The AEMO masterplan sees coal reduced from almost three quarters of the power supply to less than a third to be replaced by renewables, extra transmission lines and fast-start power, presumably gas. The possibility of extending the life of the existing coal plants is off the table.
“Essentially we’re having to rebuild the market because of the amount of ageing coal infrastructure that needs to be replaced,” AEMO chief executive Audrey Zibelman told The Australian.
Two thirds (15GW) of the coal fired capacity will go by 2040 to be replaced by more than 30 GW of new large-scale renewable. According to the report in The Australian yesterday that intermittent capacity will be backed up by some 21 GW of hydro, batteries and “ demand response”.
The problem is that no amount of the kind of backup that is planned will be enough to replace intermittent supplies that amount to about half of the baseload requirement.
I suspect that backup from hydro, batteries and demand response is a fantasy. It is generally accepted in capable engineering circles that unreliable energy has to have 100% backup from some reliable source. That is due to the choke point when the sun is off duty and the wind fleet is delivering as little as 2% of plated capacity.