September Scorcher Spikes Peak Demand on Regional Power Grid

Unseasonable temperatures, unexpected demand force PJM to declare emergencies in four states

transmission heat
How hot was it yesterday? Hot enough to set a new record for the regional power grid in September, with a peak demand of 144,370 megawatts for the 13 states, including New Jersey and Washington, D.C., served by PJM Interconnection.

The spike in demand led PJM to declare emergencies in Pennsylvania, Ohio, Michigan, and Indiana. It also warned that high temperatures persist in many areas and supplies remain tight.

PJM serves more than 61 million customers in a territory stretching from the Eastern Seaboard to Illinois. It is the nation’s largest operator of a regional power grid.

Problems in the four states where emergencies were declared forced PJM to direct local utilities to immediately and temporarily cut off power to some customers, thus avoiding the possibility of an uncontrolled blackout over a wider area.

The trouble was blamed on local equipment problems and the unusually high temperatures for this time of year, according to the PJM. The rare September heat wave spiked demand well above the peak that occurred 12 months ago, reaching 129,599 megawatts. Yesterday’s peak was much closer to the highest demand registered during the summer, when it hit 157,509 megawatts.

The emergency conditions reinforce arguments by power suppliers and utilities that more generation units need to be built and more transmission lines need to be deployed to meet rising demand for electricity —a situation some say is caused by increasingly warmer summers due to global climate change and greater use of consumer electronic devices.

But many environmental groups argue that greater efforts to conserve energy, increase energy efficiency, and develop more renewable energy sources could help meet rising demand for power — without new plants and transmission systems.

“Extreme heat in the western region of PJM resulted in record demand for September at a time when many power plants and some transmission lines were off for seasonal maintenance,’’ said Terry Boston, PJM’s CEO. “Our only option to prevent a potential equipment overload and failure that would cause a much bigger interruption was to call for emergency relief in the form of controlled outages.’’

As a grid operator, PJM determines the necessary steps to keep the grid in service, delivering electricity to consumers. In the case of an emergency, like yesterday’s, PJM must immediately call for what is usually the last resort, cutting power to some customers. PJM identifies the general area where power-use reductions are necessary and the extent of those reductions. A local utility, which operates the transmission lines, determines how to make the reductions. In an emergency like this, time is of the essence, and there is little lead time to notify everyone who will be affected.

In other areas, utilities are trying to deal with potential problems to the power grid.

Public Service Electric & Gas, the state’s largest gas and electric utility, has embarked on a series of major transmission projects, including a controversial initiative that will cost nearly $1 billion and extend transmission infrastructure from Pennsylvania to Roseland in Essex County, cutting through a number of national parks in the New Jersey Highlands. Construction began recently after a court turned down an appeal from environmentalists.