How to calculate the electricity generated by photovoltaic solar panels

          Solar energy is one of the most promising sources of renewable energy. Photovoltaic panels, also called solar panels or PV panels, are used to generate electricity from solar radiation. Calculating the amount of electricity generated by a photovoltaic system is important for predicting its performance, estimating its return on investment, and optimizing its design.

          The amount of electricity generated by a photovoltaic system depends on several factors, including the size of the system, the efficiency of the solar panels, the location and orientation of the panels, and the amount of solar radiation available.

          To calculate the electricity generated by a photovoltaic system, the following steps can be followed:

          Step 1: Estimate the solar radiation available

          The first step is to estimate the amount of solar radiation available in the location where the solar panels will be installed. Solar radiation is measured in units of kilowatt-hours per square meter per day (kWh/m2/day). This information can be obtained from local weather stations or solar radiation databases. The solar radiation data should be averaged over a year to get an accurate estimation.

          Step 2: Calculate the array size

          The output of a photovoltaic system is directly proportional to the size of the array. The array size is determined by the amount of electricity required and the available area for installation. The efficiency of the solar panels can also affect the array size. To calculate the array size, the following formula can be used:

          Array size (kW) = Total electricity required (kWh) / (Daily solar radiation (kWh/m2/day) x Efficiency of the solar panel)

          Step 3: Determine the number of solar panels

          Once the array size is known, the number of solar panels needed can be determined. The output of a solar panel is measured in watts (W). To calculate the number of solar panels, the following formula can be used:

          Number of panels = Array size (kW) x 1000 / Panel wattage

          Step 4: Estimate the system output

          The expected output of a photovoltaic system depends on several factors, including the efficiency of the solar panels, the inverter efficiency, the temperature coefficient, and the shade or obstruction of the system. To estimate the system output, the following formula can be used:

          Estimated system output (kWh) = Daily solar radiation (kWh/m2/day) x Area of the array (m2) x Efficiency of the solar panel

          Step 5: Account for losses

          The actual output of a photovoltaic system is often lower than the estimated output due to various losses, including wiring losses, inverter losses, shading losses, mismatch losses, and soiling losses. These losses can be estimated using industry standard values. To calculate the actual system output, the estimated output should be multiplied by a loss factor that accounts for these losses.

          Actual system output (kWh) = Estimated system output (kWh) x Loss factor

          Conclusion

          Calculating the amount of electricity generated by a photovoltaic system is essential for determining the system’s performance, assessing its economic viability, and optimizing its design and operation. By following the steps outlined above, it is possible to estimate the amount of electricity that can be generated by a photovoltaic system in a given location. The accuracy of the estimation depends on the quality of the solar radiation data, the efficiency of the solar panels, and the degree of shading or obstructions in the system.