ASTI
OperatingSolar power plant
- Capacity
- 1 MW
- Primary fuel
- Solar
- County
- Sonoma County
- Operator
- PERPETUAL ENERGY SYSTEMS
- Status
- Operating
- Commissioned
- 2009
- EIA plant ID
- 58889
- Coordinates
- 38.7625, -122.9728
ASTI, a 1 MW Solar power plant in Sonoma County, California. Operated by PERPETUAL ENERGY SYSTEMS, commissioned 2009.
Weather peril exposure
ASTI is a 1 MW solar power plant in Sonoma County, CA, operated by PERPETUAL ENERGY SYSTEMS, commissioned in 2009. Sonoma County carries low modeled catastrophe exposure in the FEMA National Risk Index, scoring 1.7 of 5 at the 19th national percentile. Earthquake is the leading peril, rated Relatively High by FEMA at the 99th percentile.
Sonoma County hazard ratings
| Peril | FEMA rating | National percentile | Peril score | Share of modeled loss | Events per year |
|---|---|---|---|---|---|
| Earthquake | Relatively High | 99th | 5.0 of 5 | 33% | 0.12 |
| Riverine flooding | Relatively High | 97th | 4.9 of 5 | 38% | 2.5 |
| Wildfire | Relatively High | 92nd | 4.7 of 5 | 21% | <0.01 |
| Coastal flooding | Relatively Moderate | 51st | 3.0 of 5 | 4% | 3.4 |
| Heat wave | Relatively Moderate | 11th | 1.4 of 5 | <1% | 7.0 |
| Lightning | Relatively Moderate | 10th | 1.4 of 5 | <1% | 3.7 |
| Hail | Very Low | 6th | 1.2 of 5 | 2% | 0.02 |
| Tornado | Very Low | 4th | 1.1 of 5 | <1% | 0.08 |
| Strong wind | Very Low | 2nd | 1.1 of 5 | <1% | 0.02 |
| Winter weather | Very Low | 0th | 1.0 of 5 | <1% | 0.74 |
Perils not assessed in Sonoma 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 |
| Ice storm | FEMA rating is "Not Applicable" for this county |
Hail exposure and deductible structure
Hail scores 1.2 of 5, which sits in the 1% to 2% percentage deductible range carriers are quoting for that exposure. Named windstorm and severe convective wind score 1.1 of 5, indicating a 1% to 1% wind deductible. Ranges, not single figures. The final structure is set by the carrier.
Percentage hail deductible range: 1% to 2% of insured value. Wind deductible range: 1% to 1%. These are the structures commonly seen at this exposure, not an offer and not a rate.
Modeled annual loss for a 1 MW solar array
At an assumed replacement value of $0.90 per watt, or $900,000 insured, the modeled expected annual loss for a fixed tilt ground mount array in Sonoma County is $279 a year, $279 per MW, 0.03% of insured value.
Heat is modeled as a production risk rather than a property loss: 0.3% of annual yield in this county.
Insurability signal: Standard. Riverine flooding carries 38% of modeled loss.
Model hail, wind and flood exposure for Sonoma 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, and the modeled loss applies the Bywatts solar vulnerability layer. 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. The solar vulnerability layer that turns FEMA building loss into modeled solar loss was derived by Bywatts and revised on physical reasoning. It has not been reviewed by a practising underwriter.