PVsyst Ageing Losses and LID

[ThomasP]

If degradation is included in the simulation so as to calculate the output for a specific year should the LID loss factor be set to 0% since the Year 0 warranted output as defined in the "Ageing" tab already includes LID losses.

I.e. Will LID losses be counted twice if defined in the "Module quality - LID - Mismatch" tab if degradation is included?

[André Mermoud]

See our FAQ How to interprete the warranty curve of the manufacturers?

[MCarrascosa]

In PVsyst 6 HELP, in the point about AGEING http://files.pvsyst.com/help/index.html there is this note:

"NB: The simulation for a given year takes the average loss calculated mid year. For example for the 10th year of operation, the ageing loss factor will be calculated over 9.5 years.

For the usual simulations of PVsyst (first year) we should indeed consider the degradation after 6 months (0.2% in our example). This is usually neglected"

And I would like to know why for the first year operation it is used the degradation after 6 months and is not used the degradation for the whole year.

Thank you.

[Carrascosa]

In the PV Syst Help page, it is said this note about ageing:

"NB: The simulation for a given year takes the average loss calculated mid year. For example for the 10th year of operation, the ageing loss factor will be calculated over 9.5 years.

For the usual simulations of PVsyst (first year) we should indeed consider the degradation after 6 months"

I would like to know why it is calculated like this way.

[edujim57]

Hello, I am interested also in this topic. I want to combine LID losses for the first year (as that is the definition of LID losses) and ageing but, when I check the report for any year I see LID losses applied for all years and that is wrong. Do you have this problem also? If so, Have you been able to fix this? Thank you in advance.

Best Regards,

Eduardo Jimenez

[aarenas]

In the PV Syst Help page, it is said this note about ageing:

"NB: The simulation for a given year takes the average loss calculated mid year. For example for the 10th year of operation, the ageing loss factor will be calculated over 9.5 years.

For the usual simulations of PVsyst (first year) we should indeed consider the degradation after 6 months"

I would like to know why it is calculated like this way.

 

I have the same question. Do you have a specific technical justification for this? is this because of data granularity?

thank you

[laurahin]

The degradation loss increases by the degradation rate (say, 0.4%) every year.  This means that in the first year, the loss goes from 0 to 0.4% and over the second year it goes from 0.4% to 0.8%.  Averaged over the entire year, the degradation is thus 0.2% the first year, 0.6% the second year, and so on.  By definition, the average of a linearly increasing value from one time to the next is the value at the center of the interval, so the explanation in terms of half years gives the same result.  It's just not as physically meaningful or, apparently, easy to understand. 

Edited February 14, 2023 by laurahin