In the last decades, the attention to solar energy as a renewable and nonpolluting energy source increased a lot through scientists, private and public institutions. Several efforts are made to increase the diffusion of such a source and to create the conditions making it competitive for the energy market. Particularly, for the photovoltaic (PV) sector, the module efficiency increase, manufacturing cost reduction and a strong public support, through favorable incentive schemes, generates a significant rise in the installed power, exceeding 40 GWp in 2010. Although the global trend of the PV sector is positive, differences among countries arise out of local peculiarities and evolutions in the national support policies. This paper investigate...