You are correct electrolysis is inefficient, the sun doesn't...

You are correct electrolysis is inefficient, the sun doesn't always shine and the wind doesn't always blow. However on a sunny day or windy day the energy produced from these plants is cheap and there is too much to be used at that instant, so the idea that it can be turned into hydrogen, even if inefficiently is a big benefit. Think of the Hydrogen as a battery, except it can be put into trucks and driven to places or pumped down a pipeline far more efficiently then power can be transported through powerlines.

(Below is all purely hypothetical locations and prices to explain a point)
On Sunday its sunny in Mildura and you make 1000GJ of Hydrogen at $4/GJ using the Mildura Solar farm, you store the hydrogen until Thursday when it is cold, raining and there is no wind, at this point you send the Hydrogen down a pipeline to Melbourne where it is converted back into electricity and sold for $40/GJ because there isn't enough solar or wind generation. This gives $36/GJ profit minus the cost to store, transport, maintenance etc. The kicker is that sometimes the Solar is almost free, if on a sunny day there is more solar power generated then the grid can use at that time the price in theory could go as low as $0GJ.

Will ECT play a part in this, no idea, will this be reflective of Australia's future? I'll put my house on it.

New here but hoping to ride a big wave of success with everyone

DYOR