On 19 March 2026 the AER released its draft determination for the Default Market Offer for 2026–27 (DMO 8).

ACIL Allen supported us in the design of a forecasting approach for wholesale and environmental costs. The report Wholesale energy and environment cost estimates for DMO 8 draft determination by ACIL Allen was published alongside the draft determination on 19 March 2026.

On 19 March 2026 the AER released its model for calculating DMO tariff caps and annual prices for 2026−27.

As set out in the DMO 8 draft determination, the AER uses a cost build-up approach to calculate the DMO tariff caps, taking into account forecast costs for wholesale electricity, network, environmental and retail costs, and applying a retail margin. We have assigned recovery of fixed costs to the daily supply charge and recovery of variable costs to the usage charges in the DMO tariffs.

The information contained in the model is set out in the DMO 8 draft determination, and we have published the model to provide stakeholders with additional transparency on how we propose to calculate the DMO tariff caps and annual prices for 2026–27.

We requested AEMO provide the interval meter data used to simulate the load profiles and have published this data as supporting information alongside the DMO 8 draft determination. The data provided is at 30-minute intervals with both customer types aggregated (residential and small business), by DMO region. This provides transparency regarding a key input to our wholesale energy cost modelling, allowing stakeholders to consider inputs in more detail.

Additionally, to inform creation of the controlled load profiles for DMO 8, we requested interval meter controlled load profile data from distribution network service providers in each DMO region. This data has been published alongside the DMO 8 draft determination.

We have also published the DMO 8 assumed patterns of supply in Excel format.

We have prepared an information kit to help explain the elements of the draft DMO 2026-27.

We invited interested parties to make written submissions on the DMO 8 draft determination. Submissions closed on 9 April 2026. We received 19 submissions and one further confidential submission.