PJM Interconnection, the largest US Regional Transmission Organization (RTO), has been granted approval to curtail data centers and other large loads that have backup generation under an emergency order issued by the US Department of Energy (DOE).

The RTO asked the DOE on Sunday (17 May) to have the ability to direct transmission owners and electric utilities across its Mid-Atlantic and Midwest footprint for permission to curtail those facilities if needed for three days starting May 18 due to hot weather, as well as planned outages at several power plants for maintenance.

PJM said it expected to have less than 5.8GW of reserves during the peak period, placing significant strain upon the system.

“The projected level of generation outages coupled with the forecasted demand raises a significant risk of emergency conditions that could jeopardize electric reliability and public safety,” PJM said.

The curtailments would be used as a last resort before the RTO would have to order rolling blackouts, with only large loads with backup generation affected by the rules.

“Deployment of backup generation resources (whether auxiliary, standby, directly-connected, battery storage or other, and whether synchronized or not to the bulk power system) at data centers (including, but not limited to, hyperscaler facilities), and at other large load industrial and commercial customer sites, can prevent avoidable blackouts, thereby saving lives and reducing costs to the American people,” the department said.

This is not the first time the DOE has made an order like this. In January, it issued a similar emergency order to PJM, Duke Energy Carolinas and Duke Energy Progress, and the Electric Reliability Council of Texas.