Is it possible to install solar panels on the roof of the storage building?

Yes. To calculate the maximum snow load, you have to subtract the weight of the solar panels from the snow load.

Example: if the snow load for the storage building in question is 1,2kN/m², then the roof can withstand 120 kilos of snow per square meter.

If the solar panels for example weigh 40kg, 80kg remain. In a region where the snow load is less than 0,8kN/m² (80kg per square meter), the storage building can be equipped with solar panels.