Valutazioni sulla stabilità di frequenza e sui requisiti di inerzia e potenza di cortocircuito nel sistema elettrico italiano: modelli e strumenti integrati

The energy transition involves a widespread adoption of renewable generation and the simultaneous reduction of thermoelectric generation. This implies a decrease in the resources for frequency regulation, inertia and short-circuit power, to be compensated by other resources and solutions. Adequacy assessment of the flexibility resources for power system stability is therefore essential. The report presents three activities about this topic. The first activity concerns the updating of a tool aimed at the mono-zone (based on one-busbar equivalent) adequacy assessment of resources for conventional (“slow”: primary, secondary and tertiary) frequency regulation and for short-circuit power provision. The tool has been updated for multizonal analyses of the active power reserve and has been prepared for multizonal developments concerning the short-circuit power. The application to a 2030 national scenario has shown potential criticalities in the fulfilment of secondary and tertiary reserve requirements, related to the scarcity of thermoelectric generation on the basis of significant decarbonization assumptions. The second activity concerns the evolution of the “SeTA” procedure (Innovative Services: Automatic Tuning) for the optimization of ultra-fast frequency regulation services. A new iterative approach has been implemented to improve the accuracy in identifying equivalent output-error models of the electrical system which are used for sizing the necessary regulating quantities. The new approach considers, already in the identification phase, the contribution of innovative regulations. Application to a 2030 Sardinian scenario highlights that fast-primary regulation is essential. A contribution of synthetic inertia proves necessary in case of non-implementation of the three new synchronous compensators that are indeed planned. The third activity concerns the definition of specifications for a platform dedicated to the integrated analysis of slow and ultra-fast frequency regulation resources. Considering the developments achieved in the calculation procedures described above, automating the acquisition of the market simulation results, preliminary to the flexibility analyses, is deemed a priority.