On 2 February 2023, the AEMC received a rule change request from Delta Electricity to amend the National Electricity Rules (NER).

Delta Electricity's rule change request proposes an amendment to the NER relating to the methodology for calculating the cumulative price threshold (CPT) when one or more regions have reached the CPT.

The AEMC will run this rule change in parallel with the ERC0374 - CPT calculation during administered scheduled pricing. This rule change was lodged by Snowy Hydro on 28 August 2023.

On 16 October 2025, the AEMC published a consultation paper that covers the issues and proposed solutions contained in the rule change request from Delta Electricity and Snowy Hydro.

The AEMC welcomes feedback on any aspect of this paper. Submissions close on 20 November 2025.

Background

Both rule change requests were submitted following by the market event that occurred in winter 2022, which saw multiple regions exceed their cumulative price thresholds and the market was eventually suspended.

When a region is not under administered prices but is exporting electricity to a region that is under administered prices, the dispatch price is used for dispatch, but the settled price that is received by the generator is lower. This is because the dispatch price is capped at the APC and then scaled down. Delta Electricity considers that this approach creates an outcome where a region’s CPT is reached based on higher dispatch prices despite lower prices being received in settlement.

Snowy Hydro considers that an issue became apparent during the 2022 market event whereby if the market suspension is in place long enough and administered scheduled pricing is used, it results in the cumulative spot prices being below the CPT when administered scheduled pricing is removed. This can occur despite the market conditions that initially caused the breach of the CPT persisting. Snowy Hydro suggests this can lead to the immediate resumption of extreme spot prices, undermining the protection that the CPT was designed to provide. 

Snowy Hydro submitted a rule change request to the AEMC on 28 August 2023, proposing an amendment to the NER to suspend the calculation of the cumulative price when the administered scheduled pricing is used.

Both rule change requests argue changes to the calculation of the cumulative price in specific situations, to better align it with the original policy intent of the market setting.  

The AEMC has commenced its consideration of the requests, and this consultation paper is the first stage.