2020-12-02 update
We analysed various different ontologies and vocabularies and tested their suitability in regard to the UK Energy landscape. See here for details of the landscape.
Our summary is that there is no single suitable vocabulary that addresses all applications, and have developed a prototype version for the purpose of a Knowledge Graph demonstration. In this demonstration, users can expand nodes in the above tree by clicking on them.
If users click on the name instead they are taken to the Energy Data Search, where they are presented with relevant datasets matching their search criteria.