Hydrogen has extreme structural problems. Hydrogen tanks need constant maintenance, due to how small the molecule is - it's very difficult to contain and prevent corrosion. You then have significant conversion loss between the powerplant-native format of electricity, and the hydrogen. So nothing can be as cheap as pure electricity. Fuelling the car with ammonia that then gets converted to Hydrogen inside the car is the solution to the first problem, but further increases the loss on the second.
What you're describing sounds like a small, high-capacity battery to me! Like a super AA battery. Maybe in 50 years :)
I never thought I'd say this but in defence of big coal, rent controls, which the greens advocate, have historically caused real rents for those not in existing rentals to skyrocket. I'm anti-coal but this rental cap policy is stupid.
Rental demand and supply needs to be addressed. Just fucking with prices via a cap has tons of unintended consequences. I see nothing in the greens policies about easing innner-city zoning restrictions, or increasing the supply of construction labour, both of which would be much more effective at reducing real rents.
https://www.sciencedirect.com/science/article/pii/S1051137724000020