Solar Production Calculator
Calculate solar panel energy production with precision
Solar Energy Production Calculator
Based on NREL PVWatts Standards
Solar Production Results:
System Size: 0.00 kW
Daily Production: 0.00 kWh
Monthly Production: 0.00 kWh
Annual Production: 0.00 kWh
CO₂ Offset/Year: 0.00 kg
How to Use the Solar Production Calculator
Panel Specifications
- Enter your solar panel wattage (typically 300-500W)
- Input the total number of panels in your system
- Check your panel datasheet for exact specifications
- Consider future expansion plans
Location Data
- Find peak sun hours for your location online
- Use NREL PVWatts or similar tools
- Consider seasonal variations
- Account for local weather patterns
System Efficiency
- Standard efficiency: 80-85%
- High-quality systems: 85-90%
- Includes inverter, wiring, and shading losses
- Adjust based on your system quality
Solar Production Calculation Method
Basic Formula
Daily Production (kWh) = Panel Wattage × Number of Panels × Peak Sun Hours × System Efficiency ÷ 1000
- Panel Wattage: Rated power under STC
- Peak Sun Hours: Daily solar irradiance equivalent
- System Efficiency: Overall system losses
Temperature Adjustment
Real-world conditions affect panel performance:
- Temperature coefficient reduces output in heat
- Standard Test Conditions: 25°C
- Higher temperatures = lower efficiency
Complete Formula:
Adjusted Power = Panel Wattage × [1 + Temp Coeff × (Avg Temp - 25)]
Daily kWh = Adjusted Power × Panels × Peak Sun Hours × Efficiency ÷ 1000
Step-by-Step Calculation Example
Residential Solar System Example
System Specifications:
• Panel Wattage: 400W
• Number of Panels: 25
• Peak Sun Hours: 5.5 hours/day
• System Efficiency: 85%
• Temperature Coefficient: -0.4%/°C
• Average Temperature: 30°C
Step 1: Calculate System Size
System Size = 400W × 25 = 10,000W = 10 kW
Step 2: Temperature Adjustment
Temp Factor = 1 + (-0.4% × (30°C - 25°C)) = 1 + (-0.02) = 0.98
Adjusted Power = 400W × 0.98 = 392W per panel
Step 3: Daily Production
Daily kWh = 392W × 25 × 5.5 × 0.85 ÷ 1000
Daily Production = 45.8 kWh/day
Step 4: Monthly & Annual
Monthly = 45.8 × 30 = 1,374 kWh
Annual = 45.8 × 365 = 16,717 kWh
Environmental Impact:
CO₂ Offset = 16,717 kWh × 0.4 kg/kWh = 6,687 kg CO₂/year
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