The price of roof-mounted residential photovoltaic (PV) systems in Italy decreased from 3. How much energy do solar panels produce in Milan? See real PVGIS data, monthly output charts, savings calculations, and payback periods for Milan, Italy. See costs by region, Detrazione Fiscale 50%, and GSE net metering. A typical 6 kWp system costs €6,600–€9,000 before incentives, generates. Solar panels have become a popular and reliable energy solution in Italy, offering homeowners the opportunity to significantly reduce energy costs while contributing to a more sustainable future. Why does the same 500W monocrystalline panel cost €0. 31/W in Rome? Let's cut through the noise.