This paper presents a reliable mathematical methodology to predict the energy generation from grid connected Photovoltaic plant of different technologies in India. Energy generation of different commercially used PV technologies in different locations of India is predicted using proposed mathematical method. This results show a decisive study to choose the best PV technology for particular location of India. Predicted energy generation is validated with the monthly generation for the whole year of 2014 from operational PV power plants of different technologies. Predicted generation is in good co-relation with the actual real time generation and Capacity Utilization Factor (CUF) of the PV plants.