# Assessment of the Impacts of Climate Change on Power Systems: The Italian Case Study
## 1 Introduction
### Reference Methodologies  
This section discusses the two main papers [13; 14], from which the methodologies for assessing the impacts of climate change on power systems are drawn. These papers deal with the impacts at the European level, from which information was extracted for the impacts on the Italian electricity grid.  
In [13], the climate change impacts on PV, wind, hydro, and thermo power generation for 28 European Union countries were evaluated.  
Five RCM (regional climate model) simulations taken from the EURO-CORDEX initiative [15] were used. This ensemble of simulations comes from a model simulation selection methodology, necessary to gain a cheaper computational cost. The five selected RCM model experiments were based on a combination of three GCMs (general circulation model) and three RCMs. Climate models need to be forced by an emission scenario, so in [13], four out of five simulations were forced with an RCP (representative concentration pathways) 8.5 radiation forcing scenario, whereas the remaining model was forced with an RCP 4.5 scenario.  
Referring to IMPACT2C project studies [16], [PERSON] et al. used 1971-2000 as the reference climate period to compare future changes in power generation.  
The assessment focusses on three global warming levels, i.e., 1.5 \({}^{\circ}\)C, 2 \({}^{\circ}\)C and 3 \({}^{\circ}\)C (with respect to the pre-industrial period 1881-1910), which will be reached, according to the five simulations above, in time periods spanning 2004-2043, 2016-2059, and 2037-2084, respectively.  
Three-hourly data was used for wind and PV power analyses, whereas daily time-series were used for hydro and thermoelectric power.  
A 0.11\({}^{\circ}\) in latitude and longitude (almost 12 km) was the spatial resolution of the simulations, over the European region.  
In [14], the impact of climate change on surface climate indicators (2 m temperature, 10 m wind speed, surface irradiance) and power systems components (sensitive to weather),within a chosen power system scenario, was analyzed. In this way, two types of uncertainty were considered: power system scenario and climate change projection. Moreover, the impacts of climate change and uncertainty were investigated considering the differences between technologies (amount of wind and PV installed generation) and geographic locations. Finally, [PERSON] et al. studied whether the operation of different European energy policy scenarios was impacted by climate change. The Copernicus Climate Change Service (C3S) European Climate Energy Mixes (ECEM) project was used as the data source for meteorological variables, electricity demand, onshore wind and PV generation, for each climate model and emissions scenario. Hydropower generation was excluded as it was considered to be of high operational complexity.  
These data were derived from two sources of climate data: a bias-adjusted reanalysis of the period 1979-2016, and a regionally downscaled climate model projection spanning the period 2006-2100.  
Six EURO-CORDEX global-RCM couples forced with RCP 8.5 and RCP 4.5 were considered. These models were selected to give a likely representation of current European climate, whereas the inter-model range was considered to give a range of the likely climate change responses of the 11-member EURO-CORDEX set.  
The climate change impact on electricity demand and generation was evaluated considering the 2015 power system scenario, taking the difference between the 2045-2065 mean and the 1980-2000 mean, for Europe and four case study countries (Sweden, Romania, Italy and Germany), on an annual mean and seasonal mean basis.