Energy sharing is becoming a significant goal to foster sustainable energy use in modern cities and districts. Renewable energy communities and fifth-generation district heating and cooling networks are developing technologies aimed at reducing management costs and carbon footprints while increasing renewable self-consumption. These solutions typically need different buildings to better match energy profiles (electric or thermal), but they are often difficult to deploy as industrial, commercial, and residential buildings are found in separate districts. In this context, supermarkets, which are often built in residential areas, can be an opportunity to develop efficient energy networks in city centres, providing large areas for photovoltaic installations and a significant amount of heat rejection due to refrigeration. In this work, Urban Building Energy Modelling (UBEM) simulations are used to quantify the amount of heat rejected by supermarket refrigeration systems and the solar energy that is potentially produced using supermarket rooftops and parking lots for photovoltaic panels. Results are used to assess the extent to which this rejected heat could be exploited in surrounding buildings within a fifth-generation district heating network. The case study covers a selection of supermarkets in Padova, Italy, and their surrounding areas. Findings of this analysis suggest that the potential thermal and electric energy sharing in the case study district can reduce carbon emissions in one year by around 10%. Moreover, it shows that residential PV potential can be beneficial to supermarket electricity consumption, while supermarket waste heat can help house space heating in the winter season.