COSO ENERGY DEVELOPERS
OperatingGeothermal power plant
- Capacity
- 90 MW
- Primary fuel
- Geothermal
- County
- Inyo County
- Operator
- COSO OPERATING CO LLC
- Status
- Operating
- Commissioned
- 1988
- EIA plant ID
- 10875
- Generators
- 3
- Technology
- Geothermal
- Net generation (2024)
- 244 GWh
- Capacity factor (2024, EIA nameplate)
- 31%
- Data vintage
- EIA-860 2024 final; EIA-923 2022-2024 final
- Coordinates
- 36.0019, -117.7886
COSO ENERGY DEVELOPERS, a 90 MW Geothermal power plant in Inyo County, California. Operated by COSO OPERATING CO LLC, commissioned 1988.
How COSO ENERGY DEVELOPERS compares
With 90 MW of capacity, COSO ENERGY DEVELOPERS ranks 182nd among the 874 operating power plants Bywatts maps in California and 6th of the 24 operating Geothermal plants in the state. It accounts for about 3.5% of California's operating Geothermal capacity and 0.1% of all operating capacity in the state. Nationally it is the 6th-largest of the 34 operating Geothermal plants in the database. Commissioned in 1988, it is older than 68% of the 859 operating California plants with a recorded commissioning year. Its operator, COSO OPERATING CO LLC, runs 2 operating plants in California totaling 182 MW. It shares Inyo County with 5 other operating plants, including COSO FINANCE PARTNERS and CONTROL GORGE.
EIA-860 lists 3 generators at the site with 90 MW of nameplate capacity, all geothermal technology. Net generation was 244 GWh in 2024 (a 31% capacity factor), down 14% from 2022. Its generators came online between 1988 and 1989.
Grid neighborhood
The nearest named substation is COSO 8-9 (230 kV), about 0.1 miles away; the closest transmission line found within 10 miles is a 115 kV line owned by AZUSA LIGHT & POWER, under 0.1 miles away. One other operating power plant sits within 25 miles: COSO FINANCE PARTNERS (92 MW, Geothermal).
Computed by Bywatts from HIFLD power plant, substation and transmission line records and EIA-860/923 survey data; distances are straight-line. Sources and methodology
Weather peril exposure
COSO ENERGY DEVELOPERS is a 90 MW geothermal power plant in Inyo County, CA, operated by COSO OPERATING CO LLC, commissioned in 1988. Inyo County carries low modeled catastrophe exposure in the FEMA National Risk Index, scoring 1.2 of 5 at the 6th national percentile. Earthquake is the leading peril, rated Relatively Moderate by FEMA at the 98th percentile.
The Bywatts loss layer is calibrated to solar PV hardware, so it is not applied to a geothermal plant. The ratings below are the FEMA National Risk Index county hazard ratings for this location.
Inyo County hazard ratings
| Peril | FEMA rating | National percentile | Peril score | Events per year |
|---|---|---|---|---|
| Earthquake | Relatively Moderate | 98th | 4.9 of 5 | 0.08 |
| Wildfire | Relatively Low | 85th | 4.4 of 5 | <0.01 |
| Heat wave | Relatively High | 80th | 4.2 of 5 | 10.4 |
| Riverine flooding | Relatively Low | 78th | 4.1 of 5 | 5.0 |
| Lightning | Relatively Low | 54th | 3.2 of 5 | 15.9 |
| Winter weather | Relatively Low | 6th | 1.2 of 5 | 4.6 |
| Tornado | Very Low | 2nd | 1.1 of 5 | 0.10 |
| Strong wind | Very Low | 2nd | 1.1 of 5 | 0.06 |
| Hail | Very Low | 1st | 1.0 of 5 | 0.02 |
Perils not assessed in Inyo County
These perils carry no usable National Risk Index figure for this county, so they are excluded from the scoring rather than scored zero. A zero would claim the peril was assessed and found benign.
| Peril | Why it is not scored |
|---|---|
| Hurricane | FEMA rating is "Not Applicable" for this county |
| Coastal flooding | FEMA rating is "Not Applicable" for this county |
| Ice storm | FEMA rating is "Not Applicable" for this county |
Model hail, wind and flood exposure for Inyo County in the weather risk calculator
Ratings are the FEMA National Risk Index county hazard ratings; the peril score is a Bywatts transform of the FEMA national percentile. Full data sources and the solar vulnerability methodology are in the weather risk calculator.
Modeled estimate for screening and negotiation. Built from FEMA National Risk Index county hazard data and a solar vulnerability layer documented above. Not a quote, a binder, or actuarial advice, and not a substitute for a carrier's own model. Hazard data: FEMA National Risk Index December 2025, synced 2026-07-24. Resolution is county level, not site level.