Three Mile Island restart stays on track for 2027 after FERC waiver

The Federal Energy Regulatory Commission cleared away a key blockage for the former Three Mile Island Unit 1 by granting Constellation Energy a one-time, limited waiver that lets it transfer grid interconnection rights from its Eddystone gas plant near Philadelphia to the Crane Clean Energy Centre near Harrisburg. That move does not restart the reactor by itself, but it removes a planning problem that had pointed toward a far later connection date and keeps Constellation’s 2027 schedule intact.

For a plant with the weight of Three Mile Island behind it, the detail matters. Unit 1 permanently ceased operations on September 26, 2019, after more than 40 years of commercial service, and Constellation has spent the past two years recasting it as a restart rather than a new build. The reactor, rated at 819 MW, is being brought back under the Crane Clean Energy Centre name, with Constellation saying the site’s long operating history and existing infrastructure make revival feasible.

The hard part now shifts to the critical path still ahead. The U.S. Nuclear Regulatory Commission has already created a CCEC Restart Panel to guide inspections and review, and it has docketed Constellation’s license-amendment and exemption requests for technical review. Constellation notified the agency in late 2024 that it wanted to return the plant to service, submitted a regulatory path to reauthorize power operations on November 4, 2024, and secured NRC approval for the name change in Amendment No. 306 on January 13, 2025. The company still says it is awaiting nuclear regulatory approvals and finishing the remaining restart work.

The commercial case behind the restart is tied to a 20-year power purchase agreement with Microsoft announced on September 20, 2024. Constellation said that deal would add about 835 MW of carbon-free energy to the grid, support about 3,400 direct and indirect jobs, and deliver more than $3 billion in state and federal taxes. In November 2025, Constellation said a $1 billion Department of Energy loan would cover most of the roughly $1.6 billion startup cost.

The project has also become a public test of how Pennsylvania balances old nuclear infrastructure with new demand from data centers and other large users. Public meetings have drawn sharp questions from residents and activists, including Eric Epstein of Three Mile Island Alert, while Governor Josh Shapiro has linked the restart to broader efforts to bring more power online. For now, the FERC waiver turns a bureaucratic fight into something more tangible: a reactor that still needs approvals and work, but no longer looks as if it is drifting toward 2031.