D4.3.2 List of Metadata Standards and Relevance for NFDI4Energy

Deliverable 4.3.2 LIST OF METADATA STANDARDS AND RELEVANCE FOR NFDI4ENERGY 10.11.2025 List of Metadata Standards and Relevance for NFDI4Energy Philipp Schmurr 1, Nan Liu 1, Amanda Wein 2,5, Jan Sören Schwarz 2,5, Alexandro Steinert 2,5, Ramiz Qussous 3, Aksornchan Chaianong 4, Ludwig Hülk 6, and Wolfgang Suess 1 1Karlsruhe Institute of Technology, Institute for Automation and Applied Informatics, ROR, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen 2OFFIS, Institute for Information Technology, ROR, Escherweg 2, 26121 Oldenburg 3University of Freiburg, INATECH, ROR, Emmy-Noether-Str. 2, 79110 Freiburg im Breisgau 4Friedrich-Alexander-Universität Erlangen-Nürnberg, Sustainability Transition Policy Group, ROR, 90403 Nürnberg 5Carl von Ossietzky Universität of Oldenburg, Department of Computing Science, ROR, Ammerländer Heerstraße 114-118, 26129 Oldenburg 6Reiner Lemoine Institut, ROR, Rudower Chaussee 12, 12489 Berlin Published by Karlsruhe Institute of Technology, Institute for Automation and Applied Informatics, ROR, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen Acknowledgements The authors of this article have used various preparatory works from the NFDI4Energy to create this portrait, and references have been made where possible. Thanks to all those who are not named. The authors would like to thank the German Federal Government, the German State Governments, and the Joint Science Conference (GWK) for their funding and support as part of the NFDI4Energy consortium. The work was funded by the German Research Foundation (DFG) – 501865131 within the German National Research Data Infrastructure (NFDI, www.nfdi.de). License This document is published under the Attribution 4.0 International (CC BY 4.0). This license allows users to distribute, remix, adapt, and build upon the material in any medium or format, so long as attribution is given to the creator. The license allows for commercial use. Page 1of 22 Table of Contents General Information ................................................................................ 3 Summary........................................................................................ 3 Deliverable within NFDI4Energy ............................................................... 3 Review of existing metadata standards ............................................................ 4 Classification of different types of standards................................................... 4 List of non-relevant metadata standards....................................................... 5 Standards that provide some benefits.......................................................... 5 Technically relevant metadata standards................................................. 5 Content-wise relevant metadata standards............................................... 8 Process of review for the relevant and important metadata standards........................ 10 Relevant metadata standards in the energy domain............................................... 12 Component MetaData Infrastructure (CMDI).................................................. 12 Data Package................................................................................... 12 Data Documentation Initiative (DDI) .......................................................... 12 International Organization for Standardization (ISO) 19115................................... 13 Infrastructure for Spatial Information in Europe (INSPIRE).................................... 13 Provenance Document Collection (PROV) ..................................................... 13 Research Object Crate (RO-Crate).............................................................. 14 Most important metadata standards in the energy domain ....................................... 15 Open Energy Metadata (OEMetadata) .......................................................... 15 DataCite ........................................................................................ 15 DataID.......................................................................................... 16 Dublin Core..................................................................................... 16 Schema.org ..................................................................................... 16 Data Catalog Vocabulary (DCAT) and Data Catalog Vocabulary - Application Profile (DCAT-AP) 17 Conclusion and Recommendations................................................................. 18 Glossary............................................................................................. 19 Page 2of 22 General Information Summary This deliverable represents a large survey of metadata standards from multiple sources and puts them in context for NFDI4Energy. Metadata standards are categorized by their relevance for energy research data from not relevant, over partially relevant to relevant or even important. The relevant and important standards are further categorized in what kind of standard they represent. We distinguish classical online catalog metadata standards, metadata toolkits, and domain specific metadata standards that focus on a very specific kind of data. The goal of this deliverable is threefold: First, to clarify what the expectations for an NFDI4Energy service are, when they handle energy research data. This explicitly means that we expect the support of the Open Energy Metadata Standard, as the primary domain specific Metadata Standard for energy research data. Second, to serve as a guideline for researchers in the energy domain on what metadata standards to use and lastly to be a lookup table for solution ideas on how to solve several metadata challenges or specific modeling solutions for domain specific metadata. The latter is achieved by listing the partially relevant metadata standards and by providing a link to the respective registries of metadata standards for each mentioned standard. Deliverable within NFDI4Energy In NFDI4Energy Task Area 4 is tasked with the creation and curation of ontologies and metadata standards. Measure 4.3 is tasked with collecting requirements and developing the metadata standards that shall be used for energy research data in NFDI4Energy. To do so, it is necessary to understand the existing metadata standards and evaluate their applicability. This falls under task 4.3.2, which contains two subtasks that are completed through this deliverable: First 4.3.2.1 is the collection of a list of metadata standards, which is the foundation on which this deliverable is built. And second 4.3.2.2 the evaluation of the concepts and technical makeup of all the standards with regard to applicability in energy research. Furthermore, this deliverable defines a guideline for services that handle energy research data, and therefore it also affects task area 8 which focuses on services in NFDI4Energy. Page 3of 22 Review of existing metadata standards Metadata have their origin in the libraries of ancient times. They have been used to manage large collections of documents to be able to find a specific item. The name “Metadata” was coined by Philip Bagley in 1968, originally to describe data types for programming languages, but was then used to describe physical and digital objects soon thereafter. Over the past decades many “Metadata Standards” have been created as a collection of guidelines, formats and schemas for the description of assets. Many of them are very specific for a certain kind of asset while others aim to be as generic as possible to be used for as many assets as possible. Moreover, some of them are already quite old, some have been superseded by newer ones, while there are still newcomers frequently. In Measure 4.3 we have created a review of many Metadata Standards and evaluated their usefulness for the energy domain. This is primarily based on the Research Data Alliance (RDA) metadata standards catalog1and the standards section of FAIRsharing.org2. All metadata standards have initially been categorized like this: • Non-relevant standards • Contains interesting technical concepts • Contains relevant content for the energy domain • Relevant for the energy domain • Important for the energy domain This classification has been done based on a quick review of the standard, and for the last two categories a more detailed analysis was performed. This analysis will be described in more detail later on. Classification of different types of standards A second kind of classification that we have done (at least for the standards that we considered relevant) is about the properties and field of application of the standard at hand. Not all standards have been designed to do exactly the same thing, so it is obvious that their focus may be on a different use-case or field of application. We have tried to group similar standards and we ended up with the following three categories of standards: Classical Online Data Catalog Metadata Standard The first group focuses on publishing use cases and the management of many assets in a collection. It can be considered the traditional metadata standard as also the ancient libraries might have used something like this. Further goals of these kind of standards are discoverability and catalog entry standardization across different kinds of assets. As a result those standards will usually not have any domain-specific details about an asset. The common representatives of this group for NFDI4Energy are DCAT, DataCite, and Dublin Core. Metadata Handling Toolkits This group focuses on tools that help with tasks that are necessary along the metadata life cycle. This includes for example the handling of multiple file or data formats, such that they can be parsed and understood by machines and humans alike. Further application areas might be the transport and validation of metadata, as well as the bundling of metadata alongside the data. Typical representatives of this category are Data Package, Research Object Crate (RO-Crate), and Provenance Document Collection (PROV). 1https://rdamsc.bath.ac.uk/ 2https://FAIRsharing.org/standards Page 4of 22 Domain Specific Metadata Standards This last group contains specialized standards that are tailored to particular domains and focus on details of specific use cases. They can also often be controlled by regulatory measures. For NFDI4Energy the representatives are for example International Organization for Standardization (ISO) 19115, Infrastructure for Spatial Information in Europe (INSPIRE), and our dedicated energy related metadata standard Open Energy Metadata (OEMetadata). List of non-relevant metadata standards The following lists of metadata standards, have been classified as non-relevant for NFDI4Energy. This can have several causes: • The standard was replaced by a newer one • The standard focuses only on a specific topic that is not related to energy • The standard is no longer maintained • There is no proper schema or documentation available online • There has been no notable content that is not covered by more important standards Table 1 and Table 2 are displayed in a two column layout, and the actual table also has two columns: The title of the metadata standard and an identifier. The identifier is written in Compact Uniform Resource Identifier (CURIE) form and the used prefixes are msc: https://rdamsc.bath.ac.uk/msc/ and fs: https://fairsharing.org/10.25504/FAIRsharing.. You can use these URLs to resolve the entries in the previously mentioned metadata standards catalogs. There will be no further explanation of these metadata standards. Standards that provide some benefits The standards listed in this subsection can be classified into two groups: Either they are interesting because of technical concepts (e.g. a solution for controlled vocabularies) or they provide some interesting metadata fields that can be referenced for specific kinds of energy data sets (e.g. sensor configurations). Technically relevant metadata standards This category is not necessarily relevant for metadata users within the energy domain, but more focused on developers of metadata standards and tools. Asset Description Metadata Schema (ADMS)(msc:m48) ADMS is a DCAT profile designed for annotating metadata schemas, taxonomies, dictionaries, data models, and other semantic artifacts listed in data catalogs. In that sense it is interesting for NFDI4Energy to manage different relevant metadata standards and schemas. Biolink Model (fs:ad9d85) The Biolink Model is entirely implemented in LinkML and can be seen as a real world example on how to use this technology for schema definition and management. Bioschemas ComputationalTool Profile (fs:991d4e Bioschemas heavily utilizes Schema.org to create their models. It can be seen as an example on how to create domain specific models using schema.org concepts. Page 5of 22 Name ID 4DN-BINA-OME Microscopy Metadata Specifications fs:87756d ABCD msc:m1 ABCD Zoology msc:m110 ABCDDNA msc:m42 ABCDEFG msc:m43 Adaptive Immune Receptor Repertoire Standard fs:eZ0fzl AGLS Metadata Profile msc:m44 AgMES msc:m2 AGRIS Application Profile msc:m45 ANZLIC Metadata Profile msc:m46 Apple Core msc:m47 AVM msc:m3 BIDS msc:m113 CARARE Metadata Schema msc:49 CESSDA CMM msc:m50 CESSDA Data Catalogue DDI Profiles msc:m121 CF Metadata Conventions msc:m5 CIDOC CRM msc:m114 CIF msc:m6 CIM msc:m7 COARDS Conventions msc:m51 CRMarchaeo msc:m118 CRMdig msc:m116 CRMsci msc:m115 CRMtex msc:m119 Cruise Summary Reports msc:m52 Darwin Core Geospatial Extension msc:m54 Data Standard for Sharing Quantitative Results in Mass Spectrometry Metabolomics fs:207caf Name ID Dryad Metadata Application Profile msc:m55 DwC Germplasm msc:m56 EAD msc:m96 eBank UK Metadata Application Profile msc:m57 EDMED Metadata Profile msc:m58 EML msc:m16 EURISCO Descriptors msc:m85 FAIRtracks fs:807b9d FGDC/CSDGM msc:m17 FGDC/CSDGM Biological Data Profile msc:m59 FHIR msc:m103 FITS msc:m18 FITS World Coordinate System (WCS) msc:m60 GBIF Metadata Profile msc:m61 Gene Ontology (GO) Gene Association File Format 2.2 fs:77fbbf Genome Metadata msc:m19 GGBN Data Standard HISPID msc:m64 International HLA and Immunogenetics Workshop XML fs:37nbtc ISA-JSON fs:yhLgTV ISA-Tab msc:m21 ISA-TAB Nano msc:m67 isaconfig-diXa msc:m68 ISO 19115 North American Profile msc:m70 ISO 28500:2017 Information and documentation — Web ARChive file format fs:zI0vGD Table 1: Non-relevant metadata standards for NFDI4Energy - Part 1 Center for Expanded Data Annotation and Retrieval (CEDAR) Template Model (msc:m94) Originally designed for biomedical experiment data, CEDAR defines templates of metadata fields required for different types of experiments. A similar approach could be used to streamline the creation of metadata for different types of energy system experiments. Common Data Format (fs:a4df96) The Common Data Format is not a metadata schema, but rather a data format that combines the storage of data and metadata alongside each other. It also specializes in multi-dimensional data sets which is also of relevance in the energy domain. Darwin Core (msc:m9) Darwin Core stands out as a great example of interlinked standards. It is part of the Biodiversity Information Standards (TDWG) standard collection that contains many standards and vocabularies Page 6of 22 Name ID LIDO msc:m109 MAGE-TAB msc:m87 MARC msc:m88 Marine Community Profile msc:m71 MBF Bioscience Neuromorphological File Format 4.0 fs:ac3ea3 MEDIN discovery metadata standard msc:m123 Metabolomics Workbench Tabular File Format fs:N8KDKt MIBBI msc:m23 MIBBI Portal msc:m72 MIDAS-Heritage msc:m24 Minimum Information about an Uncultivated Virus Genome fs:bd9566 MIxS msc:m108 MODS msc:m97 NBO-Q msc:m111 NetCDF Attribute Convention for Dataset Discovery msc:m89 Neuroscience Information Exchange Format fs:kK7dbW NeXus msc:m25 Nuclear Magnetic Resonance Markup Language fs:es03fk OAI-ORE msc:m26 OBO Flat File Format Syntax and Semantics fs:aa0eat Observ-OM msc:m27 ODM msc:m106 OECD Dataset Metadata msc:m90 OECD Minimum Data Set msc:m91 OME-XML msc:m29 OpenAIRE Guidelines msc:m92 Open Microscopy Environement Next Generation File Formats fs:9af712 Name ID Open Modeling EXchange format fs:27tnee openPMD msc:m107 PDBx/mmCIF msc:m30 PICA XML fs:9a67d2 Plasma-MDS msc:m105 PREMIS msc:m31 Protocol Data Element Definitions msc:m32 QuDEx msc:m34 RDA msc:m104 REMBI msc:m112 Repository-Developed Metadata Schemas msc:m36 Resource Metadata for the Virtual Observatory msc:m74 RIF-CS msc:m98 RIOXX Metadata Application Profile fs:40d902 SDAC msc:m37 Shoreline Metadata Profile msc:m75 smartAPI specification fs:f3jewy SNRNASM ISA-Tab msc:m76 Standard for Documentation of Astronomical Catalogues fs:zcjkc7 TEI Guidelines msc:m99 TEI/EPIDOC msc:m120 TIDCC msc:m78 The Core Metadata Schema for Learner Corpora fs:987836 Time Frequency Catalogue fs:cb4ca0 UK AGMAP msc:m79 UK Gemini msc:m80 UKEOF msc:m40 VarioML msc:m82 WMO Core Metadata Profile msc:m84 Table 2: Non-relevant metadata standards for NFDI4Energy - Part 2 from the Biodiversity Domain. Most of those standards are built up using the same technical principles and are hosted centrally. International DOI Foundation (IDF) Metadata Kernel (msc:m86) This metadata kernel defines the possible information that can be placed directly into a DOI record. This is going to be interesting for any kind of data publications as it might enable linking directly to more detailed metadata. International Virtual Observatory Alliance (IVOA) Technical Specifications (msc:m20) The technical specifications of the IVOA are a collection of vocabularies and schemas that are maintained and version controlled individually. It forms a large collection of metadata modules for telePage 7of 22 scope data. It can serve as a technical example on how to work with many individually versioned schemas that together form meaningful metadata. Open Microscopy Environment TIFF (OME-TIFF)(msc:m73) This standard shows how to integrate Open Microscopy Environment XML (OME-XML) metadata in Tagged Image File Format (TIFF) image files. Although images are not of the most importance in the energy domain now, it might be an interesting technical starting point if this is necessary for a specific use case. Content-wise relevant metadata standards This category can provide some insight on metadata standards on various types of data that are relevant for the energy domain. Allgemeines Metadatenprofil für Bildungsressourcen (AMB)(msc:m126) This standard - in English, the General Metadata Profile for Educational Resources - aligns with the NFDI4Energy Best Practices Service and may be of use in cataloging the metadata of the tutorials and other learning resources that will be shared in this service. Bioschemas Training Material (fs:fd7e23) This small metadata schema handles the description of training material that could be reused accordingly for the energy domain. CodeMeta (fs:TS3gpY) CodeMeta 3is a metadata standard for research software [1]. Originating from collaborations within the working groups of FORCE11,WSSSPE and the Software Sustainability Institute. CodeMeta was first released in 2017 and it establishes a concept vocabulary that enables the standardized exchange of software metadata across repositories and organizations such as GitHub, Zenodo and DataCite. Research software is an overarching topic that is also relevant in the energy domain. Common European Research Information Format (CERIF)(msc:m4) This standard is designed to capture metadata about research projects, such as the involved institutions and the funding sources. It may be relevant for the NFDI4Energy Competence Service, which aims to connect researchers and support scientific collaboration. Content Standard for Digital Geospatial Metadata (CSDGM) Extensions for Remote Sensing Metadata (msc:m53) The standard has some fields for multi-band remote sensing instruments, extending on the digital geospatial metadata that might also be relevant for specific applications in the energy domain. Core Scientific Metadata Model (CSMD)(msc:m8) This standard defines the basic concepts of scientific work linking datasets, with investigations and necessary instruments. It further touches on the topics of parameters of a dataset or instrument, while being entirely modeled in Web Ontology Language (OWL). CSV on the Web (CSVW)(msc:m125) This standard[2] is maintained by the World Wide Web Consortium (W3C) and handles the annotation of tabular data. 3https://codemeta.github.io/ Page 8of 22 Most important metadata standards in the energy domain This section covers the go-to standards if you intend to publish energy related data. Open Energy Metadata (OEMetadata)(msc:m128) The OEMetadata standard [16] has been established as the metadata standard for the Open Energy Platform (OEP) to annotate the datasets that are stored there. The first version available on GitHub was released in November 2019 and has since developed further to reach version 2.0.4 in March 2025. It is developed and maintained by the Reiner Lemoine Institute (RLI) and Open Energy Family Community. NFDI4Energy is also actively contributing to its development and has selected OEMetadata to be the primary metadata standard for data in the energy domain. It is published on GitHub to allow for issue tracking and continuous access to the past versions of the standard as well. The standard schema is available as a JSON schema10. It can be classified as a energy domain specific metadata standard. A representative example11 of a metadata record can be found directly on GitHub along with the documentation of the standard. The OEMetadata has been built on top of the Frictionless Data Package standard, which is well suited for annotating tabular data that is the main data type within the OEP. Projects that have published data on the Open Energy Platform using the OEMetadata standard include SIROP, open_FRED, open_MODEX, SzenarienDB, LOD-GEOSS and open_eGo. More details can be found on the OEP homepage12. As OEMetadata is the only real domain specific metadata standard for the energy domain, its use has extended beyond the OEP to other data publications. The standard currently aims to become more modular to allow for precise metadata records depending on the type and usage of the annotated data set. Developers can integrate the standard in their applications in form of the JSON schema. It references several other standards and ontologies like Dublin Core, DCAT, DBPedia Ontology (DBO), ADMS, Friend of a Friend Ontology (FOAF), National Cancer Institute Thesaurus (NCIT), Common Core Ontology (CCO), Software Package Data Exchange (SPDX), CSVW,PROV, Schema.org and of course the Open Energy Ontology (OEO). DataCite (msc:m11) The DataCite Metadata Schema [17] is managed by the Metadata Working Group of the DataCite community. The oldest available release, version 2.0, dates back to January 2011; currently, version 4.6 from December 2024 is the most recent update13. This schema is designed to be broadly applicable to research resources from a variety of domains, and is intended to be used in combination with other domain-specific metadata schemas whenever such a combination is necessary to fully describe a resource. The DataCite schema is published in XML format, with a JSON mapping available. It contains 20 major properties, each defined as either Mandatory (6 properties), Recommended (6 properties), or Optional (8 properties). Most of the major properties are extended with sub-properties that allow for more detailed metadata specification. In addition to the metadata schema, the maintainers publish mappings from DataCite’s schema to other existing schemas. Usage examples, both demonstration cases and live usages, can be found in the schema’s documentation. These resources greatly improve the usability and interoperability of this metadata schema. 10https://github.com/OpenEnergyPlatform/oemetadata/blob/production/oemetadata/latest/schema. json 11https://github.com/OpenEnergyPlatform/oemetadata/blob/v2.0.4/oemetadata/v2/v20/example.json 12https://openenergyplatform.org/about/ 13https://schema.datacite.org/meta/kernel-4.6/ Page 15 of 22 DataID (not registered) The DataID ontology[18] is a multilayer ontology that consists of a core ontology and several extensions. It is developed on GitHub14 by a team at the University of Leipzig and uses the prefix url http://dataid.dbpedia.org/ns/core# for the core ontology (exchanging the core suffix for the extension modules as necessary). The ontology is available in both Terse RDF Triple Language (Turtle) and OWL formats. It was designed as a generic metadata structure for the DBPedia data set and was later used as the general metadata of the DBPedia Databus. The first release happened in 2014 and received several updates in the following years, although there seems to be no clear versioning scheme. It can be considered to be a Classical Online Data Catalog Metadata Standard. The standard is primarily used for datasets that are registered on the DBPedia Databus. An automatic export from the Open Energy Platform (OEP) towards the Databus exists and it performs an automatic conversion of metadata from the Open Energy Metadata (OEMetadata) to DataID. The metadata standard is by design modular as it uses the multilayer ontology to be extensible with further domain specific modules. There is no direct support for developers to integrate the standard directly and one has to start of with the published ontology files. It does reuse other standards like Dublin Core and DCAT for terms used in the ontology. Dublin Core (msc:m15) Dublin Core is a widely used metadata standard, initially developed in 1995 and released in 1998, and currently maintained by the Dublin Core Metadata Initiative (DCMI). The latest version was released in January 2020. It aims to increase the interoperability of the Semantic Web and Linked Data principles by utilizing Uniform Resource Identifiers (URIs) for both metadata and vocabularies. The Dublin Core consists of fifteen generic elements: Creator, Contributor, Publisher, Title, Date, Language, Format, Subject, Description, Identifier, Relation, Source, Type, Coverage, and Rights. This provides a flexible resource across nearly all disciplines, available in both RDF and XML formats. While it is intentionally designed for a generic purpose, it still allows for extensions with other metadata standards, especially in specialized domains such as biomedical data, and supports crosswalks and mappings to other metadata standards, thereby enhancing interoperability and exchange across systems. Schema.org (msc:m101) Schema.org is an online schema catalog that was created by a collaboration of several big tech companies, but has evolved into a broad community effort on the web. The first release dates back to 2011 and has reached version 29.2 on May 13 2025. The schema is published in several serializations. All the formats use semantic web technologies and are either based on Resource Description Framework Schema (RDFS) or OWL. The main usage area is to provide semantic and structured data in any aspect of the web. That includes websites, emails, and any app that uses web technologies. As its focus area lies on information on the web, it can be utilized to describe many things on a broader level and often lacks the details to describe domain specific data sets like time series data. For example, a table is available in Schema.org as a table on a website that is expressed in Hypertext Markup Language (HTML). It therefore lacks the properties to give detailed descriptions on the data contained within the table, as it is considered a WebPageElement which is a CreativeWork. Example data can often be found on web pages e.g. on the BBC Homepage. Schema.org is widely used across industry and science and has impacted many other developments. Modularity in the sense of giving guidance which properties or subclasses are relevant for a specific dataset is not handled by schema.org. Neither is it referencing other metadata standards. Many common values like the author of a creative work do not reuse the URLs of other standards. However, the RDA [19] and the W3C [20] have published crosswalks for important properties to other metadata 14https://github.com/dbpedia/DataId-Ontology/tree/master Page 16 of 22 standards. For developers, there is a dedicated guide15, but that focuses more on the availability of the schema in different formats rather than what to actually do with it. Data Catalog Vocabulary (DCAT) and Data Catalog Vocabulary - Application Profile (DCAT-AP)(msc:m12) and (msc:m124) DCAT is an RDF vocabulary published as a recommendation by the W3C [21]. It provides a common framework for datasets and data catalogs to describe and expose their metadata. Initially, it was developed at the Digital Enterprise Research Institute (DERI), the version 1.0 [22] of the W3C recommendation was released in 2014 and version 3.0 in 2024 [21]. It is maintained by the Dataset Exchange Working Group (DXWG)16. DCAT-AP is an application profile of the DCAT vocabulary aiming to enhance the semantic interoperability across European data portals [23]. It was developed in parallel to DCAT and version 1.0 was released in 2013 and version 3.0 in 2024. The maintenance of DCAT-AP is done by the DCAT-AP Working Group [24]. DCAT and DCAT-AP can both be classified as Classical Online Data Catalog Metadata Standards. Different extensions of DCAT exist, like the already described DCAT-AP for governmental data, but also versions for governmental data in the USA [25] and many other countries exist, and more specific extensions have been created for example in the statistical and geodata domains. DCAT-AP can also be used with data spaces [26]. In the documentation of DCAT an example is provided showing how to represent a government catalog and its datasets17 and for DCAT-AP the use of dataset series is shown18.DCAT is used for different governmental data portals (e.g., https://data.gov in the USA) and also in different German National Research Data Infrastructure (NFDI) consortia [27] like for example HealthDCAT-AP [26]. DCAT makes extensive use of terms from other vocabularies. Especially, Dublin Core is used, but also others like PROV Ontology (PROV-O) [28], ADMS,FOAF,SKOS,SPDX, Schema.org, and more are used or mapped. 15https://schema.org/docs/developers.html 16https://www.w3.org/2017/dxwg/wiki/Main_Page 17https://www.w3.org/TR/vocab-dcat-3/#basic-example 18https://semiceu.github.io/DCAT-AP/releases/3.0.0/#example-dataset-series Page 17 of 22 Conclusion and Recommendations When you want to publish your data as an energy researcher, you will have to choose a publication platform. There are several valid options available, but they are not discussed in this deliverable. It is almost certain that the platform will have its own set of mandatory metadata which can be based on a certain metadata standard. Traditionally, this will be one of the classical data catalog standards like DCAT-AP, DataCite or Schema.org. These three standards are also the three general standards that are recommended by the NFDI [27] and should be supported by any NFDI associated service. So, there is not really much choice in that regard. However, the interesting part for future use-cases will be the use of domain specific metadata standards, as they enable proper search of existing datasets for a certain purpose. So we generally encourage energy researchers to pick a domain specific metadata standard and at least publish that metadata alongside their actual data (e.g. as a sidecar file). At the moment, the Open Energy Metadata (OEMetadata) Standard is the primary NFDI4Energy recommendation for both services and researchers for energy research data. The Standard is the only real energy domain specific metadata standard and has been actively developed to fulfill the requirements that have previously been published by measure 4.3 [29]. NFDI4Energy actively participates in its further development to achieve full compliance with the defined requirements. NFDI4Energy is currently working on solutions for domain metadata aware search that can actually harness this information. Furthermore, there will be a community space to modify existing standards to better suit researcher needs, which might end up being adopted by the community in general. This deliverable has provided an overview of many existing metadata standards and serves as an initial guide to choose the right standard for metadata that suits the use-cases of energy researchers and service providers. Page 18 of 22 Glossary ADMS Asset Description Metadata Schema AMB Allgemeines Metadatenprofil für Bildungsressourcen CCO Common Core Ontology CEDAR Center for Expanded Data Annotation and Retrieval CERIF Common European Research Information Format CIDOC-CRM International Committee on Documentation - Conceptual Reference Model CLARIN Common Language Resources and Technology Infrastructure CMDI Component MetaData Infrastructure CSDGM Content Standard for Digital Geospatial Metadata CSMD Core Scientific Metadata Model CSVW CSV on the Web CURIE Compact Uniform Resource Identifier DBO DBPedia Ontology DCAT-AP Data Catalog Vocabulary - Application Profile DCAT Data Catalog Vocabulary DCMI Dublin Core Metadata Initiative DDI-CDI DDI Cross-Domain Integration DDI Data Documentation Initiative DERI Digital Enterprise Research Institute DIF Directory Interchange Format DOI Digital Object Identifier DXWG Dataset Exchange Working Group FOAF Friend of a Friend Ontology FORCE11 Future of Research Communication and e-Scholarship Community GESMES/TS Generic Statistical Message for Time Series GSIM Generic Statistical Information Model HTML Hypertext Markup Language IDF International DOI Foundation INSPIRE Infrastructure for Spatial Information in Europe ISO International Organization for Standardization IVOA International Virtual Observatory Alliance JSON-LD Java Script Object Notation - Linked Data JSON Java Script Object Notation LRMoo Library Reference Model NASA National Aeronautics and Space Administration NCIT National Cancer Institute Thesaurus NFDI German National Research Data Infrastructure ODAM Open Data for Access and Mining OEMetadata Open Energy Metadata OEO Open Energy Ontology OEP Open Energy Platform OME-TIFF Open Microscopy Environment TIFF OME-XML Open Microscopy Environment XML OWL Web Ontology Language PROV Provenance Document Collection PROV-O PROV Ontology RDA Research Data Alliance RDF Resource Description Framework RDFS Resource Description Framework Schema RLI Reiner Lemoine Institute Page 19 of 22 RO-Crate Research Object Crate SCCTC Standing Committee for CLARIN Technical Centres SDMX Statistical Data and Metadata eXchange SKOS Simple Knowledge Organisation System SPASE Space Physics Archive Search and Extract SPDX Software Package Data Exchange SOS Sensor Observation Service Interface Schema TIFF Tagged Image File Format TDWG Biodiversity Information Standards Turtle Terse RDF Triple Language URI Uniform Resource Identifier USGIN US Geoscience Information Network W3C World Wide Web Consortium WSSSPE Working Towards Sustainable Software for Science: Practice and Experiences XML Extensible Markup Language Page 20 of 22 References [1] C. 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