A New Electricity Infrastructure for Fostering Urban Sustainability: Challenges and Emerging Trends.

In Europe, cities host around the 75% of the population (80% expected before 2050), they produce the 85% of the GDP and are responsible of around the 80% of the Total Final (energy) Consumption (TFC) and the 80% of the total Green House Gases (GHG) emissions. For securing the impact of the measures taken by cities while addressing climate change, sustainability, and the energy transition, there is the need for a wide approach, covering at least the national and European levels. Energy transitions should consider a mix of various commodities (electricity, heat, hydrogen, synthetic fuels, etc.), but it is generally agreed that electricity is going to play a central role. The electrification process is based on an “energy triangle”: 1. direct production of electricity from RESs; 2. electricity as an energy vector for distribution and storage; and 3. electrification of energy final uses. This transition requires new ways of thinking and new paradigms for exploiting electricity in the cities. Accordingly, new concepts are popping up like energy communities, positive energy districts, distributed generation and storage, autonomous micro grids, requesting a deep change in the present vision. In order to make it happen, the electricity infrastructure needs a “smart” upgrade in terms of both physical and cyber network assets, and operational approaches and practices. The present electricity infrastructure shows clearly its limits while trying to implement the new paradigms when current assets and operations criteria are kept unchanged. We need a new vision of the electricity infrastructure, capable of matching the new vision of the cities. This vision will require for its implementation not just technical measures, but also new approaches to the governance of the local energy system, new instruments for financing the transformation in a relatively short period, and new market rules for rewarding all actors. Among the emerging challenges one should consider: - the increasing penetration of small size distributed generation based on low controllable RESs, - the growth of power/energy demand due to increased electrification of final uses, - the challenging local resources’ exploitation (mainly RESs, but also storage) to satisfy the needs of local energy communities, and, - the possibility to share production with other communities with “positive energy” contributions, Finally, the changes operated on the new infrastructure could involve the distribution system shifting from the present AC (Alternate Current) to a new DC (Direct Current) energy vector as a promising option. This paper aims to present and discuss in their salient features new visions that make it possible to implement new sustainability scenarios so that the energy transition towards pre-established objectives can gradually be implemented and propagated from the cities towards the entire Country system, maintaining adequate quality levels for consumers and producers of electricity.