HOLY: An Ontology Covering the Hydrogen Market

This paper presents the Hydrogen Ontology (HOLY), a domain ontology modeling the complex and dynamic structures of hydrogen-based markets. The hydrogen economy has become a politically and economically crucial sector for the transition to renewable energy, accelerating technological and socio-economic innovations. However, the attainment of market insights requires a large variety of informational concepts which are predominantly found in unstructured text data. HOLY provides the necessary structure for the representation of these concepts. Through a top-down approach, HOLY defines taxonomies based on a hierarchical structure of products and applications. In addition, to ensure reusability, the ontology incorporates components from established ontologies in its structure. As a result, HOLY consists of over 100 classes defining information about organizations, projects, components, products, applications, markets, and indicators. Hence, ourwork contributes to the systemic modeling of the hydrogen domain with a focus on its value chain. Formally, we represent and validate the ontology with Semantic Web Technologies. HOLY includes lexical-semantic information (e.g., synonyms, hyponyms, definitions, and examples) to simplify data integration into knowledge acquisition systems. Therefore, we provide a foundation for the retrieval, storage, and delivery of market insights. A first application based on HOLY at the Fraunhofer IIS offers an up-to-datemarket overviewof developments in the fuel cell environment.