Constellation Energy Corp. announced a 20-year deal with Microsoft to supply regional data centers with power from what is described as a $1.6-billion revamp and restart of the Three Mile Island nuclear plant Unit 1 reactor near Harrisburg, Pa., which was shuttered in 2019 “for economic reasons,” after 20 years of operation, said firm CEO Joe Dominguez.  

The unit is adjacent to but not connected with the plant’s Unit 2, which closed in 1979 after a near meltdown and is being decommissioned by its new owner, Energy Solutions. A restart of Unit 1, renamed the Crane Clean Energy Center, was announced Sept. 20. The unit closed in 2019 and is set to restart in 2028, but owner Constellation Energy did not disclose design and construction firm selections for plant upgrades to enable it to add 835 MW of energy to the area grid operated by PJM Interconnection over 20 years to match power used by tech giant's data centers.