Phd in ENGINEERING AND APPLIED SCIENCE FOR ENERGY
AND INDUSTRY

Thesis title: The energy transition and the role of the Distribution System Operator - A case study: The city of Milan

This document collects various research and projects carried out in the last four years on the Milan distribution network. Chapter 1 illustrates the energy issues and political guidelines of recent years at World and European level, underlining how is central the role of the electricity system and how high are the potential of flexibility on the distribution network, especially in the metropolis. Climate emergencies impose a revolution from an energy point of view and renewable generation imposes a change of the classic paradigm of electricity system: from centralized to distributed. The distribution network acquires an additional strategic value and consequently the DSOs. Therefore, the second chapter examines all the problems related to the rapid growth of loads and at the same time the resilience and reliability requirements of the ND, which becomes strategic and fundamental for the economic and social activities of cities. Overloads, network enhancement, resilience, failures and management of the DN are studied and presented through real cases and historical events of the Unareti network. The third chapter introduces the central theme of demand response. The market of flexibility services offered on the distribution network by the DERs to the DSO is considered both from the point of view of the SO and of the users, who could potentially become a resource for the electricity system and no longer a passive user. The demand response is first defined in its fundamental principles up to the most recent European projects, which are redesigning the continent's electricity system. Market patterns are specifically presented and analyzed through European and national use cases, also through examples of applications conducted by Unareti. Likewise, DERs are also modeled to evaluate their potential, then tested on different practices in terms of network services. The most recent Italian evolutions are illustrated through the latest ARERA resolutions and the most recent projects of the major Italian DSOs, including the analysis underlying the next project on flexibility that Unareti will also present to begin its experimentation in Milan. Finally, in the last chapter, the history of the Milan electricity network is reported. The projects of a century ago that allow the first energy generated from renewable sources to arrive in the city, give value and charm to what is now the new experimentation, a new impetus given by the energy transition. This chapter explains in detail: - the identification of non-structural critical issues that can be resolved with the services; - forecasting of services in a future availability market (forward according to the help scheme from Unareti); - the simulation of the intervention of the DERs present; - the costs and economic sustainability of congestion management through demand response. A final solution from an energy transition point of view is ultimately proposed by introducing distributed photovoltaic generation. Thanks to other studies related to the potential of photovoltaics that can be installed on the roofs of Milan, a massive installation is simulated on the areas powered by the plants considered. The verification confirms that this generation would make it possible to largely satisfy the energy requests in the critical periods identified, offering renewable energy close to the load with a great economic advantage demonstrated in detail. The mix of demand response and distributed generation is therefore decisive in periods of heat waves in every city like Milan. The thesis therefore not only presents the fundamentals of the future MiNDflex project, the first experimentation of flexibility on the Milan network, but also the surrounding conditions that the Unareti distributor has been managing in recent years on its DN, the most energy-intensive in Italy.