Constellation Energy said the former Three Mile Island could come back online as the Crane Clean Energy Center a year earlier than initially expected.

PJM approved an early interconnection request, hiring and training are going well, and significant progress has been made on major equipment purchases, the company said June 25 during a celebratory event at the southeast Pennsylvania facility.

When Constellation went public with its plans in September 2024, it targeted a 2028 restart. (See Constellation to Reopen, Rename Three Mile Island Unit 1.)

The company now says the facility could come online as soon as 2027.

Crane is roughly two-thirds staffed, with nearly 400 full-time employees hired and 58 more scheduled to start soon. Technical milestones include the successful inspection of the main generator and turbines and other major systems. The new main power transformers are scheduled to be delivered in 2026.

Importantly, the facility was among those fast-tracked in May through PJM’s Reliability Resource Initiative. (See PJM Selects 51 Projects for Expedited Interconnection Studies.)

Constellation CEO Joe Dominguez spoke of the confluence of factors working in favor of the project: PJM’s actions; financial support from Microsoft, which will buy 835 MW of output for its data centers; community backing; and support from Pennsylvania Gov. Josh Shapiro (D), who also spoke at the ceremony.

PJM President Manu Asthana told the crowd about the project’s importance to the region, the nation and the grid, which is wrestling with resource adequacy.

“I’m here to say ‘thank you’ for that,” he said. “PJM understands the importance of bringing this project and other projects like it online quickly, and our engineers are back in the office, working as hard as possible to accelerate that.”

The heat wave did not pause for the ceremony: The temperatures climbed into the 90s under blazing sun at the Crane Clean Energy Center, and public demand for electricity rose with the heat.

Asthana said two days earlier, the PJM control room observed an all-time high peak, 9 GW higher than last summer’s peak.

“Now let me put that in context,” he said. “That is 11 Crane Clean Energy Centers from last year’s peak to this year’s peak. What we’re talking about here is not hypothetical. Our country needs this power.”

Dominguez marveled at the turn of history at one of the best-known nuclear facilities in the world.

“Boy, what an incredible, incredible moment,” he said. “The comeback of this plant, the comeback of the industry. It’s just kind of amazing.”

The partial meltdown of Three Mile Island Unit 2 in 1979 energized popular opposition to commercial nuclear power. Unit 1 was undamaged and came back online several years later, but Constellation’s corporate predecessor, Exelon, shut it down in September 2019 due to uneconomical market and policy conditions. Other reactors nationwide were retired for the same reasons.

Just a few years later, nuclear power is poised for a renaissance, with politicians and industry willing to help subsidize nuclear generation in return for its steady, emissions-free output. Plenty of critics remain, but even some former opponents of nuclear power now offer support.

Unit 1 is among the oldest reactors in the aging U.S. fleet, first licensed in 1974. But the anticipated $1.6 billion cost of the restart project would be a small fraction of the cost of building a comparable facility.

The easiest step forward into Three Mile Island’s next chapter also was the most literal: Constellation renamed it after the late Chris Crane, Exelon’s CEO from 2012 to 2022.

The Nuclear Regulatory Commission approved the change in May.