This note builds on previous work looking at the seasonality issues of high (> 90% share of total electricity energy produced) wind and solar penetration in Australia.
We are more pessimistic than the likes of Andrew Blakers and the ANU team, partly because ITK’s model is based on scaling up actual output as compared to using wind speed data over the entire National Electricity Market (NEM).
By building a system that over-produces wind and solar relative to demand in the past 12 months, and by employing about 15GW of 4-hour batteries we find that well less than 10TWh of “backup” energy is required.
In our spreadsheet model the longest duration that the backup is needed for is 12 hours. However, the size of the backup in power terms is about 41GW.