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110 MW Geothermal operating in Sonoma, CA — California Independent System Operator
110 MW
Nameplate Capacity
2
Generators
units
Geothermal
Technology
1983
Operating Since
Coordinates
38.7520, -122.7195
County
Sonoma, CA
Nearby Plants
| Field | EIA | GEM | Wikidata |
|---|---|---|---|
| Operator | Northern California Power Agny | Northern California Power Agency | — |
| Owner(s) | Northern California Power Agny | — | — |
| Status | Operating | operating | — |
Geothermal 1 is a 110 MW geothermal power plant located in Sonoma County, California. The plant began operating in 1983 and is owned and operated by Northern California Power Agency. It utilizes geothermal technology and consists of two generators. The plant operates within the California Independent System Operator (CAISO) balancing authority and the Western Electricity Coordinating Council (WECC) NERC region.
In the latest year of reported data, Geothermal 1 generated 338,449 MWh of electricity, achieving a capacity factor of 35.2%. The plant is ranked as the 4th largest geothermal power plant in California, and 6th nationally out of 7 geothermal plants.
Generated from EIA, GEM, and public data sources
ISO/RTO
CAISO
Market
ISO/RTO Member
NERC Region
WECC — Western Electricity Coordinating Council
Balancing Authority
26.5K MWh
Latest Month
338.4K MWh
Annual Generation
35.2%
Capacity Factor
CO₂ Intensity
89 lb/MWh
NOx
0.001 lb/MWh
SO₂
2013
$2,851/kW
Est. Construction Cost
Total estimated cost: $313.6M
Market Position
ISO/RTO Market
CAISO
LMP Node
BERCYN_7_N001
Pricing Hub
TH_NP15_GEN-APND
Location Type
Pricing Node
Node Source
Curated node match
Last updated 2026-03-14
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ask pi about Geothermal 1California Independent System Operator (CISO)
Grid Voltage
230.0 kV
Regulatory Status
RE — Regulated
Entity Type
Political Subdivision
Sector
Electric Utility
0.000 lb/MWh
CH₄
—
N₂O
—
Capacity Factor
34.7%
Annual Net Gen
335 GWh
CO₂eq
89 lb/MWh
Subregion
WECC California