Energy sharing based configurations and end-users' role towards energy efficiency and environmental sustainability

The global energy landscape is undergoing a profound transformation, driven by the need to address climate change, rising energy demand, and the consequent reconfiguration of energy production and consumption systems. In line with policy directives, the energy transition focuses on increasing the integration of renewable energy sources (RES), reducing greenhouse gas (GHG) emissions, and improving energy efficiency. This process is strongly supported by widespread electrification across all sectors, from residential to transport and industry. Within this context, the role of end-users is evolving, from passive consumers to active participants. This shift is reflected in the development of energy-sharing configurations such as Renewable Energy Communities (RECs) and Positive Energy Districts (PEDs), alongside the growing individual contribution of end-users to a more sustainable and flexible energy system. RECs represent a particularly promising pathway for practical implementation, supported by national legislative frameworks adopted across several European countries. These aim to deliver both energy and economic benefits while reducing environmental impacts and addressing social challenges such as energy poverty. In parallel, PEDs represent a further development within the evolving energy paradigm, extending the scale and governance structure of RECs. By integrating electricity, thermal, and mobility energy demand, they enable a multi-sectoral and flexible framework that enhances local resource efficiency, demand-side management and infrastructure utilization. Their primary objective is to achieve net-zero CO₂ emissions and local energy surplus from RES on an annual basis, thereby contributing to long-term environmental sustainability. Within these configurations, end-users play a central role, as their energy-related decisions can generate tangible impacts. In this perspective, increased energy awareness emerges as a key factor in reducing overall environmental impact on energy consumption. Beyond specific configurations, this approach can be generalised through the definition of methodological frameworks and evidence-based guidelines that influence end-user behaviour and align load profiles with top-down energy system strategies. With particular reference to energy and environmental targets, this thesis investigates energy sharing configurations and the role of end-users in the energy transition. A comprehensive analysis of RECs is presented, including a roadmap for their implementation based on a multidisciplinary perspective that integrates energy, economic and legal aspects. The proposed framework is structured into feasibility study, aggregation, operating phase and management. It provides a systematic approach for assessing technical performance, environmental impacts, economic viability and social implications, and it offers a replicable reference for REC development within the European context. Furthermore, a structured in-depth overview of ten multidimensional aspects of RECs is provided, covering REC definition, technological dimensions, optimization and simulation methods, monitoring and management strategies, business models and policies, and future urban trends. This is complemented by the evaluation and comparison of multiple case studies, based on numerical investigations, highlighting potential benefits, application fields, and stakeholder involvement. In addition, numerical analyses are conducted to assess the performance of RECs across diverse contexts and to evaluate the influence of different configurations, technologies and regulatory frameworks, including: o energy, economic and environmental benefits of a car-sharing system with electric vehicles integrated into a REC; o dynamic simulation model of a REC for a small municipality, also evaluating the integration of a battery energy storage system; o techno-economic feasibility of an Italian industrial member-based REC; o assessments of energy sharing models and economic remuneration schemes for RECs under Italian and Spanish regulatory frameworks, evaluating impact on communities and individual members. To support the diffusion of PEDs, a novel methodology for the energy and environmental assessment of districts and communities is introduced, aimed at verifying the achievement of PED targets. In this framework, a user-friendly tool for defining optimal plant configuration of a district, with a focus on the Mediterranean area, is presented. The tool requires annual district-level demand profiles for space heating and cooling, electricity, and domestic hot water, and allows the selection of the location. It includes different RES-based system options, whose operation is modelled by combining local renewable resource availability with plant performance characteristics. The tool enables the sizing of the selected technologies to achieve energy balance and assess annual carbon neutrality at the district level, while also showing how demand is met by the configured energy system. Finally, an innovative methodology for reducing end-users' environmental impact is presented, based on the power grid CO₂ emission factor. Considering its decreasing trend, due to the increasing penetration of renewable energy and temporal and spatial variability, both electricity load profiles and emission factors are analysed across seasons and day types. A load-shifting methodology is proposed to redistribute daily energy demand by shifting flexible consumption toward periods with lower environmental impact. In addition, specific compensation mechanisms are introduced to encourage users to adopt low-impact consumption patterns. Applications to residential and commercial end-users are carried out, with the most significant improvements observed in the residential sector.