Today’s growing energy demand requires solutions to optimize the use of available resources. Energy communities can contribute to a sustainable future by reusing excess energy, but their expansion is limited by a lack of confidence in current systems. This paper presents an infrastructure that allows for efficient and secure integration of energy communities into the power system. The developed infrastructure enables both energy exchange between communities and the provision of flexibility services to grid operators, contributing to a more efficient and dynamic system management. Blockchain technology is used to create a transparent, immutable, and decentralized system, improving the traceability and control of energy transactions while reducing costs. This allows energy communities to actively participate in grid optimization, providing agile mechanisms for congestion management and demand response. The paper introduces an innovative approach that enhances power system efficiency, promoting greater sustainability and resilience. It also includes an analysis of the state of the art in blockchain technology and its application in the energy sector, highlighting the advantages and challenges of its implementation.