Heat waves in the South and Midwest could push data centers offline and force reliance on backup generators, testing grid resilience.

Backup generators generally create more pollution than electricity from the grid.

Extreme heat is once again testing electricity systems across parts of the United States, and data centers and other major power users could be among the first customers required to disconnect from the grid.

According to Spotlight PA, federal emergency orders have expanded the authority of grid operators across broad areas of the South and Midwest to require data centers to leave the grid and run on backup generators.

Two major grid operators, PJM Interconnection and Southwest Power Pool, have been covered by six U.S. Department of Energy emergency orders since May. Together, they serve 30 states and include some of the country's largest concentrations of data centers.

Called 202(c) authorizations, these orders have historically allowed generators to operate more aggressively during heat waves, cold snaps, and other grid emergencies—even when that would normally conflict with pollution rules. They are now also being used to allow grid operators, if needed, to direct large electricity users, including data centers, to rely on their own generators.

When PJM's system reached record demand levels in early July, the grid operator instructed data centers and other major users to prepare to switch to backup power within 15 minutes. Neither PJM nor Southwest Power Pool has had to exercise that authority yet.

Harvard Electricity Law Initiative director Ari Peskoe told Spotlight PA that the move underscores data centers' impact on the grid. "It confirms that data centers are significantly increasing demand for electricity," he said.

Massive data centers power artificial intelligence tools, cloud services, and the digital systems people rely on daily. AI also holds potential to improve grid management and support cleaner energy systems through demand forecasting, power-use smoothing, and renewables optimization.

However, data centers consume enormous amounts of electricity and water. Rapid expansion strains aging infrastructure, increases pollution when backup generators activate, and potentially shifts additional costs onto households. AI also raises broader concerns around misuse, cybersecurity, and unintended social impacts.

Backup generators produce significantly more pollution than grid electricity. Crucially, the emissions from emergency operations do not count against a facility's usual regulatory limits.

Reuters reported disturbances as far away as Chicago after several Virginia data centers rapidly switched to backup power in mid-July, cutting roughly 3% of regional electric demand and affecting grid frequency.

Grid operators and federal officials are pursuing short-term solutions. The Trump administration has pushed data centers to generate, procure, or develop their own electricity rather than depend heavily on the grid. Energy Secretary Chris Wright began issuing these orders during a major January storm.

PJM plans to create a registry of major energy users to track their locations and generation capacity. However, Dartmouth associate professor of engineering Junbo Zhao cautioned that this alone will not resolve the underlying issues. More power generation capacity, smarter grid technologies, and improved coordination between utilities and data center operators are all necessary.

"They don't have dedicated coordination with each other to improve the efficiency and reliability of the grid," Zhao warned.