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WS4484168084 – NCESS for the Eastern Goldfields region

The Coordinator of Energy has determined, under clause 3.11A.4 of the Wholesale Electricity Market (WEM) Rules, to trigger a Non-Co-optimised Essential System Services (NCESS) procurement process for reliability and system strength services for the Eastern Goldfields region.

Following an outage impacting the EGF the Minister for Energy (Minister) and Energy Policy WA (EPWA) have been considering the need for improvements in reliability of the network in the Eastern Goldfields (EGF) region and have engaged Western Power and AEMO to consider options.

Due to the distance and anticipated cost involved in building a second transmission supply to the EGF, Western Power has identified that one option to deliver improved reliability to the EGF region in the short to medium term may be through an NCESS.

Expression of Interest

Western Power is seeking Expression of Interest (EOI) from potential NCESS providers to determine the most cost-effective option to improve reliability of the network in the EGF region if the Minister proposes amendments to the minimum reliability standards.

The proposed services are:

  • a reliability service – capability to minimise power supply disruption as a result of planned or unplanned outages (with ability to maintain a stable islanded network following the loss of the 220kV line and provide black-start capability in the event of total power loss to the region); and
  • a system strength service – capability to maintain voltage stability, power quality obligations and sufficiently high fault levels for intact network conditions, or as a result of planned or unplanned outages (with ability to maintain a stable islanded network following the loss of the 220kV line). Western Power also requires services to ensure system inertia requirements are met for islanded and black-start situations.

A prospective NCESS provider may offer either a reliability service or a system strength service, or both, that can fully or partially meet the relevant service requirements.

The timing of commencement of the proposed services is currently being considered by Western Power but will be refined through this NCESS process. The contract term for the proposed services could commence on 1 July 2026 (or as otherwise required by the minimum reliability standards) and have a five-year duration with the possibility of a five-year extension.

As part of the EOI process, Western Power is seeking feedback from potential NCESS providers on the draft NCESS Service Specification, including any commercial or technical benefits associated with a change to the commencement date or a different contract duration.

We’ll be holding an online public information session on the Tuesday, 23rd April 2024 at 10:30 – 11:30am  AWST to answer any questions you may have. If you are interested in attending this session, join by clicking the link below:

Queries may be submitted by email to or via Q&A function in VendorPanel portal.

Queries cut-off date will be on Friday, 10 May 2024.

Please submit your EOI via VendorPanel no later than 5:00pm (AWST) on Monday, 20th May 2024.

Interested NCESS provider should register with VendorPanel to be informed of whether any supporting documentation such as clarifications to questions may be published.

Key activities Date

Coordinator of Energy determination to trigger NCESS

Friday, 15 March 2024

Call for EOIs

Friday, 12 April 2024

Closing Date and time for lodgement of EOIs

Monday, 20 May 2024 by 5:00pm AWST

EOI Documents

NCESS Eastern Goldfields EOI Public Information Forum

Western Power’s NCESS Trigger Submission (March 2024)

To find a copy of the Coordinator of Energy’s determination please visit Energy Policy WA’s web page