Constellation Energy is pushing forward the restart of the Three Mile Island Unit 1, renaming it as the Crane Clean Energy Center (CCEC) after the U.S. Department of Energy (DOE) closed a US$ 1 billion loan. The 835 MW reactor is will start operations by 2027 and is backed by a 20-year power purchase agreement with Microsoft to supplying low-carbon energy to its data centers.
Project Factsheet for Crane Clean Energy Center (formerly Three Mile Island Unit 1)
Operator: Constellation Energy LLC
Capacity: 835 MW
Funding: US$ 1 billion loan from U.S. Department of Energy’s Loan Programs Office
PPA: 20-year contract with Microsoft for data center power supply. Constellation is also the power marketer for Microsoft-backed Orion Nuclear Fusion Power Plant in Washington expecting completion in 2028.
Projected Restart: 2027
Regulatory Status:
- License amendment filed with the U.S. Nuclear Regulatory Commission (NRC) to rename the plant and make upgrades.
- DOE issued a Final Environmental Impact Statement (EIS) in August 2025, adopted in September 2025.
Economic Impact: Expected to create 3,400 jobs and generate $16 billion in economic activity in Pennsylvania.
License Renewal Goal: Constellation plans to seek an extension to operate through 2054.
Project Timeline
September 2024: Constellation signs 20-year PPA with Microsoft, announces restart plan.
January 2025: License amendment request submitted to NRC to rename plant and approve restart.
March 2025: Constellation proposes use of 2013 ASME Boiler and Pressure Vessel Code Section XI for inspections.
August 2025: DOE issues final EIS for the restart project.
November 2025: DOE closes US$ 1 billion loan for the Crane Clean Energy Center.
2027: Constellation targets to bring Three Mile Island Unit 1 back online.
Project Overview
Crane Clean Energy Center revival is a landmark project for the U.S. nuclear energy sector as much as it is for Constellation. If Constellation meets its set timeline and regulatory standards, CCEC will not only supply reliable nuclear energy to the grid and but also “help America win the AI race” as put by the developer.
Outlook on Crane Clean Energy Center Revival (formerly Three Mile Island Unit 1)
Also noteworthy is that the restart is not a fresh build. This brings in the possibility of significant technical risk associated with refurbishing old systems and ensuring safety standards. There is also the aspect of reputational risk as Three Mile Island was at the center of a 1979 nuclear accident which drew a lot public scrutiny. Additionally, if demand from Microsoft or other possible offtakers shifts, the long-term financial structure could be exposed. And even with a US$1billion loan, which is substantial, it may not cover all cost overruns, especially if unexpected retrofit issues emerge.
Nonetheless, the project creates a sizable employment impact and will significantly contribute to Pennsylvania’s local tax bases. If all goes as planned, the revival of Three Mile Island Unit 1 by Constellation as Crane Clean Energy Center by 2027 will be one of the pivotal shifter of Pennsylvania’s and the U.S.’s green energy and economic transitions.
