Digitalization is strongly entering new application domains around the world, thus also entering people's everyday lives. Digitalization enables creating new kinds of businesses, but it also changes the way services, applications and data are provided and consumed. We carried out interviews with company representatives acting in the energy domain to receive up-to-date information about the companies' awareness of digitalization, and the required changes they have identified in their future business scenarios. The interviewed companies were aware of the change pressure caused by digitalization, and especially the data exchange with other domain actors, predictions using data, new data-based services and data-based decision making were identified as key issues. However, currently there is a lack of digital infrastructure enabling the actors in the energy domain to perform data-based cooperation. The purpose of this paper is to identify the requirements for an energy data ecosystem that enables the companies in the energy domain to reach their business goals and to cooperate in data-based business. The initial goal is to identify the future tasks and goals of energy domain actors and define the type of cooperation environment, including knowledge management models and supporting services, required to support them. The research was implemented with industry actors in the energy domain that represent several different roles in energy markets, and the results of the research were also validated among the industry. INDEX TERMS Data ecosystem, data-based business, knowledge management models, energy domain, requirements specification.