PJM says emergency electricity conservation during US heat wave kept power demand shy of record

By Anjana Anil

PJM Interconnection, the operator of the largest U.S. power grid, said on Monday that emergency conservation measures last week likely kept electricity demand from breaking a 2006 record as searing temperatures gripped much of the eastern U.S.

PJM has been struggling to meet soaring demand, driven primarily by the expansion of energy-hungry data centers. This has raised fears of reliability risks during periods of extreme weather and boosted prices sharply in capacity markets designed to ensure enough power is available during peak demand periods.

On July 2, PJM's peak instantaneous load, the total amount of electricity demanded by all users at one exact moment, was approximately 162,700 megawatts (MW) between 5 p.m. and 6 p.m., according to preliminary figures, PJM said.

This was not far off the all-time record of 165,600 MW set in 2006.

If PJM had not taken emergency electricity-reduction actions, like activating a so-called "demand response" program that pays participating users to lower their usage, the peak load would have been even higher, and would likely have surpassed the all-time PJM record, the operator said.

PJM, which serves about 67 million people in the U.S. Mid Atlantic and Midwest, had warned that demand could challenge or exceed its all-time summer peak record of 165.6 gigawatts (GW) set in 2006.

A hot and dry wave of high pressure, which weather forecasters called a "," raised temperatures to dangerous levels across the eastern U.S. over the Independence Day weekend. Homes and businesses ramped up air conditioning during the prolonged heat wave, driving up electricity consumption.

Preliminary data showed demand reached 154,976 MW between 5 p.m. and 6 p.m. on July 3, 145,098 MW between 4 p.m. and 5 p.m. on July 4, and 134,332 MW between 5 p.m. and 6 p.m. on July 5.

The operator said load peaked on Thursday and was lower on the subsequent days, citing slightly milder weather and historically lower electricity usage on weekends and holidays due to businesses and other institutions being closed.