Dive Brief:

• Last week's polar vortex broke winter peak demand records in the Midcontinent Independent System Operator, Southwest Power Pool, Electric Reliability Council of Texas, PJM Interconnection, the New York Independent System Operator and most utilities in the Southeast, according to a preliminary analysis by the Federal Energy Regulatory Commission (FERC).
• Generally, grid operators handled the bitterly cold weather by calling for conservation, reducing voltage in areas and importing and exporting power across regions. The NY-ISO called on voluntary demand response measures so it could supply power to other regions.
• After several generating units tripped offline, South Carolina Electric and Gas started using rotating outages to shed about 300 MW during a morning peak.
• During the freezing weather, grid operators dealt with an unusually high number of offline power plants. At least 50,000 MW were offline in the Eastern Interconnection compared with a wintertime average of 33,000 MW of forced outages.

Dive Insight:

Demand response, regional transmission interconnections and cooperation all helped the central and eastern U.S. get through the vortex.

“The bulk power system remained stable and generally performed reliably throughout the event,” FERC staff said. “The credit for this good outcome goes to the many system operators and other utility personnel who worked long and hard, and communicated extensively with each other to keep the grid up and running.”