Advancing data management in local energy trading: European policy, state-of-the-art, and real-world practice in FEDECOM and STUNNED

<ns3:p>Effective data management and digitalisation are central to the success of energy trading and exchange systems across Europe, with energy communities and distributed assets forming a new pillar of EU energy policy. This open letter critically reviews best practices in data management for local energy trading, beginning with the policy and technical context and a consolidated literature review, and then using the recently launched STUNNED and ongoing FEDECOM projects as in-depth case studies. Both projects highlight how robust, interoperable, and secure data infrastructures support the evolution from centralised utilities to decentralised, flexible, and consumer-centric energy markets. We analyse key architectural approaches, demonstrators, and integrated solutions, and conclude with recommendations for accelerating the adoption of these practices and facilitating collaboration across the European research and innovation landscape. This analysis reveals that aligning technical best practices with policy objectives not only enables operational efficiency, transparency, and consuler protection, but also accelerates the uptake of flexible, market-integrated energy communities across the EU.</ns3:p>