(Adds details, background)

By Laila Kearney

NEW YORK, March 26 (Reuters) - U.S. grid operator PJM

has told Constellation Energy that the former Three Mile Island

nuclear power plant in Pennsylvania likely won't be able to

connect to the grid until 2031, four years later than planned,

the company said at the CERAWeek energy conference in Houston on

Thursday.

Constellation is working to resume operations at the nuclear

power plant, which is being renamed the Crane Clean Energy

Center, to feed Microsoft ( MSFT ) data centers.

The company will be ready to produce electricity from the

plant by its 2027 goal, and it is speaking with grid operator

PJM Interconnection to reduce the timeline, said David Dardis,

chief external affairs and growth officer at Constellation.

Constellation, the country's biggest independent power

producer, announced in 2024 that it had contracted with

Microsoft ( MSFT ) to reopen the nuclear power plant. No fully shut

nuclear power plant has ever been restarted, but as demand rises

from Big Tech data centers and the electrification of buildings

and transportation, three U.S. plants are currently in that

process.