My reference to large generators staying online is in the short term i.e overnight or periods of limited demand. In the past we've had to design industries ( and power stations ) to support each other. Remember night rate electricity for hot water ? That's why the existing Snowy pumped hydro exists. Even the Portland Smelter had a important role in the reason for building Loy Yang B.
Big coal stations are lumbering beasts. It is less and less practical to run them at any less than full load.
Large storage facilities will make it easier for the existing coal stations to manage their load actually. Instead of having fossil peaking stations that hardly ever run, it will be pumped hydro, solar and wind with batteries.
