Redefine underground hydrogen storage

[l-emele]

Description of the issue

The class underground hydrogen storage has currently a definition derived from Wikipedia: Underground hydrogen storage is the practice of hydrogen storage in underground caverns,salt domes and depleted oil/gas fields. This definition is not Aristotelian.

Additionally it is currently a direct subclass of object and not of energy storage object

Ideas of solution

• Redefine to An underground hydrogen storage is an energy storage object that stores hydrogen underground. Examples are underground caverns, salt domes and depleted oil/gas fields.
• Make underground hydrogen storage a subclass of energy storage object.
• Add relation to hydrogen: uses some hydrogen

Workflow checklist

• [ ] I discussed the issue with someone else than me before working on a solution
• [X] I already read the latest version of the workflow for this repository
• [X] The goal of this ontology is clear to me

I am aware that

• [X] every entry in the ontology should have a definition
• [X] classes should arise from concepts rather than from words

[l-emele]

This small issue can be used as an example in the OEO DEV 7 meeting on 2020-06-25. We should discuss it until then but please do not implement before.