Report: System Performed Under Stressed Conditions


The PJM system performed admirably during the recent cold weather, which saw some of the coldest temperatures in decades across the PJM footprint, a preliminary report shows. PJM emphasized that the information may be subject to change based on additional review. 

Overall generation performance through the period was good. Forced outages were slightly greater than normal, which is typical for periods of extreme cold temperatures.

2019 Cold Snap

“The key to the performance during the cold weather was the transmission and generation operators, who have made reliability under stressed conditions a priority,” said Mike Bryson, vice president – Operations. “These preliminary results suggest those efforts are paying off.”

PJM has compiled preliminary generation outage information for the Wednesday evening peak period and the Thursday morning peak period.

The forced outages for the Wednesday evening peak were 17,275 MW, just over 8.6 percent of the total PJM capacity. The forced outages for the Thursday morning peak were 21,359 MW, just over 10.6 percent of the total PJM capacity.

By way of comparison, generation forced outages for the 2018 winter peak (23,751 MW) was 12.1 percent of PJM’s overall capacity.

That was significantly lower than the generation forced outages for the 2014 polar vortex outbreak of 22 percent (40,200 MW).

Market Operations

Locational Marginal Prices were moderate throughout the two days, averaging $54/MWh and $58/MWh on Wednesday and Thursday, respectively.

Reserve market clearing prices remained close to $0/MWh for the majority of the two days, although LMPs and reserve market clearing prices were elevated during the Wednesday evening and Thursday morning peaks.

There were two periods of shortage pricing in the synchronized reserve market, both of which occurred following the loss of generation. On Wednesday, the evening peak followed the forced outage of a generator in the western part of the RTO, Mid-Atlantic Dominion (MAD) and RTO synchronized reserve prices were $600/MWh and $300/MWh, respectively, and the energy price approached $750/MWh.

The second period of shortage pricing occurred in the early morning hours on Thursday. The system energy price was just over $1,000 following the loss of a generator in the eastern part of the RTO, and MAD and RTO synchronized reserve prices reached just over $900/MWh and $600/MWh, respectively.

2014 Polar Vortex

PJM Issued Cold Weather Alerts

In anticipation of the cold weather PJM issued a Cold Weather Alert for the ComEd transmission zone for Tuesday, as daytime temperatures in the ComEd zone on Tuesday were right around zero degrees. PJM then issued a Cold Weather Alert for PJM West for Wednesday and a Cold Weather Alert for the entire RTO on Thursday and Friday.

By Thursday morning temperatures in the Mid-Atlantic area of PJM were in the single digits while most of PJM West was below zero. Morning low actual temperatures (not wind chill) on Thursday in the ComEd transmission zone were negative 24 degrees. 

The load increased significantly as the frigid air mass moved into the RTO.

The overall RTO load continued to increase as the cold weather moved from the western region and into the mid-Atlantic zone of the RTO. By Wednesday the cold air was firmly entrenched in the west and temperatures were dropping through the day in the Mid-Atlantic zone as a cold front moved off the coast.

The Wednesday evening peak load was approximately 136,000 MW. The highest RTO load for the period occurred on Thursday morning when the peak load approached 140,000 MW.