The generation of electricity from the rooftop solar panel system depends on many parameters such as –

• Location of the rooftop solar (part of the country) 
• Quality of equipment used  
• No. of sunshine hours  
• Temperature and irradiance (the strength of sunlight received) 
• PV module tilt angle and orientation  
• Module cleaning, and other maintenance activities  

The daily energy generation will be dependent on the weather conditions such as temperature, solar irradiance, etc., and these may not be same every day.