Anyone who thinks that the electric energy world is not changing might check the profiles of the largest US power plants from 2019 versus 2010. The US Energy Administration Agency released that information recently. (Quotes/graphs from that report.)
Nuclear power dominates the list now. Nuclear plants provide 24/7, carbon-free electricity. “These 10 plants generated a combined 230 million megawatt hours (MWh) of electricity in 2019, accounting for 5.6% of all electricity generation in the United States. The makeup of power plants that generate the most electricity has shifted in the past 10 years from a mix of nuclear and coal plants to almost all nuclear in 2019.”
However, there is negative news about nuclear – early plant shutdowns. Two Illinois plants will shut down “despite Dresden and Byron being among the most efficient and reliable units in the USA’s nuclear fleet.” (Source) Not the right direction when we want carbon-free power.
Now look back ten years. “In 2010, the top 10 highest-generating power plants in the United States were a mix of nuclear and coal-fired generators. In 2010, coal’s share of U.S. electricity generation was 45%, compared with 23% in 2019.”
Why the change? “Decreased cost-competitiveness relative to other power resources, especially natural gas, has made coal less economical for electricity generation. Coal plants are also run at lower levels because of tighter air emission standards, which is the primary reason coal plants fell from the top 10.”
Nuclear plants are dependable. “Nuclear power plants have the highest capacity factor of any energy source in the United States, at 94% fleet-wide in 2019, because nuclear plants generally operate around-the-clock until they are taken offline for maintenance or refueling. Capacity factors for the nine nuclear plants in the top 10 range from 89% (Browns Ferry) to 99% (Byron and Peach Bottom). Natural gas combined-cycle units have the second-highest capacity factor in the United States, at 57% fleet-wide in 2019.”
In the electric energy generation business the capacity factor of a facility matters. Society needs a certain basic amount of power to operate, though that amount changes by the time of day, the day of the week, and season. Large plants that operate at high capacity factors provide that baseload power to keep the lights on. These plants are essential parts of our society, operating in partnership with more intermittent power sources. Providing electricity is a team effort.
Feature image from Duke Energy media gallery. Oconee Nuclear Station, which is on the top ten list.