EUAA Submission: AEMO – Amendments To The NSCAS Description And Quantity Procedure – Draft Determination
Emily Wood | October 16, 2024
‘…When considering to make a submission to a market body’s consultation, we consider whether the consultation is genuine, or whether the market body has already made a decision and is therefore performing consultation to “tick the box”, whereby we have no impact.
Our original submission on this matter raised two issues, both of which AEMO has not provided an adequate response:
- We wrote about a concern from AEMO taking the opportunity to shift its modelling from the 84th percentile to the 99.87th percentile (or three sigma – 3σ) for NSCAS, System Security – Reliability and Security Ancillary Services (RSAS) and inertia RSAS without any evidence. We also noted that this approach was likely to lead to over-supply of these services. We note that Powerlink has a similar concern. AEMO responded that its predicted ~87 hours a year of operational intervention for NSCAS is now inappropriate and AEMO considers the 3σ tolerance band is more appropriate as it provides for only 9 hours of forecast operational intervention (noting elsewhere AEMO uses 72 days and 15 days respectively for system strength), and implies that without the 3σ modelling, during shortfalls in system strength and inertia, there may be a lack of suitable plant for direction and therefore larger impacts such as curtailment of generation or load…..’
Please download attachment to read full submission.
