U.S. nuclear generation outgrew wind and solar despite zero capacity additions

Starting in 1990, nuclear generation in the United States grew by 260 million megawatt-hours (MWh) through 2020. Remarkably, it did this without any net capacity additions, as nuclear capacity actually saw a net decrease of over 7,000 megawatts (MW). The bump in nuclear generation was instead caused by increasing efficiency at existing plants.

Even more remarkable, however, is that the growth of nuclear generation outpaced total generation of wind and solar combined until 2017, despite wind and solar capacity growing from 2,000 MW in 1990 to over 115,500 MW.

This means it took over 100,000 MW of new wind and solar capacity additions to outpace the increase in nuclear generation caused primarily by efficiency improvements.

A major reason it took wind and solar so long to catch up is because they’re inefficient, weather-based technologies that only produce electricity when the wind blows and the sun shines. For the same reason, technological advancements can only do so much to raise their efficiency.

Nuclear power plants, however, operate on fuel, meaning they can increase electricity output by simply adding more fuel. Technological advancements have also brought nuclear efficiency to near 100 percent in recent years.

As you can see from the graph below, wind utilization increased from 18 percent in 1990 to 32 percent in 2020, while solar increased from 12 percent to 21 percent.

Meanwhile, utilization of nuclear plants increased from 63 percent in 1990 to 93 percent in 2020. Additionally, updates to existing nuclear power plants managed to increase their capacity, partially offsetting nuclear retirements elsewhere in the country. The Energy Information Administration (EIA) noted, “Power plant uprates—modifications to increase capacity—at nuclear power plants have made it possible for the entire operating nuclear reactor fleet to maintain a relatively consistent total electricity generation capacity.”

This is yet another example of how much more beneficial nuclear investments have been than wind and solar.