How to Calculate Solar Panel Output Per Month

Introduction

Calculating the monthly output of solar panels is essential for determining the effectiveness of your solar energy system. Knowing how much electricity your solar panels generate each month helps in assessing your energy needs, understanding savings, and planning for energy utilization. This guide provides a straightforward methodology for estimating solar panel output on a monthly basis.

Step-by-step instructions

1. Determine the Total Wattage of Your Solar Panels: Add together the wattage ratings of all installed solar panels. For example, if you have four 300-watt panels, the total wattage is 1200 watts.
2. Assess the Peak Sunlight Hours: Research your geographic location to find out the average peak sunlight hours per day. This value varies significantly based on the region. For example, sunny areas may experience up to 6 hours, while others may see about 4 hours.
3. Calculate Daily Energy Output: Multiply the total wattage of your solar panels by the peak sunlight hours. For a system with 1200 watts and 5 peak sunlight hours, the calculation is 1200 watts x 5 hours = 6000 watt-hours (or 6 kWh) per day.
4. Estimate Monthly Output: Multiply the daily output by the number of days in the month. For example, if you use 30 days for calculations, then the monthly output is 6 kWh x 30 days = 180 kWh.
5. Factor in System Losses: Solar panel systems typically experience losses due to temperature, inverter efficiency, and shading. Many estimate this loss at around 20%. To adjust for this, apply the loss rate to your monthly output: 180 kWh x 0.80 (representing 80% efficiency) = 144 kWh.