GRAY SUMMIT
SubstationIllinois · UNION ELECTRIC CO - (MO)
GRAY SUMMIT is an electric transmission substation in Illinois, operated by UNION ELECTRIC CO - (MO). It is classified as high-voltage (345 kv) and connects 4 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 |
|---|---|---|---|---|
| #6529 | 345 kV | UNION ELECTRIC CO - (MO) | IN SERVICE | 24.4 mi |
| #20804 | 345 kV | UNION ELECTRIC CO - (MO) | IN SERVICE | 6.0 mi |
| #28057 | 345 kV | UNION ELECTRIC CO - (MO) | IN SERVICE | 24.3 mi |
| #28640 | 345 kV | UNION ELECTRIC CO - (MO) | IN SERVICE | 6.0 mi |
Nearby datacenter candidate sites
Scored candidate sites within roughly 25 miles of GRAY SUMMIT, 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 |
|---|---|---|---|---|---|---|---|
| MASON | Substation-Adjacent | MO | St. Louis County | 345 kV | 600 MW | 4.6 yrs | 74.6 |
| MONTGOMERY | Substation-Adjacent | MO | Warren County | 500 kV | 1,000 MW | 4.6 yrs | 72.8 |
| O'FALLON RENEWABLE ENERGY CENTER | Substation-Adjacent | MO | St. Charles County | 345 kV | 600 MW | 4.6 yrs | 71.3 |
| TAP153235 | Substation-Adjacent | MO | St. Charles County | 345 kV | 600 MW | 4.6 yrs | 70.9 |
| TYSON | Substation-Adjacent | MO | St. Louis County | 345 kV | 600 MW | 4.6 yrs | 70.2 |
| UNKNOWN168411 | Substation-Adjacent | MO | St. Louis County | 138 kV | 100 MW | 4.6 yrs | 70.1 |
| UNKNOWN117746 | Substation-Adjacent | MO | St. Charles County | 161 kV | 100 MW | 4.6 yrs | 69.9 |
| TAP139428 | Substation-Adjacent | MO | Jefferson County | 345 kV | 600 MW | 4.6 yrs | 69.8 |
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 GRAY SUMMIT substation, Illinois. 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.