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Extreme weather risks should be included in an annual review of near- and long-term economic and reliability transmission needs, Southwest Power Pool concluded in a of its response to Winter Storm Elliott in December 2022.
The review “identified additional changes to internal processes, tools and functions,” the grid operator saidWednesday. The storm included blizzard conditions, high winds and record cold temperatures, and affected SPP operations for about three days.
The grid operator should also analyze areas that experienced reduced voltage and congestion issues “to determine the impact of previously approved, but not yet in-service, transmission projects,” SPP said in the report.
Winter Storm Elliott struck SPP’s territory less than two years after Winter Storm Uri in 2021 caused widespread disruption. Learnings from Uri helped the grid operator prepare for the 2022 storm, but there is still room for improvement in areas of operations, transmission planning, communications and compliance that could assist storm response, according to the report published Wednesday.
While Elliott was not as severe as Uri and resulted in fewer gas and wind outages, SPP said its grid experienced a higher level of outages and derates of coal-fired resources during the 2022 event. Load shedding was required during Uri, but not during Elliott, though one of SPP’s member transmission operators in Missouri “determined it needed to shed load locally to maintain reliability,” the grid operator said.
A of SPP’s response to Uri turned up 22 recommended actions, policy changes and assessments, said SPP. The review of Elliott resulted in another 11.
“SPP’s load forecasting performed worse than desired [during Elliott], with load coming in higher than forecast. Most of the error was accounted for in risk expectations,” the report said. “While some was due to the underlying weather model and weather forecast error, there were some areas identified (snow impact, extreme wind chill impact) that appear to have room for improvement.”
SPP staff recommendations include:
For the SPP reliability coordinator and member transmission operators to collaborate on revisions to emergency operations plans for compliance with extreme cold weather winterization standards overseen by the North American Electric Reliability Corp.;
To improve or develop processes to identify areas at risk for low voltage or extreme congestion when extreme winter events are forecast;
To identify ways to improve forward-looking studies to “more efficiently apply uncertainty of forecasting for load, wind, outages, fuel supply, interchange and external impacts.”
On forecasting, SPP staff said “one operational aspect that could continue to be improved here is communication. While some detailed information is shared on the reliability of the operations calls leading into an event, SPP may be able better identify what contextual information should be shared in advance.”