We got one of our first glimpses of the new market price cap in action today, with prices for the ‘Lower 1 Second’ contingency FCAS commodity in South Australia flickering between the FCAS price floor ($0/MWh) and the market price cap ($20,300/MWh) over the past several hours.
This volatility kicked off shortly after 11:00am (NEM time) this morning. This screenshot below was taken at 2:55pm this afternoon, and shows the price outcomes for the ‘Lower 1 Second’ commodity throughout today, and also shows the P5 price forecast for the next six intervals.
Source: ez2view’s Trading Prices widget
Earlier in the week we noted the invocation of the ‘I-HYSE’ constraint set, due to an outage on the 275kV Heywood-South East transmission line (forming part of the SA-VIC interconnector), and warned of energy and FCAS price risk due to these limitations on the Heywoood interconnector.
That outage concluded yesterday evening, but I note that the ‘S-TBTU’ constraint set has been invoked since 8am this morning, and is scheduled to conclude at 5:30pm NEM time this afternoon. That constraint set is invoked due to an outage on the 275kV Tailem Bend-Tungkillo line (which also forms part of the SA-VIC interconnector). This set contains several constraint equations that change the FCAS requirements for each contingency commodity — limiting procurement to within SA, or in this case, procurement from parts of the SA region west of the outage, due to system security risks if this section of the grid became islanded.
The screenshot below shows our constraint equation dashboard widget from within ez2view — showing the ‘F_S+TBTU_L1’ equation (within the ‘S-TBTU’ set) binding throughout today. It also shows the P5 and P30 forecasted values for this equation, for the next three hours ahead.
Source: ez2view’s Constraint Equation Dashboard widget
The ‘S-TBTU’ constraint set is scheduled to be invoked in an alternating fashion with the ‘S-TB_CB6596’ constraint set over the next four days, as shown in the screenshot below. It is then scheduled to be invoked for an extended period from Monday 28th July until Sunday 10th August, but with a brief 14 hour intermission from 5:30pm on Sunday August 3rd. This schedule may be subject to change.
Source: ez2view’s Scheduled Constraint Sets widget
Is work on the Tungkillo-Tailem Bend line the reason for a wierd AEMO dispatch interval? At 5:25pm EST the AEMO dashboard had Vic price $193.82, SA price -$19.97, NSW price $138.48. Both the SA and NSW inter-connectors had strong counter-price energy flows. From Vic to SA it was 620MW on the AC inter-connectors, which was at its limit, 15MW Vic to SA on the DC connector (at its limit), and from Vic to NSW it was 1088MW, again at its limit. Being close to 5pm SA time, work on the transmission line may have been finished for the week and the line re-energised, but as this capacity was made available to NEMDE it couldn’t find a stable solution.