Partial-year degradation in PVSyst

[Winnie Fu]

How is degradation applied in PVSyst? Is there any existing literature on this?

I can see that the Individual PV module Global degradation factor appears to be 1/2 of the average degradation factor in Year 1, then increases by the average degradation factor for subsequent years. E.g. if av. degradation factor is 0.4, year 1 global degrad. factor = 0.2, year 2 = 0.6, year 3 = 1.0... etc.

Does this mean that PVSyst just applies the degradation factor at the 6month point, or is it more sophisticated than this?

Is degradation applied progressively, e.g. degradation adjusted month = 0.5%/12 month * generation, or at a higher/lower granularity?

Also, what does this mean in the context of monthly results in the simulation? is it fair to assume that each month of simulation already has a monthly aging factor applied to it?

Context: I am looking to apply degradation factor to the nearest month for monthly generation benchmarking purposes

[André Mermoud]

The degraded PV module is calculated once. Then the simulation is performed with this module, for the simulation of the full year..

The effect on the yearly degradation loss is the average over the year, i.e. between the beginning and the end of the year. This is the reason of the half-values for the degradation factor.