Advanced Urban Energy Planning: an interdisciplinary approach to improve heat decarbonization assessments

Urban areas have been recognized as the heart of the decarbonisation process, being potential drivers of sustainable or unsustainable paths. The necessary transition to cleaner and more sustainable cities recently raised the research attention on the possible ways to perform urban energy planning. However, there is still not a wellrecognized procedure and an agreed methodological framework to support urban energy planning, leading to inappropriate strategy definitions, directly focusing on the design of a pre-defined plan. This thesis has the primary objective to contribute in providing a theoretical-methodological framework to support urban energy planning by exploring, applying, adapting and combining with other disciplines, the principal energy system planning methods and tools. A review of scientific literature was performed to identify the state-of-art significant limitations on which the thesis was structured. Without seeking to replace other existing modelling approaches and without presupposing a full knowledge in the different research disciplines, this Ph.D. dissertation provides a basis for understanding how the weaknesses of the different approaches can be rectified by the strengths of others to move beyond traditional urban energy planning applications focused on the built environment. Comprehensive energy system methods and tools are necessary at the planning stage to quantitatively consider interactions among sectors and demand and supply options over long-term horizons. Nevertheless, the thesis confirms that while they are incredibly useful for planning purposes, they cannot be used alone for urban applications and should be combined with other methodologies. This need is mostly related to the necessity of disposing of a detailed and highly disaggregated description of the demand and of the spatiality to deal with specific urban needs (critical areas, liveability, built environment constraints). In particular, spatial analyses are fundamental in urban planning to considerably improve the quality of planning and decision-making processes through intuitive visualization maps. Furthermore, the involvement of stakeholders is key to the success of the planning procedure: they speed the data collection process, support definition of assumptions and a shared city vision (qualitative evaluations). Given the complex nature of urban energy planning, an interdisciplinary and integrated methodological procedure - based on the actions of knowing, understanding and planning – is therefore proposed. The procedure combines building physics, energy planning and territorial analyses to create a preliminary methodological background able to deliver technical, financial and environmental insights for the definition of energy plans. The proposed methodological framework was applied to a case study that fixed the research boundaries to the demand and supply side of the urban built environment of district-heated cities. The case study, on the one hand, provides numerical evidence to results and on the other hand offers a theoretical background for guiding urban planners, researchers, and decision-makers in future urban planning applications. As a result, the proposed integrated and comprehensive framework provides evidence of the multiple benefits of taking into account synergies between demand and supply, particularly in term of avoided additional investments. The scenarios analysis confirms that ambitious environmental targets can be reached at reasonable added costs if investments are appropriately channelled. The suggested research advances in urban energy planning will allow achieving more informed assessments of appropriate strategic investments, their life-cycle costs, and energy/ environment ambitions. All the recommended planning phases are fundamental, and the author suggests to push future research and practices to enhance the procedure by dividing it into a planning stage (knowing & understanding/ planning/ prioritizing & deciding) and into an operational phase (designing/acting/ monitoring & informing), leading to a bi-directional flow of information between planning and operational models.