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Greenbyte Documentation

Yield KPI's IEC

Yields are ratios of an energy quantity to the array power rating P0. They indicate an actual array operation relative to its rated capacity.

Yields have units of kWh / kW



the energy production


the system power rating

The ratio of units is equivalent to hours and the yield ratio indicates the equivalent amount of time during which the array would be required to operate at P0 to provide the particular energy quantity measured during the reporting period.

Yield DC IEC

The PV array energy yield YA is the array energy output (DC) per rated kW (DC) of installed PV array:

YA = EA / P0

Yield AC IEC

The final PV system yield Yf is the net energy output of the entire PV system (AC) per rated kW (DC) of installed PV array:

Yf = Eout / P0

Reference Yield IEC

The reference yield Yr can be calculated by dividing the total in-plane irradiation by the module's reference plane of array irradiance:

Yr = Hi / Gi,ref

where the reference plane of array irradiance Gi,ref (kW / m2) is the irradiance at which P0 is determined.

The reference yield represents the number of hours during which the solar radiation would need to be at reference irradiance levels to contribute the same incident solar energy as was monitored during the reporting period while the utility grid and/or local load were available.

If the reporting period is equal to one day, then Yr would be, in effect, the equivalent number of sun hours at the reference irradiance per day.

Usage Example