Indexes and indicators for the planning and decision-making process of the urban eco-energy system: the case study of the City of Turin

Climate change phenomena, environmental degradation and air pollution impacts represent a concrete threat to the human well-being of the future years, calling for immediate action by governors, who need to develop tailored policies to tackle these problems. In particular, the current paradigms of energy consumption, being one of the main causes of the above-mentioned problems, must be revised. Although efforts are needed at all levels of governance, urban policymakers can provide a significant contribution to the cause. In fact, even if cities only account for less than 2% of the Earth’s surface, they consume 78% of the world’s energy. Dedicated science-based tools can provide an effective support to the decision-making process, helping in the development of appropriate policies. In this sense, a key role could be played by the definition of ad hoc metric systems, used both for assessing, in a quantitative and objective way, the current situation, which is essential for orientate the policies, and monitoring the evolutive trajectories of the urban energy systems, which is necessary to analyse the effect of the policies, quickly identifying issues and refocusing on priorities when needed. An effective metric system, aimed at measuring the progress of urban areas towards energy transition, should take into account the multitude of related aspects which are of relevance at local level, by also capturing eventual cross-sectoral phenomena. The scope of this work is then to provide, by means of a structured methodology, a comprehensive framework for measuring performances in the context of urban energy transition process, testing it through the case-study of Turin city. In particular, the proposed methodology entails multiple steps. First, data-gathering and storage procedures used to build a dedicated database are described, also highlighting main decision criteria in the process of data collection. Secondly, the conceptual design of the database - characterized by a hierarchical, multi-domain structure - is shown; three main domains (energy system, environment, socio-economy) involved in the energy transition process are detailed through the definition of lower-level layers (sub-domains and fields). Then, multiple indicators are set for each field of the developed framework, basing on existing literature or by own definition. A selection of these – the core indicators – are normalized and aggregated, building aggregate indicators for the fields, sub-domains and domains of the framework, as well as a global aggregate index, the “Green Transition Index”. Finally, to prove consistency of the proposed framework, statistical coherence between indicators and aggregate indexes is evaluated. The results for the study case, focused on period 2014-2019, according to the data availability, besides providing useful insights on the multitude of analysed phenomena, show that aggregate indexes well represent the underlying indicators. Still, in some cases, a certain degree of trade-off occurs in the phase of aggregation, highlighting that aggregate indexes need to be considered together with simple indicators to draw accurate conclusions and provide effective information to the policy decision-makers.