the reliability of energy sources. It estimates what percentage of the time an energy source would produce energy during the year if it ran non-stop. A capacity factor of 100% means that an energy source has always produced electricity throughout the year.
Nuclear power capacity factor
The global capacity factor for nuclear power was in the year 2021 at 82.4% [1]. It has continued the trend since 2000. See Figure 1. Regionally, it can be made even higher. For 20 years, the USA has maintained an average capacity factor close to 90%. For 2021 at 92.7% [2]. The highest of all energy sources in the United States [3]. See Figure 2.
It says nuclear power produces maximum electricity of more than 80 to 93% of the year. The reason is that nuclear power requires less maintenance. They are designed to operate for extended periods before fuel switching and are rarely paused because they do not rely on external factors to work efficiently. The last 50 years have seen a steady improvement in reactor performance. The average global capacity factor has been improved in reactors of all ages, not just new reactors of more advanced design. There is no age-related decline in the performance of nuclear reactors. See Figure 3.
Figure 3: The last 50 years have seen a steady improvement in reactor performance. The average global capacity factor has been improved in reactors of all ages, not just new reactors of more advanced design. There is no age-related decline in the performance of nuclear reactors.
It is higher than other thermal energy sources, such as natural gas and coal power, which generally have lower capacity factors. It was due to routine maintenance and filling at these plants. Renewable energy sources are variable. It is not always the sun shining, the wind blowing, or the water falling through the turbines of the hydropower plants. Therefore, these also have lower capacity factors.
Conclusion
Once a nuclear power plant operates, it generates reliable, clean electricity with few interruptions for decades, at any time of the day. That makes nuclear power one of the most reliable energy sources, especially if you maintain it.
Sources
1. https://www.world-nuclear.org/getmedia/9dafaf70-20c2-4c3f-ab80-f5024883d9da/World-Nuclear-Performance-Report-2022.pdf.aspx
2. https://www.eia.gov/electricity/monthly/epm_table_grapher.php?t=epmt_6_07_b
3. https://www.energy.gov/ne/articles/nuclear-power-most-reliable-energy-source-and-its-not-even-close
