Right now we have 100% generation from ' traditional sources ' or thereabouts. That's with our very immature and underdeveloped renewable energy system right now. So, we don't need to build any backup. The backup already exists.
So there's one of the regular claims discounted.
Most of our fossil fleet is very old and approaching end of life. We have two options. Build a new fossil system or build a new renewable system that includes large amounts of storage. Either way, we have to spend a large amount of money to secure our electricity future.
With a more mature and developed renewable system that includes big storage, we simply won't need fossil backup like we have now.
One other thing that you obviously can't work out for yourself. All the backup won't be batteries. Maybe you should do some reading on the subject sometime ?
