Transformer delivery brings Three Mile Island restart one step closer to reality

by Whitney Downard, Pennsylvania Capital-Star
August 17, 2026

On a hot, muggy day, the long-awaited arrival of a 500,000-pound transformer in Dauphin County signaled “outward, visible progress” of Constellation Energy’s intent to restart nuclear energy generation at the former Three Mile Island plant for the first time in years. 

“You can see a brand-new piece of equipment coming to the site … that’s going to connect the plant to the grid and to the transmission wires you see across the countryside,” said Bryan Hanson, the chief generation officer for Constellation. “This is the first, big component we’re having delivered to the site, and that’s the exciting part.”

The $9.88 million transformer from South Korea traveled from ocean liner to train to a specialized heavy hauler that inched its way along the final stretch through the island’s north gate in Londonderry Township just after 11 a.m. on Monday. 

Three Mile Island was the site of a 1979 nuclear accident that transfixed the world. But after that partial meltdown in one of the plant’s two reactors, the remaining Unit 1 continued safely producing electricity for another 40 years. 

In 2019, Constellation determined the facility was no longer economically viable and put plans in motion to permanently decommission the reactor. At the time, Hanson was the chief nuclear officer.

“We made a decision, a tough decision, to shut the plant down. And we had no intention of restarting the plant,” said Hanson. “For me, it’s exciting to see us restart the plant.”

The electricity generated will power Microsoft AI data centers, part of a $1.6 billion deal inked in 2024, and will support at least 650 permanent jobs.

The delivery is one of three transformers set to come to what is now the Crane Clean Energy Center, the last of which will be a backup. Each transformer will “step up” the 23,000 volts produced by the plant’s main generator tenfold, the level that’s “most efficient” for transmission lines. 

“Our commitment still is the summer of 2028,” Hanson said about a restart date, though “we’re running ahead of that and we think in ‘27 we’ll be able to provide electricity.”

“This is the integral part between the plant and the grid to make sure the electricity can flow,” he continued. “Having that here already, this early in the process, makes us comfortable we’re going to be able to deliver our electricity on time.”

In a series of public hearings, several people have expressed their concerns about the restart, noting that the site would be only the second commercial nuclear plant in the United States to return to service after being closed.

But demand for power is surging, driven largely by data centers, according to electricity grid operator PJM. That makes the reliability of energy sources like nuclear important, Hanson added.

“All we’ve done is invest in renewables for many, many years, shutting down base load facilities like this one,” said Hanson. “This is one example where we’re undoing a wrong by restarting a plant that supplies 835 megawatts of carbon-free electricity around the clock, independent of weather, independent of pipelines.”

Senior Reporter Pete Hall contributed to this story.

Pennsylvania Capital-Star is part of States Newsroom, a nonprofit news network supported by grants and a coalition of donors as a 501c(3) public charity. Pennsylvania Capital-Star maintains editorial independence. Contact Editor Tim Lambert for questions: info@penncapital-star.com.