W R Gianelli
Bureau of ReclamationMerced County
Overview
- Registry anchor
- Plant 448
- plant-448
Infrastructure record
- Alternate name
- Gianelli Powerhouse
- Mapped facility footprint
- Mapped infrastructure footprint
Mapped infrastructure geometry associated with this asset.
- In service
- 1967-03
Structured profile
- Technology
- Hydroelectric Pumped Storage
- Operator
- California Department of Water Resources
Generation and physical site
EIA plant 448 · Inventory for Aug 2026.
Reported operating nameplate by technology
- Hydroelectric
- 424 MW
Generator records (8)
| Generator | Technology | Status | Power (MW) | Energy (MWh) |
|---|---|---|---|---|
| 1 | Hydroelectric Pumped Storage | Operating | 53 | Unknown |
| 2 | Hydroelectric Pumped Storage | Operating | 53 | Unknown |
| 3 | Hydroelectric Pumped Storage | Operating | 53 | Unknown |
| 4 | Hydroelectric Pumped Storage | Operating | 53 | Unknown |
Related assets
Similar plants ranked by technology, capacity, and distance.
Units and generators
Operating generator records and technology attributes reported through EIA-860.
| Generator | Capacity | Technology | Operation | Status |
|---|---|---|---|---|
| 1 | 53 MW 51 MW summer | Hydroelectric Pumped Storage Water · PS | Jun 1968 | Operating |
| 2 | 53 MW 50 MW summer | Hydroelectric Pumped Storage Water · PS | Mar 1968 | Operating |
| 3 | 53 MW 50 MW summer | Hydroelectric Pumped Storage Water · PS | Nov 1967 | Operating |
| 4 | 53 MW 50 MW summer | Hydroelectric Pumped Storage Water · PS | Sep 1967 | Operating |
| 5 | 53 MW 50 MW summer | |||
Performance
Monthly EIA generation history and recent market-resource behavior where linked telemetry is available.
Peer context
- Technology capacity
- 424 MW
- Hydroelectric Pumped Storage
- National rank
- #15
- of 39 operating peers
- CA rank
- #3
- of 7 operating peers
Monthly generation
Download CSVLatest 12 months
206.7 GWh
Reported gross generation
Latest report
Jul 2026
EIA-923 monthly filing
2025 net exchange
-152.4 GWh
Generation less station charging
Grid and market context
Deterministic links to ERCOT market resources, price records, outage disclosures, queue records, and nearby infrastructure. Candidate joins remain labeled until corroborated.
Nearby substations
HIFLD infrastructure inventoryNOT AVAILABLE · 230 kV
0.3 km
Commercial, land, and environmental record
Source-backed project transactions, agreements, land records, permits, and environmental disclosures. Portfolio and adjacent-project facts remain explicitly scoped.
Transactions and agreements
Federal-State Project Agreement
May 16, 1960
The Bureau of Reclamation and California agreed to coordinated operation and construction of joint-use facilities with a 55/45 state-federal cost split.
Bureau of Reclamation · State of California
Authorizing Legislation
Jun 3, 1960
Public Law 86-488 (San Luis Authorizing Act), signed by President Dwight Eisenhower, authorized the San Luis Unit and the Secretary of Interior to negotiate and enter into the joint-use agreement with California.
U.S. Congress · Bureau of Reclamation
Operating Agreement
Dec 1961
The United States and California Department of Water Resources executed the Joint Use Agreement, providing for shared construction costs, state conveyance of required land title to the United States, and state operation of the joint-use facilities after completion.
Bureau of Reclamation · California Department of Water Resources
Construction Start
1963
Construction of the Gianelli Pumping-Generating Plant began as part of the San Luis Unit.
Morrison-Knudsen · Utah Construction Co. · Brown and Root
Construction Contract
1964
Morrison-Knudsen, Utah Construction Co., and Brown and Root won the pumping-generating plant construction contract with a combined bid of $38.3 million.
$38.3MMorrison-Knudsen · Utah Construction Co. · Brown and Root · Bureau of Reclamation
Construction Completion
1967
The plant was completed with eight pump-turbines and approximately 424 MW of generating capacity. Reclamation's project history states it was then California's largest hydroelectric plant.
Bureau of Reclamation
Commercial Operation
1968
The Bureau of Reclamation facility record lists initial operation in fiscal year 1968.
Bureau of Reclamation · California Department of Water Resources
System Integration
Jan 1968
State Water Project water first reached O'Neill Forebay, marking integration of the Gianelli plant into the joint-use system serving both the CVP and SWP.
California Department of Water Resources · Bureau of Reclamation
Dedication Ceremony
Apr 1968
The San Luis Dam was dedicated by Secretary of the Interior Stewart L. Udall, who highlighted the unprecedented federal-state partnership.
Bureau of Reclamation · State of California
System Ready
May 31, 1969
San Luis Reservoir was completely filled, signaling completion of the joint-use system and full operational readiness of the Gianelli plant.
Bureau of Reclamation · California Department of Water Resources
Facility Renaming
May 12, 1989
The San Luis Pumping-Generating Plant was officially designated the William R. Gianelli Pumping-Generating Plant, honoring William R. Gianelli, who served as director of the California Department of Water Resources during critical construction years (1967–1973).
State of California · California Department of Water Resources
Related parties and identifiers
Parties, market resources, and identifiers tied to this asset, with owner, operator, developer, EPC, compliance provider, and interconnecting entity roles kept separate.
Parties and identifiers
Reporting portfolio
Operating portfolio
8 plants
1 states
Reported capacity
1,589.3 MW
Conventional Hydroelectric · Hydroelectric Pumped Storage
| Largest reported plants | Capacity | State | |
|---|---|---|---|
| Edward C Hyatt | 644.1 MW | CA | |
| W R GianelliCurrent | 424 MW | CA | |
Timeline and sources
Project milestones and public references behind the asset profile.
Project timeline
- San Luis Joint-Use Agreement execution dateusbr.gov
The Bureau of Reclamation and California agreed to coordinated operation and construction of joint-use facilities with a 55/45 state-federal cost split.
- San Luis Unit authorization