This is my phase II thesis work carried out in Robert Bosch Engineering and Business Solutions India Ltd. during my master's in Energy in PSG College of Technology. This thesis mainly talks about the estimation of power output from photovoltaic arrays using mathematical models. This work was carried out with a common man's perspective, such that any non technical person can make use of this model to estimate the power output for his/her power plant installed in the roof top. Even though the model is carried for a particular climatic condition, it can be extended for other climatic zones in India. Interested people can go through my thesis and drop your comments below.