How to import Solargis hourly data into PVsyst

In PVsyst software the process of importing Solargis values of irradiation and temperature is very easy and straight forward. PVsyst simulation engine runs the simulation taking into account global horizontal irradiation, diffuse horizontal irradiation and temperature (and wind speed if available).

PVsyst users can proceed in two complementary ways when importing Solargis hourly data. One option is using a Typical Meteorological Year (TMY) file, which summarizes weather conditions in one single year of hourly data. Other option is using a Time series file, from which several separated one year periods for specific years can be created in PVsyst weather database.

Importing Solargis weather info contained in csv hourly files when working with PVsyst takes only few seconds (tested in version 6):

  1. Go through "Databases" - "Import meteo data" to open a dialog named "Import meteo data from different sources".
  2. Select external data source "Solargis (Worldwide)" hourly option (green color in drop-down box).
  3. Select the Solargis csv file and fill the site and country information required. After clicking on “Import”, PVsyst will create one hourly meteo file (.MET) for one-year period, which can be used when simulating designed systems.
pvsyst solargisimport1

Most common issues when importing Solargis hourly data into PVsyst

Time Zone. PVsyst most recent versions admit data importing in Universal Time Coordinated (UTC) time reference. When this is not the case, in Solargis we are also supporting older versions by providing csv files in Longitudinal Time Zone (LTZ) time reference, which is based on using longitudinal reference of the site as longitude°/15 (rounded value). Please note that in many regions the time zone based on longitudinal reference will deviate from the legal time.

Data Time-step. Other time steps like sub-hourly or daily are also admitted in PVsyst. Although importing such files is not so direct, it is possible through "Databases" - "Import ASCII meteo file”. A dialog named "Conversion of ASCII meteo sub-hourly files” will be opened showing other customizable importing options. This option is also suitable when using older data formats which are not supported anymore.

Data format. Although recent versions of PVsyst 6 support Solargis csv hourly format, some older versions of PVsyst only accept data in “PVsyst Standard Format”, which can be chosen from the drop-down box when importing data. Solargis also supports this format for such cases when last versions of PVsyst are not available.

The clearness index. Some sites especially in tropical climate have a very high DIF which is out of PVsyst internal default limits. Therefore, PVsyst will show this type of notification:

The Clearness index of the best clear days is very low with respect to the clear day model. Check the values with the "Best clear day Ktcc" graph.

In such cases, you need to adjust internal PVsyst limits to make it work (Main window / Preferences / Edit hidden parameters / Category Miscellaneous: Meteo, Simulation, Upper limit for monthly Clearness Index Kt). If needed, you can also adjust the Lower limit for DIF. 

Period not starting in January. For certain regions, Solargis full time series data file is starting in July 2006 (starting of operations of the satellite over Pacific region). In this case, if a period from January to December is required, Solargis csv file needs to be adjusted by removing the first rows from #54 to #4469 (corresponding to dates from July to December 2006). Before importing the data, the period should be also adjusted manually in rows #19 and #25 accordingly (01/01/2007 instead of 01/07/2006).

Older versions of PVsyst may not support direct import of CSV files. In such case, there is another option which allows copy-pasting values:

  1. Go through "Tools" - "Geographical sites" to open dialog named "Choosing a geographical site".
  2. Create new site and fill in the required values on the first tab.
  3. Then go to "Monthly meteo" tab and copy paste them from the pvPlanner report in XLS format. Be sure irradiation units are selected correctly. Synthetic hourly time-series can be also generated afterwards.
pvsyst solargisimport3

In order to run the synthetic generation of hourly data correctly, and be able to apply horizon shading analysis using PVsyst afterwards, please note that the data in XLS or CSV format needs to be extracted from pvPlanner without horizon shading:

  1. Go to pvPlanner main configuration screen and select the 'Horizon Editor'.
  2. Set the horizon values to zero. You can easily do that by deleting the values on the right side and typing the data pairs 0:0 and 359:0. Then click on apply (please see image below).
  3. Download the new XLS or CSV files from the pvPlanner section 'report'.
horizon removal

Importing pvPlanner horizon data into PVsyst

pvPlanner offers a highly accurate terrain model which can be used also in external applications such as PVsyst. In pvPlanner click on "Click to modify horizon" and then "Export to HOR file". HOR file is directly compatible with PVsyst so you can import it and use Solargis terrain in your PVsyst simulations.

hor file