How yield is computed
How SolarLayout estimates 25-year electricity production for your project.
SolarLayout estimates electricity production over a 25-year operating window. The estimate uses hourly weather data, your module and inverter specs, and an industry-standard losses model.
What goes in
Weather data
PVGIS satellite data by default, or upload your own hourly CSV (Solargis, Meteonorm, etc.)
Module spec
A PAN file from the manufacturer, or one of SolarLayout's catalog modules
Inverter spec
An OND file with efficiency curves, or a catalog inverter
Site environment
Albedo, soiling rate, tilt, mounting type
PAN and OND are the industry-standard file formats for solar modules and inverters. Most manufacturers publish them — you'll usually find them on the vendor's downloads page alongside the datasheet.
P50 vs P90 — two numbers, one report
SolarLayout reports both:
- P50 — median expected production. Half of years will exceed it. Used for base-case engineering and feasibility.
- P90 — the conservative case. 90% of years will exceed it. Lenders care about P90 because debt service has to be paid in bad years too.
The spread between P50 and P90 reflects inter-annual irradiance variability. A typical Indian utility-scale project sees P90 land roughly 5–8% below P50.
The losses model
Production losses compound multiplicatively into a single Performance Ratio. Typical Indian-context values:
| Loss type | Typical range |
|---|---|
| Soiling | 2–4% (higher in arid / dusty regions; cleaning schedule matters) |
| Temperature | 5–10% (depends on summer ambient and module tech) |
| Mismatch | 1–2% |
| DC wiring | 1–2% |
| AC wiring | 0.5–1% |
| Transformer | 0.5–1% |
| Shading | 0–1% on well-sited plants |
| Inverter | per the OND efficiency curve |
| Availability | 99%+ |
Total system-level losses typically land in the 12–18% range.
See Losses & soiling for the model details and how to tune the soiling assumption for your specific site.
Bifacial modules
If your module is bifacial (the back side also generates electricity), SolarLayout adds a rear-side production contribution. See Bifacial modules for the model inputs (bifaciality factor, ground albedo) and how to configure them.
Custom weather data
PVGIS satellite data is fine for early-stage feasibility and quick screening. For bankable submissions, lenders typically require Solargis or Meteonorm data, or 12+ months of on-site pyranometer measurements.
See PVGIS vs custom CSV for how to attach your own hourly weather file to a project.