Society expects reliable and affordable electricity and now carbon free.
Demand for electricity varies with time.
Fossil and nuclear are able to adjust output to meet demand.
Solar and wind are subject to the vagaries of the weather and cannot adjust to demand.
Consequently stand-alone renewable electricity generating systems need to either incorporate storage, consist of a number of different renewable generating types in parallel or a mixture of storage and generating types.
This is conceptually simple, but the costs of storage and having a number of generators in parallel have huge potential for rendering electricity unreliable or unaffordable.
Estimating the costs and characteristics of these systems can best be done by pilot plant studies.
Installing full-scale facilities without probing for likely costs is a risky economic situation.
The battery of choice at this time is lithium-ion which has been used in small-scale applications for some time.
Costs are prohibitive as no-one is claiming success.
So far batteries are only good for helping to stabilise the grid.
A highly significant cost issue that arises with having renewable generators in parallel (for example solar and wind together) is the low capacity utilisation factor due to the generators being on standby for a lot of the time, and given that a system must be designed to cope with peak load.
The construction cost of all the generators in the system, and not just those operating at a particular time, have to be taken into account in calculating the real cost of electricity.
Another significant cost is the transmission facilities required from the generating sites to that of demand given that the generation sites will vary with the vagaries of the weather over possibly long distances.
All costs have to be taken into account to know the real cost of electricity.
There is no clear evidence at the moment that stand-alone renewable electricity generating facilities are reasonable or affordable.
Neither can their reliability, independent of the weather, be guaranteed.
It would make sense to consider a mixture of generating types where some components are independent of the weather and test on a pilot scale.
Committing to full-scale investment without prior investigation is risky as has been experienced in many industrial processes before.
Australia is embarking on a very risky path that could adversely affect us for a generation.
Perhaps if future savings need to be made we could repurpose our future nuclear submarines to generate reliable electricity.
Email, Jul 9
Charles Hemmings, Woy Woy