In conjunction with today’s other article (which explores the operation of the VBB on Tue 13th Feb 2024) I’ve done some searching and have compiled the following background information with respect to the role of the Victorian Big Battery (VBB) with respect to the System Integrity Protection System (SIPS).
(A) High-level explanation, from Neoen
As they do for all of their assets in the NEM, Neoen has prepared an asset-specific website for Victoria Big Battery here.
From this page I particularly noted the following:
1) From this educationally-focused Neoen page for the Victorian Big Battery, I’ve copied in the explanation that’s currently there, and added some highlights:
‘NETWORK SUPPORT
The Victorian Big Battery will deliver a 250 MW network support service called SIPS which stands for System Integrity Protection Scheme.
SIPS is a mode of operation where the battery has an automatic, instantaneous response to a network failure. When SIPS is triggered by an unforeseen power line failure or generator outage, the battery automatically charges or discharges to prevent a blackout.
Batteries are incredibly well suited to perform this service because they can respond in the blink of an eye. Until recently, large power lines and state interconnectors had to maintain significant headroom to survive major interruptions. In recent years, SIPS from batteries has seen an increase in use unlocking this capacity, like opening up an extra lane on a freeway.’
2) Also on the same site, the FAQs here contain the following:
‘Q) What is SIPS?
SIPS stands for Systems Integrity Protection Scheme.
A 250 MW SIPS service contract was awarded to the Victorian Big Battery by AEMO under the Victorian Government’s SIPS 2020 procurement process. Put simply, the scheme enables the additional import of electricity over the Victoria to New South Wales interconnector of up to 250 MW at peak times.
SIPS a mode of operation where the battery has a pre-programmed response to a network failure. When SIPS is triggered by an unforeseen power line failure or generator outage, the battery automatically charges or discharges to prevent a blackout.
Batteries are incredibly well suited to perform this service because they can respond at warp speed. Until recently, large power lines and state interconnectors had to maintain significant headroom to survive major interruptions. In recent years, SIPS from batteries have been used to unlock this capacity like opening up an extra lane on a freeway.’
(B) From the Victorian Government
I managed to find this 8-page update in the Government Gazette from 15th May 2020, at the commencement of the procurement process:
(C) From the AEMO
Searching further for the Victorian Government’s SIPS 2020 procurement process, we find the AEMO Media Release ‘AEMO completes System Integrity Protection Scheme procurement process’ on 5th November 2020 (i.e. 6 months after the notice in the Government Gazette above), which includes the following note:
‘…
In the event of an unexpected network outage between November to March, the battery will automatically discharge energy within seconds, ramping to full output of 250 MW. This will allow AEMO time to safely optimise interconnector flows and dispatch other generation and storage within Victoria to keep the system stable and secure.
…’
Thirteen months after the contract was noted by the AEMO above was the follow-on the AEMO Media Release ‘Victorian battery ready to deliver energy reserves this summer’ on 8th December 2021, which includes the following note:
‘Following AEMO’s competitive tender process, Neoen was awarded the contract to supply up to 250 megawatts (MW) of energy reserve from its 300 MW/450 MWh battery to operate in a control scheme that increases the capability of the Victoria to New South Wales Interconnector (VNI).
…
About System Integrity Protection Scheme (SIPS)
On 18 March 2020, the Victorian Parliament passed amendments to the National Electricity (Victoria) Act 2005 (Vic) (NEVA). This new legislation allows the Minister for Energy, Environment and Climate Change powers to modify or disapply sections of the National Electricity Law and the National Electricity Rules as they relate to specified augmentations, augmentation services or non-network services in respect of the Victorian transmission network.
In November 2020, the Minister made orders under the NEVA that directed AEMO to enter into the SIPS Support Agreement to manage the procurement process to allow additional import of electricity over the Victoria to New South Wales Interconnector (VNI) of up to 250 MW at peak times between November and March.’
(D) From the Australian Energy Council
Additionally, I found this very useful article by Allan O’Neil (frequent guest author on WattClarity) over on the AEC website ‘Victoria’s big battery: What exactly is it for?’ on 26th November 2020 (i.e. after the contract had been awarded, but before operations). In this article, Allan explains:
‘How will it increase the capacity of the NSW-Vic interconnection?
Of course, the VBB won’t change the physical size of the transmission assets connecting NSW and Victoria via the Snowy area[ii].
What it will do in some situations is allow that transmission to be operated at higher flow levels, because the battery will be contracted by the Australian Energy Market Operator (AEMO) to provide rapid guaranteed backup to reduce flows if something goes wrong, and buy the market operator more time to rearrange the supply-demand balance.
Without this guaranteed backup, the transmission lines carrying flows from north-east Victoria and NSW have to be operated more conservatively so there is no risk of very rapid thermal overload if one of their two parallel circuits trips. The battery’s contracted capability effectively provides additional headroom of up to 250 MW on these thermal overload limits, enabling higher imports under some conditions from NSW on top of flows from hydro generators in north-east Victoria and the Snowy scheme.
These thermal overload limits are usually only important on very hot days in the peak summer period. For this reason AEMO is only contracting the battery to provide this 250 MW backup service from 1 November to 31 March each summer. AEMO will pay the battery owner $12.5 M per year (escalated with CPI) over the period 1 November 2021 to 31 March 2032.
In some past years where reliability was tight, AEMO had contractual arrangements with large aluminium smelting loads in Victoria to use rapid demand reductions as backup for running the same transmission lines at high short-term ratings. So the concept underlying the import capacity increase enabled by the VBB is not new, only the means of achieving it. It’s not clear from the published justification for the VBB why it has been chosen in preference to demand side alternatives.
Will the VBB always increase the interconnector limits?
No. Obviously outside the summer period when VBB capacity is contracted to AEMO, interconnector thermal limits will be unaffected. Nor will the VBB directly affect capacity to export power from Victoria to NSW. And as well as thermal capacity limitations, AEMO imposes other types of constraint which can limit flow levels across transmission lines. “System security” constraints are designed to ensure that credible system disturbances such as trips of generation unit or transmission lines do not cascade into widespread disruption and blackouts.
On the NSW-Victoria interconnection, as well as the thermal constraints discussed above, there are various non-thermal security constraints that can also limit power transfers. In mild weather or when hydro generation from Snowy and north-east Victoria is not near maximum levels – which is most of the time – one of these security constraints will normally be the limiting factor on maximum power imports from NSW.
In relatively recent instances of load shedding in Victoria such as those experienced on 24-25 January 2019, the limits imposed by one of these security constraints were very close to the thermal constraints addressed by the VBB. This meant that even if more headroom had been available on the thermal constraints on those days, imports from NSW could not have been materially increased.
Since then, AEMO has contracted with a NSW participant to provide voltage support services that will create more headroom under that security constraint, but only when Victoria would otherwise face load shedding or activation of Reliability and Emergency Reserve Trader (RERT) reserves. The duration of this contractual arrangement is not stated.
So while it’s clear that the VBB will assist in lifting NSW-Vic thermal constraints during peak summer periods, and is likely to assist in reducing the probability and / or size of load-shedding events, it’s not yet obvious what the overall impact on interconnector operation will be. It’s therefore worth qualifying the statement that the VBB will “lift NSW-Vic import capability by up to 250 MW” with the rider that a lot of the time the effective increase might be well under 250 MW, or even nil.’
(E) On WattClarity
More generally, there are a range of articles that have been written about the Victorian Big Battery over time … many of which we’ve remembered to tag with Victoria Big Battery (VBB).
If any readers see anything significant I have missed, or misunderstood, please feel free to add in here as comments?!
Leave a comment