PJM Interconnection, LLC activated demand response on nine days through Oct. 15 in 2026, amid rising data center load that the U.S. grid operator says is narrowing its fall window for maintenance.
Demand response pays participating customers in advance to reduce electricity use when called upon. PJM asked participants to cut use on Oct. 13 and 14; its grid spans Washington, D.C., and territory in 13 states. Unusually warm weather raised demand while generating and transmission equipment was out for scheduled work. PJM said the grid operated reliably through the alert.
The nine activation days this year exceed the eight recorded across 2015-24. PJM said it activated demand response on 15 days across 2025 and 2026 combined.
PJM counted about 11,000 megawatts of connected data center load as of Oct. 15. David Souder, PJM’s executive director of system operations, said electricity use by data centers and other large customers changes little with the weather. PJM says demand from large users is growing faster than new generation and transmission capacity, reducing the lower-demand periods available for equipment work. Delaying more outages could impair preparations for winter, it said.
During the October operating period, PJM worked with its members to bring about 10,000 megawatts of generation back into service. After those returns, more than 61,000 megawatts of generating capacity remained offline that week. More than two-thirds of the outages involved planned work or construction.
A U.S. Department of Energy (DOE) order in effect Oct. 13-16 authorized PJM to direct data centers and other large users to run backup generators only as a last resort before or during an Energy Emergency Alert 3. PJM said it did not use that authority.
The Federal Energy Regulatory Commission (FERC) is separately examining rules for connecting large electricity users. On June 18, it directed six regional grid operators to justify or revise their rules, including safeguards against shifting grid upgrade costs to other transmission customers. The orders set no new rates. PJM and four other operators must respond by Nov. 16; Southwest Power Pool, Inc. has until Nov. 20.
