The Crane Clean Energy Center is the former Three Mile Island Unit 1, an 835 MW PWR retired in September 2019 that Constellation is restarting under a 20-year Microsoft power purchase agreement. The NRC issued a final environmental assessment and FONSI in September 2026; Constellation targets a 2027 restart.
Background: Palisades fuel loading: Holtec restart timeline and what comes next · NRC reactor licensing process, explained
Current state
| Status | Refurbishment |
| Country | United States |
| Location | Londonderry Township, Pennsylvania |
| Plant | Crane Clean Energy Center (Three Mile Island) |
| Unit | 1 |
| Operator | Constellation Energy |
| Reactor type | PWR |
| Net capacity (MWe) | 835 |
| Restart type | Retired-plant restart |
| Shut down | 2019-09 |
| Restart target | 2027 |
| Years offline | 7.1 |
| Regulator | NRC reviewing exemption request and three licence amendment requests to restore power operations to the 2034 licence expiry; final EA/FONSI issued 2026-09-18 |
| Offtaker | Microsoft (20-year PPA) |
| Public funding | DOE Office of Energy Dominance Financing loan of $1.0bn (closed Nov 2025) |
Notes
NRC page gives permanent cessation as 26 Sept 2019 (shut down kept at month precision). WNN text says the unit 'closed down in 1999', an error. PJM said full transmission upgrades may take until after 2030; Constellation still expects 2027 start. Neutron Bytes reports a targeted NRC licence decision around May 2027 (secondary).
Timeline
- 2019-09 — TMI-1 permanently ceased operations after more than 40 years of commercial service. (source)
- 2024-09-20 — Constellation announced the restart backed by a 20-year Microsoft PPA. (source)
- 2025-11 — DOE closed a $1bn loan to Constellation for the restart. (source)
- 2026-06-01 — FERC approved a waiver letting Constellation transfer 760 MW of capacity interconnection rights from Eddystone to Crane. (source)
- 2026-06-03 — The NRC issued a draft environmental assessment and FONSI. (source)
- 2026-09-18 — The NRC issued the final environmental assessment and FONSI. (source)
The timeline is append-only: corrections are added as new entries. Stated targets appear in the current-state table, never as milestones.
Also tracked
- Three Mile Island Unit 2 (TMI-2) in the Nuclear Decommissioning Tracker Active dismantling
NNN coverage
About Constellation Energy
- The 6 nuclear stories that mattered this week 2026-10-10
- Google, Constellation plan 890 MW in nuclear uprates 2026-10-07
- Nuclear power for data centers, explained: every deal tracked 2026-10-01
- DOE nuclear funding, explained: every program paying for the buildout 2026-08-05
- NNN Daily Brief — July 22, 2026 2026-07-22
- The nuclear decommissioning market in 2026: size, players, pipeline 2026-07-14
About Three Mile Island
Related units
- Browns Ferry Unit 1 Restarted · United States
- Bruce A Unit 1 Restarted · Canada
- Bruce A Unit 2 Restarted · Canada
- Duane Arnold Energy Center Under review · United States
- Indian Point Unit 2 Proposed · United States
- Indian Point Unit 3 Proposed · United States
- Palisades Nuclear Plant Fuel load · United States
See all 45 units in the Nuclear Plant Restarts Tracker →
Sources
- Crane Restart (EDF project) — U.S. Department of Energy (primary), checked 2026-10-11
- Christopher M. Crane Clean Energy Center — U.S. Nuclear Regulatory Commission (primary), checked 2026-10-11
- One Year Later: Crane Clean Energy Center Still in the Spotlight and Ahead of Schedule — Constellation Energy (primary), checked 2026-10-11
- NRC and FERC boosts for Crane Clean Energy Center project — World Nuclear News, checked 2026-10-11
- Constellation seeks regulator's help for 2027 plant restart — World Nuclear News, checked 2026-10-11
- Inside Three-Mile Island's Quest to Clear Restart Hurdles — Neutron Bytes, checked 2026-10-11