Mammoth G1

♨ GeothermalIPP Non-CHP10 MW capacity

806th largest plant in California · 5651st nationally

Mammoth G1 is a geothermal power plant in California with a nameplate capacity of 10.0 MW. It generates roughly 57.7k MWh per year — enough to power about 5,493 average U.S. homes.

Its capacity factor of 66% puts it in the middle range — running steadily but not full-time.

PeakingMid-meritBaseload0%40%80%100%66%
Mid-merit — steady but not full-time
Capacity10 MWnameplate
Annual Generation57.7k MWhEPA eGRID
Capacity Factor66%of theoretical max
Annual CO₂metric tons

Location

Plant NameMammoth G1
OperatorOrmat Nevada Inc
CityMammoth Lakes
CountyMono County
StateCalifornia
ZIP93546
Coordinates37.64510, -118.91430

This plant highlighted in navy-ringed pin; other generators within 25 miles shown as fuel-colored dots.

HydroelectricGeothermal

Generators (2)

IDTechnologyFuelCapacityStatusOnline
GEN1GeothermalGeothermal5.0 MWOperating1984
GEN2GeothermalGeothermal5.0 MWOperating1984

Ownership

OwnerLocationShare
Mammoth Pacific LpMammoth Lakes, CA10000.0%

Ownership reported to EIA Form 860. Percentages reflect reported generator-level ownership share, averaged when a plant has multiple generators.

Grid context

NERC RegionWECC
Balancing AuthorityCalifornia Independent System Operator

About Geothermal plants

Geothermal plants tap heat from underground reservoirs to spin steam turbines. They provide carbon-free baseload power with very high capacity factors, but they only work where hot rock is accessible — primarily in the western U.S.

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