With the aim of estimating the short and long-term effects of climate change on hydroelectric producibility, strongly correlated to surface runoff, trajectories of the latter variable up to 2100 were generated, for each area of the Italian electricity market, in response to different climate scenarios. Eighteen projections of monthly precipitation and average monthly temperature were used as input to the distributed hydrological balance model BIGBANG, which provided projections of the components of the hydrological balance, including runoff.

Based on the results obtained, it is highlighted how climatic variations affect the water resource in a non-uniform way between the different areas of the Italian territory, recording increasingly significant percentage decreases moving towards the South. The uncertainty deriving from the emission scenarios is certainly preponderant compared to the modeling one, highlighting how the climate change mitigation measures typical of the RCP 2.6 scenario led to an overall stability of the system, predicting increases (however modest) in the availability of the resource on the territory.

On the contrary, in the case of the RCP 8.5 business as usual scenario, the effects of hydro-meteorological alterations are much more relevant, so much so that in the areas of the South, where the historical values are already currently reduced compared to the rest of the country, they would prefigure conditions of extreme water crises.