PV Module Degradation

[Felix Galan]

Does PVSol apply a default 1% discount to total production to account for the average light-induced degradation of PV modules during the first year?

I have modified the module degradation in the 3D visualization section. In the first year, the total power is 99%. However, the generation result for the first year decreases by only 0.5%. Additionally, there are no changes to the annual specific output or the CO2 savings. 

Why is the output reduced by only 0.5% instead of 1%, and why do the CO2 savings or kWh/kWp remain unchanged?

[developer_mh]

Hi Felix,

On 8/11/2025 at 5:45 PM, Felix Galan said:

Does PVSol apply a default 1% discount to total production to account for the average light-induced degradation of PV modules during the first year?

No. There is kind of the inverse value, the increase of the open circuit voltage before stabilisation:

But this factor is not applied in the simulation, only during the configuration check.

Also, the PV module degradation is not applied during simulation, but only for the financial analysis afterwards. In addition, PV*SOL does not support module degradation in the first year (between 0 and 1) other than 100%.

If you want to account for other sources of losses that are not automatically covered by PV*SOL, you can use the soiling factor for instance. It reduces the incident irradiance by that factor.

Hope that helps, kind regards,

Martin