Interactive ZIP-level viability scores for all 2,593 California ZIP codes — scored with the same NREL-calibrated engine used in the individual city reports.
All 2,593 CA ZIP codes scored on a 0–100 viability index. Opens centered on the Bay Area; scroll out to explore SoCal, the Central Valley, and the Sierra foothills.
Open Map →714 ZIPs across 15 counties including San Francisco, the Peninsula, East Bay, South Bay, Marin, Sonoma, Napa, Solano, Sacramento, and the Sierra foothills.
Open Map →Each dot represents one ZIP code, colored by its viability score (0–100, Viridis scale: purple = lower, yellow = higher). Opacity encodes data confidence based on the number of real solar installations in Berkeley Lab’s Tracking the Sun (TTS) dataset within the same three-digit ZIP prefix:
| Tier | TTS installs (ZIP3) | Appearance | Meaning |
|---|---|---|---|
| High | ≥30 | Full color, opacity 0.90 | Real median $/W from local installations; high confidence |
| Medium | 5–29 | Colored, dimmed (opacity 0.55) | Some local data; score directionally reliable |
| Low / NA | <5 | Gray, opacity 0.30 | No score shown; insufficient local install data |
Scoring model: each ZIP is modeled as a 4.5 kW south-facing residential system. Specific yield (kWh/kW/yr) is estimated from latitude using a piecewise fit calibrated to NREL PVWatts national results. The viability score combines four sub-scores: 25% solar resource · 50% economics · 15% site fit · 10% local market maturity.
Utility rates: IOU territories (PG&E, SCE, SDG&E) use a blended residential rate of $0.389/kWh with a NEM 3.0 export ratio of 14.1% (CPUC avoided-cost credit ≈ $0.055/kWh). Municipal utility territories (SMUD) use the EIA CA average of $0.30/kWh with a NEM 2.0-equivalent export ratio of 50%.
Cost inputs: installed cost uses the TTS ZIP3 median $/W where ≥5 installations exist; otherwise defaults to $3.80/W (Berkeley Lab 2024 CA median). Federal 30% ITC applied to all sites.
Part of the DATA 201 Solar Viability Analysis project at Cal Poly Humboldt. Financial projections use current California NEM 3.0 tariff schedules, the 30% federal Investment Tax Credit (ITC), and real retail electricity rates.
Data sources: NREL PVWatts, Berkeley Lab TTS, EIA utility rate databases, GeoNames ZIP coordinate data. — View individual city reports →