A series of winter storms and a blast of Arctic air has put most of the United States into a short term energy supply challenge.

Texas has been the epicenter of the winter event. Its electric power grid has been under an Emergency Energy Alert Stage 3 since the early morning hours of February 15. At that stage, reserve margins are so tight that the grid operator has issued orders to transmission companies to reduce loads on the system.

The transmission companies have few remaining tools available to keep the grid in balance and prevent widespread collapse. They have reached the response stage where they need to implement rotating outages. In some cases, the margin between reserve generating capacity and demand has been so tight that the rotating outages have been substantially longer than the typical planned duration of 15-45 minutes.

There are numerous contributing factors, including fuel-related outages at natural gas fired power stations, a lack of wind as the cold air settles in, freezing at some wind turbine generators, and challenges at coal plants.

Approximately 35 GWe of installed thermal generating capacity was not producing electricity for a significant portion of the day on Feb 15. As of this moment, 8:15 PM central time, there is no solar electricity being provided in Texas and its 30,000 MWe of installed wind turbines is generating just 800 MWe.//

On Monday, Feb. 15, 2021, at 0537, an automatic reactor trip occurred at South Texas Project in Unit 1. The trip resulted from a loss of feedwater attributed to a cold weather-related failure of a pressure sensing lines to the feedwater pumps, causing a false signal, which in turn, caused the feedwater pump to trip. This event occurred in the secondary side of the plant (non-nuclear part of the unit). The reactor trip was a result of the feedwater pump trips. The primary side of the plant (nuclear side) is safe and secured.