For environmental assessment of photovoltaic systems generation from solar power, it is necessary to consider the fact that a sequence of activities must be accomplished in its production process, not only manufacturing but also installation for proper operation. According to the composition of the energy matrix of the country where this is done, a greater or smaller quantity of CO2 emissions will occur, apart from other environmental degradations. In this case the need of verification is evident, considering the energy matrix of the country where a panel is developed or used, its ability to depreciate the energetic cost and the CO2 emissions, as well as the degradations caused by the manufacturing process. After that, if the photovoltaic panel is still capable of functioning then it will be considered as a source of clean energy. This study has therefore surveyed the energetic costs and CO2 emissions of the manufacturing process of photovoltaic modules. Later this data was used to further analyze the energetic and CO2 mitigation balance and the module capacity for mitigating the environmental liabilities caused by production, by considering different production and using panel's sites. The results obtained demonstrated that the greater the emission factor of the panel production country, the greater the required time for emissions reduction due to its production. For instance, in case of panels produced in China and used in Brazil, they could have a truly clean useful life (EULT) up to three times lower than those produced in Germany. The implications of these results were discussed. (C) 2015 Elsevier B.V. All rights reserved.