Three Mile Island Nuclear Power Plant to Reopen to Supply Energy for Microsoft Data Centers

Microsoft has entered a 20-year power purchase agreement to reopen Pennsylvania’s closed Three Mile Island (TMI) nuclear power plant.
To keep its commitment to carbon neutrality by 2030, Microsoft will rely on nuclear power to support its data centers.
“Powering industries critical to our nation’s global economic and technological competitiveness, including data centers, requires an abundance of energy that is carbon-free and reliable every hour of every day, and nuclear plants are the only energy sources that can consistently deliver on that promise,” said Joe Dominguez, president and CEO of Constellation Energy.
“Before it was prematurely shuttered due to poor economics, this plant was among the safest and most reliable nuclear plants on the grid, and we look forward to bringing it back with a new name and a renewed mission to serve as an economic engine for Pennsylvania.”
TMI sits on the Susquehanna River in the Londonderry Township near Harrisburg, Pennsylvania, and is the site of a partial nuclear meltdown in March 1979 that released radioactive gas into the air.
The meltdown destroyed the Unit 2 reactor; however, according to Constellation Energy, the Unit 1 reactor “is a fully independent facility” that wasn’t damaged by the Unit 2 accident.
Unit 2 was sealed and its core was taken to the U.S. Department of Energy’s Idaho National Laboratory.
Major restoration of Unit 1’s turbine, generator, main power transformer, and cooling control systems will be needed.
Unit 1 was shut down five years ago by its former owner, Exelon, for economic reasons, Constellation Energy said.
To reopen the plant, Constellation Energy and Microsoft will be required to get state and local permits while the U.S. Nuclear Regulatory Commission will perform a safety and environmental review.
Constellation Energy will also pursue a license renewal that will authorize Unit 1—which is expected to be online by 2028—to be operational until 2054.
“This agreement is a major milestone in Microsoft’s efforts to help decarbonize the grid in support of our commitment to become carbon negative,” said Microsoft’s vice president of energy, Bobby Hollis.
“Microsoft continues to collaborate with energy providers to develop carbon-free energy sources to help meet the grids’ capacity and reliability needs.”