NEW YORK – US power grid operator PJM, the nation’s largest covering much of the East Coast and Midwest, on July 3 ordered customers in emergency electricity-reduction programs to curb their use, as it battled generator outages, overloaded transmission lines and surging 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 6pm EDT on July 3 (6am on July 4, Singapore time), 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.

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

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

On the evening of July 2, 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 July 2 was about 163GW, 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.

A hot weather alert remains in effect through July 4 for the entire region PJM serves, and has been extended through July 5 for the Mid-Atlantic and Dominion transmission zones, which include the world’s largest collection of data centres.

Spot wholesale electricity prices in that area have surged beyond US$2,500 (S$3,200) per MW hour this week. That compares with about US$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. REUTERS

Eastern US power grid operator orders emergency curbs as electricity use nears record