From the 4-second SCADA data, a view of Production by Fuel Type on Tuesday 13th February 2024

On Saturday 17th February 2024 we posted this ‘quick first pass through ENERGY bids (for Victorian units) on Tuesday 13th Feb 2024’.

Now we are returning to the higher-speed 4-second data that the AEMO published on Thursday, which was used to produce this‘14 hours of trended (mainland) frequency on Tuesday 13th February 2024’.  In this article we’ll delve further into what’s visible with respect to the 4-second data for unit outputs in Victoria over the same 14 hour period (i.e. 06:00 to 20:00 NEM time, so spanning Event 1, Event 2, Event 3 and Event 4 as identified in the AEMO’s Preliminary Report (along with the trips* of 4 Generators and 1 Load).

Remember the disclaimers added in this article, which also apply here – notably that we’re just looking at units located in Victoria for which the AEMO has SCADA data, so:

1)  Any effects (or possible contributions?) in other regions are not going to be seen;

2)  The role of interconnection is not seen;

3)  Worth highlighting that anything that might have happened with rooftop PV in VIC or elsewhere, which is invisible through this data, through the incident is not going to be seen

Also keep in mind that my intention in combing through this data was to notionally allocate units into two baskets:

1)  Does not appear to be anything of interest to see here; and

2)  With this unit there are more details I’d like to know (albeit that, given our incessant curiosity, this bucket’s likely to be overflowing).

With these caveats in mind, let’s proceed.

What happened at Portland Aluminium Smelter?

The 4-second data (in addition to data for visible generators) contains data for a very small number of large industrial load sites … including the Portland Aluminium Smelter in Victoria.  Remembering that the AEMO preliminary report identified a trip at the Portland Smelter sometime later than Event 2, it was of interest to look here:

With respect to this chart, there’s a few things that jumped out to me – including:

1)  There’s a clear drop in consumption coincident with the frequency dropping with Event 2 … which suggests that the operations at Portland (possibly via Raise FCAS services?) would have played a role in stabilising frequency.

… something to explore in a further article (Observation/Question #1).

2)  From this data it appears that what we called Event 4 here (i.e. the trip of Portland Smelter) occurred at ~15:00:

(a)  So before Event 3 in a chronological sequence;

(b)  With the smelter back online by ~15:09;

(c)  And tripping for unknown reasons.

… something to explore in a further article (Observation/Question #2).

3)  There’s also the earlier partial drop in consumption at ~13:34 which (given the proximity to Event 2) I am guessing is somehow related:

(a)  First guess is that it might be an intentional reduction to support supply-demand balance (given all the supply-side units that tripped)

i.  for instance, there was MN114656 the AEMO issued at 17:38 about ‘AEMO has issued a direction to a participant in the VIC region’

ii.  but that notice was issued 4 hours after the reduction in load, suggesting AEMO’s direction was not related to Portland.

iii.  and noting that there was no earlier Market Notice about a Direction in Victoria.

iv.  Perhaps there was another manual trigger?

(b)  Or perhaps it was involuntary?

… something to explore in a further article (Observation/Question #3).

What happened at the Coal Units?

The identified the trip of Loy Yang A as part of Event 2, and we’ve seen this earlier – but it was of interest to look at the other coal units (as we had earlier in aggregate with respect to their bids):

With respect to this chart, there’s a few things that jumped out to me – including:

1)  The steep trip of all 4 units at Loy Yang A with Event 2 is very clear:

… something to explore in a further article (Observation/Question #3).

2)  There’s a clear increase in output at YWPS3 and YWPS4 coincident with the frequency dropping with Event 2 … which suggests that the these units might have been supplying some form of Raise FCAS services?.

… something to explore in a further article (Observation/Question #4).

3)  Earlier in the day (around Event 1, which is not marked in this case) there is a clear increase in output at YWPS4 and LYA2 and LYA4 coincident with the frequency dropping with Event 1 … which again suggests that the these units might have been supplying some form of Raise FCAS services?.

… something to explore in a further article (Observation/Question #5).

4)  Remembering that Event 3 relates to tripping of transformers and lines in the Latrobe Valley, I note that LOYYB1 and LOYYB2 and YWPS3 and YWPS4 had all been reducing prior to that event, and seem to rise in conjunction with the frequency hitting bottom …

… something to explore in a further article (Observation/Question #6).

5)  Later in the day (around ~17:22) the frequency again drops, and TWPS4 and LYA2 (which is ramping up at the time) temporarily increases output …

… something to explore in a further article (Observation/Question #7).

6)  At the same time (around ~17:22), however, there’s a clear drop in output at YWPS2 …

… something to explore in a further article (Observation/Question #8).

What happened at the Gas Units?

There was no mention of Gas units in the AEMO Preliminary Report — but it was of interest to look at the other coal units (as we had earlier in aggregate with respect to their bids):

With respect to this chart, there’s a few things that jumped out to me – including:

1)  There are six units (JLA04 + siblings, and MORTLK11, and VPGS1) that are started up about an hour before the spot price at the Market Price Cap attached to Event #2, and I’m curious in each case what the trigger might have been in each case:

… something to explore in a further article (Observation/Question #9).

2)  Unless I have missed something (low res image!) the other units all appear to start in a staggered fashion after the price spikes started in relation to Event #2:

… something to explore in a further article (Observation/Question #10).

What happened at the Hydro Units?

There was no mention of Hydro units in the AEMO Preliminary Report – but it was of interest to look at the other coal units (as we had earlier in aggregate with respect to their bids):

With respect to this chart, there’s a few things that jumped out to me – including:

1)  There are two units (MCKAY1 and MURRAy1) that are started up about 60 minutes before the spot price at the Market Price Cap attached to Event #2, and I’m curious in each case what the trigger might have been in each case:

… something to explore in a further article (Observation/Question #11).

2)  The other units appear to start slightly after Event #2, and I’m curious to delve further:

… something to explore in a further article (Observation/Question #12).

3)  Given that it’s easily the largest unit in the chart, the short term fluctuations in output around Event #2, (and also Event #3, though that’s not highlighted on the chart) are of interest … as are the contributions of the other units:

… something to explore in a further article (Observation/Question #13).

The two sides of a BESS, currently?

Until the IESS rule change is implemented in June 2024, batteries are represented by a pair of DUIDs … charging and discharging.  So there is 4-second data for both units (which currently is positive in both cases).

There was no mention of BESS (charging or discharging) in the AEMO Preliminary Report – but it was of interest to look how the battery units performed, on both sides of their ledger (as we had earlier in aggregate with respect to their bids).

So here’s a trend of BESS discharge using the 4-second data:

Here’s the other side of the ledger, with BESS charging as follows:

Looking at both charts together and visually trying to line them up, there are a number of things that jump out to me – including:

1)   Looking through each DUID in turn, the largest discharge is shown to be HBESSG1 (almost 3 times larger than the next biggest), so it stands out and we’ll start there:

(a)  there is a spike coincident with the frequency dropping with Event 1 – which presumably would have helped support frequency.

(b)  there is also a spike in output related to Event 2 … which would also support frequency.   However it appears to be much lower than earlier discharges, and I wonder why?

(c)  further, the contribution from HBESS1 drops away in the ~2 hours afterwards when the spot price was at $16,600/MWh (including the period of load shedding), and I wonder why?

(d)  Given that the HBESSG1+HBESSL1 combination had a close proximity to Event 3 , I wonder what the impact was?

… something to explore in a further article (Observation/Question #14).

2)   Next largest in contribution was VBB1+VBBL1:

(a)  With the first point being the contribution on the generation side of this unit through the day was quite small in relation to its installed capacity (higher on the load side);

(b)  In these low-res images there that VBBL1 was charging around the time of Event 1 , and it appears that there was a reduction in consumption (perhaps ~10MW) at the time of the frequency drop, which would have helped to support frequency.

(c)  There is a pronounced spike in output related to Event 2 … which would also support frequency.   However this is well below installed capacity, so I wonder if this is related to SIPS restrictions?

(d)  Unlike the case for HBESS1 discharge, the VBBG1 discharge appears more active in the hours after Event 2 – albeit not continuous output .

… something to explore in a further article (Observation/Question #15).

3)   For BALBG1+BALBL1:

(a)  Trying to eyeball what was happening around Event 1, it does not appear either charge or discharge?

(b)  There’s an increase in output around the time of Event 2 … just need to check if this is just prior to frequency dropping.

(c)  It’s clearer that there was little output in the 2 hours after Event 2 .

… something to explore in a further article (Observation/Question #16).

4)   For BULBESG1+BULBESL1:

(a)  There does seem to be a spike in output coincident with frequency dropping with Event 1.

(b)  With Event 2 it’s harder to see … certainly BULBESG1 output is lower than around Event 1.

(c)  The interesting thing is that the unit seems charge to for a period in the 2 hours after Event 2.(i.e. with spot price at $16,600/MWh and frequency low)

… something to explore in a further article (Observation/Question #17).

5)   For GANNBG1+GANNBL1, the unit is too small to see at this scale:

… something to explore in a further article (Observation/Question #18).

6)   For PIBESSG1+PIBESSL1 the unit is too small to see at this scale:

… something to explore in a further article (Observation/Question #19).

What happened at the Wind Units?

The identified the trips of Dundonnell Wind Farm and Yaloak South Wind Farm as part of Event 2 (and remember Stockyard Hill Wind Farm in Event 1), but it was of interest to look more broadly at all the Wind Farm units (which we had earlier in aggregate with respect to their bids:

Looking at both charts together and visually trying to line them up, there are a number of things that jump out to me – including:

1)   First and foremost, there are way too many wind units to show usefully on one chart … we just have a mess of spaghetti that needs to be separated out to see much that is is meaningful:

… something to explore in a further article (Observation/Question #20).

2)   I have coloured some of the topical (or otherwise larger units) … starting with STOCKYD1, the subject of Event 1:

(a)  I’ve not seen any reports yet that note why the unit was ‘lost’ (the word used in AEMO’s Preliminary Report) around 11:35, and am certainly interested to understand this;

(b)  This quick view of the 4-second data did not explain why that was the case – other than that it was a rapid loss;

(c)  But what was a surprise is that the unit appears to power up rapidly at ~12:26 for unknown reasons, and then disappear just as quickly?

… something to explore in a further article (Observation/Question #21).

3)   As noted in the AEMO’s Preliminary Report, and written about previously, the three DUIDs representing Dundonnell Wind Farm tripped off rapidly with Event 2:

(a)  I’d like to know more about what happened here;

(b)  And note that there seemed to be an earlier steep drop in output at around ~11:00

(c)  But have not had time yet to check

… something to explore in a further article (Observation/Question #22).

4)   In the AEMO’s Preliminary Report it also noted the trip at Yaloak South Wind Farm (YSWF1) with Event 2:

(a)  But we’d not written about that previously (or probably seen mentioned elsewhere either)

(b)  It’s too small a scale to see anything meaningful as well (it’s a smaller Non-Scheduled unit)

… so something to explore in a further article (Observation/Question #23).

5)   In terms of other large units coloured in above, the MACARTH1 output seems stronger after Event 2 … perhaps related to its location in the western part of Victoria?

… so something to explore in a further article (Observation/Question #24).

6)   Another large unit coloured in was MOORAWF1, which showed an interesting output profile:

(a)  steady output through the morning, apart from two steep drops in output (at ~10:35 and ~12:21… coincidentally at the same time as STOCKYD1 appears to have ramped up temporarily)

(b)  Then very lean output through the afternoon until ~19:00

… so something to explore in a further article (Observation/Question #25).

Moving to solar units now …

What happened at the Solar Units?

There was no mention of Solar Units in the AEMO preliminary reports, but it was of interest to look at all the solar units (as we had earlier in aggregate with respect to their bids):

Looking at both charts together and visually trying to line them up, there are a number of things that jump out to me – including:

1)   Some units (e.g. KIAMSF1 and WEMENSF1 and the grey ones (BANN1 and KARSF1 and YATSF1))  show output profiles that suggest being ‘constrained off’ during many hours of the morning period … each a little different; whereas

… something to explore in a further article (Observation/Question #26).

2)  Other units coloured yellow (e.g. GANNSF1 and GLNRWNSF1 and NUMURSF1 and WINTSF1) suggest unconstrained output through the morning up until just before Event 2, when output becomes much, much choppier for unknown reasons)

… something to explore in a further article (Observation/Question #27).

3)  The green unit (GLENSF1) shows a very ‘blocky’ profile which makes me wonder if this one was not involved in the Fixed Load profile seen earlier in aggregate with respect to their bids?

… something to explore in a further article (Observation/Question #28).

4)  I think COHUNSF1 was off for the day, so nothing to see here…

That’s all for now (leaving this list of another 28 Observations/Questions to explore later)…