The 99 US nuclear power reactors achieved a record 91.9% capacity factor in 2015, surpassing 91.8% capacity set in 2007, according to preliminary estimates from the Nuclear Energy Institute.
US reactors generated an estimated 797.9 billion kWh of electricity last year, the fifth-highest on record, compared with 797.1 billion kWh generated by 100 reactors operating at 91.7% capacity in 2014, NEI said Tuesday in a statement.
In 2007, 104 nuclear reactors generated 806.4 billion kWh, according to the Energy Information Administration.
NEI had estimated US units' 2014 capacity at 91.9% in a statement issued January 22, 2015, but this was revised to 91.7% in EIA's monthly energy review issued "several months later," Michael Purdie, NEI's manager of energy and economic analysis, said Wednesday in an interview. EIA also revised downward NEI's January 2015 generation estimate of 798.4 billion kWh in 2014.
Purdie said NEI's capacity and generating estimates, made annually in January, are based on extrapolations of EIA power reactor operating data from January through October.
"The amount of electricity generated in 2015 exceeded the amount produced in 2014, even though one less plant operated [because of the December] 2014 closing of Vermont Yankee," the statement said.
Power production peaked in 2010, when 806.9 billion kWh was produced by 104 reactors, achieving an average capacity factor of 90.9%, NEI said.