Republished September 13, 2013, 10:00 a.m. text was modified to clarify content.
Outages at operational nuclear power plants were generally lower this summer than in recent years, reflecting the retirement of several units along with a lower number of generators in refueling outages. Beginning in early September, several units began to reduce their output to enter into refueling outages, bringing the total level of capacity in outage closer to the levels seen last year at this time.
Because of their low variable cost, nuclear plants nearly always run whenever they are available. Thus, outages are directly reflected in the level of nuclear power generation.
Refueling and maintenance outages for nuclear units (as well as fossil-fueled units) typically occur in the spring and fall "shoulder" seasons when demand for electricity is generally lower. However, a late-summer heat wave in recent days has pushed up demand for electricity in the midwestern and eastern United States. Outages in PJM territory (an electric system that stretches from New Jersey to Chicago) and New England likely contributed to the spike in on-peak, day-ahead wholesale electricity prices in these regions on September 11-12.
The retirement of four nuclear generators decreased the amount of operational capacity in extended outage, which had elevated outage levels throughout 2012. Although the retirements reduced the amount of operational capacity in outage, they also reduced the total nuclear capacity by almost 3.6 gigawatts. Two other units are in full or partial extended outages:
Principal contributor: M. Tyson Brown
Tags: electricity, nuclear, outages