TAP139978
SubstationMichigan
At a glance
TAP139978 is an electric transmission substation in Michigan. It is classified as sub-transmission (138 kv) and connects 3 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
Ownership
No owner is recorded for the lines that connect here.
Connected transmission lines
Lines terminating at or passing through this substation, by HIFLD line ID, highest voltage first.
| Line ID | Voltage | Owner | Status | Length |
|---|---|---|---|---|
| #125888 | 138 kV | — | IN SERVICE | 7.7 mi |
| #131762 | 138 kV | — | IN SERVICE | 10.8 mi |
| #134451 | 138 kV | — | IN SERVICE | 29.2 mi |
Nearby datacenter candidate sites
Scored candidate sites within roughly 25 miles of TAP139978, 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 |
|---|---|---|---|---|---|---|---|
| UNKNOWN128399 | Substation-Adjacent | MI | Macomb County | 345 kV | 600 MW | 2.2 yrs | 69.1 |
| SENECA | Substation-Adjacent | MI | Macomb County | 345 kV | 600 MW | 2.2 yrs | 68.2 |
| UNKNOWN128507 | Substation-Adjacent | MI | Oakland County | 345 kV | 600 MW | 2.2 yrs | 68.0 |
| UNKNOWN128512 | Substation-Adjacent | MI | Macomb County | 345 kV | 600 MW | 2.2 yrs | 67.6 |
| DEADEND167215 | Substation-Adjacent | MI | Macomb County | 345 kV | 600 MW | 2.2 yrs | 67.3 |
| UNKNOWN128514 | Substation-Adjacent | MI | Macomb County | 345 kV | 600 MW | 2.2 yrs | 67.2 |
| TAP139992 | Substation-Adjacent | MI | St. Clair County | 345 kV | 600 MW | 2.2 yrs | 64.8 |
| FITZ | Substation-Adjacent | MI | St. Clair County | 345 kV | 600 MW | 2.2 yrs | 64.6 |
How do candidate sites near TAP139978 score?
The 8 highest-scoring candidate sites within about 25 miles range from 65 to 69 on the 0–100 DC Readiness scale. They fall in Macomb County, Oakland County, St. Clair County. The Michigan average across 5,157 scored sites is 55.2. 768 of those Michigan sites are classed as substation sites (candidate locations generated at an existing substation).
Frequently asked questions
What voltage is TAP139978 substation?
TAP139978 has a maximum voltage of 138 kV. That places it in the 115–229 kV band. The median named US substation in this dataset is 115 kV, so TAP139978 is above the national midpoint.
How many transmission lines connect to TAP139978 substation?
3 transmission lines terminate at or pass through TAP139978 in the HIFLD line data. The connected lines listed here run at 138 kV. Together the listed lines cover about 47.6 miles.
Where is TAP139978 substation located?
TAP139978 is in Michigan at 42.9147, -83.0093. The datacenter candidate sites closest to it are in Macomb County, Oakland County, St. Clair County.
Are there datacenter candidate sites near TAP139978 substation?
GridCensus lists at least 8 scored candidate sites within roughly 25 miles of TAP139978. The highest-scoring is UNKNOWN128399 at 69/100. Across Michigan, the average DC Readiness score is 55.2.
More in Michigan
About this data
Source: HIFLD Electric Substations and Transmission Lines (U.S. Department of Homeland Security), as published June 29, 2026. See the methodology for how records are matched, cleaned and scored.
Cite as: GridCensus, “TAP139978 substation, Michigan”, https://gridcensus.com/substations/michigan/tap139978-c658c7aa (data as of June 29, 2026).
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
Every site and score for TAP139978 substation, Michigan is free to browse. Pro adds Watchtower on 25 sites, alerts when new candidate sites, datacenters or interconnection-queue requests appear in your markets, score and capacity history, and CSV export. Enterprise adds team seats, weekly data files for all 147,272 sites, the REST API and an MCP server for AI tools.