PJM Interconnection, the operator of the largest U.S.

electrical grid covering 67 million customers from Virginia to Illinois, will begin temporarily cutting power to data centers and other large users during shortages.

The decision follows an auction for new generating capacity that fell short of demand. Cuts won’t start until June 2027 and will apply only to data centers 50 megawatts or larger.

Affected customers will be compensated, similar to longstanding demand response programs for industrial users like manufacturers, with advance notice ranging from 30 minutes to a few days depending on forecasted demand.

PJM is running another auction for new generating capacity. The move will likely push new and existing data centers to set up on-site power sources.

Those that don’t will rely on backup generators, often diesel, which are costlier to run and more polluting.

Federal regulations allow such generators up to 50 hours per year for demand response events and up to 100 hours including emergencies and maintenance.

The article notes that Vantage Data Centers recently faced criticism for coordination with Virginia regulators to cast doubt on a report that diesel backup generators could cause tens of millions of dollars in annual health damages near a 96 megawatt data center in Northern Virginia.

PJM has faced scrutiny over managing new capacity and large users; wholesale electricity prices have nearly doubled in the past year, with PJM’s independent market monitor attributing much of the increase to data centers.

By 2035, data centers are expected to consume four times more electricity than today.