CASTRO VALLEY TAP
SubstationCalifornia · PACIFIC GAS & ELECTRIC COMPANY
At a glance
CASTRO VALLEY TAP is an electric transmission substation in California, on PACIFIC GAS & ELECTRIC COMPANY's transmission network. It is classified as high-voltage (230 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
Connected transmission lines
Lines terminating at or passing through this substation, by HIFLD line ID, highest voltage first.
| Line ID | Voltage | Owner | Status | Length |
|---|---|---|---|---|
| #312123 | 230 kV | PACIFIC GAS & ELECTRIC COMPANY | IN SERVICE | 13.9 mi |
| #312564 | 230 kV | PACIFIC GAS & ELECTRIC COMPANY | IN SERVICE | 21.3 mi |
| #313080 | 230 kV | PACIFIC GAS & ELECTRIC COMPANY | IN SERVICE | 1.0 mi |
Nearby datacenter candidate sites
Scored candidate sites within roughly 25 miles of CASTRO VALLEY TAP, 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 |
|---|---|---|---|---|---|---|---|
| Hunters Point | Brownfield | CA | San Mateo County | 115 kV | 427 MW | 7.6 yrs | 61.3 |
| EMBARCADERO | Substation-Adjacent | CA | Contra Costa County | 230 kV | 300 MW | 7.6 yrs | 59.8 |
| NEWARK DISTRIBUTION | Substation-Adjacent | CA | Alameda County | 230 kV | 300 MW | 7.6 yrs | 59.3 |
| MARTIN | Substation-Adjacent | CA | San Mateo County | 230 kV | 300 MW | 7.6 yrs | 59.0 |
| S.L.A.C. | Substation-Adjacent | CA | San Mateo County | 230 kV | 300 MW | 7.6 yrs | 58.8 |
| EASTSHORE | Substation-Adjacent | CA | Alameda County | 230 kV | 300 MW | 7.6 yrs | 58.7 |
| LOS ESTEROS | Substation-Adjacent | CA | Alameda County | 230 kV | 300 MW | 7.6 yrs | 58.6 |
| FREMONT | Substation-Adjacent | CA | Alameda County | 230 kV | 300 MW | 7.6 yrs | 58.4 |
How does CASTRO VALLEY TAP 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. 384 named substations in the state are in CASTRO VALLEY TAP's 230–344 kV band (13% of named stations). 44 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 CASTRO VALLEY TAP?
The 3 connected lines listed above are owned by PACIFIC GAS & ELECTRIC COMPANY. Line voltages range from 230 kV to 230 kV. Their combined recorded length is about 36.3 miles.
How do candidate sites near CASTRO VALLEY TAP score?
The 8 highest-scoring candidate sites within about 25 miles range from 58 to 61 on the 0–100 DC Readiness scale. They fall in San Mateo County, Contra Costa County, Alameda 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 CASTRO VALLEY TAP substation?
CASTRO VALLEY TAP has a maximum voltage of 230 kV. That places it in the 230–344 kV band. The median named US substation in this dataset is 115 kV, so CASTRO VALLEY TAP is above the national midpoint.
How many transmission lines connect to CASTRO VALLEY TAP substation?
3 transmission lines terminate at or pass through CASTRO VALLEY TAP in the HIFLD line data. The connected lines listed here run at 230 kV. Together the listed lines cover about 36.3 miles.
Who owns CASTRO VALLEY TAP substation?
HIFLD does not publish substation owners directly. Most of the transmission lines that end at CASTRO VALLEY TAP belong to PACIFIC GAS & ELECTRIC COMPANY. GridCensus derives this from the line data, so confirm ownership with the utility for anything contractual.
Where is CASTRO VALLEY TAP substation located?
CASTRO VALLEY TAP is in California at 37.6933, -122.0427. The datacenter candidate sites closest to it are in San Mateo County, Contra Costa County, Alameda County.
Are there datacenter candidate sites near CASTRO VALLEY TAP substation?
GridCensus lists at least 8 scored candidate sites within roughly 25 miles of CASTRO VALLEY TAP. The highest-scoring is Hunters Point at 61/100. Across California, the average DC Readiness score is 45.4.
Other 230 kV substations in California
- NEWARK· 30 lines
- COTTONWOOD· 21 lines
- RIO OSO· 20 lines
- BELLOTA· 19 lines
- ELLIS· 18 lines
- PITTSBURG· 18 lines
- EL CENTRO· 17 lines
- MOORPARK· 17 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, “CASTRO VALLEY TAP substation, California”, https://gridcensus.com/substations/california/castro-valley-tap-a78fa6e7 (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 CASTRO VALLEY TAP 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.