Energy policies accompanying the transition towards a sustainable development process must be supported by technical analyses in which future energy scenarios are modeled and evaluated. This paper analyzes possible decarbonization scenarios in Italy for the year 2050. They envisage high electrification of transports and residential buildings, high use of renewable energies, and a modal shift towards public transport. The energy scenarios are evaluated using a software program, EnergyPLAN, starting from a reference model developed for the year 2014. Special attention has been given to the modeling of data that are unavailable in the literature, such as the time profile of heating and cooling demands, obtained with the degree-days method and validated by elaborating the results of the modeling of the residential building stock, this latter was dynamically simulated in TRNSYS. The results show that to obtain a significant decrease of greenhouse gas emissions and fossil fuel consumption, it is necessary not only to promote a deeper penetration of renewable sources, but also their integration with other technologies (cogeneration, trigeneration, power-to-heat systems, thermal storage, vehicle-to-grid operations). In fact, renewables technologies alone can raise some critical issues, such as excess and/or shortage of electricity production and non-sustainable exploitation of biomass.

Apartment position and operation within buildings play a significant role on energy consumption and also on perceived thermal comfort. Dwellings with favorable positions can have significant benefit, also when heated for a limited number of hours, if compared to apartments located in disadvantaged positions (i.e., upper or lower floors or north-oriented). This may be the cause of debates, especially in buildings with central heating, when heat costs are shared among tenants by means of sub-metering systems. In this paper, authors address this issue by studying the “heat thefts” phenomenon in dynamic conditions in a low-insulated building, when the heating system is used unevenly by the tenants (i.e., with different temperatures and/or use). To this end, a social housing building located in Mediterranean climate, where daily temperature excursions and solar heat gains enhance the dynamics of the heat flows, has been chosen as the case-study. The real operation of the building has been simulated in different operational scenarios and the model has been validated against energy consumption data collected experimentally. Results confirm that special allocation and or/compensation strategies should be taken in heat costs allocation in order to avoid accentuating situations of inequalities, especially in low-insulated and/or occasionally heated buildings.

Sector coupling strategies are increasingly adopted to improve the flexibility and efficiency of renewable energy systems by integrating multiple end-users, energy sectors, and conversion technologies. However, their widespread deployment relies on additional infrastructure and energy conversion processes, raising questions about the associated environmental and economic trade-offs. Despite the growing interest in Power-to-X technologies, integrated assessments simultaneously evaluating energy, economic, and environmental performance at the district scale remain limited. This study proposes an integrated framework combining techno-economic analysis and life cycle assessment to evaluate alternative Power-to-X strategies within a regenerated renewable energy community in Southern Italy. Three sector coupling pathways are compared: Power-to-Power, Power-to-Gas, and Power-to-Gas-to-Power. The results highlight different trade-offs among the investigated configurations. The Power-to-Power scenario achieves complete renewable electricity self-consumption and increases system self-sufficiency from 46% to 71%, whereas the Power-to-Gas configuration provides the shortest payback period (6 years). From an environmental perspective, the baseline, Power-to-Power, and Power-to-Gas scenarios reduce average life cycle impacts by 53%, 44%, and 40%, respectively, compared with the business-as-usual configuration, while the Power-to-Gas-to-Power scenario exhibits slightly higher impacts due to the additional fuel cell system. Furthermore, the environmental ranking of the scenarios depends on the adopted system expansion assumptions, particularly the avoided burden approach. The proposed framework provides a comprehensive basis for evaluating sector coupling strategies in renewable energy communities, supporting decision making through the integrated assessment of environmental performance, economic viability, and energy self-sufficiency.