The production of electricity from renewable sources plays a strategic role in the future of energy because it helps to effectively manage climate change through an energy generation portfolio with lower emissions of greenhouse gases. Photovoltaic solar energy is safe and sustainable and is characterised by a growing trend with a cumulative installed capacity that has reached a total of 40GW in 2010. In this paper, investigations are presented using multiple calculations: Energy Payback Time (EPBT), Greenhouse Gas per kilowatt hour (GHG/kWh), Energy Return on Investment (EROI), Greenhouse Gas Payback Time (GPBT) and Greenhouse Gas Return on Investment (GROI). These metrics make it possible to define the energy and environmental performances for a building-integrated photovoltaic system located in Italy. The module efficiency, the embodied energy and the annual solar irradiance are variables that play a strong role in this analysis. The key parameters include the type of solar cells (e.g., mono-crystalline silicon, polycrystalline silicon, amorphous silicon, cadmium telluride) and the location where the system is installed (Milan, Rome and Palermo). The results determine whether solar energy has a viable strategic role in the global energy market.