# Assessment of the Impacts of Climate Change on Power Systems: The Italian Case Study
## 1 Introduction
photovoltaic and wind power) were greater than hydropower capacity. Moreover, the worldwide RES capacity has experienced a net increase if compared with the previous year. While hydropower capacity grew by just 2%, the wind and solar energy power sectors witnessed a much greater growth (18% and 21%, respectively). Most renewable energy sources are non-programmable and intermittent sources, which means they are characterized by a limited capacity to adapt production to the growth of electricity consumption, and by strong, short term fluctuations. Climate change is certainly one of the main drivers of both the extent and the speed of changes happening in the power system. Climate change, responsible for fluctuations in environmental variables, will also have a quantitative and qualitative impact on future demand and generation (conventional and renewable). For instance, a recent report showed how a +2 \({}^{\circ}\)C rise in temperature will impact Europe's future electricity generation and demand, more significantly than a +1.5 \({}^{\circ}\)C increase [8]. However, these changes will not be uniform throughout the globe: northern countries will experience a greater climate difference. In support of this evidence, unevenness of climate change impact can also be forecast at a more local level. For instance, Mediterranean regions will be the most affected by climate change, with an increase in temperature 20% greater than the global average increase, and precipitation will be drastically reduced. At a more granular and local level, precipitation will be reduced unevenly through Italy, with the central and southern part being most affected during summer; while the northern regions will experience an increase in precipitation during winter. It is important to point out that precipitation levels projections and scenarios vary greatly depending on the RCP scenario selected [9]. With the scenario mentioned above in mind, power systems must evolve, and the transformation must be driven by cost reductions, energy security, reliability, resilience goals, and both local and global environmental concerns about greenhouse gas (GHG) emissions. Indeed, electricity grids are called upon to reduce greenhouse gases emissions. Power systems are in \"adaptation\" mode, being able to accommodate incremental changes in demand growth, technological change, and consumer preferences [10]. The gradual substitution of conventional programmable energy sources (mainly thermoelectric power plants) by non-programmable sources (photovoltaic and wind power) calls upon the need to face and overcome important challenges in power system adequacy and security management. In particular, a power system can be adequate only if it can ensure sufficient generation capacity to meet the electricity demand in each hour and market zone of a country. Uncertainty about the availability of RES generation poses a challenge to the adequacy of the power system. Climate change will likely increase the frequency, severity and persistence of extreme weather events which are already impacting the resilience and reliability of electric power systems [11]. Climate change will likely cause an increase in average temperature worldwide. This in turn will compromise power systems operations, because several components are sensitive to variation of the ambient air temperature. Moreover, the impact of climate change on renewable energy sources changes depending on the considered technology. Transformers are bound to a maximum operating temperature; therefore, global warming could strikingly compromise their nominal operations. Increased temperatures also affect the efficiency and power output of thermoelectric power plants. A higher frequency and severity of droughts (also caused by long heat waves) affect water availability, which in turn affects hydropower and thermoelectric energy generations. High temperatures also affect the efficiency of PV modules.