So which source were you asking for?

The claim that excess renewables + storage is the future?

If you have any amount of understanding in the energy sector, it's fairly obvious that's the future.

The biggest difficulty is being able to predict the weather in terms of providing the storage generation to overcome the intermittent nature of renewables - but there are already projects around the world working on that technology that are being completed and tested every day.

example: https://www.google.com/amp/s/reneweconomy.com.au/whole-towns-to-be-taken-off-the-grid-and-powered-by-stand-alone-renewables/amp/

That's a very very quick Google, there's a lot more information on the WA governments Western Power distributor working in the renewable electrical grid space