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Illinois Nuclear Plants Operate at Near Full Power Through Hottest Summer on Record

Business Wire

Despite scorching heat, all six Illinois nuclear plants provided around-the-clock, carbon-free electricity to 11 million homes and businesses

WARRENVILLE, Ill.--(BUSINESS WIRE)-- Exelon Generation’s nuclear plants in Illinois safely operated at nearly full power through consistently warmer-than-average days in June, July and August, producing enough carbon-free electricity to keep air conditioners running and more than 11 million homes and businesses cool throughout the summer. The power generated by these plants also enabled essential businesses and hospitals to continue operation through some of the hottest months of the year. The steady hot temperatures resulted in the Chicago area’s hottest summer ever recorded.

"Our nuclear facilities are among the most reliable power plants in the country, and we know how important it is for them to be available during extremely hot weather conditions," said Shane Marik, Senior Vice President for Midwest Operations, Exelon Generation. "Thank you to our more than 4,700 full-time Illinois nuclear employees for working hard in the heat to keep our fleet delivering carbon-free energy that protects customers from the harmful carbon and air pollution that would have resulted from fossil-fuel fired plants that would have run in their place."

Exelon Generation's Illinois nuclear fleet recorded a near-perfect reliability rate last summer as well, operating 98.9 percent of the time, one of many indicators that industry experts use to rate efficiency and performance. During the hottest summer and coldest winter temperatures, Exelon Generation's nuclear fleet has been critical to meeting electricity demand in Illinois.

Despite the high reliability provided by these plants, Exelon Generation recently announced it will retire its Byron and Dresden nuclear plants in 2021 as they face revenue shortfalls in the hundreds of millions of dollars. The two plants employ more than 1,500 full-time employees and supply 30 percent of Illinois’ carbon-free energy, making them vital to meeting the state’s goal of achieving 100 percent clean energy.

Summer resiliency and reliability requires year-long planning, preparation and maintenance. Exelon Generation workers spend months ensuring that backup generators and spare equipment are ready when temperatures start to sizzle. This spring, operators and maintenance personnel inspected, tested and repaired equipment throughout the six Illinois nuclear sites to ensure plant systems remain available at all Exelon Generation facilities during the dog days of summer.

Exelon Generation, a subsidiary of Exelon Corporation (Nasdaq: EXC), is the nation’s largest producer of carbon-free energy, powering more than 20 million homes and businesses through a diverse generation fleet with more than 31,000 megawatts of capacity. Exelon Generation operates the largest U.S. fleet of zero-carbon nuclear plants with more than 18,700 megawatts from 21 reactors at 12 facilities in Illinois, Maryland, New York and Pennsylvania. It also operates a diverse mix of wind, solar, landfill gas, hydroelectric, natural gas and oil facilities in 19 states with more than 12,300 megawatts. Exelon Generation sets the standard for world-class power plant operations that produce clean, safe, reliable electricity, and is an active partner and economic engine in the communities it serves by providing jobs, charitable contributions and tax payments that help towns and regions grow. Follow Exelon Generation on Twitter @ExelonGen, view the Exelon Generation YouTube channel or visit

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Brett Nauman

Exelon Generation Communications


Source: Exelon Generation


Bob Meinetz's picture
Bob Meinetz on Sep 19, 2020 2:55 pm GMT

Brett, I'm sure you're aware solar, wind, and hydrogen profiteers are determined to shut down nuclear in Illinois, no doubt salivating over the 51% share of electricity generation that would be up for grabs.

"Would be" - but won't be, as it becomes increasingly clear residents will never accept sacrificing more than half of their electricity at the altar of an earnest fantasy.

This week they seized upon a report from Moody's, one of the outfits whose cooked credit ratings led to the 2007 mortgage crisis. The report claims "U.S. nuclear capacity is expected to have elevated exposure to combined rising heat and water stress caused by climate change."

Oh, really? Your announcement, combined with a phenomenon that's been understood for decades, makes it sound like Moody's got it exactly backwards:

"Photovoltaic modules are tested at a temperature of 25 degrees C (STC) – about 77 degrees F., and depending on their installed location, heat can reduce output efficiency by 10-25%. As the temperature of the solar panel increases, its output current increases exponentially, while the voltage output is reduced linearly."

Intermittent renewables or reliable nuclear: which is the energy of our warmer future, again?

Jim Stack's picture
Jim Stack on Sep 21, 2020 1:13 pm GMT

In France with 70% Nuclear they have to truck in COLD water during summer and reduce power to keep the plants from over heating. I wonder how much extra water and cooling was needed at these plants? 

Bob Meinetz's picture
Bob Meinetz on Sep 21, 2020 4:33 pm GMT

Jim, they had to truck in cold water at one plant (Golfech) in 2007. Any other instances that you know of?

Occasionally, French nuclear plants they do have to reduce power to avoid overheating. If not, the country would have 75-80% of its electricity from nuclear plants - a small price to pay.

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