Crane Clean Energy Center Restart: 835 MW Targeted for 2027 for Microsoft

The Crane Clean Energy Center restart, a Pennsylvania reactor that Constellation puts at about 835 MW and targets for 2027 under a 20-year Microsoft power purchase agreement, gets its next update when Constellation reports third-quarter results on Nov. 9.

Crane is the former Three Mile Island Unit 1, which closed in September 2019. Its return depends on four NRC licensing actions that the agency's staff estimate they will decide by March 4, 2027, and on transmission upgrades that PJM found could take until after 2030 to fully complete, World Nuclear News reported. Microsoft's deal is signed; its size in megawatts, its price and its start date have not been disclosed.

How the Crane Restart Works

Crane is a pressurized water reactor rated at 2,568 MWt that began operating in 1974, according to the NRC. Constellation put its generating capacity at 837 MW before the 2019 retirement, and says the restart will return approximately 835 MW; neither figure is labelled net or gross. In its last year, the company said, the plant ran at maximum capacity 96.3% of the time. The 1979 accident happened at the neighbouring Unit 2, which is being decommissioned separately by Energy Solutions.

The one idea that matters: a restart is not new construction. The reactor, the site and the grid connection point already exist. What must be rebuilt is the licence and the equipment. Once the plant shut down and its fuel was removed in 2019, the licence no longer allowed it to run the reactor or put fuel in the vessel; the NRC says the four pending actions are all needed to reauthorize both. The agency says Constellation must win approval to restore an operating licensing basis, return components to a condition that supports safe operation, and make any upgrades that basis requires. Constellation said it would restore the turbine, generator, main power transformer and cooling and control systems. It ordered three new main power transformers and spent a further $35 million to get them to the site in 2026, World Nuclear News reported in February 2025.

Microsoft's 20-Year PPA and the $1 Billion DOE Loan

Constellation called the Sept. 20, 2024 agreement its largest-ever power purchase agreement. Under it, Microsoft buys energy from the restarted plant to help match the power its data centers in the PJM region use with carbon-free energy. The plant's output goes onto the PJM grid, Constellation and DOE say; neither describes a direct connection to a Microsoft campus. Neither company has published the price or how much of the 835 MW Microsoft takes.

Public money is the other binding piece. The Department of Energy's Loan Programs Office closed a $1 billion loan to Constellation Energy Generation on Nov. 18, 2025 to partially finance the restart, DOE said, adding that the reactor will serve PJM once it has its NRC licensing approvals. Constellation separately holds a conditional DOE commitment of up to $5 billion for uprates across its fleet, as Voltgrid reported.

NRC Licensing Timeline for the Crane Restart

Constellation filed an exemption request on Nov. 19, 2024, followed by three licence amendment requests: the operating licence and technical specifications (July 31, 2025), the security plan (Oct. 24, 2025) and the emergency plan (Oct. 31, 2025). The NRC's acceptance letters estimated the safety reviews would be done between Jan. 31 and Oct. 31, 2026. An NRC letter put the whole review at an estimated 5,540 staff and contractor hours and said staff expect final decisions by March 4, 2027. The letter says that estimate could change if requests for additional information or new scope arise.

Several steps are complete. The NRC approved the amendment allowing Crane to receive and hold new fuel on July 1, 2026, and issued a final environmental assessment and finding of no significant impact on Sept. 18, 2026, without a full environmental impact statement. Questions remain open on the main requests: the NRC sent requests for additional information on the emergency plan on Sept. 18 and on the operating licence and technical specifications on Sept. 25. Constellation answered the first on Oct. 2. The agency's project page, last updated Oct. 8, lists no reply to the second.

Constellation first said the plant would be online in 2028, then moved the target to 2027. In September, it told World Nuclear News the restart remained ahead of schedule. According to World Nuclear News, the current requests would let the unit run until 2034, when its old licence expires. Constellation plans a separate renewal to run to at least 2054; the sources reviewed show no renewal application yet.

What it means for Microsoft and the PJM grid

For Microsoft, a restart skips building a reactor: the risk sits in licensing and refurbishment, not first-of-a-kind construction. The grid sets a second clock, however. PJM approved reconnecting the plant from 2027 but found that the transmission upgrades needed to deliver all of its output could take until after 2030, World Nuclear News reported. World Nuclear News also reports that FERC's June 1, 2026 waiver let Constellation remove Eddystone Units 3 and 4, 380 MW each, from Capacity Resource status and make their capacity interconnection rights available to move to Crane. Those rights are tied to a plant's ability to meet capacity obligations in PJM's capacity market.

The rights are a grid-connection allowance, not new generation. FERC said the transfer could raise Crane's interim deliverability and let it be fully operational before Dec. 31, 2030, while PJM found the upgrades to deliver all of the unit's power could take until after 2030. For Microsoft's PPA, that suggests the plant's licence and its wires run on separate clocks.

Crane is one of three US reactor restarts backed by federal loans and big-tech buyers. Holtec's 805 MWe Palisades restart has no announced date after its fuel recovery, so neither restart yet offers a firm in-service date.

What to Watch After the Nov. 9 Call

On Nov. 9 at 9 a.m. ET, Constellation's third-quarter call is the place to look for any change to the 2027 target. Next come the NRC's completion of its safety reviews and Constellation's reply to the Sept. 25 questions, then the staff's final licensing decisions, estimated by March 4, 2027. After those come fuel loading, a licence renewal filing for operation past 2034, and PJM's transmission upgrades, which could determine how much of the plant's output reaches the grid in the meantime; no source gives a partial figure.