TMI Owners Back 2027 Restart Amid Grid Doubts

Source: pennlive.com

TL;DR

The story at a glance

Constellation Energy executives responded to a Reuters report from the CERAWeek conference where their official David Dardis said PJM Interconnection's initial analysis points to 2031 for full grid deliverability of the restarted Three Mile Island Unit 1, now the Crane Clean Energy Center near Middletown, Pennsylvania. The company insists the restart remains on track for the second half of 2027 and expects energy delivery then, calling PJM's date preliminary from the first phase of a three-part study. This comes amid ongoing Nuclear Regulatory Commission licensing reviews, with 2026 set as a key inspection year.

Key points

Details and context

The Crane Clean Energy Center, formerly Three Mile Island Unit 1, requires transmission upgrades because grid conditions evolved after its 2019 closure, with new generation and demand added. PJM's process has three phases; the 2031 date covers "full deliverability of capacity injection rights," but Constellation sees paths forward through talks with utilities.[[1]](https://www.pennlive.com/business/2026/03/tmi-owners-affirm-2027-restart-date-despite-grid-readiness-questions.html)

Nuclear Regulatory Commission inspections ramp up in 2026 now that Constellation's licensing amendments are submitted; prior on-site checks were limited as restoration was early stage. No word yet on Microsoft deal impacts if delayed.[[1]](https://www.pennlive.com/business/2026/03/tmi-owners-affirm-2027-restart-date-despite-grid-readiness-questions.html)

Key quotes

“The Crane restart remains on track for the second half of 2027, and we continue to expect to be able to deliver energy to the grid at that time.” — Constellation statement to PennLive[[1]](https://www.pennlive.com/business/2026/03/tmi-owners-affirm-2027-restart-date-despite-grid-readiness-questions.html)

“The 2031 date relates to the certainty of full deliverability of its capacity injection rights for the facility and is based on the first phase of PJM’s three-part study process. These initial study results are preliminary...” — Constellation statement[[1]](https://www.pennlive.com/business/2026/03/tmi-owners-affirm-2027-restart-date-despite-grid-readiness-questions.html)

“PJM’s analysis of the transmission upgrades needed to reintroduce the Crane Clean Energy Center remains preliminary. The study will go through additional iterations before final agreements are issued, expected by the end of 2026.” — PJM spokesman Jeff Shields[[1]](https://www.pennlive.com/business/2026/03/tmi-owners-affirm-2027-restart-date-despite-grid-readiness-questions.html)

Why it matters

Adding 835 megawatts of nuclear power tests U.S. grid capacity amid rising demand from data centers and electrification. For Constellation, Microsoft, PJM utilities, and Pennsylvania ratepayers, it means balancing restart speed against transmission reliability without delays eroding the 20-year deal's value. Watch PJM's study phases through 2026 and NRC inspections, as both could shift the timeline from preliminary concerns.

What changed

No prior state described.

Q: What did PJM's preliminary analysis say about Crane's grid connection?

A: PJM's first-phase study suggests full deliverability of the plant's capacity injection rights may not occur until 2031 due to needed transmission upgrades. The analysis accounts for grid changes since 2019, including new generation and demand. Final agreements are expected by end of 2026 after more study iterations.[[1]](https://www.pennlive.com/business/2026/03/tmi-owners-affirm-2027-restart-date-despite-grid-readiness-questions.html)

Q: Why does Constellation still expect a 2027 restart?

A: Constellation calls PJM's 2031 date preliminary and is engaging with PJM and utilities on options to advance the schedule. A spokesman said the issue "is going to get resolved." The company plans to have the plant ready to produce power in summer 2027.[[1]](https://www.pennlive.com/business/2026/03/tmi-owners-affirm-2027-restart-date-despite-grid-readiness-questions.html)

Q: What approvals does the restart still need besides grid connection?

A: Federal Nuclear Regulatory Commission licensing amendments require major inspections in 2026 to confirm safety and readiness. On-site checks have been limited until restoration advances further. No timeline given for completion.[[1]](https://www.pennlive.com/business/2026/03/tmi-owners-affirm-2027-restart-date-despite-grid-readiness-questions.html)

Q: Why was the plant shut down originally?

A: Exelon closed Three Mile Island Unit 1 in 2019 because high operational costs made its power unable to compete with cheap natural gas. A shift in energy demand, including Microsoft's purchase deal, now supports restart profitability.[[1]](https://www.pennlive.com/business/2026/03/tmi-owners-affirm-2027-restart-date-despite-grid-readiness-questions.html)