Development of a Regional Energy System Optimization Model in an Open-Source Framework to Implement Water-Energy Nexus and Circular Economy Paradigms

Energy System Optimisation Models (ESOMs) are consolidated tools widely used to plan and evaluate the technoeconomic requirements of energy transition and decarbonisation strategies. High sectoral extension and detailed technological coverage of ESOMs, enhanced by the economic parameters, provide a robust monitoring tool for assessing the potential evolution of a targeted energy system under different scenarios including environmental, technical. Besides environmental and engineering aspects, the cost factors embedded in these models covers also the economic aspects of energy systems. Nevertheless, the field of energy modelling has some gaps to be addressed: Traditionally, these models have been adopted to study large geographic areas, from the country level and up. Another issue of these models regards their restriction to energy commodities. This leads to overlooking feasibility and sustainability of energy generation, conversion, use and scenarios addressing energy systems in relation to other resources. Water is among the critical resources which besides being an irreplaceable resource, is tightly and multidimensionally linked to various components and sectors of energy systems. Other important point that has gained increasing attention in recent years is the availability of open-source energy system modelling tools. Open energy system modelling frameworks give the opportunity to make the models accessible to academics and policymakers and the outcomes reproducible. By enhancing accessibility, open frameworks allow to use and build upon the existing models, while also ensure transparency and reproducibility of the results. The central objective of this thesis is to address the mentioned gaps in the existing literature. Firstly, it aims to introduce a regional-scale model within an open-source energy system optimisation tool. Secondly, it seeks to extend the energy model into water-energy integration by expanding the methodology, introduced and implemented previously for a simple case study, to a complex energy system instance. Thirdly, provide an assessment instrument capable of quantifying the reciprocal impacts of water and energy in different sectors of the model and enable evaluation of the effects the energy and water scenarios on both systems. The energy system optimization model, TEMOA-Piedmont’s developments steps and assumptions are widely explained. TEMOA-Piedmont is the first ESOM of the region, developed from scratch and withing an open-source framework. Beig a brand new model, the validity of the it is then examined comparing the outcomes of historic period with the best available data. The validation showed a perfect alignment with the statistics of the region. Moreover, the robustness of the model was tested by implementing scenarios adopted from the environmental and energy documents of the Piedmont Region. In parallel to the energy system development, the water-energy nexus implementation methodology was introduced. The methodology was tested in a simpler energy system model, i.e., the Pantelleria Island, Italy. As characteristics of water systems are highly dependent on the specific features of the studied system, the presented methodology, required further extension and improvements to fit to a more complicated energy system, i.e., the Piedmont case study. The work thus presents the detailed steps to define and characterise the technologies which connect the water and energy modules, especially in power and residential sectors. In addition, some of water sector specific technologies, constructing the Reference Water System of the model, needed to be modelled. These technologies include water treatment facilities, water pipelines, sewer system and wastewater treatment facilities. The integrated model is finally used to implement an exploratory scenario to evaluate its robustness and correct functioning.