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How is the PV Yield Calculated?

Divine Bunda-Rühl avatar
Written by Divine Bunda-Rühl
Updated over 2 months ago

The PV yield of your system depends on various factors such as location, orientation, roof pitch, hours of sunshine, and installed capacity.

Calculation of the system’s peak capacity (kWp)

Peak capacity (kWp)=Number of modules×Module output [Watt]Peak capacity (kWp)=Number of modules×Module output [Watt]

Specific monthly PV yield

Specific monthly PV yield=Peak capacity (kWp)×Specific yield (kWh/kWp) by postal code and month×Correction factor based on tilt and orientationSpecific monthly PV yield=Peak capacity (kWp)×Specific yield (kWh/kWp) by postal code and month×Correction factor based on tilt and orientation

Annual specific PV yield

Annual specific PV yield=Sum of all specific monthly PV yields from January to DecemberAnnual specific PV yield=Sum of all specific monthly PV yields from January to December

Explanation of important elements for PV yield calculation:

Roof / Module

  • Tilt angle and orientation:
    Both variables influence the actual yield of the module. The ideal is a south-facing orientation with a 45° angle of incidence.
    Autarc applies correction factors based on orientation and tilt from energy experts: percentage yield deviations from optimal orientation and ideal tilt (source: Energie-Experten:)

    Prozentuale Ertragsabweichungen von der optimalen Ausrichtung und dem idealen Neigungswinkel (Grafik: Energie-experten.org).

PV Module

  • Number of modules: The total number of PV modules in the system.

  • Module output: Indicates the maximum output in kilowatts (kW) that the module can deliver.

Location and Time

  • Specific yield in kWh/kWp by postal code and month:
    Each location has different levels of solar radiation (global irradiance) depending on the month. In addition, the angle of incidence changes throughout the year.
    Autarc uses data from a PV yield study by Umwelt-Campus, which provides specific yields in kWh/kWp for all postal code areas in Germany. We use the more conservative value “Good".

Other factors

  • Shading, temperature: These factors are currently not considered in the simulation.

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