Why would you need to replicate that wind capacity multiple times for a low wind period of a couple of weeks per year ?
Don't forget that you would also have large amounts of other generation i.e solar operating at the same time .
The pumped storage doesn't have to refilled everynight . It just needs to large enough to get through the low wind period . It might be only needed for a large backup role for a couple of weeks in a year . The rest of the time it might only be needed in small bursts ( peaker style ) so for the rest of the year it can be topping up thanks to surplus wind and solar energy .
Think of it this way . Australia has more fossil generation than it needs . That is because not all that generation can run all the time . Btw , downtime is closer to 20% and that's for a more modern station . The average age of Australia's power stations is over 30 years old . On top of that , because of increased load and the lack of any new builds in 30 years , we have had to build a significant network of peaker plants to make up the difference . More expense and more complication .
So the fossil fleet is made up of intermittent group of generators that combine to provide a 24/7 supply .
So , in a similar way , multiple renewable resources contribute to 100% power . Yes , there are non windy days just as there are periods of darkness where solar doesn't work . But all that is very predictible and therefore manageable . Much more so than the unreliability that is now creeping in to our fossil fleet . The recent media where the boss of Tomago has been complaining is an example of that .
You do realise that the existing pumped hydro on the Snowy is quite often paid to pump water ? Yes , paid to pump water . I would like to see the detail of that radio story you heard . Was it someone like Ray Hadlee by chance ?
Trouble with those shock jocks is that they are very selective with their information so I would treat their example with a grain of salt .
Comparing Snowy to a power station that has never been built in Australia is ridiculous . Further to that , the minerals council commissioned a study on that very subject and still couldn't come up with a convincing case .
http://www.minerals.org.au/news/independent_report_backs_modern_coal_generation_for_australia
http://www.climatecouncil.org.au/uploads/f9ba30356f697f238d0ae54e913b3faf.pdf
