Skip to content

Data center · Facility

Announced

Constellation Energy data center in Londonderry Township, Pennsylvania

Updated Nov 3, 2026Sources: Server Country; Kapwork Grow tracker

Announced Sep 20, 2024, in Dauphin County. No permit on record yet.

No permit on record yet. First seen Aug 15, 2026.

Where

Londonderry Township, Dauphin County, Pennsylvania.

Exact site not public. Shown at township level.

Open in Google Maps ↗

Londonderry TownshipDauphin County
Reported capacity
835MW
Planned, as Server Country (Sep 24, 2026) reports it. May be planned, not energised, capacity.
Work it brings
Electrical, mechanical, low-voltage, site, fiber
The trades a data center build hires, from the site work to the last mile of fiber.
Who bills here
Constellation Energy
The operator, per Server Country. No public record names its general contractor yet. The carriers show here when a record names them.

  • Builds in Pennsylvania

    108

    Proposed, approved, under construction or expanding, this one included. Kapwork Grow tracker, published Nov 3, 2026.

  • U.S. data center construction

    $84.95B a year

    August 2026, seasonally adjusted annual rate, preliminary. Up 73.2% from $49.05B in August 2025; 63.3% of private office construction. U.S. Census Bureau, C30, released Oct 1, 2026.

What this means for you

Same customers, bigger invoices.

The electrical, mechanical and fiber work on this campus bills Constellation Energy, its GC and the carriers you already know. Certify the invoices behind it, and funders compete to fund them.

An announced or permitted build is not a contract, an open bid or a purchase order.

Who your invoice goes to

  • Constellation EnergyOperator
  • General contractorNot named yet
  • CarriersNot named yet
  • UtilityNot named yet

Key facts

Stage
ProposedServer Country · Sep 24, 2026
Reported capacity
835 MWServer Country · Sep 24, 2026
Reported investment
$1.6BKapwork Grow tracker · Nov 2, 2026
Reported jobs
627Kapwork Grow tracker · Nov 2, 2026
Announced
Sep 20, 2024Server Country · Sep 24, 2026
Construction start reported
2025Server Country · Sep 24, 2026
Expected completion
2028Server Country · Sep 24, 2026
Location
Londonderry Township, Dauphin County, PennsylvaniaServer Country · Sep 24, 2026
AI workload
AI or machine-learning workload reportedKapwork Grow tracker · Nov 2, 2026
Facility type
AI data centerKapwork Grow tracker · Nov 2, 2026
Incentives reported
Other; $1.00BKapwork Grow tracker · Nov 2, 2026

What the public record lacks: the building area, the general contractor's name and the utility.

Who's involved

Operator
Constellation EnergyServer Country · Sep 24, 2026
Tenants
MicrosoftKapwork Grow tracker · Nov 2, 2026
General contractor
Not named in a public record yet
Carriers
Appear here as the records name them

How far along it is

  1. · Server Country

    Reported as announced

  2. · Server Country

    Construction start

  3. · Kapwork's date

    First seen in the Kapwork Grow tracker (its first snapshot)

  4. · Server Country

    Expected completion

  5. Date not reported · Server Country

    Expected completion reported

  6. Date not reported · Server Country

    Construction start reported

Dates as reported. Not a bid calendar. A planned date is not evidence that work occurred. Dates marked Kapwork's date come from the tracker's own snapshots, not from the sources.

More builds

In Pennsylvania

All Pennsylvania data center builds

The Kapwork Grow tracker lists 108 published builds in Pennsylvania, as published Nov 3, 2026; these are the ones linked to this record.

Questions this page answers

Is Microsoft Three Mile Island Energy Supply under construction?
No permit record shows it yet, so this page prints it as announced. Server Country (Sep 24, 2026) reports it as proposed.
Who is building Microsoft Three Mile Island Energy Supply?
Constellation Energy is the operator; the tenants reported are Microsoft. No public record names the general contractor yet. It shows here the day one does.
When is Microsoft Three Mile Island Energy Supply expected to finish?
Server Country reports expected completion in 2028. That is a reported target, not a schedule.
Which carriers serve Microsoft Three Mile Island Energy Supply?
No public record names them yet. They show here when a filing does.
How do contractors on Microsoft Three Mile Island Energy Supply get paid sooner?
The owner pays the general contractor, and the general contractor pays its subcontractors. Once your customer approves your invoice, certify it with Kapwork. Funders compete to fund it, so you don't wait for the payment date. Free for businesses. Kapwork doesn't lend and doesn't contact your customer.

Already invoice Constellation Energy?

Crews on a campus like this invoice the GC and the carriers in their own portals. Certify the unpaid invoices. Kapwork proves they're real so funders fund them sooner while the GC takes its time. Free for businesses.

  • Multiple offers
  • No notice of assignment
  • Free for businesses
Get offersTalk to an expert

Sources, updates and data

Server Country · Kapwork Grow tracker · U.S. Census C30

Where this comes from

What each source reports

  • Server Country: Proposed, 835 MW

Updates

  • Date not reported: Construction start reported. Server Country
  • Date not reported: Expected completion reported. Server Country
  • 2028: Expected completion. Server Country
  • Aug 15, 2026: First seen in the Kapwork Grow tracker (its first snapshot). Kapwork's date
  • 2025: Construction start. Server Country
  • Sep 20, 2024: Reported as announced. Server Country

Limitations and interpretation

  • This record is the Kapwork Grow tracker's merged view of a facility, from the tracker snapshot built 2026-11-02. Facts tagged KW are the tracker's resolved values; the per-source rows it was merged from are listed under Sources and on the tracker record.
  • Sources on this record: Server Country, https://servercountry.org/data/ (CC BY 4.0). Every source is licensed for commercial use with attribution.
  • An announced or permitted build is not a contract, an open bid or a purchase order.
  • Capacity figures are as reported by the cited sources and may describe planned rather than energised capacity.

“Not reported” means missing information, not zero. Completed and withdrawn records can remain available as historical records.

Nearest build: Haversine great-circle distance on the tracker latitude and longitude, in statute miles, rounded to 0.1. First-seen dates: first_seen: the earliest committed snapshot of data/dcfo.sqlite holding any of the facility's source keys (source:source_id), narrowed to the nightly run day by the alert sender's facility_new events when they are available. status_first_seen: the start of the unbroken run of snapshots, ending at this one, in which a facility sharing a source key had the current status, narrowed by the latest status_changed event to that status. Dates are Kapwork's, not the sources'.

What we don't know yet

  • The building area, the general contractor's name and the utility.
  • The carriers that serve the campus.
  • How the operator and its GC pay their contractors: portal, terms, days to pay.

Spot an error? Tell us

Cite: Kapwork Grow, “Microsoft Three Mile Island Energy Supply”, https://kapwork.com/grow/directory/datacenters/microsoft-three-mile-island-energy-supply-pa-dc_30229d30464f, materially updated Nov 3, 2026.

Report an error on this page.

Related:Data center buildsBEAD in Pennsylvania

Every data center build in the directory, in one place.

Search by company, place or trade.