ONeill
Pumped storage power plant in Merced County, California. 25.2 MW of nameplate capacity across 6 generators, operated by U S Bureau of Reclamation.
Also known as EIA plant 446
Analyst: free account, 1 question a day.
Key facts
- Capacity
- 25.2 MWNameplate
- Generators
- 6 operatingEIA-860M, August 2026
- Operating since
- November 1967First generator online
- Operator
- U S Bureau of ReclamationEIA operator ID 2518
- Grid
- CAISOBalancing authority CISO
- Price nodes
- 1 CAISO nodeResource nodes with prices
- Location
- Merced County, CA37.0987, −121.0477
- EIA plant ID
- 446EIA plant page
Data as of EIA-860M August 2026 (published 2026-09-24). Capacity is nameplate, not live output.
How much power ONeill produces
Free · EIA-923Net generation, 2025
−65.9 GWh
−65,854 MWh, final
Capacity factor, 2025
Not reported
2024: Not reported
January to July 2026
−31.7 GWh
Provisional
Range, 2015 to 2025
−105.8–−12.2
GWh a year. Low 2017, high 2015
| Year | Net generation, MWh | Capacity factor | Months reported |
|---|---|---|---|
| 2000 | −9,982 | Not reported | 12 of 12 |
| 2001 | Not reported | Not reported | 0 of 12 |
| 2002 | 6,672 | Not reported | 12 of 12 |
| 2003 | 2,802 | Not reported | 12 of 12 |
| 2004 | 5,964 | Not reported | 12 of 12 |
| 2005 | −31,958 | Not reported | 12 of 12 |
| 2006 | 61 | Not reported | 12 of 12 |
| 2007 | 5,404 | Not reported | 12 of 12 |
| 2008 | −1,502 | Not reported | 12 of 12 |
| 2009 | 5,936 | Not reported | 12 of 12 |
| 2010 | 1,624 | Not reported | 12 of 12 |
| 2011 | −8,677 | Not reported | 12 of 12 |
| 2012 | 3,752 | Not reported | 12 of 12 |
| 2013 | −29,413 | Not reported | 12 of 12 |
| 2014 | −5,735 | Not reported | 12 of 12 |
| 2015 | −12,192 | Not reported | 12 of 12 |
| 2016 | −50,859 | Not reported | 12 of 12 |
| 2017 | −105,768 | Not reported | 12 of 12 |
| 2018 | −61,489 | Not reported | 12 of 12 |
| 2019 | −62,469 | Not reported | 12 of 12 |
| 2020 | −45,652 | Not reported | 12 of 12 |
| 2021 | −17,821 | Not reported | 12 of 12 |
| 2022 | −32,972 | Not reported | 12 of 12 |
| 2023 | −86,926 | Not reported | 12 of 12 |
| 2024 | −66,881 | Not reported | 12 of 12 |
| 2025 | −65,854 | Not reported | 12 of 12 |
| 2026 (provisional, partial year) | −31,730 | Not reported | 7 of 7 |
* 2026 covers January to July and is provisional. Capacity factor is net generation divided by nameplate capacity times the hours of each reported month.
Power prices and basis
Free account · CAISOEmissions
Free · EPA CAMPDNo EPA emissions units are linked to this plant.
Water use
Free · EIA-923 cooling, USGSNo EIA cooling-water record for this plant in 2024. Plants without steam cooling, such as wind, solar and batteries, do not report cooling water.
Generators
Free · EIA-860M| Generator | Technology | Nameplate MW | Online since |
|---|---|---|---|
| 1 | Hydroelectric Pumped Storage | 4.2 | January 1968 |
| 2 | Hydroelectric Pumped Storage | 4.2 | February 1968 |
| 3 | Hydroelectric Pumped Storage | 4.2 | November 1967 |
| 4 | Hydroelectric Pumped Storage | 4.2 | November 1967 |
| 5 | Hydroelectric Pumped Storage | 4.2 | February 1968 |
| 6 | Hydroelectric Pumped Storage | 4.2 | December 1967 |
Ownership and offtake
ProOwnership and offtake are part of Pro
Owners and their shares, parent companies, and power purchase agreements with their buyers. EIA-860M lists U S Bureau of Reclamation as the operator, which is not always the owner.
Modeled data
ProPro adds modeled values for this plant. Everything above stays free.
300 analyst questions a month, plus MCP
Query ONeill and 14,224 other projects from Claude or your own tools. Free accounts get 1 question a day.
Power plants near ONeill
More plants operated by U S Bureau of Reclamation
Questions about ONeill
How much power does ONeill produce?
ONeill reported −65,854 MWh (−65.9 GWh) of net generation in 2025. From January to July 2026 it reported −31.7 GWh, which is provisional.
Where is ONeill?
ONeill is in Merced County, California, at 37.0987, −121.0477. It is in the California Independent System Operator balancing area (CISO).
Who operates ONeill?
EIA-860M for August 2026 lists U S Bureau of Reclamation as the operator (EIA operator ID 2518). The operator is not always the owner.
When did ONeill start operating?
Its first generator began operating in November 1967, according to EIA-860M.
Does InfraMap have power prices for ONeill?
Yes. InfraMap has CAISO day-ahead and real-time prices at 1 price node linked to ONeill, with the hub price and node-to-hub basis. Prices are free with an InfraMap account; pricing node names are part of InfraMap Pro.
Sources
- EIA-860 2025 (final) and EIA-860M August 2026: plant, generators, capacity, operator and location
- EIA-923 monthly net generation, 2000 to July 2026 (2026 provisional)
- CAISO day-ahead and real-time prices; node and hub assignments as of 2026-10-05
Page updated 2026-10-04 from the InfraMap data build. Methodology · Data sources · EIA plant page