Mammoth G1
Geothermal power plant in Mono County, California. 10 MW of nameplate capacity across 2 generators, operated by Ormat Nevada Inc.
Also known as EIA plant 10480
Analyst: free account, 1 question a day.
Key facts
- Capacity
- 10 MWNameplate
- Generators
- 2 operatingEIA-860M, August 2026
- Operating since
- December 1984First generator online
- Operator
- Ormat Nevada IncEIA operator ID 34691
- Grid
- CAISOBalancing authority CISO
- Price nodes
- 2 CAISO nodesResource nodes with prices
- Location
- Mono County, CA37.6451, −118.9143
- EIA plant ID
- 10480EIA plant page
Data as of EIA-860M August 2026 (published 2026-09-24). Capacity is nameplate, not live output.
How much power Mammoth G1 produces
Free · EIA-923Net generation, 2025
43.6 GWh
43,579 MWh, final
Capacity factor, 2025
49.7%
2024: 67.9%
January to July 2026
Not reported
Provisional. 0 of 7 months reported
Range, 2015 to 2025
43.6–59.6
GWh a year. Low 2025, high 2024
| Year | Net generation, MWh | Capacity factor | Months reported |
|---|---|---|---|
| 2000 | Not reported | Not reported | 0 of 12 |
| 2001 | 51,031 | Not reported | 12 of 12 |
| 2002 | 44,679 | Not reported | 12 of 12 |
| 2003 | 43,212 | Not reported | 12 of 12 |
| 2004 | Not reported | Not reported | 0 of 12 |
| 2005 | 38,543 | Not reported | 12 of 12 |
| 2006 | 40,329 | Not reported | 12 of 12 |
| 2007 | 39,012 | Not reported | 12 of 12 |
| 2008 | 42,880 | Not reported | 12 of 12 |
| 2009 | 44,100 | Not reported | 12 of 12 |
| 2010 | 49,142 | 56.1% | 12 of 12 |
| 2011 | 34,071 | 38.9% | 12 of 12 |
| 2012 | 17,886 | 20.4% | 12 of 12 |
| 2013 | 2,016 | 2.3% | 12 of 12 |
| 2014 | 56,293 | 64.3% | 12 of 12 |
| 2015 | 51,448 | 58.7% | 12 of 12 |
| 2016 | 58,949 | 67.1% | 12 of 12 |
| 2017 | 58,669 | 67.0% | 12 of 12 |
| 2018 | 56,845 | 64.9% | 12 of 12 |
| 2019 | 57,351 | 65.5% | 12 of 12 |
| 2020 | 58,465 | 66.6% | 12 of 12 |
| 2021 | 59,191 | 67.6% | 12 of 12 |
| 2022 | 45,383 | 51.8% | 12 of 12 |
| 2023 | 57,681 | 65.8% | 12 of 12 |
| 2024 | 59,620 | 67.9% | 12 of 12 |
| 2025 | 43,579 | 49.7% | 12 of 12 |
| 2026 (provisional, partial year) | Not reported | Not reported | 0 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.
Generators
Free · EIA-860M| Generator | Technology | Nameplate MW | Online since |
|---|---|---|---|
| GEN1 | Geothermal | 5.0 | December 1984 |
| GEN2 | Geothermal | 5.0 | December 1984 |
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 Ormat Nevada Inc as the operator, which is not always the owner.
Modeled data
ProPro adds modeled values for this plant. Everything above stays free.
Generation potential vs reported
Monthly potential at seasonal net capability, next to EIA-923 output. Shows how much of the plant's capability was used.
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Power plants near Mammoth G1
More plants operated by Ormat Nevada Inc
Questions about Mammoth G1
How much power does Mammoth G1 produce?
Mammoth G1 reported 43,579 MWh (43.6 GWh) of net generation in 2025, a 49.7% capacity factor on 10 MW of nameplate capacity.
Where is Mammoth G1?
Mammoth G1 is in Mono County, California, at 37.6451, −118.9143. It is in the California Independent System Operator balancing area (CISO).
Who operates Mammoth G1?
EIA-860M for August 2026 lists Ormat Nevada Inc as the operator (EIA operator ID 34691). The operator is not always the owner.
When did Mammoth G1 start operating?
Its first generator began operating in December 1984, according to EIA-860M.
Does InfraMap have power prices for Mammoth G1?
Yes. InfraMap has CAISO day-ahead and real-time prices at 2 price nodes linked to Mammoth G1, 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