You are a bit out Devil. One GW is only a thousand MW, not a million MW.
Only 20 thousand wind turbines would be needed by your calc.
In reality it will be less wind turbines than even that - California is finding that if you charge batteries during the day with solar, they can play a big part in squashing that evening peak.
For a country like us with so much sun, storage is going to play a key part, and the major power companies in Oz are going to be heading in that direction for a bit.
