Dion R Holm is a hydroelectric facility with 180.2 MW of EIA-reported operating capacity in Tuolumne County, California, registered as EIA Plant ID 380. City & County of San Francisco is the registered plant entity or operator. Holm is the largest of the three hydroelectric powerhouses in San Francisco’s Hetch Hetchy Power System. Its two vertical-shaft, turbine-driven generators are each rated at 82,500 kVA.
EIA-reported operating capacity; nameplate, seasonal, AC/DC, and unit ratings may differ.
Primary generation technology.
City & County of San Francisco · Tuolumne County · CAISO
Dion R Holm is operating.
Conventional Hydroelectric
Dion R Holm is operating.
CAISO
CAISO · Tuolumne County
Similar plants ranked by technology, capacity, and distance.
Operating generator records and technology attributes reported through EIA-860.
| Generator | Capacity | Technology | Operation | Status |
|---|---|---|---|---|
| 1 | 90.1 MW 90.1 MW summer | Conventional Hydroelectric Water · HY | Aug 1960 | Operating |
| 2 | 90.1 MW 90.1 MW summer | Conventional Hydroelectric Water · HY | Aug 1960 | Operating |
Monthly EIA generation history and recent market-resource behavior where linked telemetry is available.
Deterministic links to ERCOT market resources, price records, outage disclosures, queue records, and nearby infrastructure. Candidate joins remain labeled until corroborated.
Parties, market resources, and identifiers tied to this asset, with owner, operator, developer, EPC, compliance provider, and interconnecting entity roles kept separate.
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Project milestones and public references behind the asset profile.
EIA-860 lists generator 1, generator 2 with this operating date.
Monthly generation is reported through EIA-923. Capacity factor uses the current EIA nameplate capacity and is shown only for complete calendar years.
| Largest reported plants | Capacity | State | |
|---|---|---|---|
| Dion R HolmCurrent | 180.2 MW | CA | |
| R C Kirkwood | 132.8 MW | CA | |
| Moccasin | 103.6 MW | CA | |
| Moccasin Low Head Hydro Project | 2.9 MW | CA | |
| SF Southeast Cogen Plant | 2.1 MW | CA |
Portfolio membership follows the latest EIA-860 reporting entity. It does not imply ultimate ownership.
View full reporting portfolioThe Cherry Powerhouse began commercial operation; the facility was later known as Dion R. Holm Powerhouse.
The powerhouse was named after Dion R. Holm, a former San Francisco City Attorney and Hetch Hetchy counsel.
Answered from the published record above. Questions whose inputs this profile does not carry are omitted rather than estimated.
Dion R Holm has a reported capacity of 180.2 MW. Source: EIA Form 860.
Dion R Holm is a Conventional Hydroelectric facility in Tuolumne County, CA, participating in the CAISO market.
Dion R Holm is in Tuolumne County, CA, inside the CAISO balancing area.
Dion R Holm is operated by City & County of San Francisco according to the EIA generator inventory. Reporting membership does not by itself establish ultimate ownership.
Dion R Holm reported 550.4 GWh over the twelve months to 2026-06. Figures are net generation as filed to EIA-923.
Dion R Holm on the City & County of San Francisco system.
By capacity, Dion R Holm ranks #77 of 1,349 operating plants of the same technology nationally. It ranks #10 of 210 in CA.
Plants within 25 km, nearest first, regardless of technology. Proximity is straight-line distance between mapped plant coordinates; it does not by itself establish a shared point of interconnection.
