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Ancillary Services Parameters

Ancillary Services Parameters

AEMO determines, procures, and schedules Ancillary Services in the WEM in accordance with the Market Rules. The Economic Regulation Authority (ERA) is required to determine regulated prices for the following Ancillary Services:

  • Spinning Reserve;
  • Load Rejection; and
  • System Restart

To support the ERA’s determinations regarding these Ancillary Services, AEMO is required under the Market Rules to submit proposals to the ERA for the following Ancillary Service parameters:

  • Margin_Peak and Margin_Off Peak parameters (Spinning Reserve Payment); and 
  • Ancillary Service Cost_LR parameters (Load Rejection Reserve and System Restart).

Spinning Reserve: Margin Peak and Margin Off-Peak Review

The Market Rules require the ERA to determine values for Margin Peak and Margin Off Peak (Margin Values) for each financial year in accordance with the methodology set out in clause 3.13.3A(a) of the Market Rules. Under clause 3.13.3A(a) of the Market Rules, AEMO must submit a proposal for these values to the ERA by 30 November each year for the following financial year. 

Documents from previous Margin Values proposals are below. 

Load Rejection and System Restart: Ancillary Service Cost_LR Review

The Market Rules require the ERA to determine values for the Cost_LR parameters (Load Rejection Reserve Service and System Restart Service parameter) for each Review Period in accordance with the methodology set out in clause 3.13.3B(a) of the Market Rules. Under clause 3.13.3B(a) of the Market Rules, AEMO must submit a proposal for these values to the ERA by 30 November each year for the following Review Period.

Documents from previous Cost_LR proposals are below. 

2019 Reviews: Margin Values (2020-21) and Load Rejection Service Cost (2020-21)

AEMO has engaged Ernst & Young, an independent consultant, to conduct modelling and provide an assessment of:

  • the Margin Values for the 2020-21 financial year; and 
  • the Load Rejection Reserve component for the Cost_LR parameters for 2020-21 financial year.

AEMO will be consulting directly with Market Participants on the assumptions that will be used in the development of the proposals for these parameters. The following is the indicative schedule for the assumptions consultation process with Market Participants.

Date Activity 

Friday

2 August 2019

Start of consultation period for confidential generator assumptions

There will be a two-week consultation period in which AEMO will approach individual market generators with their confidential assumptions and seek feedback on the technical and cost parameters for their plant. This will include (but may not be limited to):

  • Minimum and maximum generation values (MW)
  • Average heat rates at minimum, maximum generation output (GJ/MWh sent-out)
  • Average heat rates for two data points between minimum and maximum generation values (GJ/MWh sent-out)
  • Variable, operating and maintenance costs representing operation cost that varies with the level of generation output ($/MWh sent-out)
  • Fixed, operating and maintenance costs representing operation cost that does not vary with the level of generation output (($/MW sent-out)
  • Start-up costs ($ per start-up)
  • Shut-down costs ($ per shut-down)
  • Fuel price ($/GJ)
  • Fuel transport cost ($/GJ)
  • Forced Outage rate (%)
  • Mean time to repair (hours)
  • Planned maintenance days (hours)

Wednesday

18 September 2019

Publication of 2019 Draft Methodology and Assumptions Report

Provides an overview of the model that will be used to simulate the WEM, including key inputs and outputs used. 

There will be a two-week consultation period in which AEMO will accept formal submissions in relation to the Methodology and Assumptions Report.
AEMO invites interested stakeholders to make submissions by 5:00 PM AWST 2 October 2019.

Submissions should:

  • clearly address any issues that interested parties consider relevant to this review
  • provide any supporting evidence or calculations (if appropriate).

AEMO is required by clause 10.5.1(q) of the Market Rules to make all submissions public. If confidential information is provided in a submission as supporting evidence, it must be clearly marked as confidential. Any confidential information will be excluded when the submission is made public.

AEMO prefers to receive submissions by email to wa.operations@aemo.com.au.

Tuesday

24 September 2019

2:30 PM - 4:00 PM

Stakeholder Workshop 

AEMO will host a workshop for Market Participants and other stakeholders where Ernst & Young will present on the Draft Methodology and Assumptions Report.

Please RSVP by Friday 20 September 2019 to wa.operations@aemo.com.au

Tuesday

2 October 2019

Closure of consultation period

Deadline for formal submissions on the Draft Methodology and Assumptions Report.


Documents

All public reports for the Ancillary Service Parameter reviews are as follows: 

2019 Review

Public Submissions

2018 Review

Public Submissions

2017 Review

2016 Review

2015 Review

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