US' largest power grid PJM orders emergency curbs as electricity use nears record peak

The largest U.S. power grid operator PJM on Friday ordered customers enrolled in emergency electricity-reduction programs to curb their use as it battled generator outages, overloaded transmission lines and a ‌surge in air-conditioning ⁠demand during ⁠a prolonged heat wave.

In an emergency alert, activated in line with utilities' conservation programs, PJM said the order applied to industrial and residential electricity users with contracts that pay them in return for mandatory consumption cuts during emergencies.

The alert was issued to increase reserves on the system and avert outages during peak demand around 6 p.m. EDT (2200 GMT) on Friday, it said.


PJM also notified neighboring regional grids, including in New York and the Midwest, that electricity exports ⁠from PJM may be ‌curtailed, a procedural step that allows those neighboring regions to plan accordingly.

Throughout the week, PJM escalated actions to conserve electricity as demand has approached an all-time ⁠record of 165.6 gigawatts (GW) set 20 years ago.

On Thursday evening, when electricity use neared that record, PJM experienced a sharp and sudden drop in generation capacity, forcing it to call on expensive fossil fuel "peaker" plants that are kept on standby to fill supply gaps. No outages occurred.

PJM's peak instantaneous load on Thursday was about 163 GW, according to preliminary data. That figure was suppressed, however, by the use of so-called demand response programs that pay customers to curb their electricity use during emergencies.

PJM serves ‌67 million people in the Mid-Atlantic, South and Washington, D.C., areas. Even before this week's heat wave, PJM had been straining to overhaul a system pushed to the brink by surging energy demand ⁠from data centers and electric vehicles.

A hot weather alert remains in effect through Saturday for the entire region PJM serves, and has been extended through Sunday for the Mid-Atlantic and Dominion transmission zones, which include the world's largest collection of data centers.

Spot wholesale electricity prices in that area have surged beyond $2,500 per megawatt hour this week. That compares with about $40 per MWh when PJM is not in distress.

The surge in prices mostly reflects the expense of providing power across congested high-voltage power lines, according to industry analysts and PJM's operations data.