How big is Edward C Hyatt?

Edward C Hyatt has a reported capacity of 644.1 MW. Source: EIA Form 860.

What kind of plant is Edward C Hyatt?

Edward C Hyatt is a Conventional Hydroelectric, Hydroelectric Pumped Storage facility in Butte County, CA, participating in the CAISO market.

Where is Edward C Hyatt located?

Edward C Hyatt is in Butte County, CA, inside the CAISO balancing area.

Who operates Edward C Hyatt?

Edward C Hyatt is operated by California Dept. of Water Resources according to the EIA generator inventory. Reporting membership does not by itself establish ultimate ownership.

How much electricity does Edward C Hyatt generate?

Edward C Hyatt reported 1,916.4 GWh over the twelve months to 2026-04. Figures are net generation as filed to EIA-923.

Where does Edward C Hyatt connect to the grid?

Edward C Hyatt interconnects at 230 kV bus of the Table Mountain substation, on the Pacific Gas and Electric Company system.

How does Edward C Hyatt compare to other plants?

By capacity, Edward C Hyatt ranks #39 of 1,349 operating plants of the same technology nationally. It ranks #2 of 210 in CA.

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Hydroelectric Pumped Storage, Conventional HydroelectricCAISO · Butte County

Edward C Hyatt

California Department of Water Resources · Butte County · CAISO

Edward C Hyatt is a battery energy storage facility with 644.1 MW of EIA-reported nameplate capacity in Butte County, California, registered as EIA Plant ID 437. California Department of Water Resources is the public owner or developer; California Dept. of Water Resources is the registered plant entity or operator. The Oroville pumped-storage scheme was the first such facility constructed in California and was described by the California Department of Water Resources as one of the largest in the United States. Edward Hyatt Powerplant was also identified as the largest underground powerplant in the United States and received the American Society of Civil Engineers’ 1969 Outstanding Engineering Achievement recognition.

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plant:plant-437

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Investigate technology, capacity, output, price behavior, ownership, and related facilities using this profile plus current grid data.

Overview

Key fields

Reported capacity: 644.1 MW
EIA-reported nameplate capacity; other nameplate and seasonal ratings may differ.
Technology: Conventional Hydroelectric, Hydroelectric Pumped Storage
Primary generation technology.
Registry anchor: Plant 437
California Dept. of Water Resources · Butte County · CAISO
Operating status: Operating
Edward C Hyatt is operating.
Grid connection: 230 kV bus of the Table Mountain substation
230 kV · Pacific Gas and Electric Company

Profile

Grid role: Pumped-storage hydroelectric facility that returns water to storage during off-peak periods and generates during peak power demand.
Grid connection: 230 kV bus of the Table Mountain substation · 230 kV · Pacific Gas and Electric Company.
Context: The Oroville pumped-storage scheme was the first such facility constructed in California and was described by the California Department of Water Resources as one of the largest in the United States. Edward Hyatt Powerplant was also identified as the largest underground powerplant in the United States and received the American Society of Civil Engineers’ 1969 Outstanding Engineering Achievement recognition.
Financing: The documented construction financing was State Water Project power-revenue-bond financing, not sale consideration.

Structured profile

Reported capacity: 644.1 MW
Conventional Hydroelectric, Hydroelectric Pumped Storage
Operating status: operating
Edward C Hyatt is operating.
Interconnection: 230 kV bus of the Table Mountain substation
230 kV · Pacific Gas and Electric Company
Location: Butte County
CAISO
Operator

Units and generators

Operating generator records and technology attributes reported through EIA-860.

Generator	Capacity	Technology	Operation	Status
1	117 MW 135.3 MW summer	Conventional Hydroelectric Water · HY	Mar 1968	Operating
2	97.7 MW 112.4 MW summer	Hydroelectric Pumped Storage Water · PS	Nov 1968	Operating
3	117 MW 135.3 MW summer	Conventional Hydroelectric Water · HY	Jun 1968	Operating
4	97.7 MW 112.4 MW summer

Performance

Monthly EIA generation history and recent market-resource behavior where linked telemetry is available.

Peer context

Technology capacity: 351 MW
National rank: #39
CA rank: #2

Monthly generation

Download CSV

Latest 12 months

1.92 TWh

Reported net generation

Latest report

Apr 2026

EIA-923 monthly filing

2025 capacity factor

34.6%

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 inventory

HYATT

IN SERVICE · 230 kV

1.2 km

TAP305374

Commercial, land, and environmental record

Source-backed project transactions, agreements, land records, permits, and environmental disclosures. Portfolio and adjacent-project facts remain explicitly scoped.

Land and environmental record

Environmental Mitigation And Compliance

Dec 15, 2010

Water-quality mitigation and monitoring conditions include pumpback curtailment, Hyatt-intake shutter removal, river-valve releases up to 1,500 cfs, temperature objectives, and four continuous temperature-monitoring devices.

The Section 401 certification addresses altered Feather River hydrology, temperature impacts, instream flows, and beneficial uses. Conditions require operational and monitoring measures relevant to Hyatt and the wider P-2100 project.

DEPARTMENT OF WATER RESOURCES OROVILLE FACILITIES FEDERAL ENERGY REGULATORY COMMISSION PROJECT NO. 2100

Environmental Operational Milestone

Jan 4, 2022

Hyatt was taken offline on August 5, 2021 due to low Lake Oroville levels and resumed hydropower generation on January 4, 2022.

DWR reported the drought-related operational interruption and subsequent resumption after storms increased reservoir levels. Plant was offline for major maintenance while water levels were low. This is an environmental and operational milestone, not a retirement event.

Hyatt Powerplant at Oroville Dam Resumes Operation

Hydroelectric Water Operation

Dec 15, 2010

645 MW maximum plant capacity and 16,950 cubic feet per second maximum flow

The 2010 Water Quality Certification describes the Hyatt Pumping-Generating Plant as having 645 MW capacity and a maximum flow of 16,950 cfs.

DEPARTMENT OF WATER RESOURCES OROVILLE FACILITIES FEDERAL ENERGY REGULATORY COMMISSION PROJECT NO. 2100

Parcel Record

Jul 11, 2020

236.42 acres across APNs 033-010-055 and 069-010-019

PG&E property record identifies two Butte County assessor parcels totaling approximately 236.42 acres. This concerns PG&E property and a proposed transmission-tower-line easement for Hyatt's interconnection; it is not the Hyatt powerhouse building footprint or DWR-owned acreage.

Advice Letter 5847E

Reservoir Land And Water

Dec 15, 2010

Lake Oroville reservoir: 15,180 acres of surface area and 3.5 million acre-feet of storage

Lake Oroville surface area and storage capacity identified in the State Water Board's P-2100 Water Quality Certification.

DEPARTMENT OF WATER RESOURCES OROVILLE FACILITIES FEDERAL ENERGY REGULATORY COMMISSION PROJECT NO. 2100

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.

Relationship graph

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AssetOwner / operatorRelated asset

Parties and identifiers

Timeline and sources

Project milestones and public references behind the asset profile.

Project timeline

1964
1964
Construction StartedOroville
Excavation and construction began for the underground Hyatt Powerplant at Oroville.
1967
1967
Construction Completed

Reporting portfolio

EIA reporting entity

California Dept. of Water Resources

Entity 3255

Operating portfolio

8 plants

1 states

Reported capacity

1,589.3 MW

Conventional Hydroelectric · Hydroelectric Pumped Storage

Largest reported plants in this portfolio
Largest reported plants	Capacity	State
Edward C HyattCurrent	644.1 MW	CA
W R Gianelli	424 MW	CA
Devil Canyon	276.2 MW	CA
Thermalito	115.1 MW	CA
W E Warne	74.2 MW	CA
Mojave Siphon	32.7 MW	CA
Alamo	19.6 MW	CA
Thermalito Diverson Dam	3.4 MW	CA

Portfolio membership follows the latest EIA-860 reporting entity. It does not imply ultimate ownership.

View full reporting portfolio

Edward C Hyatt

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Edward C Hyatt

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Overview

Key fields

Profile

Structured profile

Units and generators

Performance

Peer context

Monthly generation

Grid and market context

Nearby substations

Commercial, land, and environmental record

Land and environmental record

Related parties and identifiers

Relationship graph

Parties and identifiers

Timeline and sources

Project timeline

Reporting portfolio

Sources

Common questions about Edward C Hyatt

How big is Edward C Hyatt?

What kind of plant is Edward C Hyatt?

Where is Edward C Hyatt located?

Who operates Edward C Hyatt?

How much electricity does Edward C Hyatt generate?

Where does Edward C Hyatt connect to the grid?

How does Edward C Hyatt compare to other plants?

Co-located assets

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