Arctic Blast Roiling Reliability in TVA, MISO, SPP, PJM

An arctic blast felt by much of North America is causing reliability turbulence in some segments of its mass flow system, forcing reliability coordinators to call emergencies, issue protection warnings or derate the load.

TVA, grappling with the surge in demand, throttles the load

Average temperatures in the single digits The Tennessee Valley Authority (TVA) called on the federal agency — a reliability coordinator — and local energy companies to act proactively and take steps “to temporarily reduce power to local areas,” TVA said. “These actions may result in short, temporary power outages in certain areas,” it said.

TVA has partnerships with 153 local electric utilities in seven states. These are “industrial customers wThey’re helping us ensure system reliability during what the National Weather Service has described as ‘once in a generation’, affecting most of the country.” Ashton Davies, a TVA spokesman, said ENERGY on the 24th of December.

The problem stems from an unprecedented surge in demand. “For the 24 hours on Friday, December 23, TVA set an all-time TVA record for energy delivery: 740 GWh. The previous record was 706 GWh in 2018. We also set an all-time winter peak power record: 33,425 MW. It’s also the third largest peak demand in TVA’s history,” she said. “Typically our system handles around 24,000 MW of demand at this time of year.”

In addition to the increased demand, “a limited number of TVA generating plants did not perform as expected during this event, resulting in a power outage,” Davies said. “Events like this are part of TVA’s plans and we have teams working around the clock to get these units back up and running as quickly as possible.”

Local energy companies reduced their electricity load “at the direction of TVA” on Friday and again on Saturday morning, she said. “Each local energy company executes their own plans to minimize impact on the communities they serve.”

MISO declares generational emergency

That Midcontinent Independent System Operator (MISO) on December 23 explained an emergency event with maximum generation at 5:23 p.m. and increased it to a level 2 minutes later due to higher forced power outages than the forecast load.

While the reliability coordinator, who serves 15 US states and the Canadian province of Manitoba, finished the event at 8:35 p.m., he explained “conservative operations” through noon on December 24 for the central and northern regions. MISO cited concerns related to “extreme cold, power outages and neighboring [regional transmission organizations (RTOs)] struggle to service the load.”

The Southwest Power Pool (SPP), which has members in 14 states in the central US, also declared an Energy Emergency Alert (EEA 1) at 8:27 a.m. Friday, ending at 10 a.m. The reliability coordinator pointed to “effects of widespread and extreme cold,” which led to new records, it said. “SPP set a new record for power consumption during the winter season on December 22 with a load of over 47,000 MW. The previous record was 43,661 MW, set on February 15, 2021” during Winter Storm Uri, an event that triggered it the worst US reliability crises in decades.

The network company had previously issued a resource recommendation on De. 22 for its entire accounting authority in the Eastern Interconnection and is expected to end at 12:00 p.m. on December 25. This remains in effect, SPP said.

PJM pushes for energy saving, ERCOT monitors the demand

PJM Interconnection, a network operator serving 65 million people in 13 states and the District of Columbia, late December 23rd also called for the public in his region until December 25 at 10 a.m. to save electricity.”Electricity demand in PJM region and neighboring regions of PJM is expected to increase due to extremely cold weather,” it said. While the grid operator is monitoring power supply conditions and would do whatever it takes to keep electricity flowing in the region, it said it would take additional steps “like reducing the voltage.”

That The Electric Reliability Council of Texas (ERCOT), which has made several grid improvements since the winter storm debacle in Uri, said it is closely monitoring changing weather patterns. That’s what it said in an operating status report from December 16th Temperatures would meet ERCOT criteria of 25 degrees or less in the Austin/San Antonio and Dallas Fort-Worth areas between Thursday, December 22 and Monday, December 26.

The grid operator was still watching conditions closely as Friday’s peak load broke all records. Demand rose to 74 GW as of Friday morning, beating the previous winter record of 68,871 MW during Winter Storm Uri. “This is the deepest freeze in Texas (apart from Uri, if we don’t know what demand would have been without the blackouts) since electric heating surged. That creates a lot of uncertainty in demand forecasts,” he noted Daniel Cohan, atmospheric scientist at Rice University.

ERCOT is forecasting a large margin tonight, but that assumes demand tonight falls nowhere near last night’s 73GW (which was 8GW above expectations) despite similar temperatures. When the wind is light, conditions become tight. pic.twitter.com/VJxTIJVqYs

— Daniel Cohan (@cohan_ds) December 23, 2022

—Sonal Patel is Senior Associate Editor at POWER (@sonalpatel, @POWERmagazine).

Editor’s Note: This story will be updated.