This document addresses the concept of a Common European Energy Data Space (CEEDS), providing detailed approaches and recommendations for its real-world realization. In particular, the main objective of this blueprint is to guide on enhancing the existing data infrastructures, in the energy domain, towards the full embracement of data space solutions. Bridging this gap will empower the introduction of novel energy services, which will increase the efficiency and reliability of the energy systems while providing substantial benefits for every stakeholder. The key scope of this document is to present (i) a framework for new economically feasible business use cases and (ii) the general data space architecture that can enable them. This architecture aims to interconnect the existing data infrastructures, of legacy systems, with federated data spaces; at this scope, technical specifications have been included.