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Nuclear Energy Institute
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Operating at 98% Efficiency, U.S. Nuclear Plants Play Vital Role in Beating Sweltering Heat Wave

WASHINGTON—Helping Americans to cope during the summer’s most sweltering heat, the nation’s nuclear power plants posted an average daily capacity factor of more than 98 percent during the first two weeks of August.
Capacity factor is a measure of power plant efficiency, measuring the amount of electricity the plant generates compared to the amount it could have produced at continuous full power operation during the same period.
Over the first 14 days of the month, the nuclear energy industry’s average daily capacity factor was 98.3 percent, with the one-day average high of 99.6 percent capacity on Aug. 1, according to electricity production data reported by energy companies to the Nuclear Energy Institute and drawn from reactor operations status reports compiled by the U.S. Nuclear Regulatory Commission.
The 104 nuclear power plants operating in 31 states have a combined generating capacity of 100,125 megawatts of electricity, enough to meet the yearly electricity needs of approximately 62 million Americans. Nuclear power plants account for about 11 percent of America’s total electricity generation capacity, but because they operate at high levels of efficiency and reliability, they produce nearly 20 percent of the country’s annual electricity supply.
“When the dog days of August barked, U.S. nuclear power plants were the most efficient producers of electricity on the nationwide grid, churning out massive emission-free supplies of electricity to meet demand,” said Marvin Fertel, NEI’s chief nuclear officer and senior vice president. “As accustomed as we are to the excellent operations that make nuclear power plants part of the backbone of the nation’s electricity grid, the performance of our plants and of the dedicated men and women who operate them has been truly outstanding in recent weeks.
“The country’s 104 reactors are powering our economy as well as air conditioners that are so vital to help Americans withstand withering temperatures and humidity,” Fertel said.
For the week that ended Aug. 11, U.S. electricity output was the second-highest ever recorded at 96,955 gigawatt-hours, according to the Edison Electric Institute.
Megawatt Daily, a Platts publication that follows the energy industry, reported Aug. 10, “Peak demand records are tumbling like dominoes this week across the Southeast as blistering heat blankets the region.” For example, Southern Company set new system peak demand records twice that week, according to Platts. SCANA’s South Carolina Electric & Gas subsidiary set a new peak demand record Aug. 8, and the Tennessee Valley Authority the same day set its third consecutive demand record.
Also on Aug. 8, the PJM interconnection issued an electricity conservation warning in the Mid-Atlantic region due to electricity demands that approached the area’s record-high set in August 2006, according to Platts.
U.S. nuclear power plants have performed at an average industry capacity factor of more than 87 percent for the past seven years. Last year, nuclear plants produced the second-highest amount of electricity in the industry’s history—more than 787 billion kilowatt-hours (kwh). Only three countries in the world—China, Japan and Russia—generated more electricity from all sources than U.S. nuclear power plants produced by themselves.
U.S. nuclear plants also operated with record-low electricity production costs for fuel and operations and maintenance expenses—1.72 cents/kwh. Coal-fired power plants produced electricity at 2.37 cents/kwh and natural gas-fired power plants had average production costs of 6.75 cents/kwh in 2006, according to Global Energy Decisions data.
The average daily capacity factors for all U.S. nuclear power plants during the first two weeks of August are as follows:
Aug. 1: 99.6 percent
Aug. 2: 99.3 percent
Aug. 3: 98.6 percent
Aug. 4: 98.5 percent
Aug. 5: 99.1 percent
Aug. 6: 99.3 percent
Aug. 7: 97.9 percent
Aug. 8: 97.9 percent
Aug. 9: 98.3 percent
Aug. 10: 98.1 percent
Aug. 11: 97.4 percent
Aug. 12: 97.3 percent
Aug. 13: 97.3 percent
Aug. 14: 97.7 percent