# Assessment of the Impacts of Climate Change on Power Systems: The Italian Case Study
## 4 Climate Change Impacts on Demand and Electricity Supply of Present-Day Power Systems
### Wind Power  
Focusing on Europe, a +1.5 \({}^{\circ}\)C warming level (above preindustrial levels) could likely cause a northward shift of the Atlantic jet (North Atlantic wasted) by the end of the 21 st century, under the Business As Usual scenario (BAU) and RCP 8.5 [39]. Because of this, wind energy production in northern Europe would potentially increase, whereas in southern Europe (mainly Mediterranean basin) a potential decrease in wind production (even if negligible) has been projected [39]. This result confirms what was previously stated in [40], in which CMIP5 has been used as a database. These projections are also useful to understand the intra-annual and inter-annual variabilities of the wind energetic resource of a given region. Depending on the magnitude of intra-annual variability, the amount of produced energy injected into the electric power system would also change, compromising the adequacy of the system (short and medium term operation). The magnitude of inter-annual variability affects the long term operation of a wind farm, undermining projects and investments for future wind farms in a given region [40]. In [22] the changes in wind speed caused by climate change have been shown for Spain. In particular, four wind farms in four different regions of Spain have been considered. The results showed that, depending on the wind farm considered, a decrease or increase in wind speed was observed, with consistent variations in the annual production (an increase in production if the mean wind speed was forecasted to increase, and vice versa). Focusing on seasonal production, in summer the production was higher than in winter for all four plants. Nevertheless, non-significant changes in wind production have been forecasted; this fact confirms what was stated in [39,40] about the negligible wind energy production changes forecasted for southern Europe. In [13], considering the ensemble mean results for all countries, a wind power reduction was observed (except for Greece). Unlike PV generation, passing from 1.5 \({}^{\circ}\)C to 2 \({}^{\circ}\)C global warming scenarios did not imply a higher magnitude change; however, for 3 \({}^{\circ}\)C warming scenario marked changes in generation were noticed in most countries. In particular, reductions in production below 5% under 1.5 \({}^{\circ}\)C to 2 \({}^{\circ}\)C scenarios were obtained, whereas for the 3 \({}^{\circ}\)C scenario, the reduction change remained almost at 5%, except for Cyprus, Portugal and Ireland, where reduction exceeded 5%, reaching 10% for Cyprus. For Italy, passing from 1.5 \({}^{\circ}\)C to 3 \({}^{\circ}\)C warming scenario, the magnitude of reduction increased in a smoother way with respect to other countries (e.g., Cyprus), remaining below 5%. In this sense, unlike PV generation, wind generation variations were not significant between northern and southern Europe but depended on the specific geographical area considered. With regard to individual climate model responses, unlike PV generation, a marked spread in magnitude and sign of changes among the models were observed. Specifically, noticing that the strongest model projections were country dependent, for Italy, a spread in signs and magnitudes of changes within 5% has been noted. In [14], the overall European annual wind generation ensemble mean response projects a decrease of about 1% due to climate change. The interesting point of these responses concerns the individual climate model simulations. In [14], coherently with [13], a considerable spread in magnitude and sign of changes among the individual models was observed. Regarding the Italian case study, focusing on summer, the responses of the individual models showed two out of six models with an increase in wind generation (under RCP 8.5) greater than 30%, whereas three out of six models projected a decrease of 10% in production, and the remaining model showed no change in wind generation. The ensemble mean result for summer only yielded an increase in wind production (greater for RCP 8.5 than for RCP 4.5).