This paper analyzed the impact of climate change on two of the most widespread renewable resources in the country, the photovoltaic and hydroelectric resources. With regard to the photovoltaic resource, the scenarios developed in the year 2020 by the Euro-CORDEX climate models were updated with an analysis of all three emission scenarios (Representative Concentration Pathways – RCP) with a time horizon up to 2100. A new bias correction methodology has been applied and the new meteorological reanalysis MERIDA-HRES has been used, which is better in estimating solar radiation than the previously used MERIDA.

For the hydropower resource, a runoff scenario was generated for each of the three major RCPs, using only one regional climate model at this time. This variable represents the main driving force for a data-driven model, developed in the previous three-year period and updated in this paper, that predicts monthly hydroelectric producibility in response to resource availability.

In terms of PV producibility, the study shows an increase in producibility compared to the reference period 1990-2010, albeit by a few percentage points and with some variability depending on the market area, scenario and season, with average values not exceeding 5%. These increases characterize in particular the summer and part of the autumn period over northern Italy, seasons in which the greatest production is concentrated. The negative effect of high temperature on panel performance is observed especially for the RCP 8.5 scenario and in the summer. In this regard, some regions in the central south and the large islands experience a slight decrease in producibility towards the end of the century, albeit in the presence of an increase in solar radiation.

With regard to the hydroelectric resource, the analysis of the results in terms of runoff highlighted the significant impact of climate change on its availability. In fact, among the three scenarios analyzed, RCP2.6 is the only one characterized by long-term increases in streamflow in all electricity market areas, while RCP8.5 even shows decreases of more than 30%. In addition, in this scenario there is a profound change in the hydrological regime, with an increase in winter water availability at the expense of summer water availability, which reaches a minimum in northern Italy towards the end of the century, settling at values around 50 % of the current ones.