A powerful cold front (or polar vortex) developed in the United States and Canada beginning December 21. After strengthening over the Northern Plains, it descended and covered much of the eastern two-thirds of the United States from December 23 to December 25, bringing dangerous cold, high winds, and blizzard conditions to many areas.

Early indications are that the combination of unexpected high demand and failure of a significant amount of generation to perform as expected during this period pushed many regions into emergency operations. Many regions declared emergencies, and load-shedding occurred in Tennessee and the Carolinas.

On December 28, the Federal Energy Regulatory Commission, the North American Electric Reliability Corporation (NERC), and NERC’s regional entities announced a joint inquiry into the operations of the wholesale power system during the event, since named Winter Storm Elliott. In the words of NERC CEO Jim Robb, “This storm underscores the increasing frequency of significant extreme weather events (the fifth major winter event in the last 11 years) and underscores the need for the electric sector to change its planning scenarios and preparations for extreme events.”

Since December, various operators are conducting reviews to determine root causes and potential changes in planning, processes, and communication. While storms such as Elliott are unusual, they are not rare. A second brief but powerful polar vortex lasting from February 3 to February 4 drove extremely low temperature and bitter wind chills from New England through the Mid-Atlantic and upper Midwest. At one point, Mount Washington in New Hampshire was purportedly colder than Mars with a temperature of -47° F and wind gusts of 127 miles per hour, and a wind chill below -100° F. With growing electrification and a changing resource mix, grid operators will need to adapt their approaches to cold weather stresses on the grid.

As a first-order analysis, in the following infographic, we look at selected regions' fuel mix during Winter Storm Elliott.