Regional Structure
CHAPTER 2A

2A.	Regional Structure
Part A	Region change applications and region determinations by AEMC
2A.1	Introduction to Chapter 2A
2A.1.1	Definitions
Expressions in Chapter 2A are defined in Schedule 2A.1.
2A.1.2	AEMC determination of regions
(a)	For the purpose of conducting the spot market, the market is to be divided into regions determined by the AEMC in accordance with the Rules.
(b)	A region change may only be made by a region change application to the AEMC in accordance with this Chapter 2A.
(c)	Until the AEMC makes a region change in accordance with this Chapter 2A, for the purposes of the Rules, the regions are taken to be the regions defined in the Regions Publication published under clause 2A.1.3
2A.1.3	Publication of regions by AEMO
AEMO must maintain, review and, by 1 April each year, publish a list of all regions, regional reference nodes and the region to which each market connection point is assigned as determined or approved by the AEMC for alteration, under this Chapter 2A and rule 3.6 (the Regions Publication).
2A.2	Region change applications
2A.2.1	A complete region change application
(a)	Subject to and in accordance with this Chapter 2A, a Registered Participant or AEMO ("an applicant") may make a region change application to the AEMC.
(b)	In order to be accepted by the AEMC, a region change application must comply with the requirements under this rule 2A.2 ("a complete application").
(c)	In order to be a complete application, a region change application must:
(1)	identify a congestion problem – see clause 2A.2.2;
(2)	present a preliminary case as to the economic efficiency of a proposed region solution – see clause 2A.2.3;
(3)	propose a region solution to the congestion problem that is technically competent – see clause 2A.2.4;
(4)	demonstrate that the proposed region solution is appropriate having regard to alternative means for managing the congestion problem – see clause 2A.2.5;
(5)	if the congestion problem has been considered within 5 years of the date of the region change application, demonstrate why it should be re-considered – see clause 2A.2.6; and
(6)	propose an implementation period.
2A.2.2	Identifying a congestion problem
A region change application must demonstrate, with supporting economic analysis:
(1)	that there is a problem with the existing region configuration;
(2)	that the problem is attributable to the presence of material and enduring network congestion; and
(3)	that the problem has or will detract materially from economic efficiency, where economic efficiency includes (but is not limited to):
(i)	efficiency in relation to the impact on efficiency of dispatch, including in respect of bidding incentives and dispatch outcomes;
(ii)	efficiency in relation to the management of risk and the facilitation of forward contracting through contracts in the financial markets and the spot market; and
(iii)	long term dynamic efficiency – including in relation to making investment decisions,
(a congestion problem).
2A.2.3	Explanation of economic efficiency of proposed region solution
(a)	A region change application must explain how the proposed region solution would or would be likely to materially improve economic efficiency.
(b)	For the purposes of paragraph (a), economic efficiency includes (but is not limited to):
(1)	efficiency in relation to the impact on efficiency of dispatch, including in respect of bidding incentives and dispatch outcomes;
(2)	efficiency in relation to the management of risk and the facilitation of forward contracting through contracts in the financial markets and the spot market; and
(3)	long term dynamic efficiency – including in relation to making investment decisions.
2A.2.4	Region change application must be technically competent
A region change application must:
(1)	demonstrate that the proposed region solution identified in the application satisfies the following technical requirements:
(i)	each region must have a single regional reference node which is to be deemed to be a notional busbar at:
(A)	a nominated major transmission substation located at or close to the largest load centre within the region; or
(B)	where a region has no major load centre or there is some other reasonable cause for not defining a regional reference node at a particular major load centre, a nominated major transmission substation located at or close to the largest generation centre within the region;
(ii)	all transmission connection points affected by a proposed region solution must be identified;
(iii)	a transmission connection point may only be assigned to a single region;
(iv)	the boundary of a region must be closed and must enclose at least one significant load centre and/or generation centre;
(v)	the physical transmission elements that form the interconnection with adjacent regions must be described, including the points at which the boundary cuts through the transmission elements; and
(vi)	the availability of revenue metering to measure the energy flow across each physical transmission element that forms the interconnection with other regions; and
(2)	where the application proposes an implementation period that is more or less than 3 years, specify the proposed implementation period and provide reasons why a different time period should be determined by the AEMC,
(a technically competent application).
2A.2.5	Alternative congestion management options
(a)	A region change application must demonstrate that the region solution proposed in the application is an appropriate and timely course of action in all the circumstances, having regard to alternative means of managing the congestion problem (the alternative congestion management options).
(b)	The alternative congestion management options include:
(1)	changes to the geographic distribution of generation and load over time;
(2)	changes in the configuration of the transmission network such as a change which is a consequence of the application of the last resort planning power regime; or
(3)	changes in capability of the transmission network arising under other arrangements for the provision of network support and control ancillary services.
2A.2.6	Previous application relating to congestion problem
Where a region change application ("a subsequent application") addresses the same or substantially the same congestion problem as a previous region change application accepted by the AEMC within the previous 5 year period, the subsequent application must demonstrate, with supporting evidence, why it is appropriate for the AEMC to accept a subsequent application having regard to:
(1)	any material changes in circumstances since the previous region change application;
(2)	the general desirability of a stable region structure for the making of contracting and investment decisions:
(i)	in the NEM; and
(ii)	in financial markets;
(3)	the adequacy of the previous application; and
(4)	any other relevant consideration in the particular circumstances of the case.
2A.2.7	AEMO to provide information to intending applicants
(a)	An intending applicant (other than AEMO) or an alternative proponent may request information from AEMO in order to prepare a technically competent application.
(b)	A person making a request to AEMO under paragraph (b) must include in the request details of the information sufficient for AEMO to identify the information sought.
(c)	Subject to paragraph (d), AEMO must on request from an intending applicant or an alternative proponent, as soon as practicable after receiving the request, furnish to the relevant person, such information that is:
(1)	requested in accordance with paragraphs (a) and (b); and
(2)	in AEMO’s possession or provided to AEMO under paragraph (c).
(d)	For the purpose of furnishing information under paragraph (c), AEMO may direct a Transmission Network Service Provider to provide information to AEMO and the Transmission Network Service Provider must provide that information to AEMO as soon as reasonably practicable.
(e)	Information that AEMO is required to furnish under paragraph (c) does not include information that AEMO may be directed to provide under clause 2A.5.2.
(f)	AEMO must publish:
(1)	requests made to AEMO under paragraph (a);
(2)	information (excluding confidential information) provided by AEMO in accordance with paragraph (b); and
(3)	details of the circumstances where AEMO has not provided information in accordance with paragraph (d),
as soon as practicable.
2A.2.8	AEMC may refuse to accept incomplete applications
If the AEMC considers that a region change application is not a complete application under this rule 2A.2, the AEMC:
(1)	must notify the applicant, including written reasons that set out the respects in which the application is not complete; and
(2)	is not required to further consider the application until it is satisfied that the application is a complete application.
2A.3	Acceptance of region change application by AEMC
2A.3.1	Acceptance of a region change application by AEMC
(a)	The AEMC must not accept a region change application unless it is satisfied that the application is a complete application in accordance with rule 2A.2.
(b)	Where the AEMC:
(1)	is not satisfied that a region change application is a complete application in accordance with rule 2A.2; or
(2)	considers, whether as a result of submissions received in preliminary consultation under clause 2A.3.2 or otherwise, that a region change application should not proceed,
it may make a decision not to accept the region change application, setting out the reasons for that decision.
(c)	The AEMC must, without delay, notify the applicant of a decision not to accept a region change application, and publish that decision (including the reasons) on the AEMC’s website.
(d)	Where the AEMC is satisfied that a region change application:
(1)	is a complete application in accordance with rule 2A.2;
(2)	satisfactorily addresses any issues raised by preliminary consultation under clause 2A.3.2; and
(3)	should, in all the circumstances, be the subject of consultation and considered under this Chapter 2A,
the AEMC must make a decision to accept a region change application and must take action in relation to the application in accordance with this Chapter 2A.
(e)	An applicant may not withdraw a region change application after the AEMC has accepted that application and has published a first round consultation notice under clause 2A.4.1.
2A.3.2	Preliminary consultation prior to acceptance of a region change application
(a)	After the AEMC decides that a region change application is a complete application in accordance with rule 2A.2, but prior to making a decision whether or not to accept the application under clause 2A.3.1, the AEMC must publish the proposed region change application (including all supporting evidence) on its website and invite written submissions from any person within 21 business days of the date of that publication.
(b)	The AEMC is not required to publish confidential information provided to it under this clause.
(c)	Where the AEMC considers that submissions received under paragraph (a) raise issues that should be addressed in the region change application, it may:
(1)	request the applicant to amend the region change application to address those issues; or
(2)	decide not to accept the region change application under clause 2A.3.1.
2A.4	First round consultation on region change application
2A.4.1	Notice of first round consultation
(a)	As soon as practicable after accepting a region change application under clause 2A.3.1(d), the AEMC must publish on its website notice of the application ("the first round consultation notice").
(b)	Subject to clause 2A.3.2(b), the first round consultation notice must:
(1)	contain the region change application and supporting evidence provided by the applicant;
(2)	invite written submissions from any person within 75 business days of the date of the first round consultation notice ("the first round consultation period");
(3)	specify that a person may put forward an alternative region solution in a written submission either:
(i)	as an informal alternative region solution; or
(ii)	as a formal alternative region solution under clause 2A.4.3,
and (in the case referred to in subparagraph (ii)), the notice must further specify that the person may be required to provide to the AEMC supplementary economic analysis to support the formal alternative region solution; and
(4)	include a statement to the effect that any interested party may request, in writing within one week after the publication of the notice, the AEMC to hold a consultation meeting in accordance with clause 2A.9.2.
2A.4.2	Right to make written submissions during first round consultation period
Any person may, within the first round consultation period, make a written submission in relation to a region change application ("a first round submission").
2A.4.3	Alternative region solution put forward by third parties
(a)	A person who makes a first round submission may propose an alternative region solution to the solution proposed in the region change application ("a proposed alternative region solution").
(b)	A Registered Participant or AEMO ("an alternative proponent") who submits a proposed alternative region solution under paragraph (a) may request the AEMC to treat the solution as a formal alternative region solution by expressly requesting the AEMC to do so in the first round submission.
(c)	A proposed alternative region solution submitted by an alternative proponent under paragraph (b) must:
(1)	demonstrate that the proposed alternative region solution relates to the congestion problem identified in the region change application and accepted by the AEMC under clause 2A.3.1;
(2)	meet the requirements of a technically competent application in accordance under clause 2A.2.4; and
(3)	explain how the proposed alternative region solution would or would be likely to materially improve economic efficiency in accordance with the requirements for a region change application under clause 2A.2.3,
("a complete alternative region solution").
2A.4.4	Acceptance as a formal alternative region solution by AEMC
(a)	The AEMC is not obliged to treat a proposed alternative region solution as a formal alternative region solution unless the AEMC is satisfied that it is a complete alternative region solution.
(b)	Where the AEMC is not satisfied that a proposed alternative region solution is a complete alternative region solution, the AEMC must decide not to treat it as a formal alternative region solution and must:
(1)	set out the reasons for that decision;
(2)	without delay, notify the alternative proponent of the decision;
(3)	publish the decision (including the reasons) on the AEMC’s website; and
(4)	treat the proposed alternative region solution as an informal alternative region solution.
(c)	Where the AEMC is satisfied that a proposed alternative region solution is a complete alternative region solution, the AEMC must:
(1)	publish the proposed alternative region solution as a formal alternative region solution on its website as soon as practicable after accepting the solution as a formal alternative region solution; and
(2)	treat the proposed alternative region solution as a formal alternative region solution.
(d)	An alternative proponent may not withdraw a proposed alternative region solution after the AEMC has published it as a formal alternative region solution under paragraph (c)(1).
2A.5	Provision of supplementary economic analysis
2A.5.1	AEMC may direct provision of supplementary analysis
(a)	The AEMC may, in respect of a region change application accepted under rule 2A.3, direct an applicant to provide to the AEMC supplementary economic analysis to support the applicant’s proposed region solution within a specified time.
(b)	The AEMC may, in respect of a formal alternative region solution, direct an alternative proponent to provide to the AEMC supplementary economic analysis to support the alternative region solution within a specified time.
(c)	An applicant or an alternative proponent directed under paragraphs (a) or (b) must provide the supplementary economic analysis to the AEMC within the period of time specified by the AEMC in the direction.
(d)	A direction under paragraphs (a) or (b) may be given at any time after the start of the first round consultation period.
(e)	Despite paragraphs (a) to (c), the AEMC or its representative may prepare supplementary economic analysis in respect of a region solution, whether proposed in a region change application, or in a formal alternative region solution or otherwise.
2A.5.2	AEMC may direct AEMO to provide information
(a)	Where the AEMC:
(1)	directs an applicant or an alternative proponent to provide supplementary economic analysis under clause 2A.5.1; or
(2)	decides that it or its representative will prepare supplementary economic analysis under clause 2A.5.1(e),
the AEMC may request AEMO to provide information (including constraint equations) to the applicant or to the alternative proponent, or directly to the AEMC (as the case may be), but only where such information is necessary to facilitate the provision of supplementary economic analysis to those persons or to the AEMC.
(b)	Where the AEMC requests AEMO to provide information under paragraph (a), AEMO must provide the information to the applicant, to the alternative proponent, or directly to the AEMC (as the case may be), as soon as practicable in all the circumstances.
(c)	AEMO may, in respect of a constraint on a network, direct the Transmission Network Service Provider who owns, controls or operates the relevant network to provide information to AEMO for the purpose referred to in paragraph (a) and the Transmission Network Service Provider must provide that information to AEMO as soon as reasonably practicable.
(d)	AEMO must publish:
(1)	requests made to AEMO under paragraph (a); and
(2)	information (excluding confidential information) provided by AEMO in accordance with paragraph (b),
as soon as practicable.
(e)	The AEMC is not required to publish information provided to the AEMC under this clause 2A.5.2 that has been obtained by the applicant or alternative proponent in accordance with clause 8.6.2(o).
2A.6	Region determinations
2A.6.1	AEMC powers to make a region determination
(a)	In making a region determination in respect of a region change application, the AEMC may:
(1)	accept or reject the region solution proposed in the application;
(2)	accept or reject a formal alternative region solution;
(3)	determine that no region change should be made;
(4)	determine a region solution that is different (including materially different) from the region solution proposed in the application; or
(5)	determine a region solution that is different (including materially different) from a formal alternative region solution.
(b)	In making a decision under paragraph (a), the AEMC may, subject to this rule 2A.6, adopt the region solution that it considers provides the best available solution to the congestion problem identified in the region change application in all the circumstances.
2A.6.2	Matters for consideration in making region determination
In making a region determination to adopt a region solution, the AEMC must be satisfied:
(1)	that there is a problem with the existing region configuration which is attributable to the presence of material and enduring network congestion ("a congestion problem");
(2)	that the region solution is technically competent in accordance with the requirements of clause 2A.2.4;
(3)	that:
(i)	the congestion problem will detract materially from economic efficiency; and
(ii)	the region solution will materially improve economic efficiency, where economic efficiency includes (but is not limited to):
(iii)	efficiency in relation to the impact on efficiency of dispatch, including in respect of bidding incentives and dispatch outcomes;
(iv)	efficiency in relation to the management of risk and the facilitation of forward contracting in the financial markets and the spot market; and
(v)	long term dynamic efficiency – including in relation to making investment decisions;
(4)	that the region solution is an appropriate and timely course of action in all the circumstances, having regard to the alternative congestion management options;
(5)	that the region solution is consistent with power system security and reliability; and
(6)	where the proposed implementation is greater than or less than 3 years, that the implementation period is reasonable in all the circumstances of the region determination.
2A.7	Draft region determination and second round consultation
2A.7.1	Publishing of draft region determination
(a)	Before making a final region determination, but within 60 business days of the end of the first round consultation period, the AEMC must publish a draft region determination in relation to an application.
(b)	A draft region determination must contain:
(1)	the reasons of the AEMC as to its decision, with reference to the matters set out in rule 2A.6; and
(2)	a proposed implementation period.
2A.7.2	Second round consultation
(a)	The AEMC must publish a notice on its website of a draft region determination on a complete application ("the second round consultation notice").
(b)	A second round consultation notice must:
(1)	contain the draft region determination;
(2)	invite written submissions from any person within 60 business days of the date of the second round consultation notice ("the second round consultation period"); and
(3)	include a statement to the effect that any interested party may request, in writing within one week after the publication of the notice, the AEMC to hold a consultation meeting in accordance with clause 2A.9.2.
2A.7.3	Right to make written submissions during second round consultation
Any person, within the second round consultation period, may make a written submission in relation to a draft region determination (second round submission).
2A.8	Final region determination
2A.8.1	Final determination for region change
(a)	The AEMC must publish on its website a final region determination in relation to a region change application within 40 business days of the end of the second round consultation period.
(b)	A final region determination must contain:
(1)	the reasons of the AEMC as to its decision with reference to the matters set out in rule 2A.6; and
(2)	the implementation period.
2A.8.2	Formal publication of region determination
(a)	If the AEMC in a final region determination determines to make a region change, the AEMC must publish a notice of the making of the region change in the South Australian Government Gazette and on its website.
(b)	A notice referred to in paragraph (a) must include:
(1)	the date of publication of the final region determination under clause 2A.8.1;
(2)	the implementation period; and
(3)	the start date.
2A.9	Miscellaneous matters for region change process
2A.9.1	AEMC may extend periods of time specified in Chapter 2A
(a)	Despite anything to the contrary in this Chapter 2A, the AEMC may, by notice published on its website, extend a period of time specified in Chapter 2A, if the AEMC considers that a region change application raises issues of sufficient complexity or difficulty or there is a material change in circumstances such that it is necessary that the relevant period of time specified in Chapter 2A be extended.
(b)	A notice under paragraph (a) must identify the period of time under Chapter 2A to be extended, and specify the new time that is to apply.
(c)	The AEMC may only extend a period of time in accordance with this clause 2A.9.1 before the expiry of that time.
2A.9.2	Consultation meeting in relation to region change application
(a)	Any person may request, in writing, within one week of the publication of a first round consultation notice or second round consultation notice (as the case may be), the AEMC to hold a consultation meeting in relation to a region change application or a draft region determination.
(b)	Despite paragraph (a), the AEMC may decide not to hold a consultation meeting, and if so, must give the person who made the request its reasons, in writing, for declining to hold a consultation meeting.
(c)	The AEMC may on its own initiative hold a consultation meeting.
(d)	If the AEMC decides to hold a consultation meeting under this clause 2A.9.2, it must:
(1)	appoint a date (being not later than the close of the first round consultation period or the second round consultation period (as the case may be), time and place for the meeting; and
(2)	publish on its website a notice advising of:
(i)	the intention to hold such a meeting; and
(ii)	the date, time and place for the holding of the meeting.
Part B	Implementation of region determination
2A.10	Purpose and application of Part B
2A.10.1	Purpose of Part B
The purpose of this Part B of Chapter 2A is to enable the efficient and effective implementation of a region determination made by the AEMC under Part A of Chapter 2A during an implementation period, and to support a smooth market transition from old region boundaries to new region boundaries.
2A.10.2	Application of Part B
Part B of Chapter 2A applies despite any other provision of the Rules (including any guideline or procedure made under the Rules), and to the extent of any inconsistency prevails during an implementation period for the purpose of the implementation functions described in rule 2A.12.
2A.11	Region Change Implementation Procedure
2A.11.1	Submission of draft Region Change Implementation Procedure
(a)	If the AEMC in a draft region determination, determines to make a region change, AEMO must prepare a draft Region Change Implementation Procedure in respect of the region solution adopted by the AEMC in that draft region determination.
(b)	A draft Region Change Implementation Procedure must set out:
(1)	the proposed implementation period as included in the draft region determination under clause 2A.7.1(b);
(2)	an implementation plan that identifies the key implementation steps to be taken during the implementation period; and
(3)	the implementation functions referred to in rule 2A.12 that AEMO proposes to exercise to implement the region solution proposed by the draft region determination.
(c)	AEMO must submit the draft Region Change Implementation Procedure to the AEMC no later than the close of the second round consultation period.
(d)	AEMO may in consultation with the AEMC, make amendments to the draft Region Change Implementation Procedure submitted under paragraph (c) that are necessary to implement a final region determination.
(e)	The AEMC must approve a Region Change Implementation Procedure submitted under paragraph (c) and amended in accordance with paragraph (d) (as the case may be), in respect of a final region determination that determines to make a region change.
2A.11.2	Approved Region Change Implementation Procedure
(a)	AEMO must, as soon as practicable after the date of the final region determination publish the approved Region Change Implementation Procedure.
(b)	AEMO may, during the implementation period, amend the approved Region Change Implementation Procedure as necessary, and must publish any such amended procedure, giving reasons why the amendment is necessary.
2A.12	AEMO region change implementation functions
2A.12.1	General implementation functions
Subject to other functions AEMO is required to exercise in accordance with this Chapter 2A, AEMO may, during the implementation period, make a decision or take action (including the power to refrain from making a decision or taking action) that is necessary for the implementation of a final region determination.
2A.12.2	Implementation functions referable to published implementation procedure
The exercise of the region change implementation functions by AEMO referred to in clause 2A.12.1 must be referable to and consistent with, the key implementation steps set out in the current published Region Change Implementation Procedure.
2A.12.3	Amendment of current or subsequent Regions and Loss Factors Publication
(a)	AEMO must, as an implementation function, in respect of the current or subsequent Regions Publication or Loss Factors Publication, amend those publications as necessary for the effective implementation of a final region determination that determines to make a region change.
(b)	For the avoidance of doubt, in relation to the publications referred to in paragraph (a), nothing prevents AEMO:
(1)	amending those publications to:
(i)	implement future region determinations under the Rules; or
(ii)	deal with future physical changes to the network; or
(2)	publishing the annual Regions Publication and the Loss Factors Publication in a single document.
2A.13	Continuity of regions
On and from a start date:
(1)	the unmodified regions continue and are taken to be regions for all purposes under the Rules; and
(2)	the modified regions continue and are taken to be regions for all purposes under the Rules.
Schedule 2A.1	Glossary for Chapter 2A
alternative congestion management options
The alternative means of managing the congestion problem identified in clause 2A.2.2 as referred to in clause 2A.2.5.
alternative proponent
A Registered Participant or AEMO who requests the AEMC in a first round submission, to treat a proposed alternative region solution as a formal alternative region solution in accordance with clause 2A.4.3(b).
applicant
A Registered Participant or AEMO who makes a region change application to the AEMC under rule 2A.2
complete alternative region solution 
A proposed alternative region solution that satisfies the requirements of clause 2A.4.3(c).
complete application
A region change application that meets the requirements of rule 2A.2.
congestion problem
The problem identified in clause 2A.2.2.
first round consultation notice
The notice published by the AEMC in accordance with clause 2A.4.1.
first round consultation period
The period of time referred to in clause 2A.4.1(b)(2) that is within 75 business days of the date of the first round consultation notice.
first round submission 
A written submission made within the first round consultation period in accordance with clause 2A.4.2.
formal alternative region solution
A proposed alternative region solution that the AEMC is satisfied is a complete alternative region solution under clause 2A.4.4(c).
implementation period
The period commencing on the date of a final region determination made in accordance with clause 2A.8.1 and ending on the start date.
Loss Factors Publication
The document published by AEMO from time to time under clauses 3.6.1(f) and 3.6.2(f1) that sets out marginal loss factors.
modified regions
The regions identified in the current Regions Publication modified as a result of a region determination taking effect that determines to make a change to existing regions.
new regions
The unmodified regions and the modified regions.
old regions
The regions identified in the current Regions Publication immediately prior to the start date.
proposed alternative region solution
An alternative region solution proposed by an alternative proponent in a first round submission as an alternative to the solution proposed in the region change application.
region change application
An application for a region change made under rule 2A.2.
region change implementation function
A function referred to in rule 2A.12.
region change implementation procedure
A procedure referred to in rule 2A.11 approved by the AEMC in a region determination, as amended from time to time in accordance with Part B of Chapter 2A.
region determination
A determination made by the AEMC under Chapter 2A and includes a draft region determination or a final region determination as the context requires.
second round consultation notice
The notice published by the AEMC in accordance with clause 2A.7.2.
second round consultation period
The period of time referred to in clause 2A.7.2(b)(2) that is within 60 business days of the date of the second round consultation notice.
second round submission
A written submission made within the second round consultation period in accordance with clause 2A.7.3.
start date
The date nominated by the AEMC in a final region determination on which a change to the existing regions comes into effect.
technically competent application
A region change application that meets the technical requirements in clause 2A.2.4.
unmodified regions
The regions whose boundaries are not affected by a region determination.