JavierGV

But, what about if you want to know (1) the PR of a PV Plant as soon as the installation is finished, let's say, three months after the first exposition to the sun of the modules? And then, (2) produced energy for the first year. Then we should: (1): consider only LID. (2): consider LID + ageing for the first year Is that right?

A question about ageing of modules and LID: LID (Light Induced Degradation) is a loss of performances arising in the very first hours of exposition to the sun. The PV module degradation gives rise to a progressive loss of efficiency, which we will characterize by a "Degradation Loss factor". Do you have to start considering degradation as soon as the modules are exposed to the sun or as soon as the modules start producing energy (i.e.: connected to the grid)?

The evaluation of the "Losses" of a PV array (as for the definition of the normalized performance ratio), takes as starting point the energy which would be produced if the system worked always at STC conditions (1000 W/m², 25°C, AM1.5). In the loss diagram of PVsyst we can see: 1) the PV loss due to irradiance level: the loss due to operating irradiance (instead of 1000 W/m²). 2) the PV loss due to temperature: the loss due to operating temperature (instead of 25°C STC). But there is no PV loss due to operating AM level (instead of AM1.5). Why?

I found the next text on the help about the performance ratio: "Unlike the "Specific energy production" indicator, expressed in [kWh/kWp/year], the PR is not directly dependent on the meteo input or plane orientation. It is related to the system quality, and allows the comparison between installations in different locations and orientations". For a given system (array + place) PR varies with the meteo data used (irradiation + temperature). The different values for the PR for each month of the year can be seen on the report and the difference between months is the meteo data (different irradiation and different temperature). The same irradiation data with diferent temperature data will result in a different PR. How could you compare between two installations in different locations and orientations with different meteo data?

Do you mean that the program takes the efficiency of the inverter from the Efficency curve defined in the inverter OND file to relate it with the transformer losses? :shock:

Once the system is defined, you can see the Nominal PV power and the nominal AC power (Global System Summary) and while you introduce parameters for the calculation of Detailed losses -> Ohmin Losses -> AC circuit, you can see "STC: P ac". This parameter, P ac at STC, is used at the external transformer iron loss calculation: when you introduce a percentage value for the iron loss, a value in kW appears beside it. This value in kW is the percentage value * (P ac at STC). How is this value (P ac at STC) calculated?

I'm using version 6.41. So, I guess I will have to pay for an Update support (for one year): 237 EUR, to get rid of the version with problems in your software. Am I right?

I have just added and horizon to a project and... the results are better now. Free horizon: -1.4% Near shadings: irradiation loss 3498 MWh/year. PR=83.3% Horizon (average height: 3.9·): -0.8% Far Shadings / Horizon -0.3% Near shadings: irradiation loss 3511 MWh/year PR=83.6% Can anybody share an explanation?

The problem is that there's no option for this losses (energy consumed by trackers): Option 1: Continuous auxiliary loss (fans, etc.) ... from thresfold on oper. power. Here I include inverter auxiliary losses. Option 2: Proportional to plant operating power These losses aren't proportional to opertaing power, they can't be included here. Options 3: Night loss. Not here. I think there should be another option for this kind of losses.

The problem is that there's no option for this losses: Option 1: Continuous auxiliary loss (fans, etc.)

What's the best way to introduce the energy consumed by trackers? Let's say our trackers consume 0.5 Wh/Wp per year. It could be accounted as a constant loss, but it is difficult to include this auxiliary energy loss if you are already considering fans consumption from a given produced power. It looks there should be another way to include these losses.