Estimating expected solar energy production
Estimating energy production involves combining system size with local solar resource data and expected system losses. This gives a realistic annual energy yield for planning and financial calculations.
Steps to estimate production:
- Determine system size: Estimate kilowatts (kW) of panels you can install based on roof area or chosen capacity.
- Use local irradiance values: Peak sun hours or annual insolation data for your location are available from solar resource maps and meteorological databases.
- Apply system performance factors: Account for inverter efficiency, temperature losses, shading, soiling, and wiring losses. A common derating factor is 0.75–0.85 depending on conditions.
Simple calculation example:
- System size (kW) × average daily peak sun hours × 365 × performance ratio = annual kWh
Tools and resources
- Online solar calculators and PV simulation tools offer location-specific estimates using historical weather data.
- Professional design software provides more precise modeling with shading, azimuth, and tilt factored in.
Refining estimates
- Review similar local installations or installer performance data.
- Use monitoring after installation to compare predicted vs. actual output and refine expectations.
Combining accurate location data with realistic performance assumptions yields useful energy production estimates for decision making.