In the previous post I showed that wind power was largely AWOL at critical times during the peak electricity demand heatwave of December 2015 in South Australia . This post looks at how peak demand was met during that heatwave, and at how much capacity was in reserve.
The question of reserve capacity is important due to the imminent closure of Northern Power Station, which is currently consuming its last supplies of coal: http://www.adelaidenow.com.au/news/south-australia/leigh-creeks-final-coal-train-leaves-the-station-in-wake-of-port-augusta-power-stations-closure/news-story/5fb22f84e0b10ed418d65a55d3b2edc9
The following figure shows three of the key power supplies during the peak demand day of 17th December 2015, the “load following” supply from Torrens Power Station (blue curve), the total “peaking” supply (black), and the total power imported from Victoria (red):
Each of these three supplies were close to their maximum capacities, though not all at the same time. Torrens Power Station supplied close to its maximum of 1280 MW at the time of peak demand, as did the peakers (830 MW maximum). Imported power was close to its maximum of 680 MW at times, though it did drop away at the time of peak demand, when there was a sudden increase in peaking power.
Baseload power was close to its maximum capacity throughout the heatwave of 15-19th December:
Northern Power Station supplied its maximum of 500 MW, and also provided frequency control by dropping its output from time to time. The other baseload generators were Osborne and Pelican Point Power Stations, both of which supplied nearly constantly at close to their maximums.
The following figure shows the load following supply of Torrens Power Station throughout the heatwave:
Torrens supplied close to its maximum at the peak demand time for four consecutive days, something it won’t be able to do from sometime in 2017, when Torrens A will close, losing 480 MW of its 1280 MW capacity.
The following figure shows the total supply from the peaking power stations throughout the heatwave:
It can be seen that there was very little reserve peaking capacity at the time of peak demand on 17th December.
Finally, the total thermal generator supply throughout the heatwave is shown in the following figure, together with total demand, and (total demand – wind power). Wind power removed only around 100 MW of demand at the peak time of 17th December. The difference between total thermal supply and (demand – wind) was met by the interconnectors.
There was very little reserve scheduled capacity at times of peak demand during the heatwave of 15-19th December 2015, though there may have been some mothballed and/or local generators that could have been called on. A repeat of the same weather in the future will have to be met without 500 MW from Northern Power Station, and with 480 MW less power from Torrens Power Station from 2017, both of which played vital roles in 2015. It would appear that South Australia needs some more supply, and/or less demand.
See the NEM ELECTRICITY DATA page above for the sources of past electricity data.
Current and future electricity capacity figures were taken from spreadsheets available from this AEMO webpage: http://www.aemo.com.au/Electricity/Planning/Related-Information/Generation-Information