THERMALITO
OperatingHydro power plant
- Capacity
- 115 MW
- Primary fuel
- Hydro
- County
- Butte County
- Operator
- CALIFORNIA DEPT. OF WATER RESOURCES
- Status
- Operating
- Commissioned
- 1968
- EIA plant ID
- 438
- Generators
- 4
- Technology
- Hydroelectric Pumped Storage
- Net generation (2024)
- 338 GWh
- Capacity factor (2024, EIA nameplate)
- 33%
- Data vintage
- EIA-860 2024 final; EIA-923 2022-2024 final
- Coordinates
- 39.5149, -121.6301
THERMALITO, a 115 MW Hydro power plant in Butte County, California. Operated by CALIFORNIA DEPT. OF WATER RESOURCES, commissioned 1968.
How THERMALITO compares
With 115 MW of capacity, THERMALITO ranks 147th among the 874 operating power plants Bywatts maps in California and 34th of the 195 operating Hydro plants in the state. It accounts for about 0.8% of California's operating Hydro capacity and 0.2% of all operating capacity in the state. Nationally it is the 156th-largest of the 1,243 operating Hydro plants in the database. Commissioned in 1968, it is older than 86% of the 859 operating California plants with a recorded commissioning year. Its operator, CALIFORNIA DEPT. OF WATER RESOURCES, runs 7 operating plants in California totaling 1,430 MW. It shares Butte County with 14 other operating plants, including EDWARD C HYATT and POE.
EIA-860 lists 4 generators at the site with 115 MW of nameplate capacity, mainly hydroelectric pumped storage technology. Net generation was 338 GWh in 2024 (a 33% capacity factor), about 2.2 times its 2022 output.
Grid neighborhood
The nearest named substation is THERMALITO (69 kV), about 0.1 miles away; the closest transmission line found within 10 miles is a 230 kV line owned by PACIFIC GAS & ELECTRIC COMPANY, about 2.2 miles away. Another 12 operating power plants totaling 1,133 MW sit within 25 miles; the largest is EDWARD C HYATT (762 MW, Hydro).
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
THERMALITO is a 115 MW hydro power plant in Butte County, CA, operated by CALIFORNIA DEPT. OF WATER RESOURCES, commissioned in 1968. Butte County carries low modeled catastrophe exposure in the FEMA National Risk Index, scoring 1.6 of 5 at the 14th national percentile. Wildfire is the leading peril, rated Relatively High by FEMA at the 97th percentile.
The Bywatts loss layer is calibrated to solar PV hardware, so it is not applied to a hydro plant. The ratings below are the FEMA National Risk Index county hazard ratings for this location.
Butte County hazard ratings
| Peril | FEMA rating | National percentile | Peril score | Events per year |
|---|---|---|---|---|
| Wildfire | Relatively High | 97th | 4.9 of 5 | <0.01 |
| Earthquake | Relatively Moderate | 94th | 4.8 of 5 | 0.04 |
| Heat wave | Relatively Moderate | 69th | 3.8 of 5 | 6.9 |
| Riverine flooding | Relatively Moderate | 69th | 3.8 of 5 | 1.4 |
| Hail | Relatively Low | 14th | 1.6 of 5 | 0.11 |
| Tornado | Relatively Low | 12th | 1.5 of 5 | 0.15 |
| Lightning | Relatively Moderate | 8th | 1.3 of 5 | 11.9 |
| Strong wind | Very Low | 1st | 1.0 of 5 | 0.02 |
| Winter weather | Relatively Low | 1st | 1.0 of 5 | 10.9 |
Perils not assessed in Butte 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 Butte 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.