SolarGIS methodology for collecting long term irradiance data verus short term

[chudy14]

Hi All,

I am having some huge diferences between datasets and site is underperforming. Besically Solar GIS having "less optimistic" approach than pyrometer on site which is causing differences for weather adjusted data. Have anyone else had this problems before? Which data sets you find best?

[Linda Thoren]

Dear chudy14,

In the Meteo database tab you have a button “Compare meteo data”, allowing you to compare datasets. Also keep in mind that the origin of the data might vary between being a typical meteorological year (TMY), synthetic data or measured data for a specific year, this might affect the year-to-year variability.

You can also find an extensive amount of help-pages with information on meteorological data sources (see link below), as well pages on the constructions of meteo-files, sources of uncertainty etc
https://www.pvsyst.com/help/index.html?meteo_datasources.htm

Regards.