Location & station identification
Need coordinates? Look up the address on the PVWatts Calculator map.
Weather station (last run)
Not run yet. Running PVWatts calculates kWh for every array on the Panel arrays page (15 calls) and fills in the weather station here.
System info
PVWatts Reference tab| DC system size | 64.4 kW | 161 × 400 W — from Panel arrays |
|---|---|---|
| Module type | Standard ≈ 19% efficient crystalline silicon; premium ≈ 21% | |
| Array type | Roof mount runs hotter than open rack, so it produces slightly less | |
| Array tilt | per panel array | 20° – 36° across 15 arrays (6 distinct) |
| Array azimuth | per panel array | 23° – 295° across 15 arrays (11 distinct) |
| System losses | % | Calculator below gives 14.08% |
| DC to AC size ratio | PVWatts default 1.2 | |
| Inverter efficiency | % | 90 – 99.5% (PVWatts default 96%) |
| Ground coverage ratio | NA — only used for 1-axis tracking | |
| Albedo | Ground reflectivity (grass ≈ 0.2, fresh snow ≈ 0.8) | |
| Bifacial | Bifaciality 0 – 1 (typically 0.65 – 0.9) |
System losses calculator
Combined as 1 − Π(1 − loss)| Soiling | % |
|---|---|
| Shading | % |
| Snow | % |
| Mismatch | % |
| Wiring | % |
| Connections | % |
| Light-induced degradation | % |
| Nameplate rating | % |
| Age | % |
| Availability | % |
| Estimated total | 14.08% |
How PVWatts estimates energy
PVWatts is published by the National Laboratory of the Rockies (formerly the National Renewable Energy Laboratory, NREL) for the U.S. Department of Energy. MySolarModel calls the PVWatts V8 API, which runs the pvwattsv8 compute module — the same module used by the PVWatts Calculator and the System Advisor Model. Version reported by the API: shown after your first PVWatts run. The NSRDB option uses gridded typical-year weather (PSM V3 2020 TMY for the Americas and Asia-Pacific; PSM V4 for Europe/Africa and above 60° latitude). The PVWatts Calculator website (currently app version 8.7.4) runs on this same API.
Annual output (kWh) = Capacity (kW) × Annual AC capacity factor (kWh/kW)
- Solar radiation — hourly typical-meteorological-year irradiance for the site.
- Plane of array (POA) irradiance — the direct, diffuse and ground-reflected sunlight striking the tilted panel surface.
- Temperature — module output falls as cell temperature rises; roof mounts run hotter than open racks.
- Angle and orientation — each array's tilt and azimuth set how much sunlight it receives through the day and year.
- System losses — soiling, shading, wiring, mismatch, availability and similar effects.
- DC to AC ratio and inverter efficiency — clipping when the array exceeds the inverter rating, and conversion losses.
MySolarModel is not affiliated with or endorsed by the National Laboratory of the Rockies, NREL or the U.S. Department of Energy. PVWatts results are estimates for a typical year; actual production varies with weather and site conditions.