Costi ed emissioni...alla luce del sole

Renewable energies are an important resource for electricity production, thanks to the lower environmental impact with respect to the utilization of fossil fuels. However in most of the cases, benefits in terms of fossil fuel savings and avoided emissions, are determined neglecting the contribution required by the power plant itself within its life cycle (i.e.the emissions and the energy required from the plant construction to the decommissioning).
In this paper an analysis of the energy pay back time (EPBT) is carried out for a 3kWp domestic photovoltaic plant starting from the LCA information provided by the scientific literature for mono and poly-crystalline modules. The analysis specifically refers to the situation in force in Italy considering the actual insolation data for two representative cities and a proper value of electricity conversion efficiency which allows the calculations of the primary energy savings referred to the annual electricity production of the PV plant. It comes out that EPBT values ranging from 3 to 9 years are obtained depending on the latitude of the city and the original LCA data considered.
It is finally pointed out that results strictly refer to grid-connected PV plants while for stand-alone applications higher EPBT values can be predicted.