The energy sector is at the core of the twin transition towards digitalization and renewable energies. Therefore, a technological transformation toward renewables is coinciding with an inevitable uptake of innovative digital services. At the same time, fossil fuels are increasingly being replaced by electrification in major sectors such as mobility, heat, and industrial processes. Supply and demand in the electrical system operation needs to be seamlessly coordinated. Markets allow for this coordination through trading on different timescales. With the increasing share of renewable generation and flexible demand, these processes demand ever more stringent time resolutions, which in turn rely on fluent communication and the availability of data. Energy is to a large extent a regulated sector. Non-discriminatory access to the grid and to markets is a key principle that needs to be maintained in a data space setting. Furthermore, European and national regulatory bodies are imposing rules and guidelines that affect interactions and communications in the market. These will feed into the design and the governance of energy data spaces. In comparison with other industries, energy data spaces need to comply with a larger set of domain-specific regulations. At the same time there are strong regulatory bodies and industry associations that already have well-established processes to develop market-wide standards for communication, protocols, and data. These existing structures, which have much in common and often show a high degree of commonalities with modern data space reference architecture, should be linked and built-upon to form a uniform and federated ecosystem designated as Common European Energy Data Spaces (CEEDS). This is especially important due to the European principle of subsidiarity and European regulation, which leaves the organization of energy data management to the member states (MSs), as per Directive (EU) 2019/944, Article 23. This federated approach also complies with Article 24 of the directive and the European approach to energy data interoperability coined by implementing Regulation (EU) 2023/1162. Needless to say, it will also comply with future legislative actions.