Essential System Services
As part of Security Constrained Economic Dispatch (SCED), Essential System Services (ESS) are used by AEMO to maintain security and reliability of supply, thereby supporting the energy market.
Frequency Co-optimised Essential System Services
AEMO operate five Frequency Co-optimised Essential System Services (FCESS):
- Regulation Raise
- Regulation Lower
- Contingency Reserve Raise
- Contingency Reserve Lower
- Rate of Change of Frequency (RoCoF) Control Service
Market Participants with Facilities which meet the Performance Requirements for an FCESS can seek accreditation and subsequently participate in any FCESS market for which their Facility is accredited. If insufficient FCESS is projected to be available in the Real Time Market (RTM), AEMO can trigger longer-term procurement of FCESS through the Supplementary Essential System Service Mechanism (SESSM). The ERA can also trigger the SESSM where FCESS market outcomes are inconsistent with competitive provision.
Non-Co-optimised Essential System Services
The Non-Co-optimised Essential System Services (NCESS) framework has replaced the current frameworks for Network Control Services (NCS) and Dispatch Support Services (DSS) in the WEM Rules and provides a more efficient framework for transparently identifying the need, specifying the requirements, procuring, dispatching and recovering costs for new types of ESS not already catered for under FCESS.
NCESS, including System Restart Services (SRS), are procured on a case-by-case basis:
NCESS can be procured by AEMO or the Network Operator where an NCESS procurement process is triggered by the Coordinator. The NCESS framework is designed to support system and network needs which are not being met through the existing market mechanisms (clause 3.11A.2(e) of the WEM Rules) or can be more economically procured through contracting. Examples to date have included services to mitigate minimum demand events.
System Restart Services
AEMO procures System Restart Services (SRS) in the unlikely event that it will need to restart the system following a widespread blackout of the SWIS (a ‘system black’ event). AEMO procures these services contractually under the framework in the WEM Rules.
Please contact AEMO at email@example.com for general enquiries or technical enquiries regarding the procurement of these Essential System Services.
For more information on the Essential System Services framework, please refer to the below resources:
Chapter 3.9 describes the details for each ESS.
Technical Specification: Automatic Generation Control, SCADA Dispatch Instructions, and Fast Start Facility Operational Behaviour
Currently named 'Technical Specification: AGC and ABC Interface Requirements' (this document will be superseded)794.35 KB
WEM Procedure Communications and Control Systems678.13 KB
Technical Specification Operational Data Points for Generating Plant523.37 KB
Frequency Co-optimised Essential System Services Accreditation WEM Procedure1.1 MB
Frequency Co-optimised Essential System Services Testing Guideline550.54 KB
ESS Accreditation Form68.63 KB
Guideline Rate of Change of Frequency Sensitive Equipment302.04 KB
Currently Accredited FCESS Facilities List
A current list of accredited FCESS Facilities13.94 KB
Current RoCoF Ride-Through Values
A current list of RoCoF Ride-Through values9.99 KB
List of Facilities requiring re-accreditation
Facilities required by AEMO to undertake re-accreditation87 B