MONARCH
SubstationCalifornia · PACIFIC GAS & ELECTRIC COMPANY
At a glance
MONARCH is an electric transmission substation in California, on PACIFIC GAS & ELECTRIC COMPANY's transmission network. It is classified as distribution (<69 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
Ownership
Connected transmission lines
Lines terminating at or passing through this substation, by HIFLD line ID, highest voltage first.
| Line ID | Voltage | Owner | Status | Length |
|---|---|---|---|---|
| #303014 | 60 kV | PACIFIC GAS & ELECTRIC COMPANY | IN SERVICE | 0.8 mi |
| #305823 | 60 kV | PACIFIC GAS & ELECTRIC COMPANY | IN SERVICE | 0.9 mi |
| #308656 | 60 kV | PACIFIC GAS & ELECTRIC COMPANY | IN SERVICE | 0.8 mi |
| #310303 | 60 kV | PACIFIC GAS & ELECTRIC COMPANY | IN SERVICE | 1.7 mi |
Nearby datacenter candidate sites
Scored candidate sites within roughly 25 miles of MONARCH, 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 |
|---|---|---|---|---|---|---|---|
| TESLA Power Project | Brownfield | CA | Alameda County | 500 kV | 1,322 MW | 7.6 yrs | 66.5 |
| TESLA | Substation-Adjacent | CA | Alameda County | 500 kV | 1,000 MW | 7.6 yrs | 59.2 |
| TRACY | Substation-Adjacent | CA | San Joaquin County | 500 kV | 1,000 MW | 7.6 yrs | 58.6 |
| COUNTRY CLUB | Substation-Adjacent | CA | San Joaquin County | 230 kV | 300 MW | 7.6 yrs | 57.6 |
| PRESCOTT | Substation-Adjacent | CA | Stanislaus County | 230 kV | 300 MW | 7.6 yrs | 57.1 |
| ROSEMORE B | Substation-Adjacent | CA | Stanislaus County | 230 kV | 300 MW | 7.6 yrs | 57.0 |
| STAGG | Substation-Adjacent | CA | San Joaquin County | 230 kV | 300 MW | 7.6 yrs | 56.6 |
| WEBER | Substation-Adjacent | CA | San Joaquin County | 230 kV | 300 MW | 7.6 yrs | 56.5 |
How does MONARCH compare with other substations in California?
California has 4,260 substation records in HIFLD, of which 3,003 carry a station name; the rest are unnamed tap points, risers and line ends. 1,439 named substations in the state are in MONARCH's below 69 kV band (48% of named stations). 1,504 sit in a higher band. 44 named substations in California operate at 345 kV or above. The highest voltage recorded in the state is 500 kV, and the state median is 69 kV.
Who owns the transmission lines at MONARCH?
The 4 connected lines listed above are owned by PACIFIC GAS & ELECTRIC COMPANY. Line voltages range from 60 kV to 60 kV. Their combined recorded length is about 4.3 miles.
How do candidate sites near MONARCH score?
The 8 highest-scoring candidate sites within about 25 miles range from 57 to 67 on the 0–100 DC Readiness scale. They fall in Alameda County, San Joaquin County, Stanislaus County. The California average across 8,490 scored sites is 45.4. 1,573 of those California sites are classed as substation sites (candidate locations generated at an existing substation).
Frequently asked questions
What voltage is MONARCH substation?
MONARCH has a maximum voltage of 66 kV and a minimum of 60 kV. That places it in the below 69 kV band. The median named US substation in this dataset is 115 kV, so MONARCH is below the national midpoint.
How many transmission lines connect to MONARCH substation?
4 transmission lines terminate at or pass through MONARCH in the HIFLD line data. The connected lines listed here run at 60 kV. Together the listed lines cover about 4.3 miles.
Who owns MONARCH substation?
HIFLD does not publish substation owners directly. Most of the transmission lines that end at MONARCH belong to PACIFIC GAS & ELECTRIC COMPANY. GridCensus derives this from the line data, so confirm ownership with the utility for anything contractual.
Where is MONARCH substation located?
MONARCH is in California at 37.9694, -121.2803. The datacenter candidate sites closest to it are in Alameda County, San Joaquin County, Stanislaus County.
Are there datacenter candidate sites near MONARCH substation?
GridCensus lists at least 8 scored candidate sites within roughly 25 miles of MONARCH. The highest-scoring is TESLA Power Project at 67/100. Across California, the average DC Readiness score is 45.4.
Other 66 kV substations in California
- SATICOY· 7 lines
- BRIGGSMORE· 5 lines
- CAROLINA· 5 lines
- DELSUR· 5 lines
- FEDERALGEN TAP· 5 lines
- GANESHA· 5 lines
- HAMILTON· 5 lines
- JERSEY· 5 lines
- All named substations in California· 3,003 stations
- Datacenter candidate sites in California· 8,490 sites
- Brownfield and retired plant sites in California
- Substations by state
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, “MONARCH substation, California”, https://gridcensus.com/substations/california/monarch-b0043ccf (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 MONARCH substation, California 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.