Performance Ratio (PR) shows the percentage of total potential energy for the array that is converted to AC energy. 

Mathematically, the PR is defined in the following formula:


Annual AC Energy to Grid (kWh)
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Annual POA Irradiance (kWh/m2) * DC Solar System Size (kWp)

 

· Annual AC Energy to Grid: 158917 kWh

· DC Size: 100 kW

· Annual POA Irradiance: 1868.23 kWh/m2

We can calculate the performance ratio as 158917 / (1868.23 * 100) = 85.06% 

Note: PR is different from unit generation (kWh/kWp). PR is also different from System Loss.