We’ve already progressively explored the volatility in South Australia through Sunday evening 21st June 2026 and into Monday morning 22nd June 2026 … but it’s probably better to think of a four day period with prices elevated as a result of low wind yield.

So I thought (as one next step) we might look at bidding.  With that in mind, we’ve grabbed the ‘Bids & Offers’ widget in ez2view to produce the following:

A couple tips to interpretation:

1)  This window is ‘time-travelled’ back to 0:00 this morning (Tuesday 23rd June 2026), and looking back four days

2)  Bids are sorted in the default blue-green-red bid ranges

… so useful for readers to recall earlier articles trending longer term (and NEM wide) bids in blue-green red:

(a)  that show lower volumes bid in green

(b)  as an illustration of how ‘the level of risk in the NEM is increasing’.

3)  Following the implementation  of the IESS Rule Change, bids to consume (i.e. batteries in SA, and also pumped hydro – that does not exist in SA (yet?)) are below the line.

4)  I’ve highlighted the two instances of highest volatility, to frame your reference over the 4-day period.

Utilising the ‘VRE + Shaping + Firming’ approach to viewing this energy transition (ala the Nelson Review) we separate out the bids as follows:

Variable Renewable Energy (VRE)

Breaking this into two categories … but mindful that there is a third.

Aggregate Bidding across SA Wind Farms

With low wind being a proximate cause of the elevated prices, we’ll start here.

Key take-aways here include:

1)  That it’s low wind (i.e. energy resource) and not curtailment that’s clearly the issue through this stretch of time (i.e. ‘~72 hours becalmed in South Australia’);

2)  So from the perspective of a ‘learning from this event to inform the energy transition’ perspective:

(a)  More wind capacity in SA would have been very unlikely to help

(b)  That’s also the case most of the way across the NEM … yield in QLD not quite so low, but transmission challenges enormous at cost-effective scale from there.

Aggregate Bidding across SA Large Solar Farms

With low wind being a proximate cause of the elevated prices,

This is a reminder that the main price events occurred outside of solar hours.

The solar yields on Sunday and Monday were quite strong (for winter), relative to Maximum Capacity … but South Australia does not have much solar capacity installed (in comparison to its wind fleet).

A reminder about (Medium and) Small Solar

A quick reminder that the energy mix also contains:

1)  ‘Small Solar’ … which is quite opaque (in terms of its contribution) and does not bid

2)  And also ‘Medium Solar’ … which is completely invisible … and also does not bid

Shaping + Firming

Let’s break apart the various dispatchable units:

Aggregate Bidding across SA (Large-Scale) Batteries

Let’s start with the battery fleet, which:

1)  demonstrates its value below in Shaping

2)  but also the challenges it will face to be a dominant supplier of Firming in situations such as these:

Over the ~36 hour period from Sunday noonish to Monday evening it’s illustrative to think of the performance in six phases:

Phase 1 = into Sunday afternoon and evening, the batteries did inject strongly into the grid (including by a fair volume bid in green) … and this would have helped to keep the price down through this period – remembering:

(a)  Wind was low for the whole period; and

(b)  Exports (from VIC into SA) were also progressively more suppressed through Sunday afternoon

Phase 2 = but by 19:35 on Sunday evening:

(a)  the batteries were practically empty and capacity bid dropped sharply (to 289MW from 984MW at peak), and continued to fall

(b)  even though exports (from VIC into SA) had begun to recover somewhat (notwithstanding the ‘CA_SYDS_594882A3_1’ constraint equation) it was not enough, and prices shot up and remained above $1000/MWh for some time.

Phase 3 = in the overnight period:

(a)  we do see some movement in battery bidding, in an attempt to buy-at-higher-price to charge

(b)  but we also see that not much of that actually happened.

Phase 4 = so, come Monday morning:

(a)  the batteries were largely unavailable to supply into the morning peak,

(b)  and the price shot up again.

Phase 5 = during the day on Monday:

(a)  we see much more charging happening through daylight hours

(b)  despite the elevated prices

Phase 6 = so that by 19:35 on Monday evening:

(a)  the batteries full enough to have an impact on price outcomes

(b)  and the absence of the ‘CA_SYDS_594882A3_1’ constraint equation meant less limited exports (from VIC into SA)

… so the price did not pop.

Aggregate SA (Small-Scale) Batteries

A reminder that there is a growing pool of assets here (albeit that most are not in VPPs) … but there’s no visibility of what they did – or did not – do, over this period.

Aggregate Bidding across SA Gas units

Moving onto the gas units, we see the following:

Briefly:

1)   There was some capacity unavailable.

… for reasons not investigated at this point.

2)  Capacity was bid:

(a)  for Sunday evening mostly in green ranges

(b)  But for Monday morning in higher price ranges (perhaps informed by the absence of the battery fleet).

Aggregate Bidding across SA Diesel-fired units

To the more expensive peakers (at least in terms of SRMC), the diesel units did get a run during both events:

In this case, less than half of the installed capacity was actually available.

… again, I’ve not investigated why.

Aggregate Bidding across SA Negawatts

Its nary a negawatt over this period:

There actually is 7MW registered, but it did not show up and bid for reasons I can’t be bothered to consider …