In the transition from fossil fuels to renewable energy sources, local energy communities are a smart solution to create self-sufficiency and reduce grid congestion. However, traditional evaluations of local energy systems mainly consider energy quantities, which creates a risk of overlooking energy quality (exergy). This reduces the possibility of thermodynamic optimization through exergy analysis. Thus, this study investigates the energy and exergy performance of a local energy community in Uppsala. The study investigates how different technical configurations impact the independence from the external grid and the overall resource utilization of the system. Based on hourly energy data, exergy flows were calculated, showing the thermodynamic quality difference between electricity, fuel and heat. Then, the community’s self-sufficiency rate, self-consumption rate and exergy efficiency were calculated in different technical scenarios. In addition to the reference scenario which relies on imported energy, three scenarios were investigated: solar panels, solar panels combined with a heat pump and solar panels in combination with combined heat and power (CHP) integrated with thermal energy storage (TES). The results indicate that the technical configuration significantly impacts the exergy efficiency as well as the self-sufficiency of the system. Additionally, the results indicate that scenarios with a higher self-sufficiency have a lower exergy efficiency. This study demonstrates that exergy analysis is an interesting complement to traditional energy calculations, for revealing hidden thermodynamic losses. It also highlights the importance of the choice of system definition when conducting an exergy analysis.

The conclusion is that future designs of energy communities should be optimized based on both energy quantity and quality. This could maximize resource efficiency and support a truly sustainable energy transition. Furthermore, the study highlights the need for future research to evaluate exergy efficiency from a broader perspective to understand the efficiency outside of the community’s border, to investigate the full impact of energy communities in the bigger energy system.