The NEM is currently a very 'long' grid that has few strong interconnects. SA only interconnects with Victoria, for instance - one interconnector has a 650MW transfer capacity (Heywood, recently upgraded) and the other (MurrayLink) has a 220MW capacity. Extra transmission lines from 'renewables-rich' areas to populated ones would be required - a very large and real integration cost.No argument with this LD.
AEMO's 100% Renewable Grid study indicated that 100% renewables required a nameplate renewables capacity double the maximum forecast peak demand.
The significant thing about the AEMO report - and others - is that we could have a 100% renewable electricity supply. And there would not be the need for 1:1 gas turbine back-up for each wind farm (or solar farm) as confidently stated by RTT-Rules in the post above.
The UniNSW study doesn't require the renewables to have double the capacity of forecast peak demand - because it does allow for a few gas turbine generators.
Ahh yes but you need to set the context. In reference for 1:1 I was talking an isolated net work.
If you want say SA to close the bulk of its thermal systems and have only a few back up peak gas plants then you need to be able to basically run SA off the inter-tie from Vic minus what ever gas out put there is. Having coal and gs plants sitting on idle waiting for a cloudy windless day is not free even if the stations are long paid off. The workforce is basically the same running or on stand-by, the plant also needs to be maintained and upgraded from time to time.
If you are now going to have a variable load from Vic, you need to make sure Vic/NSW has the capacity to supply. Don't treat it as a bottomless pit and its not free, do you pay them to be ready to dump X many MW into SA based on the weather? Vic also has large wind farms, if its not blowing in SA, its probably not blowing on Vic's wind farm rich coast line.
Yes the Snowy and Tas with large hydro systems has the ability to dump power for short periods when there is no wind and yes most of the time I'm sure the thermals have spare juice. But right now, Tas is nearly dry and Bass Link is off-line anyway, thus limiting the variable load available from hydro to the SE grid.
I am all for practical cost effective renewable, but no state can go it alone in any of this as none has the infrastructure or local conditions to enable it.
Coal is here for many years to come and its a shame SA chooses to be so dependent on other states for power when it could have at least have a large cheap base load thermal coal power plant, say 2000MW providing local jobs. The wind, solar and newable gas coupled with battery storage in the Snowy could take care of the rest. You can also couple thermal solar to a coal fired power station for greater output.