That sounds fun, I'll take a stab at it.
Energy Storage -- Conditio Potentiae
- I like potentia because its meaning suggests that it is understood as a resource.
- Conditio comes from condo, condere. It has many meanings, but the nuances suggest a gathering to one place with an ordered structure. As such, it seems very appropriate for your usage.
Hydrogen and Fuel Cells -- Hydrogenum et Cellula Potentiae
- Hydrogenum is a neolatin word which means exactly what you want - hydrogen.
- I found photoelectrica cellula glossed in LatinLexicon as photoelectric cells, so with a little prodding, I came up with cellula potentiae meaning "cells of power" aka "power cells."
Renewable-Hydrogen Integration -- (Hydrogenum) quae renovari possit integrata (sunt)
- Quod renovari possit is a relative clause of characteristic, here meaning Hydrogen of the sort which is able to be used.
- I'm uncertain whether it is right to use integrata. On the one hand, it is cognate with the English you want to use and it shares that English meaning. But on the other, that use of integro is a rare one, used by only one author. This may mean that coniungo for example, could be a better verb in this context.
For home usage -- Ut uti (liceat) (eis) domi
- Ut, used as a subjunctive result clause.
- Uti is a deponent verb, which carries roughly the same meaning as "to use" in English.
- The parenthetical represents possible words which could be inferred as the verb which introduces uti. To me, licet or debet make the most sense as a verb. Eis is just the pronoun "them." They do not need to be included in the final product sentence, it simply makes my intentions clearer to you.
- Domi is a locative, with the meaning "at home."
Altogether you get:
Conditio Potentiae: Hydrogenum et Cellula Potentiae, quae renovari possint integrata ut uti (liceat) (eis) domi.
In very literal English: The bringing together of power: Hydrogen and Power Cells which are able to be renewed (have been) brought together in order that (one is able) to use (them) at home.