"Snowy Hydro said its modelling showed the cost of wind power was $70-$80/MWh, and the cost of solar power was $77-$99/MWh, including price premiums for energy storage. It said new power from new high-efficiency low-emissions coal generators cost $78-$120/MWh."
To compare apples with apples you need to add the cost of storage to the intermittent power generators before you compare them to baseload generators like HELE coal generators.