America’s largest grid operator plans a special March auction to secure new generating capacity for data-center demand if federal regulators approve revised rules governing who pays.

PJM Interconnection LLC, which serves more than 67 million people from the Mid-Atlantic to the Midwest, filed the proposal late Thursday after the Federal Energy Regulatory Commission called its original plan “deeply flawed” and delayed the auction by five months.

Under the revised plan, PJM would base the amount of supply it procures on the increase in forecast peak demand between 2026 and summer 2028. Costs would then be allocated according to each utility zone’s share of that growth.

At stake are potentially more than $20 billion in payouts for new natural gas-fired plants and other sources, creating a significant opportunity for power producers such as Constellation Energy Corp., NRG Energy Inc., Vistra Corp. and Talen Energy Corp.

American Electric Power has threatened leave PJM. Under the proposal, any utility that exits would remain responsible for payments to generators needed to serve data-center demand in its territory. PJM also wants to eliminate the ability of certain municipal utilities and cooperatives to opt out.

The 13-state grid is already home to the nation’s largest concentration of data centers and has become embroiled in consumer, regulatory and political turmoil over how to meet the needs of the fast-moving AI industry without saddling households and businesses with higher power bills. This latest filing would determine how those costs are spread among customers and who remains liable if a utility leaves the market.

“The allocation method was what FERC had reservations about, and I still think the revised leaves the door open to criticism but is likely to get approved,” said Gary Cunningham, director of research at brokerage Tradition Energy. “It is worth noting that all consumers in any utility where there is expected demand growth will pay, not just new load.”PJM is in the process of revising its demand forecasts. Earlier projections showed a 6.8-gigawatt capacity shortfall for summer 2028, before accounting for the accelerating pace of data-center development.

“In the end, PJM isn’t going to buy much new capacity under the program so it is a lot of noise for not a lot of actual help for reliability,” Cunningham said.

If FERC approves the revisions, the auction — dubbed the Reliability Backstop Procurement — would run from March 1 through March 28. PJM still aims to procure supplies for 15 years with price cap of $555 per megawatt-per day, which would be a record payout. PJM has never held an auction of this kind. Its next annual capacity auction is scheduled for December.

Procuring the full 6.8 gigawatts at that price would result in nearly $1.4 billion a year in payments to generators, or about $20.7 billion over the full 15 years.