A polar vortex sitting over New Jersey is causing record-breaking cold – and record demand for power.

Flickr User Gus Thomson

That has power officials very concerned.

“The cold has caused an all-time high in electricity use for the winter, and as a result we are seeing a large number of generator units that either have shut down or are potentially may have problems due to the cold weather,” said Michael Kormos, executive vice president of Operations for PJM Interconnection.

Kormos told reporters during a conference call this morning that a maximum generation alert has been issued across the system and last night, a 5 percent voltage reduction was ordered system-wide.

"We are seeing a large number of generator units that either have shut down or potentially may have problems due to the cold weather, Kormos said."

As a result, he said customers are being asked, if at all possible “to postpone any major electric appliance use," especially between 3 and 7 p.m. today.

"Obviously, if they’re able to turn down their thermostats, obviously health permitting, and obviously turn off any lights that are not necessary or needed," Kormos said.

He stressed if the electric grid begins to become overloaded, controlled rolling blackouts might be needed, but right now that is not anticipated.

The PJM grid serves New Jersey as well as Delaware, Illinois, Indiana, Kentucky, Maryland, Michigan, North Carolina, Ohio, Pennsylvania, Tennessee, Virginia, West Virginia and the District of Columbia.