For several days in early December, temperatures reached 40 degrees (or thereabouts) in many parts of QLD and NSW.  As a result, airconditioning load (and hence total demand) soared in both regions.  Record all-time regional demand went close to being exceeded in both regions.  This can be clearly seen in the following image, with a near record demand in QLD on Tuesday 6th and in NSW on Wednesday 7th (please click on the image for a larger view):

The snapshot of trading in the NEM taken from NEM-Watch during the afternoon of 7th December illustrates the volatility produced that day (again, please click on the image for a closer view):

The high demands resulted in very high prices being experienced in both QLD and NSW (and also the SNOWY region), as seen in the above image.

Both VIC and SA were insulated from the high prices because (at least in part) of the fact that transfers over the SNOVIC interconnector were constrained to minimise negative inter-regional surplus – see NEMMCO Market Notice #13695 for more details (and noted that NEM-Watch provides automated updates of Market Notices along with other data sets, and the ability to set alarms based on Market Notice content).

After waiting till the next day (when generator dispatch data is released by NEMMCO), we have been able to continue our analysis of the events of these two days by producing the following charts:

Generators in QLD

This chart illustrates the total output for each of the major (coal-fired) QLD generation stations.

In particular,it can be seen that the production at the Callide B and Callide C stations reduced at the time of maximum price.

Generators in NSW

This charts shows a similar story for the 3 government-owned NSW generators, and Snowy Hydro.  It can be clearly seen that Snowy Hydro has increased its output to meet the peak in demand, whereas production at Eraring Energy reduced slightly.

Generators in VIC

Despite the fact that the price spike experienced in Victoria over these 3 days were much more subdued, similar behaviour is evidenced in the production patterns of the 4 large coal-fired stations.