Nuclear power remains one of the most productive sources on the US grid, according to federal energy data, even as its share of total generation gradually shifts. The nation's operating reactors have a combined net summer generating capacity of roughly 98,441 megawatts, or about 98.4 gigawatts, making nuclear a substantial contributor to baseload electricity supply.

What sets the fleet apart is how consistently it runs. The average annual capacity factor for US nuclear plants in 2025 was 91 percent, higher than any other type of power plant. Capacity factor measures actual output against maximum possible output, and the high figure reflects nuclear's ability to generate power continuously rather than intermittently.

Nuclear supplied about 17 percent of US electricity generation in 2025. Federal projections show that share gradually declining to between 12 and 15 percent by 2050 as overall generation grows and other sources expand, even as total nuclear capacity is expected to remain relatively stable in the baseline outlook.

The newest addition to the fleet is Unit 4 at the Alvin W. Vogtle Electric Generating Plant in Georgia, which began commercial operation in April 2024. The figures underscore why nuclear continues to feature prominently in discussions about meeting rising electricity demand, particularly for applications that require steady, uninterrupted power.

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