How to Calculate Solar Insolation (kWh/m2) for a Solar Power Plant using Solar Radiation (W/m2)
To calculate it you will need to integrate your solar radiation (w/m2) data over a time interval.
Monitoring platforms calculates the area of the graph accurately by integrating the available radiation with time. Higher the data frequency more accurate will be the calculated Solar Insolation
However, to calculate it manually in excel we’ll start it by breaking the region into multiple rectangular strips of the same width
where
Width of rectangle = Data Frequency (for example 10 mins)
10 mins= 10/60 hrs
Height of rectangle = Solar Radiation (in kW/m2)
Note: solar radiation value is received in W/m2 via pyranometer and can be converted to kW/m2 by dividing it with 1000
Area of 1 smaller rectangle= Length * Width
Height = Solar radiation in kW/m2
Width= Data frequency in hr
Now to calculate the solar insolation we will need to calculate the area of each rectangle and add the results together to have the area of the region under the graph
Solar Insolation = Sum of area of all rectangles
Sample Excel having similar calculation with 10 min data frequency is available below for reference
