THREE MILE ISLAND, Pennsylvania (Reuters) -The former Three Mile Island nuclear power plant in Pennsylvania may restart in 2027, about a year ahead of schedule after being put on a fast track to connect to the regional grid, executives with the plant's owner Constellation Energy ( CEG ) said on Wednesday. 

Constellation struck a deal last September to power Microsoft ( MSFT ) data centers, paving the way to reopen Three Mile Island, widely known as the site of a partial meltdown in 1979 that chilled the nuclear industry.

Constellation's 20-year power purchase agreement with Microsoft ( MSFT ) is emblematic of the dramatic lengths Big Tech has been willing to go to fuel its artificial intelligence expansion, which began to intensify a year-and-a-half ago. 

The reactor re-entering service at Three Mile Island, which is being renamed the Crane Clean Energy Center, was not part of the 1979 accident, and shut in 2019 for economic reasons.

"We made a mistake in shutting down this plant, but we're not here to dwell on the past," said Constellation CEO Joe Dominguez at an event on Three Mile Island, backed by giant cooling towers and the nuclear plant that will be brought back as Crane.

The nuclear building is in similar shape to when it shut in 2019, and since the restart announcement, most of the work has been around planning and hiring, Constellation said.

The company has ordered several key items for the restart, including its main transformer and fuel. It has also restored water systems needed to run the plant and completed various infrastructure inspections needed for permitting approvals.

At the time of the restart announcement last year, Constellation said it expected the plant to re-open in 2028. Officials with the company had said they expected the process to be slowed by wait times associated with connecting power projects to the regional grid, which is operated by PJM Interconnection.

"When PJM gets this connected, we're going to be ready," Dominguez said on Wednesday.

Despite the enthusiasm, nuclear power plant projects have historically been far over budget and behind schedule. 

No fully shut nuclear power plant has been restarted, but at least one other attempted restart - of the Palisades nuclear plant in Michigan - is under way.  

As the technology industry drives U.S. electricity demand to record highs, nuclear power has broadly seen a resurgence of interest after decades in decline. New York plans to build a new nuclear power plant, which would be one of the first to be constructed in a generation. 

FAST-TRACKED PROJECTS

Hundreds of Constellation workers joined Wednesday's event, along with PJM CEO Manu Asthana and Pennsylvania Governor Josh Shapiro, who pushed for the restart to be fast-tracked for approval through PJM.

Power projects can linger in PJM's queue, which is essentially the application and engineering study process to hook up a power plant to the broader grid. PJM's territory spans 13 states and the District of Columbia, covering about 67 million customers.

As a way to alleviate some of that bottleneck, particularly as data centers rapidly proliferate on PJM's territory, the country's largest grid operator has fast-tracked its interconnection process for select projects.

Crane was the largest of the projects expedited by PJM, Shapiro said.

"I am focused like a laser beam on the future of Pennsylvania and the future runs through places right here like Crane," he said. 

More than 400 people have been hired to work at the plant so far, and there are 30 operators who can work in control rooms in training for the reopened plant, according to Dominguez and other Constellation officials. 

The Nuclear Regulatory Commission is expected to visit Crane in July to observe the training process, they said.