GeothermalOperatingCAISO

Mammoth G2

Geothermal power plant in Mono County, California. 15 MW of nameplate capacity across 3 generators, operated by Ormat Nevada Inc.

Also known as EIA plant 10481

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Rush CreekUpper GorgeMiddle GorgeMammoth G210 km
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6 plants within 34 km, from EIA coordinates.

Key facts

Capacity
15 MWNameplate
Generators
3 operatingEIA-860M, August 2026
Operating since
December 1990First generator online
Operator
Ormat Nevada IncEIA operator ID 34691
Grid
CAISOBalancing authority CISO
Price nodes
2 CAISO nodesResource nodes with prices
Location
Mono County, CA37.6464, −118.9092
EIA plant ID
10481EIA plant page

Data as of EIA-860M August 2026 (published 2026-09-24). Capacity is nameplate, not live output.

How much power Mammoth G2 produces

Free · EIA-923

Net generation, 2025

83.8 GWh

83,764 MWh, final

Capacity factor, 2025

63.7%

2024: 62.5%

January to July 2026

Not reported

Provisional. 0 of 7 months reported

Range, 2015 to 2025

51.9–83.8

GWh a year. Low 2022, high 2025

Annual net generation, GWhCapacity factor below each year
Annual net generation from EIA-923
YearNet generation, MWhCapacity factorMonths reported
2000Not reportedNot reported0 of 12
200182,088Not reported12 of 12
200281,010Not reported12 of 12
200376,575Not reported12 of 12
2004Not reportedNot reported0 of 12
200575,156Not reported12 of 12
200679,922Not reported12 of 12
200782,206Not reported12 of 12
200894,119Not reported12 of 12
200993,418Not reported12 of 12
201081,62231.1%12 of 12
201188,53833.7%12 of 12
201285,55732.5%12 of 12
201379,96930.4%12 of 12
201469,00126.3%12 of 12
201557,95322.1%12 of 12
201671,94327.3%12 of 12
201761,77523.5%12 of 12
201862,42147.5%12 of 12
201968,59752.2%12 of 12
202074,94556.9%12 of 12
202171,10954.1%12 of 12
202251,93139.5%12 of 12
202362,32147.4%12 of 12
202482,30762.5%12 of 12
202583,76463.7%12 of 12
2026 (provisional, partial year)Not reportedNot reported0 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 · CAISO

Emissions

Free · EPA CAMPD

No EPA emissions units are linked to this plant.

Water use

Free · EIA-923 cooling, USGS

No EIA cooling-water record for this plant in 2024.

Generators

Free · EIA-860M
GeneratorTechnologyNameplate MWOnline since
1Geothermal5.0December 1990
2Geothermal5.0December 1990
3Geothermal5.0December 1990

Ownership and offtake

Pro
Pro

Ownership 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

Pro

Pro adds modeled values for this plant. Everything above stays free.

Modeled

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.

Analyst and MCP

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Power plants near Mammoth G2

More plants operated by Ormat Nevada Inc

Questions about Mammoth G2

How much power does Mammoth G2 produce?

Mammoth G2 reported 83,764 MWh (83.8 GWh) of net generation in 2025, a 63.7% capacity factor on 15 MW of nameplate capacity.

Where is Mammoth G2?

Mammoth G2 is in Mono County, California, at 37.6464, −118.9092. It is in the California Independent System Operator balancing area (CISO).

Who operates Mammoth G2?

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 G2 start operating?

Its first generator began operating in December 1990, according to EIA-860M.

Does InfraMap have power prices for Mammoth G2?

Yes. InfraMap has CAISO day-ahead and real-time prices at 2 price nodes linked to Mammoth G2, 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