I've used QGIS LTR 3.40.15 and SAGA-GIS 9.11.1 (both from OSGeo4W) and the "Processing Saga NextGen Provider" plugin 1.1.0 and I've obtained realistic values for an area in the South of Italy just setting the parameters "Time period" to "Range of days", range of days between 1/1/2025 and 31/12/2025 and Resolution to 15 days, among the others: Total Insolation have values between 1303-2140 kWh/m^2 Andrea Giudiceandrea
I've used QGIS 3.40.15 and SAGA-GIS 9.11.1 (both from OSeo4W) and the "Processing Saga NextGen Provider" plugin 1.1.0 and I've obtained realistic values for an area in the South of Italy just setting the parameters "Time period" to "Range of days", range of days between 1/1/2025 and 31/12/2025 and Resolution to 15 days, among the others: Total Insolation have values between 1303-2140 kWh/m^2 Andrea Giudiceandrea