Record-Breaking US Grid Experienced 23% Power Plant Outages During December Storm

The largest US grid operator saw almost one-fourth of power plants serving 65 million people shut down during the Christmas weekend storm. This pushed the region to the brink of blackouts.
PJM Interconnection LLC released a presentation on Wednesday detailing the results of the first autopsy of the winter freeze that strained the grid operator last month. According to the presentation, 23% of PJM's power-generation fleet shut down on the morning of December 24. PJM manages the electrical network that stretches from New Jersey to Illinois.
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Natural gas-fired power plants were responsible for the majority of the nearly 46 gigawatts of power outages over the holiday weekend, with few of the generators giving any notice of impending failure. This left the grid operator scrambling as temperatures plunged and electricity demand surged. One gigawatt is enough to power around 800,000 homes in the PJM region.
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"We were seeing too many generation outages, and they were happening at the worst possible times," Donnie Bielak, senior manager of dispatch at PJM, said during the presentation.
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The largest US grid lost 23% of its power supply during the December storm. This is a significant loss of power that will have an impact on the country.
The widespread failures that forced PJM to plead with customers to limit electricity use highlighted the network’s vulnerability to volatile weather. According to PJM’s preliminary analysis, electricity suppliers that received up-front payouts in exchange for promises to provide emergency power may face up to $2 billion in penalties.
Bielak said that a large portion of the fleet failed to perform.
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The December storm was historic, with temperatures plunging 29F degrees in a 12-hour period on Dec. 23. This was the most dramatic drop in a decade, according to PJM's analysis. Electricity use that afternoon was forecast to reach almost 127 gigawatts, well within the 156 gigawatts of capacity that was expected to be available.
The chill intensified much faster than expected, driving up electricity demand by 10% more than forecast. Plants that couldn't handle the cold began shutting down, and more than 90% of them either alerted PJM with less than an hour's notice - or no notice at all, Bielak said.
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In addition, another 6 gigawatts of generation - mostly gas-fired units - failed to turn on heading into the Dec. 24 morning peak, crippling efforts to run pumps at some hydro stations. All told, 57 gigawatts - enough capacity to power 45.6 million households - were out of service in the early hours of Christmas Eve.
PJM is continuing to investigate the event and will release its full analysis in April.