High prices in NSW eventuate early, and briefly, on Tue 3rd Dec 2024 as Collector-Marulan 330kV outage invoked

Earlier this morning, Paul wrote about a long run of high prices forecast in NSW this afternoon, coinciding with the ‘N-CTMN_4_WG_CLOSE’ constraint set being invoked – starting today and scheduled to end on the 14th of December.

From the 11:40 dispatch interval this morning, we saw a run of four intervals where the NSW price spiked above $10,000/MWh as seen in the screenshot below.

The NSW price spiked up to near the market cap for four intervals between 11:40 and 11:55 this morning (NEM time).

Source: ez2view’s Trading Prices Widget

Prices in NSW have since pulled back, with P5 forecasted prices for the next hour at more typical levels. A closer inspection of several of our ez2view widgets shows a bit more detail into what was happening within the region at the time.

A view of the NSW schematic for the 11:40 dispatch interval.

Source: ez2view’s NSW Schematic widget

Our new Congestion Map prototype shows a very distinct congestion divide in NSW, as at the 11:40 dispatch interval

Source: ez2view’s Congestion Map Prototype widget

The NEM Map widget – shown here for the 11:40 dispatch interval – shows interconnector flows and prices.

Source: ez2view’s NEM Map widget

As always, there are many things happening at once… but worth noting a few dynamics that catch our attention at first glance:

• Very negative local price adjustments for wind farms around the Goulburn area (i.e. with connection points on or near the Collector to Marulan 330kV line)
• QNI and VNI flowing at southerly limits
• A counter-price flow from NSW to VIC
• Not shown in screenshots, but “NRM_NSW1_VIC1” (a negative residue management constraint), then clamped at the 11:50 dispatch interval
• Tumut 3 switched on from 0MW to 763MW at the 11:35 dispatch interval

At the time of writing (12:45pm NEM time), the current P30 price forecasts are showing the NSW up near $17,500/MWh between 16:00 and 20:00 today, with a forecast LOR1 condition currently appearing for the period between 14:00 and 16:00.

We will be keeping an eye on how the situation evolves.