Performance Ratio

Performance Ratio (PR) is a quality indicator of both the energy efficiency and reliability of your PV plant.

In general, the performance ratio describes the ratio of theoretically possible generation (also known as nominal yield) to the actual generation of the PV system

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Performance Ratio also takes into account the losses from the conversion of electricity from DC to AC.
In Enerest, we use the irradiation data from weather models to calculate the theoretically possible generation. We do this so that plants without external sensors also receive a value for the performance ratio. In addition, the calculation is also protected against a technical failure of sensors, as the weather models could also be recalculated retrospectively in an emergency, which would not be possible in the event of a sensor failure with missing measurement data.

We currently adjust the theoretically achievable energy with a static degradation factor of 0.5% per year. The commissioning date of the system is therefore relevant here as the starting point of the system's service life. We are aware that this general correction may be too high or too low in individual cases. A change or individualisation of the calculation parameter is therefore likely in the future.

This formula is used to calculate the status quo of our performance ratio: