Snow impact in Snow/Soiling losses

I was wondering why does PVWatts v5 address snow impact on PV arrays, two times: in soiling and in snow losses categories.

This is a quote from "Soiling":

For northern locations, snow reduces the energy produced, depending on the amount of snow and how long it remains on the PV modules.


And from "Snow":

Reduction in the system's annual output due to snow covering the array. The default value is zero, assuming either that there is never snow on the array, or that the array is kept clear of snow.


What is the difference between snow impacts in these two loss categories?

Thank you.

Hello,

We will revise those descriptions. The snow category was not part of the original set of cateogries, and we forgot to revise the description of the soiling category when we added it. You should either account for losses due to snow in the soiling factor or the snow factor, but not both.

PVWatts only uses the total system losses value, so how you categorize the different kinds of losses is less important than the final total value.

Best regards,
Paul.

Understood. Thank you Paul.