Solar energy is non-polluting and one of the most efficient and affordable energy alternatives available today. Hybrid photovoltaic thermal (PV/T) technology is the most promising technology for co-generation of heat and electricity. The conversion efficiency of PV depends upon its operating temperature which can be maintained by withdrawing/utilizing the thermal energy associated with it using water/air. In the present book, design, modelling and experimental study of an integrated PV/T water heater under Indian climatic conditions have been studied. Book includes, annual performance, overall thermal and electrical efficiency, instantaneous efficiency, energy and exergetic analysis, analysis of various configurations of PV/T collectors and withdrawal rates, energy metrics, energy pay back time and production factor, life cycle cost analysis, embodied energy and energy density, CO2 mitigation, and carbon trading. It also covered the economic, cost effective and sustainable aspects of PV/T technology. This study will be very helpful for undergraduate and post-graduate students, scientists, and professionals working on application of photovoltaics and global climate change.