We need to remember that putting 30% renewables is reasonably easy. As the penetration get more we need to start adding storage and it gets harder as the base load generators start falling off because it is not profitable. Ireland has some pumped hydro that is filled every night and handles the extra demand during the day. Renewable storage that we need has to handle the multiple days of low wind we had NEM wide like we had at the end of May and other times this year. We still don't really know what this is going to cost because it has never been done anywhere in the world at Australia's scale. (large amount of hydro would help but we don't have the resources for this.)