This chapter presented some of the case studies on application of photovoltaic systems, like, decentralised power supply to house/building, water pumping, photovoltaic park, etc. The case studies demonstrate the design and installation aspects, output power analysis, energy and emission savings and cost incurred. They also demonstrate the successful use of sustainable materials, conservation of resources, and integration of renewable energy technologies. The examples are chosen from different climatic zones so as to present a wide variety of techniques.