Offline pipeline · solar yield
Solar: how much sunshine becomes kWh at your address
For a solar array, the engine needs two things: how many kWh each kW of panels makes in each month, and when in the day those kWh arrive, since noon output can't cover a 7 pm peak unless a battery stores it. Both come from NREL's PVWatts calculator, run ahead of time.
The pipeline
The offline script calls PVWatts once per site for a 1 kW system and saves the reduced result. At run time the model only looks the answer up and scales it by your system size. No API calls happen while you use the app.
What one kilowatt makes
Across California
Yield per kW differs by about a third from the foggy north coast to the desert. Where a ZIP has its own PVWatts run (so far, Silicon Valley Clean Energy's 29 ZIPs), that is used; otherwise the ZIP's climate-zone station; otherwise San Jose.
| Zone | Station | kWh / kW / yr |
|---|
What it feeds
Your system size × this yield gives the solar generation G for each month's representative day. The hourly energy balance matches it against the home's hourly load (from the NREL load profiles): solar serves the home first, then charges the battery, then exports at the NEM 3.0 hourly credit.
What's modeled, what's simplified
- Real sunshine data (NSRDB typical year) for your zone's station, or your ZIP where harvested.
- Hour-by-hour shape per month, so evening peaks and battery value are priced correctly.
- Same clock as the tariff: stored in standard time, shifted +1 h in daylight-saving months, like the load profiles.
- One orientation: south-facing, 20° tilt. East/west roofs make less and later.
- No shading from trees or neighbors.
- No panel degradation: year 20 makes the same as year 1 (real panels lose ~0.5%/yr).