D5.1.1.1 Define requirements for metadata schema

This deliverable, “Define Requirements for Metadata Schema” (Deliverable D5.1.1.1), was produced within the NFDI4Energy consortium as part of Measure 5.1 (“Categorization of energy simulation software”). It presents the foundational requirements for a metadata schema aimed at improving the findability, accessibility, interoperability, and reusability (FAIR principles) of energy simulation software across research domains. The document summarizes a comparative review of existing research software registries (including RSD, Open Energy Platform, OpenMod, and CoMSES Net) and identifies both generic and domain-specific metadata requirements. It defines core fields such as software identification, versioning, modeling approaches, and technical specifications, and proposes a modular schema design that supports controlled vocabularies and interoperability with related NFDI4Energy ontologies. The deliverable also outlines the stakeholder engagement and validation process through workshops involving energy modeling experts, ensuring that the resulting schema reflects the practical needs of the community. The outcomes of this work directly inform subsequent schema implementation and registry development activities (Deliverables D5.1.1.2 and D5.1.1.3).