It's probably counter intuitive but the curtailment is free and it is cheaper to build capacity which can be ramped up and down. If the Renewable is curtailed it can be ramped up if required and this helps the long term because the capacity in the grid increases. Curtailment happens all the time but that is currently done via the pricing mechanism.
Small amounts of storage and curtailment are ok but the quantity of storage we are talking about here is beyond common sense if people seriously ran the numbers. In isolation a solar system needs at least 15 hrs storage imo. and that is determined by the hours of sunlight in a given day. If the LCOE is used to justify a project then the Capacity factor used in the LCOE calc is the level where the $/MWh is achieved, it also becomes the base that defines the storage required.
The established NEM utility solar is 401MW (Parkes, Griffith, Moree, Nyngan, Mugga Lane, Broken Hill, Gullen Range, Royalla) at 30% CF then they will produce 119MW's or 2,850 MWh's per day. At night we require storage of 1,780MWh's and the surplus in the day is required to meet the deficit at night, currently there are 8hrs where they produce above 30% so if that is used for anything else that capacity will need to be replaced. Also I have ignored the losses so that further reduces the CF. Solar is largely predictable so storage is probably better suited because the limitations can be managed imo. If the solar needs batteries then the emissions of the battery are attributed to the solar and it is no longer zero emission. The battery is a consumable and needs to be included in the cost.
Wind is more complicated because there is no set pattern like solar. Imo curtailed wind is a winner because the output is controlled and reduces the variability which causes most disruption in the grid. They get paid for the output not for the quality or demand for the output and everyone else pays.
SA is a perfect example as they always have baseline gas around 200MW, rooftop (Peak 550MW) and some new utility solar (Peak 150MW) which run reliably every day. When the wind blows in the middle of the day there is too much supply and it goes to Victoria but Vic have now added their own Renewables so there is no where for it to go. When the wind stops they take all the gas causing supply issues for everyone. If the wind is stored then the next day it will be curtailed. Using unrealistic capacity factors mean the $/MWh are understated, the storage requirements are also understated.
I agree with your water comment and also the 'faraday Grid" was interesting. Election imo won't change anything both have a No Electricity Guarentee. Only joking - sort of!
