Documentation

Documentation Product guides Prospect app

How to check data sources and represented periods

From the project view, under the section "metadata" you can see more details about the source of the data, period of years used in the calculation and other useful information. You can also check and the version of Prospect you are using (remember that it is updated automatically) on the bottom left corner of the screen.

You can check more information about data periods by region on Prospect product page.

What spatial and temporal resolutions are used in Prospect ?

The spatial resolution used in Prospect is in the range of 90 m to 4 km, but this depends on the map layer type (solar radiation layers have a higher resolution than meteo layers). 

Prospect app uses sub-hourly irradiance data for internal calculations. Other parameters like ground albedo are used as monthly values for the calculations. For showing the results, solar and meteo data are then aggregated as monthly averages. Some parameters are also shown as hourly-monthly (24x12) profiles.

More information about technical specifications is on Prospect product page.

How is the PVOUT calculated?

The PVOUT is produced according to the used configuration for your simulation using Solargis PV simulation methods.

When no PV configuration is selected, you just get a PVOUT annual average value for a generic PV system. Other default settings are considered depending on the configuration of your choice.

Please note that the PVOUT map layer is calculated with a different horizon precision than the calculated PVOUT (thus the GHI data is different).

Which PV modules are considered in the simulation?

Solargis’ prospecting tool Prospect uses a generic c-Si (mono or polycrystalline) module for the simulations. The reason why we currently use this approach is that Prospect is a tool for pre-feasibility studies, when decisions on modules are typically not finalized.

The below table summarizes the different parameters of the modules used in Prospect simulation.

Parameter description Default value Unit
PV module technology Multi c-Si  
Maximum power output 250 W
Module NOCT temperature 46.2 ºC
Number of cells in series  60  
Reference short circuit current 8.6 A
Reference open circuit voltage 37.6 V
 Reference maximum power current  8.1  A
 Reference maximum power voltage 30.9 V
Maximum power temperature coefficient -0.43 %/K

What is the efficiency assumption for generic cSi modules?

We are not using an efficiency model for conversion of radiation to electricity. We are calculating with default modules and their parameters in a single diode model.

Which inverters are considered in the simulation?

Each inverter type has its own efficiency curve simulated in Prospect, and each curve can be approximated by Euro efficiency number as they are defined in settings.

The Euro efficiency has an impact on the performance ratio (PR). For example in the below picture, when you use a centralized inverter instead of a string inverter, you will gain approximately 1.4% (97.8 - 96.4) on PR result.

The below table summarizes the inverters type (small, string and centralized) as well as default values parameters used in Prospect simulation.

Default inverter simulation parameters Unit Small String Centralized
Maximum AC power kW 2 15 1000
Maximum DC voltage V 480 800 1000
Nominal DC voltage V 400 445 745
Minimum MPPT DC voltage V 180 325 470
Maximum MPPT DC voltage V 480 800 900
Euro efficiency % 95.9 96.4 97.8
CEC efficiency % 96.6 96.5 97.8

How is the optimum angle calculated?

The optimum calculation is related to PV array tilt and this is only from GTI point of view.

This means that the calculation doesn’t take into account electrical connections of PV modules and strings layout, shading losses, mismatch losses etc. Therefore, even if the calculated tilt is optimal for maximum GTI, the expected PVOUT may not be at its maximum due to mentioned electrical losses. 

On the other hand, the azimuth is always set to 180° (and 0° in the Southern hemisphere) for which optimum tilt is calculated.

How is the slope calculated on a specific point?

We provide info on terrain slope, and It is calculated from raster data with a pixel resolution of approximate 90 m (exactly 3 arcsec). It means that for every ~90 m we have an elevation value and the slope is calculated from this array of values.

Please notice that 90 m resolution might not reflect all details of the terrain especially in the rocky mountains.

What models are used for simulations of floating PV?

The current implementation of energy simulation for floating PV systems is based on scientific literature about floating solar. A selection of reference research articles here:

Temperature model of PV modules in existing installations. 

FLOATING PHOTOVOLTAIC MODULE TEMPERATURE OPERATION CHARACTERISTICS, Waithiru Charles Lawrence K., Chang-Sub Won, Dong-Chan Kim, Kwang-wook Kim, Bo-ram Kang, Gun-Hyun Lee, Ogeuk Kwon, Sumin Lee, Power Conversion Research Team, LSIS Corporation Korea, 36th European Photovoltaic Solar Energy Conference and Exhibition, Marseille, France 2019.

Mismatch losses caused by water movement. 

INFLUENCE OF WAVE INDUCED MOVEMENTS ON THE PERFORMANCE OF FLOATING PV SYSTEMS, Maarten Dörenkämper, Daan van der Werf, Kostas Sinapis, Minne de Jong, Wiep Folkerts, TNO-SEAC, 36th European Photovoltaic Solar Energy Conference and Exhibition, Marseille, France 2019.

Since there are existing several types of floating system constructions (usually specifically selected according to local conditions), the results of the calculations for floating PV systems in Prospect should be handled only as preliminary estimation.