Under the National Electricity Rules, Scheduled and Semi-Scheduled units need to have submitted ‘Daily Bids’ (sometimes called ‘Initial Bids’) for the following Market Day by 12:30 the day before (this is sometimes talked about as ‘Gate Closure’).
At this time, the unit’s 10 x Bid Price Bands are fixed for the following market day, but the volume offered in each of those bands for all Dispatch Intervals (both now, and into the future of predispatch) can vary – using a Rebidding process.
Through the history of the NEM, there has been several different permutations of Rebidding Guidelines issued by the AER (and its predecessors). These are summarised in the following table:
|1st Oct 2021 – future||
In conjunction with the introduction of 5 Minute Settlement, the AER introduced updated Rebidding Guidelines.
As discussed on this AER page, this process was initiated on 18th September 2019, with a draft decision on that day and a final decision on 27th November 2019.
The principle documents are the two that follow:
In conjunction with these AER Guidelines, the AEMO also published this document “Format and Validation for Energy, FCAS, and MNSP Bids and Offers” in January 2020. This was accompanied by the upgrade of the MMS Data Model to version 5.0 to support the implementation of Five Minute Settlement.
|28th Feb 2017 – 30th Sept 2021||
In February 2017 the AER published a revised version of the Guideline to replace the previous (December 2009) version. The release of the revised Guideline (and accompanying final decision) marked the end of a consultation process which began with a consultation paper in September 2016 followed by a draft decision in December 2016.
The revised Guideline became effective from 28 February 2017.
Documentation is available from the AER website here – including the “Rebidding and Technical Parameters Guideline – Feb 2017”.
Note that this guideline provided some updates to the requirements established in 2009 – however it was the guideline of 2009 that provided a large step in the formalization of guidelines for rebidding in the NEM
|1st Dec 2009 – 27th Feb 2017||
On 25 September 2009, the AER published the preceding version of the final Rebidding and Technical Parameters Guideline.
The revised Guideline became effective from 1st December 2009.
Documentation is available from the AER website here – including the “Rebidding and Technical Parameters Guideline – Dec 2009”.
It’s also worth noting that, in this period (on 10th December 2015) the AEMC made a final rule to enhance the arrangements that govern generator’s offers in the wholesale electricity market. The final rule amended the relevant provisions in the National Electricity Rules as follows:
|13th December 1998 – 30th Nov 2009||
The initial 11 years of NEM operation incorporated the operation of the National Electricity Code Administrator (NECA) as the predecessor to the Australian Energy Regulator (which was established in July 2005).
With respect to discussion about Bids and Rebids on WattClarity and elsewhere, readers might be interested in the following:
Category of Rebid
In the 2017 Guidelines, the AER required rebids to be attributed to one of the following categories:
Category “P” for Plant Reasons
In the 2019 version of the Guidelines, the AER clarified that the submission of Rebid Category was recommended, but not mandatory.
Form of Rebids –
‘Well Formed’ and
‘Not Well Formed’
It is the AER’s role to assess ‘Compliance’ of each Participant’s participation in the NEM … including with respect to the compliance of their rebidding practices.
Readers should be clear that nothing we do is intended to imply whether (or not) any particular Participant is Compliant with the Rules.
In the various iterations of the Generator Statistical Digest that we have released from 2019 onwards, we have found it useful to categorise bids as to whether they are ‘Well Formed’ or ‘Not Well Formed’:
Readers should be clear that the ‘Well Formed’ label:
The method of determining ‘Well Formed’ or ‘Not Well Formed’ has varied through time, as different versions of the AER’s Rebidding Guidelines have been implemented – as outlined loosely in the following table:
Each annual issue of the Generator Statistical Digest is described separately on its own page.
|Number of Rebids||
In the Generator Report Card 2018 we trended the number of rebids over time (by plant type and category).
This was discussed in this article from February 2019, and in more detail in the GRC2018.