As the US faces extreme heat, data centers must use backup power to avoid power outages

As extreme heat threatens the stability of power grids in the eastern United States, major power users have been ordered to help keep air conditioners from turning off and homes darkening.

Energy Secretary Chris Wright this week instructed grid operators to require data centers to use their backup power sources if they need to reduce the load on the power system. Across the United States, Mr. Wright said, backup generators that could power dozens of large data centers sit idle most of the time.

Orders to use such generators are most likely to come in the 13 Mid-Atlantic states that share a strained grid and are home to the largest concentration of data centers in the world. The region has also been hit by a heat wave this week. The main network operator in the area, PJM, operates a system that stretches from Chicago to Virginia Beach and covers most of Pennsylvania, Maryland and New Jersey. PJM expects electricity demand on its grid to reach a record high on Thursday, surpassing the previous record set two decades ago.

“Maintaining affordable, reliable and secure power in PJM’s service area is undisputed,” Mr. Wright said.

Some energy experts worry that widespread use of backup systems in data centers could significantly increase air pollution in residential areas. Backup generators typically run on diesel or natural gas and emit more nitrogen oxides, particulate matter and other harmful emissions than large power plants or solar and wind farms.

Unlike grids in California and Texas, PJM is slowly adding energy storage batteries that can support power systems during heat and cold waves. For several years, California has not had to ask residents and businesses to conserve electricity during periods of high demand, in large part because it has added many batteries, each the size of a shipping container.

PJM issued a heat warning until at least Friday and told power plants to be available to operate at maximum capacity to ensure sufficient electricity during the heat wave.