The transition to a decarbonized energy system is driven at the European level by theStrategic Energy Technology Plan(SET-Plan), which is based on the priorities of theEnergy Union, while at the Italian level it is driven by the National Energy Strategy issued at the end of 2017. This transition is actually changing the structure of electrical grids in European countries and, more generally, is changing thegovernanceof the entire energy system.

Currently, generation from non-programmable renewable energy sources with dispatch priority is continuing to grow to the detriment of thermoelectric generation. Although the flexibility of conventional plants is increasing, the provision of system services is still difficult and economically burdensome, which increases the risk of contingencies. Adding to these critical issues is the risk ofwide areapropagation of disruptions due to the exploitation of interconnections between countries which were originally created to ensure mutual aid but are now increasingly used for massive commercial energy transactions. Last but not least, there is a clear urgency to improve the resilience of the energy system with respect to extreme weather and environmental events, as these are becoming more frequent and intense due to climate change and cause social impacts and huge economic damages every year.

In order to ensure citizens a safe, sustainable and cheap energy supply for citizens even under the said conditions, the Project has continued, in line with the 2015-2017 Three-year Period, to develop methods and tools aimed at providing operators support for the quasi-onlinemanagement of the dynamic security of the interconnected grid in the event of uncertainties, and assess the resilience of the energy system in the face of extreme events, proposing active and passive mitigation actions.

Within the CEI working group on resilience, a close collaboration has been created withstakeholderswith whom the issues caused bywet snowand falling plants were analyzed, making use of the WOLF warning and monitoring tool and experiments conducted at the WILD station. We also proposed the MERIDA meteorological reanalysisdataset to describe the variables that characterize extreme events.

As part of the ISAP+ (Integrated Security Assessment Platform), models of some passive countermeasures were developed to quantify the benefits brought to system resilience in the face of wet snowfall, in terms of reduction of lost load: anti-torsional devices andcoatingice-phobic devices.

To assess the possibility to make combined cycles more flexible, accelerated maneuvers were analyzed with a dynamic plant simulator and a finite element model, estimating the relative material life consumption based on the damage law inferred from experimental tests carried out in previous years.

During the Three-year Period, the IRIS tool was developed aimed at the classification of the seismic risk of concrete dams, based on fast methods that allow to assess structural safety and leaks resulting from uncontrolled water release. Maps of floodable areas were made available in IRIS for facilitate their use. Advanced models for seismic verifications of dams capable of reproducing seismic wave propagation in foundations as well as simplified models for predicting the long-term expansion potential of concrete which causes its degradation were also developed. Finally, the new FOSS SPH SPHERA code version 9.0.0 (RSE SpA) was released to study floods, landslides and estimate flood damage in electrical substations.