W R Gianelli — Plant Summary
- EIA Plant ID
- 448
- Capacity
- 424 MW
- Primary Fuel
- Hydro
- Technology
- Hydroelectric Pumped Storage
- Status
- Operating
- Location
- Merced, CA
- Operating Since
- 1967
- Generators
- 8
- Operator
- California Dept. of Water Resources
- Parent Company
- —
- Annual Generation
- -152,350 MWh
- Capacity Factor
- -4.2%
- Balancing Authority
- California Independent System Operator
- ISO/RTO
- CAISO
- NERC Region
- WECC
W R Gianelli
OperatingHydro
Ranked #7 of 247 Hydro plants in CA#56 of 1454 nationally
424 MW Hydro operating in Merced, CA — California Independent System Operator
EIAGEMWD
424 MW
Nameplate Capacity
8
Generators
units
Hydroelectric Pumped Storage
Technology
1967
Operating Since
Location
Coordinates
37.0692, -121.0772
County
Merced, CA
Nearby Plants
- ONeillHydro25.2 MW · 4.2 km
- Gonzaga Ridge Wind FarmWind132.8 MW · 4.6 km
- Quinto Solar PV ProjectSolar108 MW · 6.2 km
Ownership & Operator
Owner data does not fully agree across sources.
EIA typically reports the operating utility, while GEM resolves to the financial owner or parent corporation. Both can be correct.
| Field | EIA | GEM | Wikidata |
|---|---|---|---|
| Operator | California Dept. of Water Resources | California Department of Water Resources | — |
| Owner(s) | California Dept. of Water Resources, U S Bureau of Reclamation | US Bureau of Reclamation [100%] | — |
| Status | Operating | operating | — |
Ownership Chain
GEM identifies the owner as US Bureau of Reclamation [100%]
This entity is not yet in the GEM ownership database — chain unavailable.
About
The Gianelli Power Plant, also known as the San Luis Power Plant, is a pumped-storage hydroelectric plant that is at the base of the San Luis Dam in California. During the wet season, turbines pump water from the O'Neill Forebay into the reservoir, then when needed during the irrigation season, water flows from the reservoir back through the turbines and generates electricity. This is an unusual use of pumped storage where the intention is to capture irrigation water not to store power. Storage capacity delivers up to 298 hours of generation at full power.
Read more on WikipediaThe W R Gianelli power plant, located in Merced County, California, is a 424 MW hydroelectric pumped storage facility. It began operating in 1967 and is owned and operated by the California Department of Water Resources. The plant consists of 8 generators utilizing water as its primary fuel source.
W R Gianelli operates within the California Independent System Operator (CAISO) balancing authority and the Western Electricity Coordinating Council (WECC) NERC region. It is the 7th largest power plant out of 42 in California, and ranks 56th nationally out of 194 plants.
Generated from EIA, GEM, and public data sources
Engineering & Generators
Grid Context
NERC Region
WECC
Balancing Authority
California Independent System Operator
Grid Voltage
230 kV
Regulatory Status
RE
Entity Type
State
Sector
Electric Utility
Generation
−41.9K MWh
Net Charging
-152.3K MWh
Annual Net Energy
-4.2%
Capacity Factor
Jan 2023 – Dec 2025
Positive values indicate net discharge (generation exceeds station load). Negative values indicate net charging. Pure battery storage plants are typically net negative due to round-trip efficiency losses.
Financial Data
No financial data available for this plant.
Pricing & Market Data
HIGH confidenceMarket Position
ISO/RTO Market
CAISO
LMP Node
SANLUIS8_7_B3
Pricing Hub
TH_NP15_GEN-APND
Secondary Zone
TH_ZP26_GEN-APND
Location Type
Pricing Node
Node Source
Curated node match
News & Articles (2)Beta
Industry·corporate
In Memoriam of DWR’s Leader William Gianelli
William Gianelli, the Department of Water Resources' (DWR's) third Director, passed away at the age of 101 in Monterey, California on March 30.
William Gianelli (other)Department of Water Resources (other)
California Department of Water Resources (.gov)·5 years ago
Industry·corporate
William Gianelli Obituary - Pacific Grove, CA
William R. Gianelli, a retired Consulting Civil Engineer, passed away in Monterey on March 30, 2020, at the age of 101 of natural causes.
William R. Gianelli (other)
Dignity Memorial·5 years ago
Last updated 2026-03-14
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