Assessing the impact of climate change on solar energy production on the Italian peninsula

This study aimed to assess the impact of climate change on solar energy production up to 2100 on the Italian peninsula by focusing on the key variables of global solar irradiance (GHI) and temperature and examining the photovoltaic (PV) energy production by means of the capacity factor (CF). Regional Climate Models (RCM) simulations from Euro-CORDEX models assimilating time-evolving aerosols were selected to ensure accurate estimations of solar radiation trends in future RCP scenarios. A bias correction was applied using the SARAH-3 solar radiation dataset for GHI and MERIDA reanalysis for 2 m temperature data to enhance the accuracy of CF estimation.

The trend analysis revealed a slight decrease in the GHI under RCP 2.6, while the other RCPs exhibited significant increases, especially over the mountain regions in central Italy. The opposite trend is foreseen in the Alpine region, particularly under RCP 8.5. Moreover, temperature is projected to increase, notably under RCP 4.5 and RCP 8.5, with potential implications for production efficiency and snow cover reduction in the Alps, with subsequent decreases in solar irradiance related to the diffuse component.

Analyzing the trend of the ensemble mean CF for the 2021–2100 span across the different RCPs, under RCP 8.5, a significant decrease is predicted, particularly in the Alps, due to the reduced GHI. Despite the general increase in the GHI, a decrease in the CF is likely for most of Italy due to rising temperatures potentially reducing solar panel efficiency. RCP 4.5 and RCP 2.6 showed less pronounced decreases in solar production, with RCP 2.6 being the scenario with the lowest magnitude of the climate signal.

Seasonal cycle analysis revealed variations primarily linked to changes in GHI throughout the year. RCP 8.5 exhibited a significant decrease in production during winter, followed by a slight increase in summer, which was likely dampened by increasing temperatures. RCP 4.5 maintained similar characteristics, with a less pronounced decrease in winter and stable production in other months. RCP 2.6 showed a slight increase in spring and generally stable production throughout the year.

In conclusion, climate change is expected to marginally influence photovoltaic power production in the Italian peninsula under different RCP scenarios, with temperatures playing a predominant role, particularly under the RCP 4.5 and RCP 8.5 scenarios, dampening the effect of increased solar radiation on PV production. The Alpine region represents an exception, with marked solar radiation decreases likely associated with reduced snow cover expected by the end of the century, leading to a significant decrease in the CF. The future expansion of photovoltaic installations should consider these findings, especially those in the Alpine region.