Verso un sistema energetico italiano basato sulle fonti rinnovabili. Prima parte: analisi introduttiva, problematiche e scenari propedeutici

Scopo di questo lavoro è valutare la generale fattibilità di un sistema energetico italiano completamente basato su fonti energetiche rinnovabili. In particolare, si sono volute quantificare le dimensioni necessarie per l’apporto di fotovoltaico ed eolico,e le problematiche legate alla intermittenza di queste fonti, sia su scala circadiana che annuale. Si è confrontato quindi un ipotetico profilo di produzione, basato sui dati reali di produttività degli impianti esistenti per ciascuna delle 8760 ore che compongono un anno, con il profilo di consumo derivato, con alcune assunzioni, da quello reale del 2019.Il confronto è basato su un modello e su assunzioni differenti in relazione alle possibili strategie per affrontare il problema.Il lavoro non èquindi un piano energetico o il progetto di un sistema energetico reale, ma solamente uno strumento per fornire indicazioni quantitative sulle dimensioni attese e sui problemi che questo sistema dovrà affrontare

GT2007-28063 NUMERICAL ASSESSMENT OF SCAP: A PASSIVE SYSTEM FOR PREVENTING THERMOACOUSTIC OSCILLATIONS IN GAS TURBINE ANNULAR COMBUSTORS

ABSTRACT ENEL operates a dozen combined cycle units whose V94.3A gas turbines are equipped with annular combustors. In such lean premixed gas turbines, particular operation conditions could trigger large pressure oscillations due to thermoacoustic instabilities. The ENEL Research unit is studying this phenomenon in order to find out methods which could avoid or mitigate such events. The use of effective numerical analysis techniques allowed us to investigate the realistic time evolution and behaviour of the acoustic fields associated with this phenomenon. KIEN, an in-house low diffusive URANS code capable of simulating 3D reactive flows, has been used in the Very Rough Grid approach. This approach permits the simulation, with a reasonable computational time, of quite long real transients with a computational domain extended over all the resonant volumes involved in the acoustic phenomenon. The V94.3A gas turbine model was set up with a full combustor 3D grid, going from the compressor outlet up to the turbine inlet, including both the annular plenum and the annular combustion chamber. The grid extends over the entire circular angle, including all the 24 premixed burners. Numerical runs were performed with the normal V94.3A combustor configuration, with input parameters set so as no oscillations develop in the standard ambient conditions. Wide pressure oscillations on the contrary are associated with the circumferential acoustic modes of the combustor, which have their onset and grow when winter ambient conditions are assumed. These results also confirmed that the sustaining mechanism is based on the equivalence ratio fluctuation of premix mixture and that plenum plays an important role in such mechanism. Based on these findings, a system for controlling the thermoacoustic oscillation has been conceived (Patent Pending), which acts on the plenum side of the combustor. This system, called SCAP (Segmentation of Combustor Annular Plenum), is based on the subdivision of the plenum annular volume by means of a few meridionally oriented walls. Repetition of KIEN runs with a SCAP configuration, in which a suitable number of segmentation walls were properly arranged in the annular plenum, demonstrated the effectiveness of this solution in preventing the development of wide thermoacoustic oscillations in the combustor

Studio ScETuR del settore elettrico del PNIEC (nella versione della proposta MASE del giugno 2023)

This report analyzes the proposal of the National Integrated Energy and Climate Plan (PNIEC), published in June 2023 by the Italian Ministry of Environment and Energy Security (MASE). In anticipation of the final version - due in June 2024 - the ScETuR (Scenari Energetici Tutto Rinnovabile) code was tested through scenario simulations of the Italian electricity sector to 2030. The supplementary assumptions necessary to reconstruct the electricity (EE) demand and production profiles of the various energy sources considered are described, particularly of those Renewable Energy (RES) sources for which a strong increase in penetration in the Italian production mix is expected in compliance with European directives on FitFor55