Largest US Power Grid Stays On Emergency Alert Due To Ongoing Heat Wave

PJM Interconnection, the largest electric grid operator in the United States, issued an emergency alert earlier this week and asked power plants to operate at full capacity as a massive heat wave continues to affect the nation.

The company is currently in charge of power supply in 13 states and the Washington D.C. area. In total, PJM Interconnection provides power to 65 million people.

According to the July 27 emergency notice, the company is no longer confident that it can sustain required electrical contingency reserves.

“A Hot Weather Alert helps to prepare transmission and generation personnel and facilities for extreme heat and/or humidity that may cause capacity problems on the grid,” the power company said in a statement issued on July 24. “Temperatures are expected to go above 90 degrees Fahrenheit (32°C) across the footprint, which drives up the demand for electricity.”

High temperatures generally strain electric grids as more people use air conditioners and other cooling systems. Companies responsible for a larger load generally need to seek assistance from other companies in order to deal with surges.

“A dedicated team of operators uses sophisticated technology to balance supply and demand and direct the power grid 24/7 from PJM’s control rooms. They prepare multiple potential scenarios that could be impacted by weather, emergency conditions, or equipment failure,” the statement continued. “They adjust resource output with changes in demand and ensure that no transmission lines or facilities are overloaded. The team also watches for unusual conditions and reacts to them to protect the electricity supply.”

For July 27 and 28, PJM Interconnection issued a maximum generation alert. The Pennsylvania-based company predicted a regional transmission organization (RTO) of approximately 150,700 megawatts on July 27, and 152,800 megawatts on July 28.

On July 29, the company cancelled the maximum generation alert, though heat wave emergency measures remain in effect.