THREE MILE ISLAND
SubstationPennsylvania · METROPOLITAN EDISON CO
THREE MILE ISLAND is an electric transmission substation in Pennsylvania, operated by METROPOLITAN EDISON CO. It is classified as extra-high-voltage (500 kv) and connects 10 transmission lines. Substation proximity is one of the strongest speed-to-power signals for siting a datacenter — interconnection distance to an energized, high-voltage bus is often the binding constraint on time-to-energization.
Voltage & classification
Connected transmission lines
Lines terminating at or passing through this substation, by HIFLD line ID, highest voltage first.
| Line ID | Voltage | Owner | Status | Length |
|---|---|---|---|---|
| #3229 | 500 kV | — | IN SERVICE | 44.1 mi |
| #27496 | 500 kV | — | IN SERVICE | 40.5 mi |
| #46731 | 500 kV | — | IN SERVICE | 74.6 mi |
| #25179 | 230 kV | METROPOLITAN EDISON CO | IN SERVICE | 1.6 mi |
| #26420 | 230 kV | METROPOLITAN EDISON CO | IN SERVICE | 1.6 mi |
| #47868 | 230 kV | METROPOLITAN EDISON CO | IN SERVICE | 0.7 mi |
| #34405 | 230 kV | METROPOLITAN EDISON CO | IN SERVICE | 0.4 mi |
| #64368 | 230 kV | METROPOLITAN EDISON CO | — | 0.1 mi |
| #7307 | 230 kV | METROPOLITAN EDISON CO | IN SERVICE | 1.6 mi |
| #7814 | 230 kV | METROPOLITAN EDISON CO | IN SERVICE | 0.2 mi |
Nearby datacenter candidate sites
Scored candidate sites within roughly 25 miles of THREE MILE ISLAND, ranked by DC Readiness. Sites this close to an energized substation carry a strong speed-to-power advantage.
| Site | Type | State | County | Voltage | Capacity | Queue wait | Score |
|---|---|---|---|---|---|---|---|
| SOUTH MANHEIM | Substation-Adjacent | PA | Lancaster County | 230 kV | 300 MW | 3.0 yrs | 71.9 |
| UNKNOWN147514 | Substation-Adjacent | PA | Cumberland County | 230 kV | 300 MW | 3.0 yrs | 71.7 |
| UNKNOWN123852 | Substation-Adjacent | PA | Lebanon County | 230 kV | 300 MW | 3.0 yrs | 71.7 |
| TALENENERGY MARTINS CREEK LLC WEST SHORE | Substation-Adjacent | PA | Dauphin County | 230 kV | 300 MW | 3.0 yrs | 71.4 |
| THREE MILE ISLAND | Substation-Adjacent | PA | Lebanon County | 500 kV | 1,000 MW | 3.0 yrs | 70.9 |
| UNKNOWN123853 | Substation-Adjacent | PA | Lebanon County | 230 kV | 300 MW | 3.0 yrs | 70.7 |
| MILLWOOD | Substation-Adjacent | PA | Lancaster County | 230 kV | 300 MW | 3.0 yrs | 70.2 |
| DEADEND167313 | Substation-Adjacent | PA | York County | 230 kV | 300 MW | 3.0 yrs | 70.2 |
Dataset updated . Screening estimates derived from public data sources.
Substation attributes are derived from public HIFLD / EIA infrastructure data and may lag real-world upgrades or retirements. Voltage and connected-line counts are screening figures — confirm available capacity and interconnection terms directly with the operating utility and ISO.
Go deeper than the public screen
This page shows a public slice of the GridCensus dataset for THREE MILE ISLAND substation, Pennsylvania. Pro and Enterprise plans unlock the full 164,098-site catalog, raw sub-scores, parcel ownership, interconnection-queue detail, saved searches, and programmatic API access.