This pumped hydro scheme in Kangaroo Valley has been operating since 1977. Built well before renewable energy became a thing, pumping water from the Kangaroo River to the Southern Highlands relied on fossil fuel driven pumps.
If this scheme was viable without renewable energy, then projects that can tap into RE should be even more so.
I am a former resident of the Shoalhaven and have visited this project. It is such a simple concept, a country the size of Australia should have many more of these.