FERC-NERC opened joint inquiry to review storm’s impact

As families gathered together for the Christmas holiday, a potent winter storm with high winds and plummeting temperatures affected most of the eastern two-thirds of the country. Below-freezing temperatures spread as far south as Florida and Texas.

While the cold was not as extreme as other winter events, the temperature dropped quickly in many parts of the U.S. Grid operators throughout the Eastern Interconnection, including MRO’s footprint, saw higher than forecast electricity demand and unplanned generation outages resulting from the storm. SPP set a new winter peak load record of 47.1 GW on December 22, 2022, exceeding the previous peak of 43.7 GW experienced during Winter Storm Uri in February 2021.  

Despite the challenges created by Winter Storm Elliott, grid operators in the Midwest and plains successfully implemented their emergency operating procedures to ensure a balance of supply and demand of electricity throughout the storm. SPP called an Energy Emergency Alert (EEA) 1 twice on December 23, 2022, from 8:27 a.m. to 10:00 a.m. and again from 5:20 p.m. to 8:20 p.m. due to higher than forecast electricity use. MISO declared an EEA 2 on December 24, 2022 between 5 p.m. and 8 p.m. largely due to forced generation outages and higher than forecast demand. Neither MISO nor SPP needed to curtail firm load during the event.

Systems further to the east of MISO and SPP had greater challenges. On December 23, 2022, and December 24, 2022, the Tennessee Valley Authority (TVA) directed targeted load curtailments due to extreme power demand brought on because of the sustained cold temperatures. Duke Energy was required to rotate customer outages to protect the grid from the extremely high customer demand it experienced due to the storm. Both instances were the first time those entities had to direct firm load curtailment in their long histories. Due to the impacts from the storm, FERC and NERC announced the opening of a joint inquiry into the operations of the bulk power system on December 28, 2022. Similar inquiries into the 2018 and 2021 winter storms will help to inform this inquiry and provide an opportunity to confirm the appropriateness of the recommendations from those inquiry reports. This inquiry may also produce additional recommendations to issues not seen in the 2018 or 2021 storms. The inquiry team has been formed comprised of FERC, NERC, and Regional Entity experts and expects to move quickly to review the impacts of this event. This event provides another learning opportunity to address the risks brought on by extreme weather to improve the reliability of the bulk power system.

– Mark Tiemeier, MRO Principal Technical Advisor