Further hydrogen colours

[l-emele]

Description of the issue

We already included:

• green hydrogen: renewable electrolytic hydrogen
• grey hydrogen: fossil steam reforming hydrogen
• blue hydrogen: abated steam reforming hydrogen

However, the types of hydrogen in discussion gets more and more and there now is almost a full rainbow. E.g. this source has additionally:

• black and brown hydrogen: hydrogen from hard coal (black) or lignite (brown)
• pink hydrogen/red/purple hydrogen: electrolytic hydrogen using electricity from nuclear power plants
• turquoise hydrogen: methane pyrolysis producing hydrogen and solid carbon
• yellow hydrogen: hydrogen from electrolysis using solar energy (so a subtype of green hydrogen).

Do we want to add those concepts? If so, I suggest (as in issue #1013 / PR #1443) to use the colours only as alternative labels.

Ideas of solution

If you already have ideas for the solution describe them here

Workflow checklist

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

I am aware that

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

[l-emele]

Two proposals for the more easy ones:

• nuclear electrolytic hydrogen (pink hydrogen): Nuclear electrolytic hydrogen is electrolytic hydrogen that is produced with nuclear electrical energy. 'nuclear electrolytic hydrogen' EquivalentTo: 'electrolytic hydrogen' and ('physical output of' some ('water electrolysis process' and ('has energy input' some 'nuclear electrical energy')))
• solar electrolytic hydrogen (yellow hydrogen): Solar electrolytic hydrogen is electrolytic hydrogen that is produced with solar electrical energy. 'solar electrolytic hydrogen' EquivalentTo: 'electrolytic hydrogen' and ('physical output of' some ('water electrolysis process' and ('has energy input' some 'nuclear electrical energy')))

Further new classes used in the definitions above:

• nuclear electrical energy: Nuclear electrical energy is electrical energy with a nuclear origin. Parallel to renewable electrical energy, but this definition depends on #1491.
• solar electrical energy: Solar electrical energy is electrical energy that is energy output of a solar energy transformation.

[stap-m]

The proposals look fine to me.