Yesterday (Wednesday 8th July 2026), whilst the evening price volatility was underway we posted several articles … including noting that ‘Something’s up (with output down*) at the 6 x Loy Yang units…!?’.

Today, with the benefit of ‘next day public’ data we can use the ‘Bids & Offers’ widget in ez2view to take a look, with a view:

• time-travelled back to 00:00 this morning
• looking back 2 days
• focused on just the 10 x Brown coal units in Victoria:

An unexpected restriction on the amount of coal available

We see a clear change in bidding pattern at commence at 10:05 (NEM time) on Wednesday 8th July 2026 and see that the 6 x Loy Yang units across Loy Yang A (AGL) and Loy Yang B (Alinta) rebid with some form of ‘coal shortfall’ or ‘coal conservation’ reason.

Given that it’s a common coal supply to the two neighbouring stations, I wonder what the specific issue was … some sort of issue with the dredgers, for instance?

Repricing limited energy

Note that they did not remove volume completely from the market, but rather re-priced it up into the pink and red bid bands … we came across this same behaviour with batteries in mid 2022 and explained that this is the way portfolios ration limited stored energy:

1)  given that NEMDE only co-optimises across ENERGY and FCAS for a single dispatch interval

2)  In other words, NEMDE does not look forward to evening peak and ‘reserve’ energy-limited capacity (ordinarily batteries, but in the case of Loy Yang yesterday, limited coal supplies).

(a)  The market relies on the experiences traders themselves to do this;

(b)  With recent events (on 21st and 22nd June 2026 in South Australia) revealing some shortcomings in the still-too-crude versions of auto-bidders deployed today.

We might expect to see more of this across the changing portfolio mix with ‘the rise of Just-in-Time’

Only one (of a number of) factors contributing to volatility

Note that, whilst the spot price climbed a little from 10:05 as a result of the volume repricing, it was only much later in the day that ‘the price popped’, because that also depended on a couple other factors.

When time permits we might loop back around and collate more of the contributing factors in subsequent article(s) collated here.

Problem resolved, around midnight

Flipping the same ‘Bids & Offers’ widget in ez2view to ‘Real time’ mode to gain visibility of additional data, we see bid data through until 04:00 on Thursday 9th July 2026:

Whatever the specific issue was, it was resolved around midnight this morning.