The recent growth of photovoltaic (PV) electricity generation despite its high levelized costs is largely explained by strong national policy supports. Indeed, renewable energy sources are receiving increasing support worldwide from public authorities because of the environmental benefits they bring in comparison with conventional energy sources. Thus, many countries have set targets for PV deployment. The possibility to achieve them at a lower cost has now become a central issue, making it necessary to examine the efficiency of the instruments used to promote PV. After describing the mechanisms of the impact of demand and supply on the reduction cost of PV systems, the public support for PV is assessed for five representative countries (France, Germany, Japan, Spain and the US) from an extensive policy review. Based on their financial evaluations, the performances of these policies are compared from the different states of PV development in each country. The main conclusion is that it is necessary to have a well-planned policy, i.e., with a controlled level of expenditures and balanced allocation of these, in order to install the desired amount of PV, to control its impact on the electricity prices and to give a sufficient visibility to the industrialists. (C) 2012 Elsevier Ltd. All rights reserved.