Synergies and challenges between Energy Communities and Positive Energy Districts: a systematic review

Cities generate approximately 70% of greenhouse gas emissions but also hold significant potential to achieve the European Green Deal targets by shifting towards sustainable, efficient, and renewable-based energy models. Positive Energy Districts (PEDs) and Energy Communities (ECs) are two emerging concepts that support the transition toward a just, community-driven, and low-carbon energy model. While both concepts have garnered academic attention and been introduced in European legislation, they still face significant barriers, including the absence of standardized definitions and limited real-world adoption. Despite their common objectives - promoting renewable energy, and citizen engagement - Positive Energy Districts and Energy Communities are often treated separately rather than in an integrated way. This study conducts a systematic literature review and identifies 80 documents, including 11 that address both topics simultaneously. These studies mainly focus on PED design and feasibility, methodological tools, and technical configurations. The articles are analyzed concerning the geographical scale, the governance structure, and the social, technical, economic, and environmental sides of PED and EC planning and implementation. The review highlights several key challenges, including fragmented definitions, the scarcity of practical examples, and different approaches to technical implementation. Nonetheless, combining both models could unlock synergies that improve technical and economic optimization, increase project appeal, and create room for innovation. Integrated PED-EC models could consist in PEDs incorporating ECs as a governing body or in district-level ECs with clear carbon reduction targets. The virtual-PED model might be the most adequate for these applications.