Project dossier · Londonderry Township (Dauphin County), Pennsylvania

Microsoft Three Mile Island (Crane Clean Energy Center) In review

$1.6B power purchase agreement to restart TMI Unit 1 (renamed Crane Clean Energy Center) by 2028; Microsoft will buy 100% of the 835MW nuclear output for 20 years to power its AI data centers.

Key facts

Operator: Constellation Energy
Owner: Constellation Energy
Tenant: Microsoft
Size: 835 MW
Location: Londonderry Township (Dauphin County), Pennsylvania
Stage today: In review

Source

What to do next

Next step: An application is in the record. Ask the planning office for the next hearing date and request formal notice.

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What has happened so far (19 events)

2024-09-04protest
Pennsylvania anti-nuclear activists began organizing to oppose the restart, citing safety and evacuation concerns tied to the 1979 TMI-2 accident. · source
2024-09-20announcement
Constellation Energy announced a 20-year power purchase agreement with Microsoft to restart the 835 MW Three Mile Island Unit 1, renamed the Crane Clean Energy Center, to supply carbon-free power for Microsoft data centers; the deal is expected to create ~3,400 jobs and add $16 billion to Pennsylvania GDP. · source
2024-09-25coverage
Local reporting captured mixed community reactions in Londonderry Township/Dauphin County, with labor groups voicing support while some residents raised fear of another accident. · source
2024-10-25hearing
Constellation laid out its reopening timeline at a public hearing, telling regulators and residents it aimed to have Unit 1 producing power again by 2027-2028. · source
2024-11-04filing
Constellation submitted its initial restart application to the Nuclear Regulatory Commission for Three Mile Island Unit 1 (Crane Clean Energy Center). · source
2025-03-20environmental
Constellation began evaluating the environmental impacts of the restart as part of the NRC review process, covering water use from the Susquehanna River, air quality, and spent fuel management. · source
2025-04-03lawsuit
Activist Gene Stilp sued Dauphin County commissioners and the Public Safety Department, alleging misuse of taxpayer funds to promote the plant restart. · source
2025-05-06filing
The NRC formally accepted Constellation restart request for Three Mile Island Unit 1 for detailed technical review. · source
2025-08-01public-comment
Residents told federal regulators the NRC review process feels like a charade, pressing concerns about safety, evacuation planning, and environmental impact at a public forum near the plant. · source
2025-08-06hearing
The NRC held a second public meeting, this one virtual, allowing community members nationwide to comment on the proposed restart of the Crane Clean Energy Center reactor. · source
2025-08-15filing
NRC staff issued a Request for Additional Information (RAI) to Constellation as part of the technical review of the Unit 1 restart application. · source
2025-09-15filing
Constellation submitted its response to the NRC Request for Additional Information regarding the Crane Clean Energy Center restart. · source
2025-10-06filing
NRC docket correspondence addressed to Constellation Energy regarding the Crane Clean Energy Center restart review. · source
2025-11-18financing
The U.S. Department of Energy closed a $1 billion loan to Constellation Energy to help finance the roughly $1.6 billion restart of Three Mile Island Unit 1/Crane Clean Energy Center. · source
2025-12-18coverage
U.S. Energy Secretary Chris Wright touted the $1 billion DOE loan for the Three Mile Island restart as delivering on the Trump administration nuclear energy promises. · source
2026-04-21filing
PJM independent market monitor Monitoring Analytics filed comments with FERC opposing Constellation requested tariff waivers for the Crane restart. · source
2026-06-01ruling
FERC approved a waiver allowing Constellation to transfer 760 MW of Capacity Interconnection Rights from its Eddystone plant to the Crane Clean Energy Center, over the objection of PJM independent market monitor. · source
2026-07-28report
The NRC issued draft environmental assessment findings that the Crane Clean Energy Center restart would have no significant environmental impact, opening a public comment period. · source
2026-07-28coverage
Reporting noted continued community concern as the Crane nuclear plant restart progressed toward its targeted 2027 date, including concerns about reliance on the Susquehanna River amid climate-driven flood risk. · source

Find the paper trail

Find the paper trail (0 filed · 11 places to look)

State environmental permits

Backup generators, water withdrawal and stormwater are permitted by the state, usually earlier and in more detail than anything filed locally.

Pennsylvania DEPThe program page: which permits this state requires, and the office that issues them.
DEP Data Center Permit Tracker (the only state register built for data centers — it already feeds this tracker)Searchable public filings — search the operator, the shell LLC on the deed, and the address.

County & town filings

The rezoning application, site plan, traffic and noise studies, staff report and every revision.

Search Londonderry Township (Dauphin County) planning filingssearchPlanning departments post application files under many different names. Find the department, then ask the clerk for the application number — that number unlocks everything else.
Search Londonderry Township (Dauphin County) property records / GISsearchThe parcel record names the buying LLC and the sale date, which is what ties an anonymous filing to an operator.

Utility & grid records

The electricity request is filed with the grid operator and the utility long before the town hears about it — and states the real load.

PJM Interconnection (Mid-Atlantic, Ohio Valley) — interconnection queueRequested megawatts, queue position and target in-service date. The MW here is the real number; the one at the town meeting is often phase one.
Pennsylvania Public Utility Commission — docket searchSpecial contracts, large-load tariffs and rate cases are docketed here. Testimony and exhibits are public, and are usually more candid than the press release.
FERC eLibraryFederal filings: transmission agreements, interconnection service agreements, and co-location disputes.
Search the serving utility for a will-serve lettersearchThe will-serve or load-service letter is the utility's own written commitment. Ask the utility and the PUC for it by name — it is frequently the first document to exist.

Federal databases

Works anywhere, and covers the operator's record at its other sites.

EPA ECHO facility searchEvery federally-reported air, water and waste permit at a facility, plus its inspection and violation history. Search by address or draw a radius around the site.
EPA EnvirofactsThe same underlying records, queryable by county — useful for 'what else is permitted near this site' rather than one facility.
EPA Facility Registry ServiceResolves the shell LLC on a permit to the facility it belongs to. Worth a look when the filing name means nothing locally.

These are places to look, not evidence that anything has been filed. Links were checked on 2026-08-21; search links are queries, not records. What to ask for.

Around here

Pennsylvania briefing — rates, grid carbon, PUC contacts.

Other tracked projects in Pennsylvania

4-3 Salem Township Data Center — Salem Township (Luzerne County) Rumored
900 Conshohocken Road data center (former Cleveland-Cliffs steel mill) — Plymouth Township (Montgomery County) Awaiting decision
AWS Berwick — Berwick Under construction
AWS Falls Township campus (Keystone Trade Center) — Falls Township (Bucks County) Approved
AWS Salem Township campus (Susquehanna nuclear plant) — Salem Township (Luzerne County) Under construction

Cite this page: GridWatch AI, “Microsoft Three Mile Island (Crane Clean Energy Center)”, aigridwatch.com/projects/microsoft-three-mile-island-pa, retrieved 2026-10-11.

As of August 2026 (2m ago) · changes weekly — re-check before citing

A working set of identified proposals a community can track, not a census — most of the country's activity is not in here yet. Pennsylvania is the exception: its rows are synced from PA DEP's own data-center permit tracker, so the state's coverage is close to complete and carries the permit trail with it. **Each row carries its own provenance.** Rows showing a verification date link to reporting or the governing body's own record and were read on that date; rows marked *unverified* have no source on record — a lead to check, not a fact to cite. **Stage is derived, not asserted.** *Hearing scheduled*, *Awaiting decision*, *Approved* and *Withdrawn* are computed from each row's milestone dates on every rebuild, so a hearing date that has passed stops reading 'scheduled'. Hearings get moved and projects re-file under new names — treat a scheduled date as the earliest to act by, and confirm with the clerk before relying on it. Leads are mined into data/project_candidates.json and promoted here only after a human reads a primary source.

Part of the data center project tracker — open data, CC BY 4.0 (JSON · CSV).